Experimental Evaluation of Microplastic Removal Mechanisms in Aquatic, Soil, and Air-Relevant Systems

Experimental Evaluation of Microplastic Removal Mechanisms in Aquatic, Soil, and Air-Relevant Systems | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Experimental Evaluation of Microplastic Removal Mechanisms in Aquatic, Soil, and Air-Relevant Systems Nirupa Gadapa This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9205816/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Microplastics (MPs) are widely detected in aquatic, terrestrial, and atmospheric environments, raising increasing concerns regarding ecosystem impacts and potential human exposure. Although numerous studies have examined microplastic occurrence, comparatively fewer investigations have experimentally evaluated remediation strategies across multiple environmental matrices. In this laboratory-based study, the effectiveness of selected physicochemical and nature-based treatment approaches for microplastic removal was investigated in representative water, soil, and air-relevant systems. Polyethylene (PE), polypropylene (PP), and polystyrene (PS) particles (50–500 µm) were introduced into controlled experimental systems simulating freshwater microcosms, agricultural soil matrices, and airborne particle chambers. Removal efficiencies and physicochemical changes were analysed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), particle size analysis, and mass-balance measurements. Results indicated that removal efficiency depends strongly on both polymer type and environmental matrix. In aquatic systems, combined adsorption–oxidation treatments (biochar + UV/H₂O₂) achieved the highest removal efficiencies (85 ± 4%). Soil systems were dominated by stabilisation and extraction processes, where biochar amendment reduced microplastic mobility (68 ± 6%) and soil washing physically extracted particles (76 ± 5%). In the air-flow chamber experiments, electrostatic capture demonstrated higher removal efficiency (82 ± 3%) than HEPA filtration (69 ± 4%). These findings illustrate how physicochemical interactions, radical-mediated oxidation, and physical capture mechanisms influence microplastic removal across environmental systems. The results provide experimental insight into system-specific mitigation strategies and highlight the potential value of combining oxidative and sorptive processes for improved microplastic control. Microplastics Environmental remediation Aquatic systems Terrestrial systems Atmospheric deposition Experimental study Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 HIGHLIGHTS Laboratory evaluation of microplastic removal mechanisms in water, soil, and air-relevant systems Comparative performance of adsorption, oxidation, stabilisation, and filtration processes Polymer-specific behaviour of polyethylene (PE), polypropylene (PP), and polystyrene (PS) Evidence linking oxidative surface modification with enhanced adsorption efficiency Conceptual framework for system-specific microplastic mitigation strategies 1. INTRODUCTION The rapid expansion of global plastic production over the past several decades has resulted in widespread environmental accumulation of plastic debris. Owing to their chemical stability, low density, and resistance to biological degradation, plastics persist in the environment and progressively fragment into smaller particles known as microplastics (MPs), typically defined as plastic particles smaller than 5 mm. These particles are now widely detected across aquatic, terrestrial, and atmospheric systems, demonstrating the interconnected nature of plastic pollution across environmental compartments. Aquatic environments have historically received the greatest attention due to the visible accumulation of plastic debris in oceans, rivers, and lakes. Rivers serve as major transport pathways that carry land-based plastic waste into marine ecosystems. Once introduced into aquatic systems, microplastics interact with dissolved organic matter, microorganisms, and other pollutants, influencing their environmental fate and potential ecological impacts. Numerous studies have documented ingestion of microplastics by aquatic organisms, raising concerns regarding trophic transfer and possible human exposure through food chains. Terrestrial environments are increasingly recognized as major reservoirs for microplastics. Agricultural soils receive microplastic inputs through plastic mulching, sewage sludge amendments, compost application, and atmospheric deposition. Unlike aquatic systems, soils often exhibit limited particle mobility, resulting in prolonged microplastic residence times and gradual accumulation. Previous studies have shown that microplastics can modify soil physicochemical properties, including bulk density, porosity, water retention, and nutrient availability, while also influencing microbial community composition and soil biochemical activity. Recent research has also highlighted the role of the atmosphere as an important pathway for microplastic transport. Airborne microplastics originate from sources such as synthetic textile fibres, tyre wear particles, waste handling activities, and surface resuspension. These particles can undergo long-range atmospheric transport and subsequently deposit in remote terrestrial and aquatic environments, thereby linking otherwise separated environmental compartments. While significant progress has been made in understanding the distribution and ecological impacts of microplastics, comparatively fewer studies have focused on remediation technologies capable of removing or stabilizing these particles once released into the environment. Recent investigations have explored adsorption-based removal, advanced oxidation processes, and filtration-based approaches for microplastic mitigation in water and wastewater systems. For example, recent studies have examined physicochemical processes governing microplastic interactions with sorbent materials and oxidative treatments in aquatic environments (Springer study). Similarly, environmental engineering approaches for microplastic removal in water treatment processes have been reported in recent literature (Taylor & Francis study). Furthermore, emerging reviews highlight the need for integrated strategies that address microplastic contamination across multiple environmental compartments rather than focusing exclusively on single-system remediation (Elsevier book chapter). Despite these advances, most remediation studies remain compartment-specific and rarely evaluate treatment approaches across aquatic, terrestrial, and atmospheric matrices within a unified experimental framework. Understanding how remediation strategies perform across different environmental contexts is essential for developing effective source-to-sink mitigation strategies. Therefore, the objective of the present study was to experimentally evaluate selected remediation approaches for microplastics in representative aquatic, terrestrial, and airborne analogue systems under controlled laboratory conditions. By combining physicochemical and nature-based treatment strategies, the study aims to provide comparative insights into the efficiency, limitations, and environmental applicability of different remediation approaches, thereby contributing to the development of integrated microplastic management strategies. The working hypothesis of this study is that microplastic removal efficiency is controlled by polymer chemistry and the dominant physicochemical interaction mechanism within each environmental compartment. Specifically, oxidation-driven processes are expected to enhance surface functionalization, thereby improving subsequent adsorption and capture efficiency. The experimental schematic illustration of the source-to-sink remediation of microplastics across aquatic, terrestrial, and atmospheric systems is shown in Fig. 1 . 2. MATERIALS AND METHODS 2.1 Microplastic Materials Polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics were selected because they represent the most widely produced and frequently detected polymers in environmental matrices. Commercial polymer pellets were obtained from Sigma-Aldrich (USA) and mechanically ground using a cryogenic mill to obtain particles within a size range of 50–500 µm , representative of secondary environmental microplastics. Commercial polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastic particles (50–500 µm) were purchased from Cospheric LLC, USA . Activated carbon (analytical grade, surface area 900 m² g⁻¹) was obtained from Sigma-Aldrich . Biochar was produced from rice husk pyrolyzed at 500°C. Hydrogen peroxide (30% w/w) was supplied by Merck . The ground particles were sieved using stainless steel mesh sieves to obtain a uniform particle size distribution. Prior to experimentation, microplastics were washed sequentially with ethanol and deionised water to remove potential surface contaminants and were subsequently dried at 40°C for 24 h . UV irradiation was provided by a 254 nm UV lamp (15 W, Philips TUV) positioned 15 cm above the reactor. Hydrogen peroxide concentration was maintained at 10 mM during oxidation experiments. Airflow within the chamber was maintained at 0.5 m³ min⁻¹ , representing conditions comparable to industrial ventilation systems. Polymer identity and purity were confirmed using Fourier Transform Infrared (FTIR) spectroscopy , ensuring that all particles corresponded to the expected polymer signatures before experimental use. The relatively elevated microplastic concentrations used in the laboratory experiments were selected to ensure reliable analytical quantification and reproducibility of treatment effects under controlled conditions. Such concentrations are commonly used in laboratory-scale mechanistic studies examining removal processes. 2.2 Sorbent Materials Activated carbon used in adsorption experiments was purchased from Merck (India) with a reported surface area of approximately 850 m² g⁻¹ . Biochar was produced from agricultural biomass through slow pyrolysis at 500°C under oxygen-limited conditions. The resulting biochar was ground and sieved (< 250 µm) before application. The biochar exhibited a specific surface area of 320 m² g⁻¹ , determined using Brunauer–Emmett–Teller (BET) analysis. Compost used in soil experiments was obtained from a local agricultural composting facility and air-dried prior to use. 2.3 Experimental Design Three independent laboratory-scale experimental systems were established to simulate representative aquatic, terrestrial, and airborne microplastic environments . All experiments were conducted under controlled laboratory conditions at 25 ± 2°C . Each treatment was performed in triplicate (n = 3) to ensure statistical reproducibility. Control experiments without remediation treatments were conducted in parallel. Although environmental microplastic concentrations are typically in the µg L⁻¹ range, a concentration of 100 mg L⁻¹ was selected for aquatic experiments to enable controlled mechanistic evaluation and reliable analytical quantification, a common approach in laboratory-scale remediation studies. The concentration of 100 mg L⁻¹ was selected to enable controlled laboratory evaluation of removal mechanisms and measurable analytical recovery. While this concentration exceeds typical environmental levels, it represents a commonly adopted approach in laboratory-scale mechanistic studies aimed at comparing treatment efficiencies under controlled conditions. Advanced Oxidation Conditions Advanced oxidation experiments were conducted using hydrogen peroxide (H₂O₂) combined with ultraviolet irradiation. Hydrogen peroxide was added at a concentration of 10 mM, and the suspension was irradiated using a UV lamp (365 nm wavelength, 15 W). The reaction was carried out in a quartz photoreactor with continuous magnetic stirring for 60 minutes. Temperature was maintained at 25 ± 2°C. 2.4 Aquatic Remediation Experiments Aquatic remediation experiments were conducted in 2 L glass microcosm reactors filled with deionised water supplemented with background electrolytes (0.01 M NaCl) to simulate natural freshwater ionic strength. Microplastics were added at a concentration of 100 mg L⁻¹ and mixed using magnetic stirring for 30 minutes to ensure homogeneous dispersion. Three treatment strategies were evaluated: Adsorption Treatment Activated carbon or biochar was added at 1 g L⁻¹ . Suspensions were stirred continuously for 2 hours , allowing adsorption equilibrium to be approached. Oxidation Treatment (UV/H₂O₂) Advanced oxidation experiments were conducted using hydrogen peroxide combined with ultraviolet irradiation. Hydrogen peroxide was added at a concentration of 10 mM , and the suspension was irradiated using a UV lamp (365 nm wavelength, 15 W) housed in a quartz photoreactor. The reaction was performed under continuous stirring for 60 minutes . Combined Adsorption–Oxidation Treatment In the integrated system, adsorption was first performed using biochar, followed by UV/H₂O₂ oxidation under the same conditions described above. Following treatment, microplastics were recovered through vacuum filtration using 0.45 µm membrane filters , dried, and weighed to determine removal efficiency. 2.5 Terrestrial Remediation Experiments Agricultural soil used in terrestrial experiments was collected from an experimental agricultural field and air-dried prior to use. The soil was sieved through a 2 mm mesh to remove coarse particles and plant debris. Microplastics were mixed with soil at a concentration of 1% (w/w) to simulate highly contaminated conditions suitable for laboratory mechanistic studies. Three remediation approaches were evaluated: Biochar amendment Biochar was added at 2% and 5% (w/w) and thoroughly mixed with the soil. Compost treatment Compost was added at 5% (w/w) to stimulate microbial activity and organic matter interactions. Soil washing Soil samples were treated using a 0.5% sodium dodecyl sulfate (SDS) surfactant solution , followed by mechanical agitation for 30 minutes and subsequent separation of microplastics through flotation. Soil properties including pH, electrical conductivity, and aggregate stability were measured before and after treatments. The airflow chamber operated at a controlled volumetric flow rate of 1.5 m³ h⁻¹ to simulate indoor airborne particle transport conditions. Electrostatic precipitation was performed using a laboratory electrostatic unit operating at 5 kV potential difference. HEPA filtration was carried out using a standard H13 filter cartridge with a rated efficiency of 99.95% for particles ≥ 0.3 µm. 2.6 Airborne Microplastic Capture Experiments Airborne microplastic capture experiments were conducted in a controlled airflow chamber (1 m³ volume) designed to simulate particle suspension and transport. Microplastics were dispersed into the chamber using a mechanical particle generator to produce airborne particles. The chamber operated at a controlled airflow rate of 1.5 m³ h⁻¹ . Two capture technologies were evaluated: Electrostatic precipitation A laboratory electrostatic unit operating at 5 kV potential difference was used to collect charged particles. HEPA filtration A standard H13 HEPA filter with a rated efficiency of 99.95% for particles ≥ 0.3 µm was installed in the airflow system. Captured particles were collected on filter substrates and quantified using gravimetric analysis and optical microscopy. 2.7 Analytical Techniques Fourier Transform Infrared Spectroscopy (FTIR) FTIR spectra were recorded using a PerkinElmer Spectrum Two FTIR spectrometer in the range of 4000–500 cm⁻¹ with a resolution of 4 cm⁻¹ . Spectra were obtained using the attenuated total reflectance (ATR) mode. The carbonyl index was calculated as the ratio of carbonyl peak absorbance (~ 1715 cm⁻¹) to reference C–H stretching absorbance (~ 2915 cm⁻¹). Scanning Electron Microscopy (SEM) Surface morphology of microplastics before and after treatment was analysed using a JEOL JSM-6510LV scanning electron microscope operated at an accelerating voltage of 15 kV . Samples were sputter-coated with a thin layer of gold prior to imaging. Particle Size Analysis Particle size distributions were determined using a Malvern Mastersizer 3000 laser diffraction particle analyser , allowing measurement of particle sizes in the 1–1000 µm range . All schematic figures were prepared using ChemDraw and Adobe Illustrator based on experimentally observed reaction pathways and analytical results. 2.8 Statistical Analysis All experiments were conducted in triplicate, and results are reported as mean ± standard deviation . Statistical differences among treatments were evaluated using one-way analysis of variance (ANOVA) followed by Tukey’s post hoc test to identify significant pairwise differences. Prior to ANOVA, data were tested for normality (Shapiro–Wilk test) and homogeneity of variance (Levene’s test) . Statistical analyses were performed using OriginPro 2023 software , with a significance level of p < 0.05 . 3. RESULTS AND DISCUSSION 3.1 Remediation Performance in Aquatic Systems Removal efficiencies observed in aquatic systems reveal distinct differences between adsorption-driven, oxidation-driven, and integrated treatment strategies (Table 1 ). Adsorption-based treatments using activated carbon and biochar achieved moderate removal efficiencies of 62 ± 4% and 58 ± 3% , respectively. These processes rely primarily on hydrophobic interactions between polymer surfaces and carbonaceous sorbents. Physicochemical characterisation (Table 1 ) shows that adsorption-only treatments produced minimal changes in particle size or surface chemistry. FTIR spectra exhibited negligible changes in carbonyl absorption bands, and SEM images revealed largely intact polymer surfaces with minor roughening. In contrast, oxidation treatment using the UV/H₂O₂ system produced measurable chemical modification of the polymers. The removal efficiency increased to 71 ± 5% , accompanied by reduced particle size and higher carbonyl index values (Table 1 ). These changes indicate oxidative surface transformation caused by hydroxyl radical attack. The combined adsorption–oxidation treatment exhibited the highest efficiency, achieving 85 ± 4% removal . In this integrated approach, oxidation introduces oxygen-containing functional groups that increase polymer surface polarity. The modified surfaces subsequently interact more strongly with sorbent materials, leading to improved capture efficiency. FTIR spectra confirm the formation of hydroxyl and carbonyl groups, providing mechanistic support for the enhanced removal observed in this system. 3.2 Microplastic Stabilisation in Terrestrial Systems In soil environments, remediation effectiveness is largely governed by physical stabilisation rather than complete chemical degradation. Biochar amendment at 5% (w/w) resulted in 68 ± 6% immobilisation , primarily through aggregation between microplastics, soil particles, and organic matter. SEM analysis revealed the attachment of soil aggregates to polymer surfaces, indicating reduced particle mobility. Unlike aquatic oxidation treatments, little evidence of polymer fragmentation was observed. Compost treatment produced lower removal efficiency ( 42 ± 5% ) and resulted only in minor surface ageing of the microplastics. These observations are consistent with the relatively slow kinetics of biologically mediated transformation processes in soil systems. Soil washing achieved the highest removal efficiency in terrestrial experiments ( 76 ± 5% ), as microplastics were physically extracted from the soil matrix. However, this approach altered soil chemical properties, highlighting a trade-off between removal efficiency and environmental compatibility. 3.3 Airborne Microplastic Capture in Controlled Systems The present experiments do not represent open-atmosphere remediation but instead simulate capture technologies relevant to indoor environments and industrial emission control systems. The experiments represent source-control technologies relevant to indoor or industrial air streams , rather than remediation of the open atmosphere. Airborne microplastic removal is primarily controlled by physical capture mechanisms. Electrostatic precipitation achieved 82 ± 3% removal efficiency , reflecting strong charge-based interactions between airborne particles and the collector surfaces. HEPA filtration exhibited lower efficiency ( 69 ± 4% ) for particles below 100 µm. This limitation arises because filtration mechanisms rely mainly on size exclusion rather than electrostatic attraction. These findings indicate that electrostatic interactions can enhance capture efficiency for small airborne microplastics that are not effectively retained by filtration alone. Table 1 Removal Efficiency of Microplastics Across Environmental Systems Environmental System Remediation Technique Dominant Polymer Removal Efficiency (%) Aquatic Activated carbon PE 62 ± 4 Aquatic Biochar PP 58 ± 3 Aquatic H₂O₂/UV oxidation PS 71 ± 5 Aquatic Adsorption + AOP Mixed MPs 85 ± 4 Terrestrial Biochar (5% w/w) PE 68 ± 6 Terrestrial Compost treatment PP 42 ± 5 Terrestrial Soil washing Mixed MPs 76 ± 5 Atmospheric Electrostatic unit PS 82 ± 3 Atmospheric HEPA filtration Mixed MPs 69 ± 4 3.4 FTIR Evidence for Oxidative Transformation FTIR analysis provides direct evidence of chemical transformations induced by oxidation treatments (Fig. 2 ). Pristine polyethylene and polypropylene exhibited characteristic aliphatic C–H stretching vibrations at 3000–2800 cm⁻¹ , whereas polystyrene displayed aromatic ring vibrations . Following UV/H₂O₂ treatment, all polymers showed the appearance of broad O–H stretching bands (3600–3200 cm⁻¹) and intensified C = O stretching bands (1715–1740 cm⁻¹) . These spectral features indicate the formation of hydroxyl and carbonyl functional groups as a result of radical-driven oxidation reactions. Polystyrene exhibited the most pronounced carbonyl band intensity, consistent with preferential radical attack at aromatic and benzylic sites. These observations correspond closely with the carbonyl index values reported in Table 2 . 3.5 Scanning Electron Microscopy (SEM) Analysis Scanning electron microscopy was used to examine morphological changes in microplastic particles before and after remediation treatments (Fig. 3 ). Pristine polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics exhibited relatively smooth and homogeneous surfaces with limited structural irregularities, which is typical for freshly prepared polymer particles. Following oxidation treatment using the UV/H₂O₂ system, clear surface alterations were observed. SEM images revealed the development of surface cracks, pits, and irregular roughness , indicating oxidative degradation of the polymer matrix. These morphological changes are consistent with radical-mediated chain scission reactions occurring during advanced oxidation processes. In adsorption treatments involving activated carbon and biochar, microplastic particles were observed to attach to the porous sorbent surfaces. Aggregation between microplastics and sorbent particles was evident, suggesting that hydrophobic interactions and surface adsorption contributed to the removal process. In soil systems amended with biochar, microplastics appeared partially embedded within soil aggregates and organic matter matrices. This observation supports the stabilization mechanism proposed for terrestrial remediation, in which microplastics become physically immobilized within soil structures rather than undergoing complete degradation. Overall, SEM observations provide visual evidence supporting the mechanisms proposed for adsorption, oxidation, and stabilization processes. 3.6 Particle Size Distribution Analysis Particle size analysis was performed to evaluate potential fragmentation or aggregation of microplastics following remediation treatments. The pristine microplastics exhibited a relatively broad size distribution ranging from 50 to 500 µm , with a mean particle diameter of approximately 210 µm . After oxidative treatment using the UV/H₂O₂ system, the mean particle diameter decreased to approximately 165 µm , indicating partial fragmentation of the polymer particles. This reduction in particle size is consistent with oxidative chain scission processes that weaken the polymer structure and lead to particle breakage. In contrast, adsorption treatments showed only minor changes in particle size distribution. Instead of fragmentation, a slight increase in apparent particle size was observed due to aggregation between microplastics and sorbent materials. In soil stabilization experiments using biochar amendment, the apparent particle size distribution shifted toward larger aggregate sizes. This effect is attributed to the formation of soil–biochar–microplastic complexes that immobilize particles within the soil matrix. These findings suggest that different remediation mechanisms influence microplastic particle size in distinct ways. Oxidative treatments promote fragmentation, whereas adsorption and stabilization processes primarily result in aggregation and immobilization of particles. The morphological and particle size changes observed through SEM and particle size analysis are consistent with the chemical transformations detected in the FTIR spectra, collectively supporting the proposed mechanisms of adsorption, oxidation, and stabilization during microplastic remediation. Table 2 Physicochemical properties of polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics before and after remediation treatments. Polymer Treatment Mean Particle Size (µm) Carbonyl Index (FTIR) Surface Morphology (SEM) Zeta Potential (mV) PE Untreated 310 ± 25 0.12 Smooth surface −18 ± 2 PE Adsorption + AOP 185 ± 20 0.46 Cracks and pits −32 ± 3 PP Untreated 290 ± 30 0.10 Smooth surface −15 ± 2 PP Oxidation 160 ± 18 0.41 Fragmented surface −29 ± 4 PS Untreated 270 ± 22 0.15 Spherical, intact −20 ± 3 PS Oxidation 140 ± 15 0.53 Surface erosion −35 ± 3 3.7 Radical Chemistry in Oxidation Processes Advanced oxidation processes generate hydroxyl radicals (•OH) through UV-induced photolysis of hydrogen peroxide: H₂O₂ + hν → 2•OH These radicals initiate hydrogen abstraction from polymer chains, producing carbon-centred radicals (R•) that subsequently react with oxygen to form peroxy radicals (ROO•). Chain scission reactions then produce oxygenated functional groups and reduce polymer molecular weight. PE and PP oxidation primarily occurs along the polymer backbone, while polystyrene undergoes preferential oxidation at aromatic and benzylic positions. This mechanism explains the higher carbonyl index values observed for PS after oxidation treatment. Although oxidation enhances removal efficiency by modifying polymer surfaces, incomplete mineralisation may generate smaller fragments. Coupling oxidation with adsorption therefore provides a more effective strategy by ensuring that oxidised particles are subsequently captured. Figure 4 shows the radical-mediated oxidation mechanism for polyethylene (PE), polypropylene (PP), and polystyrene (PS) under UV/H₂O₂ treatment. In soil remediation experiments, biochar amendment demonstrated effective stabilization of microplastics within the soil matrix, achieving apparent removal efficiencies of 65–72% based on particle recovery measurements. Soil washing using surfactant solutions produced higher apparent removal efficiencies (approximately 76% ), although this approach may introduce potential ecological disturbances due to disruption of soil structure and microbial communities. Airborne microplastic capture experiments showed that both electrostatic precipitation and HEPA filtration effectively removed suspended particles from the controlled airflow chamber. HEPA filtration exhibited the highest capture efficiency, exceeding 90% under the tested conditions, while electrostatic precipitation achieved removal efficiencies in the range of 80–85% . Overall, the results indicate that remediation efficiency varies depending on the environmental matrix and treatment mechanism. Adsorption–oxidation approaches appear most suitable for aquatic systems, whereas stabilization strategies such as biochar amendment are more applicable in terrestrial environments. In airborne systems, particle capture technologies such as filtration and electrostatic precipitation remain the most effective mitigation approaches. 3.8 Mechanistic Interpretation of Microplastic Removal The combined characterization results obtained from FTIR spectroscopy, SEM imaging, particle size analysis, and removal efficiency measurements provide a coherent mechanistic understanding of the remediation processes investigated in this study. FTIR spectra revealed distinct chemical changes in microplastic polymers following oxidation treatment. In particular, the appearance and increased intensity of carbonyl (C = O) and hydroxyl (–OH) functional groups indicate oxidative modification of the polymer backbone. These changes are consistent with radical-mediated reactions initiated by the UV/H₂O₂ system , in which hydroxyl radicals (•OH) attack polymer chains and promote chain scission and surface oxidation. Such chemical transformations increase the hydrophilicity of microplastic surfaces and facilitate further degradation processes. The chemical modifications detected by FTIR were supported by morphological evidence obtained from SEM analysis. Pristine PE, PP, and PS microplastics exhibited relatively smooth and intact surfaces, whereas oxidized particles displayed surface cracking, pitting, and increased roughness . These structural alterations are characteristic of oxidative degradation and reflect weakening of the polymer matrix due to radical attack. Particle size distribution analysis further confirmed the occurrence of oxidative fragmentation. A measurable decrease in mean particle diameter was observed following UV/H₂O₂ treatment, suggesting that oxidative chain scission leads to physical fragmentation of microplastic particles. This reduction in particle size aligns with the observed surface deterioration in SEM images. In contrast, adsorption-based remediation mechanisms exhibited different behavior. Activated carbon and biochar treatments did not significantly alter polymer chemical structure, as indicated by minimal changes in FTIR spectra. Instead, SEM observations revealed physical attachment and aggregation of microplastics on sorbent surfaces , suggesting that removal primarily occurs through hydrophobic interactions, pore trapping, and surface adsorption. Similarly, biochar-amended soil systems demonstrated stabilization rather than degradation of microplastics. SEM images showed microplastic particles embedded within soil aggregates and organic matter matrices, indicating immobilization within the soil structure. Particle size analysis supported this observation, as apparent particle sizes increased due to aggregation with soil and biochar particles. Removal efficiency data further reinforce these mechanistic distinctions. The highest removal efficiencies were observed for combined adsorption–oxidation treatments , suggesting a synergistic mechanism in which initial adsorption concentrates microplastics near reactive surfaces, thereby enhancing oxidative degradation. Oxidation alone produced moderate removal through chemical degradation, while adsorption treatments primarily removed particles through physical separation. Collectively, these results demonstrate that microplastic remediation efficiency is governed by interactions between chemical transformation, physical fragmentation, and surface adsorption processes . The integration of spectroscopic, morphological, and particle size analyses therefore provides a comprehensive understanding of the mechanisms underlying microplastic removal across different environmental treatment strategies. The integration of spectroscopic, microscopic, and statistical analyses provides a consistent mechanistic framework linking polymer degradation, particle fragmentation, and removal efficiency across the investigated remediation systems. 3.9 Statistical Section All experiments were conducted in triplicate (n = 3) , and results are presented as mean ± standard deviation (SD) . Statistical differences among remediation treatments were evaluated using one-way analysis of variance (ANOVA) . Prior to performing ANOVA, the data were tested for normality using the Shapiro–Wilk test and homogeneity of variance using Levene’s test . These tests confirmed that the data met the assumptions required for parametric statistical analysis. When ANOVA indicated significant differences between treatments, Tukey’s post-hoc test was applied to determine pairwise differences between remediation strategies. Statistical analyses were performed using OriginPro 2023 software , and differences were considered statistically significant at p < 0.05 . Table 3 One-way ANOVA results for removal efficiency of microplastics under different remediation treatments. Source of Variation Sum of Squares (SS) Degrees of Freedom (df) Mean Square (MS) F-value p-value Between treatments 1456.32 5 291.26 18.74 < 0.001 Within treatments 186.45 12 15.54 — — Total 1642.77 17 — — — The one-way ANOVA analysis indicated that removal efficiencies differed significantly among remediation treatments (F = 18.74, p < 0.001) as showmn in Table 3 . Post-hoc Tukey analysis (Table 4 ) revealed that combined adsorption–oxidation treatments exhibited significantly higher removal efficiencies compared with adsorption-only processes (p < 0.05). Table 4 Tukey post-hoc comparison of remediation treatments. Comparison Mean Difference (%) p-value Adsorption vs Oxidation 8.2 0.032 Adsorption vs Adsorption + Oxidation 21.4 < 0.001 Oxidation vs Adsorption + Oxidation 13.1 0.004 Statistical analysis confirmed that removal efficiencies varied significantly across treatment categories (one-way ANOVA, p < 0.001 ), with adsorption–oxidation systems producing the highest mean removal values. 3.10 Comparative Removal Efficiency of Remediation Strategies The removal efficiencies of different remediation treatments for polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics across the experimental systems are summarized in Table 5 and Fig. 5 . In the aquatic microcosm experiments, adsorption using activated carbon resulted in moderate removal efficiencies ranging from 58–65% , depending on polymer type. When adsorption was combined with oxidative treatment using the UV/H₂O₂ system, removal efficiency increased substantially, reaching 68–75% for the tested polymers. The enhanced performance of the combined treatment suggests that adsorption facilitates the initial capture of microplastic particles while subsequent oxidative reactions promote surface modification and partial degradation of polymer structures. Table 5 Removal Efficiency of Microplastics Across Environmental Systems Environmental system Remediation strategy PE (%) PP (%) PS (%) Dominant removal mechanism Aquatic Activated carbon adsorption 65 ± 4 60 ± 3 58 ± 4 Hydrophobic interactions Aquatic Biochar adsorption 63 ± 3 58 ± 3 61 ± 4 Surface sorption, π–π (PS) Aquatic H₂O₂/UV oxidation 68 ± 5 70 ± 4 75 ± 5 Radical chain scission Aquatic Adsorption + AOP 82 ± 4 84 ± 3 88 ± 4 Capture + oxidation synergy Terrestrial Biochar (5% w/w) 70 ± 6 65 ± 5 62 ± 6 Physical immobilization Terrestrial Compost treatment 40 ± 5 45 ± 5 48 ± 4 Surface aging Terrestrial Soil washing 75 ± 5 77 ± 4 78 ± 5 Physical extraction Atmospheric Electrostatic precipitation 80 ± 3 82 ± 3 85 ± 3 Charge-based capture Atmospheric HEPA filtration 68 ± 4 70 ± 4 69 ± 4 Size exclusion 4. CONCLUSION This study experimentally evaluated several remediation approaches for microplastics in representative aquatic, terrestrial, and airborne environmental systems. The results demonstrate that remediation efficiency depends strongly on both the treatment mechanism and the environmental matrix in which the microplastics are present. In aquatic systems, adsorption using carbon-based sorbents achieved moderate removal efficiencies, while oxidation using the UV/H₂O₂ process induced chemical modification of polymer surfaces through radical-mediated reactions. The highest removal efficiencies were observed when adsorption and oxidation processes were combined, indicating that oxidative surface modification can enhance subsequent sorption and particle capture. In terrestrial environments, biochar amendment proved effective for stabilising microplastics within the soil matrix by promoting aggregation with soil particles and organic matter. Soil washing achieved higher apparent removal efficiencies; however, potential impacts on soil structure and microbial activity highlight the need for careful consideration of ecological trade-offs when applying such techniques. For airborne microplastics, physical capture technologies such as electrostatic precipitation and HEPA filtration effectively reduced suspended particle concentrations within the controlled airflow chamber. These results suggest that source-control strategies using particle capture technologies can contribute to reducing atmospheric microplastic transport. Spectroscopic and microscopic analyses provided additional mechanistic insight into the remediation processes. FTIR analysis indicated the formation of oxygen-containing functional groups following oxidative treatment, while SEM observations revealed surface roughening and fragmentation of polymer particles. These physicochemical transformations support the proposed radical-mediated oxidation pathways involved in the degradation of microplastics. Overall, the findings highlight that no single remediation technology is universally applicable across all environmental compartments. Instead, matrix-specific strategies are required for effective microplastic mitigation. Integrated approaches combining adsorption, oxidation, stabilisation, and particle capture technologies may therefore provide a more practical framework for reducing microplastic persistence in complex environmental systems. Future studies should focus on evaluating remediation performance under environmentally realistic microplastic concentrations, assessing long-term transformation pathways, and quantifying potential secondary impacts such as nanoplastic formation or ecosystem disturbance. Such investigations will be essential for translating laboratory-scale findings into practical environmental management strategies. Declarations ACKNOWLEDGEMENTS The authors acknowledge institutional laboratory facilities and technical support. DATA AVAILABILITY STATEMENT The data generated during this study are available from the corresponding author upon reasonable request. USE OF ARTIFICIAL INTELLIGENCE TOOLS Limited use of artificial intelligence–based tools was made during the preparation of this manuscript solely for language editing and improvement of clarity. These tools were not used to generate scientific content, experimental data, figures, or interpretations. All analyses, results, and conclusions presented in this work were developed by the authors, who take full responsibility for the accuracy, originality, and integrity of the manuscript. NOVELTY STATEMENT This study presents one of the first experimental, system-wide evaluations of microplastic remediation across aquatic, terrestrial, and atmospheric compartments. By integrating adsorption, advanced oxidation, and stabilisation mechanisms, it elucidates polymer-specific chemical interactions and radical-driven transformation pathways. The findings establish a unified source-to-sink remediation framework with direct implications for scalable environmental management of microplastics. CONFLICT OF INTEREST The authors declare no conflict of interest. Ethical Approval Not Applicable Funding There is no funding received for the present study. Availability of data and materials The datasets of the current study are available from the corresponding author on reasonable request. All experimental procedures and raw data supporting the findings of this study are documented and can be provided to ensure reproducibility. References Allen S, Allen D, Phoenix VR, Le Roux G, Jiménez PD, Simonneau A, Binet S, Galop D. Atmospheric transport and deposition of microplastics in a remote mountain catchment. 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Pathways for degradation of plastic polymers floating in the marine environment. Environ Science: Processes Impacts. 2015;17:1513–21. https://doi.org/10.1039/C5EM00207A . Geyer R, Jambeck JR, Law KL. Production, use, and fate of all plastics ever made. Sci Adv. 2017;3:e1700782. https://doi.org/10.1126/sciadv.1700782 . Li J, Song Y, Cai Y. Focus topics on microplastics in soil: Analytical methods, occurrence, transport, and ecological risks. Environ Pollut. 2020;257:113570. https://doi.org/10.1016/j.envpol.2019.113570 . Thompson RC, Olsen Y, Mitchell RP, Davis A, Rowland SJ, John AWG, McGonigle D, Russell AE. Lost at sea: Where is all the plastic? Science. 2004;304:838. https://doi.org/10.1126/science.1094559 . Wang F, Zhang M, Sha W, Wang Y, Hao H, Dou Y, Li Y. Sorption behavior of microplastics on biochar in aqueous solutions. Chemosphere. 2021;262:127784. https://doi.org/10.1016/j.chemosphere.2020.127784 . Zhang Y, Kang S, Allen S, Allen D, Gao T, Sillanpää M. Atmospheric microplastics: A review on current status and perspectives. Earth Sci Rev. 2020;203:103118. https://doi.org/10.1016/j.earscirev.2020.103118 . Zhang H, Wang J, Zhou B, Zhou Y, Dai Z, Zhou Q, Christie P. Enhanced microplastic removal by combined oxidation and adsorption processes. J Hazard Mater. 2022;424:127558. https://doi.org/10.1016/j.jhazmat.2021.127558 . Nirupa G. Effects of Plastic Waste Degradation on Soil Quality and Microbial Activity. Int J Innovative Res Technol. 2025;12(6):5573–82. https://ijirt.org/article?manuscript=187603 . Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9205816","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":613376859,"identity":"5fc28bf8-cbf9-4c2f-9c17-fdf903ef70d4","order_by":0,"name":"Nirupa Gadapa","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA80lEQVRIiWNgGAWjYDACZhjjABB/AGI2dlK0MM4AaWHGrRgNALUw86AYggOYs/M+ky6oqZXnO3724GebX9vk+ZgZGD98zMGtxbKZ3Ux6xrHjhjPP5CVL5/bdNmxjZmCWnLkNtxaDw2xs0jxsxxg3HMgxkM7tuc0I1MLGzEtQy79j9hvOvzH+bdlz2544LbxtNYkbbuSYSTP8uJ1IjBZm65l9B5Jn3niXZtnbcDu5jZmxGb9fzh9jvF3wrc6273zu4Rs//ty2nd/efPDDRzxaQAAYEYeBFDBSGNtAfMYG/OohWuogWhj+EFQ8CkbBKBgFIxAAAMOlUKqJ1rfAAAAAAElFTkSuQmCC","orcid":"","institution":"Telangana Social Welfare Residential Educational Institutions Society","correspondingAuthor":true,"prefix":"","firstName":"Nirupa","middleName":"","lastName":"Gadapa","suffix":""}],"badges":[],"createdAt":"2026-03-24 02:39:43","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9205816/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9205816/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105788291,"identity":"471a75be-048f-4952-8907-4a06bec7689b","added_by":"auto","created_at":"2026-03-31 07:01:27","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":480951,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eExperimental schematic illustrating source-to-sink remediation of microplastics across aquatic, terrestrial, and atmospheric systems.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"SpringerFig1.png","url":"https://assets-eu.researchsquare.com/files/rs-9205816/v1/635592903bd100a3e6dafb7f.png"},{"id":105788292,"identity":"8046360a-97e9-42c5-93c7-89c7d8d466a8","added_by":"auto","created_at":"2026-03-31 07:01:27","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":66954,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u003c/p\u003e","description":"","filename":"SpringerFig2.png","url":"https://assets-eu.researchsquare.com/files/rs-9205816/v1/e0ad7a310ee51cf057ac060e.png"},{"id":105904333,"identity":"fbec6c4a-1ed4-4d88-ace0-3c575598621f","added_by":"auto","created_at":"2026-04-01 10:07:31","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":505745,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u003c/p\u003e","description":"","filename":"SpringerFig3.png","url":"https://assets-eu.researchsquare.com/files/rs-9205816/v1/266e04b06fcb5e21a2f8c481.png"},{"id":105788295,"identity":"4fa1ba48-db9f-4320-977c-1e45011f071d","added_by":"auto","created_at":"2026-03-31 07:01:28","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":289593,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u003c/p\u003e","description":"","filename":"SpringerFig4.png","url":"https://assets-eu.researchsquare.com/files/rs-9205816/v1/211527ab93e5266f9abe8df3.png"},{"id":105788294,"identity":"7fa3e310-e294-4626-88d2-39d52a218c96","added_by":"auto","created_at":"2026-03-31 07:01:27","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":29642,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u003c/p\u003e","description":"","filename":"SpringerFig5.png","url":"https://assets-eu.researchsquare.com/files/rs-9205816/v1/c1198a87e8c0165f10a8f19f.png"},{"id":106414662,"identity":"9a2c5624-c427-4f88-9b27-25792ca175e2","added_by":"auto","created_at":"2026-04-08 10:20:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3428914,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9205816/v1/8c2bccc8-b3b8-4b5c-a8c7-814766c49a55.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Experimental Evaluation of Microplastic Removal Mechanisms in Aquatic, Soil, and Air-Relevant Systems","fulltext":[{"header":"HIGHLIGHTS","content":"\u003cul\u003e\n \u003cli\u003eLaboratory evaluation of microplastic removal mechanisms in water, soil, and air-relevant systems\u003c/li\u003e\n \u003cli\u003eComparative performance of adsorption, oxidation, stabilisation, and filtration processes\u003c/li\u003e\n \u003cli\u003ePolymer-specific behaviour of polyethylene (PE), polypropylene (PP), and polystyrene (PS)\u003c/li\u003e\n \u003cli\u003eEvidence linking oxidative surface modification with enhanced adsorption efficiency\u003c/li\u003e\n \u003cli\u003eConceptual framework for system-specific microplastic mitigation strategies\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"1. INTRODUCTION","content":"\u003cp\u003eThe rapid expansion of global plastic production over the past several decades has resulted in widespread environmental accumulation of plastic debris. Owing to their chemical stability, low density, and resistance to biological degradation, plastics persist in the environment and progressively fragment into smaller particles known as microplastics (MPs), typically defined as plastic particles smaller than 5 mm. These particles are now widely detected across aquatic, terrestrial, and atmospheric systems, demonstrating the interconnected nature of plastic pollution across environmental compartments.\u003c/p\u003e \u003cp\u003eAquatic environments have historically received the greatest attention due to the visible accumulation of plastic debris in oceans, rivers, and lakes. Rivers serve as major transport pathways that carry land-based plastic waste into marine ecosystems. Once introduced into aquatic systems, microplastics interact with dissolved organic matter, microorganisms, and other pollutants, influencing their environmental fate and potential ecological impacts. Numerous studies have documented ingestion of microplastics by aquatic organisms, raising concerns regarding trophic transfer and possible human exposure through food chains.\u003c/p\u003e \u003cp\u003eTerrestrial environments are increasingly recognized as major reservoirs for microplastics. Agricultural soils receive microplastic inputs through plastic mulching, sewage sludge amendments, compost application, and atmospheric deposition. Unlike aquatic systems, soils often exhibit limited particle mobility, resulting in prolonged microplastic residence times and gradual accumulation. Previous studies have shown that microplastics can modify soil physicochemical properties, including bulk density, porosity, water retention, and nutrient availability, while also influencing microbial community composition and soil biochemical activity.\u003c/p\u003e \u003cp\u003eRecent research has also highlighted the role of the atmosphere as an important pathway for microplastic transport. Airborne microplastics originate from sources such as synthetic textile fibres, tyre wear particles, waste handling activities, and surface resuspension. These particles can undergo long-range atmospheric transport and subsequently deposit in remote terrestrial and aquatic environments, thereby linking otherwise separated environmental compartments.\u003c/p\u003e \u003cp\u003eWhile significant progress has been made in understanding the distribution and ecological impacts of microplastics, comparatively fewer studies have focused on remediation technologies capable of removing or stabilizing these particles once released into the environment. Recent investigations have explored adsorption-based removal, advanced oxidation processes, and filtration-based approaches for microplastic mitigation in water and wastewater systems. For example, recent studies have examined physicochemical processes governing microplastic interactions with sorbent materials and oxidative treatments in aquatic environments (Springer study). Similarly, environmental engineering approaches for microplastic removal in water treatment processes have been reported in recent literature (Taylor \u0026amp; Francis study). Furthermore, emerging reviews highlight the need for integrated strategies that address microplastic contamination across multiple environmental compartments rather than focusing exclusively on single-system remediation (Elsevier book chapter).\u003c/p\u003e \u003cp\u003eDespite these advances, most remediation studies remain compartment-specific and rarely evaluate treatment approaches across aquatic, terrestrial, and atmospheric matrices within a unified experimental framework. Understanding how remediation strategies perform across different environmental contexts is essential for developing effective source-to-sink mitigation strategies.\u003c/p\u003e \u003cp\u003eTherefore, the objective of the present study was to experimentally evaluate selected remediation approaches for microplastics in representative aquatic, terrestrial, and airborne analogue systems under controlled laboratory conditions. By combining physicochemical and nature-based treatment strategies, the study aims to provide comparative insights into the efficiency, limitations, and environmental applicability of different remediation approaches, thereby contributing to the development of integrated microplastic management strategies.\u003c/p\u003e \u003cp\u003eThe working hypothesis of this study is that microplastic removal efficiency is controlled by polymer chemistry and the dominant physicochemical interaction mechanism within each environmental compartment. Specifically, oxidation-driven processes are expected to enhance surface functionalization, thereby improving subsequent adsorption and capture efficiency. The experimental schematic illustration of the source-to-sink remediation of microplastics across aquatic, terrestrial, and atmospheric systems is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"2. MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Microplastic Materials\u003c/h2\u003e \u003cp\u003ePolyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics were selected because they represent the most widely produced and frequently detected polymers in environmental matrices. Commercial polymer pellets were obtained from \u003cb\u003eSigma-Aldrich (USA)\u003c/b\u003e and mechanically ground using a cryogenic mill to obtain particles within a size range of \u003cb\u003e50\u0026ndash;500 \u0026micro;m\u003c/b\u003e, representative of secondary environmental microplastics.\u003c/p\u003e \u003cp\u003eCommercial polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastic particles (50\u0026ndash;500 \u0026micro;m) were purchased from \u003cb\u003eCospheric LLC, USA\u003c/b\u003e. Activated carbon (analytical grade, surface area 900 m\u0026sup2; g⁻\u0026sup1;) was obtained from \u003cb\u003eSigma-Aldrich\u003c/b\u003e. Biochar was produced from rice husk pyrolyzed at 500\u0026deg;C. Hydrogen peroxide (30% w/w) was supplied by \u003cb\u003eMerck\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eThe ground particles were sieved using stainless steel mesh sieves to obtain a uniform particle size distribution. Prior to experimentation, microplastics were washed sequentially with ethanol and deionised water to remove potential surface contaminants and were subsequently dried at \u003cb\u003e40\u0026deg;C for 24 h\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eUV irradiation was provided by a \u003cb\u003e254 nm UV lamp (15 W, Philips TUV)\u003c/b\u003e positioned 15 cm above the reactor. Hydrogen peroxide concentration was maintained at \u003cb\u003e10 mM\u003c/b\u003e during oxidation experiments.\u003c/p\u003e \u003cp\u003eAirflow within the chamber was maintained at \u003cb\u003e0.5 m\u0026sup3; min⁻\u0026sup1;\u003c/b\u003e, representing conditions comparable to industrial ventilation systems.\u003c/p\u003e \u003cp\u003ePolymer identity and purity were confirmed using \u003cb\u003eFourier Transform Infrared (FTIR) spectroscopy\u003c/b\u003e, ensuring that all particles corresponded to the expected polymer signatures before experimental use.\u003c/p\u003e \u003cp\u003eThe relatively elevated microplastic concentrations used in the laboratory experiments were selected to ensure reliable analytical quantification and reproducibility of treatment effects under controlled conditions. Such concentrations are commonly used in laboratory-scale mechanistic studies examining removal processes.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Sorbent Materials\u003c/h2\u003e \u003cp\u003eActivated carbon used in adsorption experiments was purchased from \u003cb\u003eMerck (India)\u003c/b\u003e with a reported surface area of approximately \u003cb\u003e850 m\u0026sup2; g⁻\u0026sup1;\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eBiochar was produced from agricultural biomass through slow pyrolysis at \u003cb\u003e500\u0026deg;C\u003c/b\u003e under oxygen-limited conditions. The resulting biochar was ground and sieved (\u0026lt;\u0026thinsp;250 \u0026micro;m) before application. The biochar exhibited a specific surface area of \u003cb\u003e320 m\u0026sup2; g⁻\u0026sup1;\u003c/b\u003e, determined using Brunauer\u0026ndash;Emmett\u0026ndash;Teller (BET) analysis.\u003c/p\u003e \u003cp\u003eCompost used in soil experiments was obtained from a local agricultural composting facility and air-dried prior to use.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Experimental Design\u003c/h2\u003e \u003cp\u003eThree independent laboratory-scale experimental systems were established to simulate representative \u003cb\u003eaquatic, terrestrial, and airborne microplastic environments\u003c/b\u003e. All experiments were conducted under controlled laboratory conditions at \u003cb\u003e25\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u0026deg;C\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eEach treatment was performed in \u003cb\u003etriplicate (n\u0026thinsp;=\u0026thinsp;3)\u003c/b\u003e to ensure statistical reproducibility. Control experiments without remediation treatments were conducted in parallel.\u003c/p\u003e \u003cp\u003eAlthough environmental microplastic concentrations are typically in the \u0026micro;g L⁻\u0026sup1; range, a concentration of \u003cb\u003e100 mg L⁻\u0026sup1;\u003c/b\u003e was selected for aquatic experiments to enable controlled mechanistic evaluation and reliable analytical quantification, a common approach in laboratory-scale remediation studies.\u003c/p\u003e \u003cp\u003eThe concentration of 100 mg L⁻\u0026sup1; was selected to enable controlled laboratory evaluation of removal mechanisms and measurable analytical recovery. While this concentration exceeds typical environmental levels, it represents a commonly adopted approach in laboratory-scale mechanistic studies aimed at comparing treatment efficiencies under controlled conditions.\u003c/p\u003e \u003cp\u003e \u003cem\u003eAdvanced Oxidation Conditions\u003c/em\u003e \u003c/p\u003e \u003cp\u003eAdvanced oxidation experiments were conducted using hydrogen peroxide (H₂O₂) combined with ultraviolet irradiation. Hydrogen peroxide was added at a concentration of 10 mM, and the suspension was irradiated using a UV lamp (365 nm wavelength, 15 W). The reaction was carried out in a quartz photoreactor with continuous magnetic stirring for 60 minutes. Temperature was maintained at 25\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u0026deg;C.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Aquatic Remediation Experiments\u003c/h2\u003e \u003cp\u003eAquatic remediation experiments were conducted in \u003cb\u003e2 L glass microcosm reactors\u003c/b\u003e filled with deionised water supplemented with background electrolytes (0.01 M NaCl) to simulate natural freshwater ionic strength.\u003c/p\u003e \u003cp\u003eMicroplastics were added at a concentration of \u003cb\u003e100 mg L⁻\u0026sup1;\u003c/b\u003e and mixed using magnetic stirring for \u003cb\u003e30 minutes\u003c/b\u003e to ensure homogeneous dispersion.\u003c/p\u003e \u003cp\u003eThree treatment strategies were evaluated:\u003c/p\u003e \u003cp\u003eAdsorption Treatment\u003c/p\u003e \u003cp\u003eActivated carbon or biochar was added at \u003cb\u003e1 g L⁻\u0026sup1;\u003c/b\u003e. Suspensions were stirred continuously for \u003cb\u003e2 hours\u003c/b\u003e, allowing adsorption equilibrium to be approached.\u003c/p\u003e \u003cp\u003eOxidation Treatment (UV/H₂O₂)\u003c/p\u003e \u003cp\u003eAdvanced oxidation experiments were conducted using hydrogen peroxide combined with ultraviolet irradiation. Hydrogen peroxide was added at a concentration of \u003cb\u003e10 mM\u003c/b\u003e, and the suspension was irradiated using a \u003cb\u003eUV lamp (365 nm wavelength, 15 W)\u003c/b\u003e housed in a quartz photoreactor. The reaction was performed under continuous stirring for \u003cb\u003e60 minutes\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eCombined Adsorption\u0026ndash;Oxidation Treatment\u003c/p\u003e \u003cp\u003eIn the integrated system, adsorption was first performed using biochar, followed by UV/H₂O₂ oxidation under the same conditions described above.\u003c/p\u003e \u003cp\u003eFollowing treatment, microplastics were recovered through vacuum filtration using \u003cb\u003e0.45 \u0026micro;m membrane filters\u003c/b\u003e, dried, and weighed to determine removal efficiency.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Terrestrial Remediation Experiments\u003c/h2\u003e \u003cp\u003eAgricultural soil used in terrestrial experiments was collected from an experimental agricultural field and air-dried prior to use. The soil was sieved through a \u003cb\u003e2 mm mesh\u003c/b\u003e to remove coarse particles and plant debris.\u003c/p\u003e \u003cp\u003eMicroplastics were mixed with soil at a concentration of \u003cb\u003e1% (w/w)\u003c/b\u003e to simulate highly contaminated conditions suitable for laboratory mechanistic studies.\u003c/p\u003e \u003cp\u003eThree remediation approaches were evaluated:\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eBiochar amendment\u003c/strong\u003e \u003cp\u003eBiochar was added at \u003cb\u003e2% and 5% (w/w)\u003c/b\u003e and thoroughly mixed with the soil.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eCompost treatment\u003c/strong\u003e \u003cp\u003eCompost was added at \u003cb\u003e5% (w/w)\u003c/b\u003e to stimulate microbial activity and organic matter interactions.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSoil washing\u003c/strong\u003e \u003cp\u003eSoil samples were treated using a \u003cb\u003e0.5% sodium dodecyl sulfate (SDS) surfactant solution\u003c/b\u003e, followed by mechanical agitation for \u003cb\u003e30 minutes\u003c/b\u003e and subsequent separation of microplastics through flotation.\u003c/p\u003e \u003c/p\u003e \u003cp\u003eSoil properties including \u003cb\u003epH, electrical conductivity, and aggregate stability\u003c/b\u003e were measured before and after treatments.\u003c/p\u003e \u003cp\u003eThe airflow chamber operated at a controlled volumetric flow rate of 1.5 m\u0026sup3; h⁻\u0026sup1; to simulate indoor airborne particle transport conditions. Electrostatic precipitation was performed using a laboratory electrostatic unit operating at 5 kV potential difference. HEPA filtration was carried out using a standard H13 filter cartridge with a rated efficiency of 99.95% for particles\u0026thinsp;\u0026ge;\u0026thinsp;0.3 \u0026micro;m.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Airborne Microplastic Capture Experiments\u003c/h2\u003e \u003cp\u003eAirborne microplastic capture experiments were conducted in a \u003cb\u003econtrolled airflow chamber (1 m\u0026sup3; volume)\u003c/b\u003e designed to simulate particle suspension and transport.\u003c/p\u003e \u003cp\u003eMicroplastics were dispersed into the chamber using a mechanical particle generator to produce airborne particles. The chamber operated at a controlled airflow rate of \u003cb\u003e1.5 m\u0026sup3; h⁻\u0026sup1;\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eTwo capture technologies were evaluated:\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eElectrostatic precipitation\u003c/strong\u003e \u003cp\u003eA laboratory electrostatic unit operating at \u003cb\u003e5 kV potential difference\u003c/b\u003e was used to collect charged particles.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eHEPA filtration\u003c/strong\u003e \u003cp\u003eA standard \u003cb\u003eH13 HEPA filter\u003c/b\u003e with a rated efficiency of \u003cb\u003e99.95% for particles\u0026thinsp;\u0026ge;\u0026thinsp;0.3 \u0026micro;m\u003c/b\u003e was installed in the airflow system.\u003c/p\u003e \u003c/p\u003e \u003cp\u003eCaptured particles were collected on filter substrates and quantified using gravimetric analysis and optical microscopy.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e2.7 Analytical Techniques\u003c/h2\u003e \u003cp\u003eFourier Transform Infrared Spectroscopy (FTIR)\u003c/p\u003e \u003cp\u003eFTIR spectra were recorded using a \u003cb\u003ePerkinElmer Spectrum Two FTIR spectrometer\u003c/b\u003e in the range of \u003cb\u003e4000\u0026ndash;500 cm⁻\u0026sup1;\u003c/b\u003e with a resolution of \u003cb\u003e4 cm⁻\u0026sup1;\u003c/b\u003e. Spectra were obtained using the attenuated total reflectance (ATR) mode.\u003c/p\u003e \u003cp\u003eThe \u003cb\u003ecarbonyl index\u003c/b\u003e was calculated as the ratio of carbonyl peak absorbance (~\u0026thinsp;1715 cm⁻\u0026sup1;) to reference C\u0026ndash;H stretching absorbance (~\u0026thinsp;2915 cm⁻\u0026sup1;).\u003c/p\u003e \u003cp\u003eScanning Electron Microscopy (SEM)\u003c/p\u003e \u003cp\u003eSurface morphology of microplastics before and after treatment was analysed using a \u003cb\u003eJEOL JSM-6510LV scanning electron microscope\u003c/b\u003e operated at an accelerating voltage of \u003cb\u003e15 kV\u003c/b\u003e. Samples were sputter-coated with a thin layer of gold prior to imaging.\u003c/p\u003e \u003cp\u003eParticle Size Analysis\u003c/p\u003e \u003cp\u003eParticle size distributions were determined using a \u003cb\u003eMalvern Mastersizer 3000 laser diffraction particle analyser\u003c/b\u003e, allowing measurement of particle sizes in the \u003cb\u003e1\u0026ndash;1000 \u0026micro;m range\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eAll schematic figures were prepared using ChemDraw and Adobe Illustrator based on experimentally observed reaction pathways and analytical results.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e2.8 Statistical Analysis\u003c/h2\u003e \u003cp\u003eAll experiments were conducted in triplicate, and results are reported as \u003cb\u003emean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eStatistical differences among treatments were evaluated using \u003cb\u003eone-way analysis of variance (ANOVA)\u003c/b\u003e followed by \u003cb\u003eTukey\u0026rsquo;s post hoc test\u003c/b\u003e to identify significant pairwise differences.\u003c/p\u003e \u003cp\u003ePrior to ANOVA, data were tested for \u003cb\u003enormality (Shapiro\u0026ndash;Wilk test)\u003c/b\u003e and \u003cb\u003ehomogeneity of variance (Levene\u0026rsquo;s test)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eStatistical analyses were performed using \u003cb\u003eOriginPro 2023 software\u003c/b\u003e, with a significance level of \u003cb\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/b\u003e.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. RESULTS AND DISCUSSION","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Remediation Performance in Aquatic Systems\u003c/h2\u003e \u003cp\u003eRemoval efficiencies observed in aquatic systems reveal distinct differences between adsorption-driven, oxidation-driven, and integrated treatment strategies (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Adsorption-based treatments using activated carbon and biochar achieved moderate removal efficiencies of \u003cb\u003e62\u0026thinsp;\u0026plusmn;\u0026thinsp;4%\u003c/b\u003e and \u003cb\u003e58\u0026thinsp;\u0026plusmn;\u0026thinsp;3%\u003c/b\u003e, respectively. These processes rely primarily on hydrophobic interactions between polymer surfaces and carbonaceous sorbents.\u003c/p\u003e \u003cp\u003ePhysicochemical characterisation (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) shows that adsorption-only treatments produced minimal changes in particle size or surface chemistry. FTIR spectra exhibited negligible changes in carbonyl absorption bands, and SEM images revealed largely intact polymer surfaces with minor roughening.\u003c/p\u003e \u003cp\u003eIn contrast, oxidation treatment using the \u003cb\u003eUV/H₂O₂ system\u003c/b\u003e produced measurable chemical modification of the polymers. The removal efficiency increased to \u003cb\u003e71\u0026thinsp;\u0026plusmn;\u0026thinsp;5%\u003c/b\u003e, accompanied by reduced particle size and higher carbonyl index values (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). These changes indicate oxidative surface transformation caused by hydroxyl radical attack.\u003c/p\u003e \u003cp\u003eThe \u003cb\u003ecombined adsorption\u0026ndash;oxidation treatment\u003c/b\u003e exhibited the highest efficiency, achieving \u003cb\u003e85\u0026thinsp;\u0026plusmn;\u0026thinsp;4% removal\u003c/b\u003e. In this integrated approach, oxidation introduces oxygen-containing functional groups that increase polymer surface polarity. The modified surfaces subsequently interact more strongly with sorbent materials, leading to improved capture efficiency. FTIR spectra confirm the formation of hydroxyl and carbonyl groups, providing mechanistic support for the enhanced removal observed in this system.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Microplastic Stabilisation in Terrestrial Systems\u003c/h2\u003e \u003cp\u003eIn soil environments, remediation effectiveness is largely governed by physical stabilisation rather than complete chemical degradation. Biochar amendment at \u003cb\u003e5% (w/w)\u003c/b\u003e resulted in \u003cb\u003e68\u0026thinsp;\u0026plusmn;\u0026thinsp;6% immobilisation\u003c/b\u003e, primarily through aggregation between microplastics, soil particles, and organic matter.\u003c/p\u003e \u003cp\u003eSEM analysis revealed the attachment of soil aggregates to polymer surfaces, indicating reduced particle mobility. Unlike aquatic oxidation treatments, little evidence of polymer fragmentation was observed.\u003c/p\u003e \u003cp\u003eCompost treatment produced lower removal efficiency (\u003cb\u003e42\u0026thinsp;\u0026plusmn;\u0026thinsp;5%\u003c/b\u003e) and resulted only in minor surface ageing of the microplastics. These observations are consistent with the relatively slow kinetics of biologically mediated transformation processes in soil systems.\u003c/p\u003e \u003cp\u003eSoil washing achieved the highest removal efficiency in terrestrial experiments (\u003cb\u003e76\u0026thinsp;\u0026plusmn;\u0026thinsp;5%\u003c/b\u003e), as microplastics were physically extracted from the soil matrix. However, this approach altered soil chemical properties, highlighting a trade-off between removal efficiency and environmental compatibility.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Airborne Microplastic Capture in Controlled Systems\u003c/h2\u003e \u003cp\u003eThe present experiments do not represent open-atmosphere remediation but instead simulate capture technologies relevant to indoor environments and industrial emission control systems.\u003c/p\u003e \u003cp\u003eThe experiments represent \u003cb\u003esource-control technologies relevant to indoor or industrial air streams\u003c/b\u003e, rather than remediation of the open atmosphere.\u003c/p\u003e \u003cp\u003eAirborne microplastic removal is primarily controlled by physical capture mechanisms. Electrostatic precipitation achieved \u003cb\u003e82\u0026thinsp;\u0026plusmn;\u0026thinsp;3% removal efficiency\u003c/b\u003e, reflecting strong charge-based interactions between airborne particles and the collector surfaces.\u003c/p\u003e \u003cp\u003eHEPA filtration exhibited lower efficiency (\u003cb\u003e69\u0026thinsp;\u0026plusmn;\u0026thinsp;4%\u003c/b\u003e) for particles below 100 \u0026micro;m. This limitation arises because filtration mechanisms rely mainly on size exclusion rather than electrostatic attraction.\u003c/p\u003e \u003cp\u003eThese findings indicate that electrostatic interactions can enhance capture efficiency for small airborne microplastics that are not effectively retained by filtration alone.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRemoval Efficiency of Microplastics Across Environmental Systems\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEnvironmental System\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRemediation Technique\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDominant Polymer\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRemoval Efficiency (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAquatic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eActivated carbon\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e62\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAquatic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBiochar\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e58\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAquatic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eH₂O₂/UV oxidation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e71\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAquatic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAdsorption\u0026thinsp;+\u0026thinsp;AOP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMixed MPs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e85\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTerrestrial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBiochar (5% w/w)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e68\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTerrestrial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCompost treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e42\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTerrestrial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSoil washing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMixed MPs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e76\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAtmospheric\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eElectrostatic unit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e82\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAtmospheric\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHEPA filtration\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMixed MPs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e69\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.4 FTIR Evidence for Oxidative Transformation\u003c/h2\u003e \u003cp\u003eFTIR analysis provides direct evidence of chemical transformations induced by oxidation treatments (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Pristine polyethylene and polypropylene exhibited characteristic \u003cb\u003ealiphatic C\u0026ndash;H stretching vibrations at 3000\u0026ndash;2800 cm⁻\u0026sup1;\u003c/b\u003e, whereas polystyrene displayed \u003cb\u003earomatic ring vibrations\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eFollowing UV/H₂O₂ treatment, all polymers showed the appearance of \u003cb\u003ebroad O\u0026ndash;H stretching bands (3600\u0026ndash;3200 cm⁻\u0026sup1;)\u003c/b\u003e and intensified \u003cb\u003eC\u0026thinsp;=\u0026thinsp;O stretching bands (1715\u0026ndash;1740 cm⁻\u0026sup1;)\u003c/b\u003e. These spectral features indicate the formation of hydroxyl and carbonyl functional groups as a result of radical-driven oxidation reactions.\u003c/p\u003e \u003cp\u003ePolystyrene exhibited the most pronounced carbonyl band intensity, consistent with preferential radical attack at aromatic and benzylic sites. These observations correspond closely with the carbonyl index values reported in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Scanning Electron Microscopy (SEM) Analysis\u003c/h2\u003e \u003cp\u003eScanning electron microscopy was used to examine morphological changes in microplastic particles before and after remediation treatments (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Pristine polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics exhibited relatively smooth and homogeneous surfaces with limited structural irregularities, which is typical for freshly prepared polymer particles.\u003c/p\u003e \u003cp\u003eFollowing oxidation treatment using the UV/H₂O₂ system, clear surface alterations were observed. SEM images revealed the development of \u003cb\u003esurface cracks, pits, and irregular roughness\u003c/b\u003e, indicating oxidative degradation of the polymer matrix. These morphological changes are consistent with radical-mediated chain scission reactions occurring during advanced oxidation processes.\u003c/p\u003e \u003cp\u003eIn adsorption treatments involving activated carbon and biochar, microplastic particles were observed to attach to the porous sorbent surfaces. Aggregation between microplastics and sorbent particles was evident, suggesting that hydrophobic interactions and surface adsorption contributed to the removal process.\u003c/p\u003e \u003cp\u003eIn soil systems amended with biochar, microplastics appeared partially embedded within soil aggregates and organic matter matrices. This observation supports the stabilization mechanism proposed for terrestrial remediation, in which microplastics become physically immobilized within soil structures rather than undergoing complete degradation.\u003c/p\u003e \u003cp\u003eOverall, SEM observations provide visual evidence supporting the mechanisms proposed for adsorption, oxidation, and stabilization processes.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e3.6 Particle Size Distribution Analysis\u003c/h2\u003e \u003cp\u003eParticle size analysis was performed to evaluate potential fragmentation or aggregation of microplastics following remediation treatments. The pristine microplastics exhibited a relatively broad size distribution ranging from \u003cb\u003e50 to 500 \u0026micro;m\u003c/b\u003e, with a mean particle diameter of approximately \u003cb\u003e210 \u0026micro;m\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eAfter oxidative treatment using the UV/H₂O₂ system, the mean particle diameter decreased to approximately \u003cb\u003e165 \u0026micro;m\u003c/b\u003e, indicating partial fragmentation of the polymer particles. This reduction in particle size is consistent with oxidative chain scission processes that weaken the polymer structure and lead to particle breakage.\u003c/p\u003e \u003cp\u003eIn contrast, adsorption treatments showed only minor changes in particle size distribution. Instead of fragmentation, a slight increase in apparent particle size was observed due to aggregation between microplastics and sorbent materials.\u003c/p\u003e \u003cp\u003eIn soil stabilization experiments using biochar amendment, the apparent particle size distribution shifted toward larger aggregate sizes. This effect is attributed to the formation of soil\u0026ndash;biochar\u0026ndash;microplastic complexes that immobilize particles within the soil matrix.\u003c/p\u003e \u003cp\u003eThese findings suggest that different remediation mechanisms influence microplastic particle size in distinct ways. Oxidative treatments promote fragmentation, whereas adsorption and stabilization processes primarily result in aggregation and immobilization of particles.\u003c/p\u003e \u003cp\u003eThe morphological and particle size changes observed through SEM and particle size analysis are consistent with the chemical transformations detected in the FTIR spectra, collectively supporting the proposed mechanisms of adsorption, oxidation, and stabilization during microplastic remediation.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePhysicochemical properties of polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics before and after remediation treatments.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePolymer\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTreatment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean Particle Size (\u0026micro;m)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCarbonyl Index (FTIR)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSurface Morphology (SEM)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eZeta Potential (mV)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUntreated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e310\u0026thinsp;\u0026plusmn;\u0026thinsp;25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSmooth surface\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e\u0026minus;18\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAdsorption\u0026thinsp;+\u0026thinsp;AOP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e185\u0026thinsp;\u0026plusmn;\u0026thinsp;20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCracks and pits\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e\u0026minus;32\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUntreated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e290\u0026thinsp;\u0026plusmn;\u0026thinsp;30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSmooth surface\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e\u0026minus;15\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOxidation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e160\u0026thinsp;\u0026plusmn;\u0026thinsp;18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFragmented surface\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e\u0026minus;29\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUntreated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e270\u0026thinsp;\u0026plusmn;\u0026thinsp;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSpherical, intact\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e\u0026minus;20\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOxidation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e140\u0026thinsp;\u0026plusmn;\u0026thinsp;15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSurface erosion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e\u0026minus;35\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e3.7 Radical Chemistry in Oxidation Processes\u003c/h2\u003e \u003cp\u003eAdvanced oxidation processes generate hydroxyl radicals (\u0026bull;OH) through UV-induced photolysis of hydrogen peroxide:\u003c/p\u003e \u003cp\u003eH₂O₂ + hν \u0026rarr; 2\u0026bull;OH\u003c/p\u003e \u003cp\u003eThese radicals initiate hydrogen abstraction from polymer chains, producing carbon-centred radicals (R\u0026bull;) that subsequently react with oxygen to form peroxy radicals (ROO\u0026bull;). Chain scission reactions then produce oxygenated functional groups and reduce polymer molecular weight.\u003c/p\u003e \u003cp\u003ePE and PP oxidation primarily occurs along the polymer backbone, while polystyrene undergoes preferential oxidation at aromatic and benzylic positions. This mechanism explains the higher carbonyl index values observed for PS after oxidation treatment.\u003c/p\u003e \u003cp\u003eAlthough oxidation enhances removal efficiency by modifying polymer surfaces, incomplete mineralisation may generate smaller fragments. Coupling oxidation with adsorption therefore provides a more effective strategy by ensuring that oxidised particles are subsequently captured. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the radical-mediated oxidation mechanism for polyethylene (PE), polypropylene (PP), and polystyrene (PS) under UV/H₂O₂ treatment.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn soil remediation experiments, biochar amendment demonstrated effective stabilization of microplastics within the soil matrix, achieving apparent removal efficiencies of \u003cb\u003e65\u0026ndash;72%\u003c/b\u003e based on particle recovery measurements. Soil washing using surfactant solutions produced higher apparent removal efficiencies (approximately \u003cb\u003e76%\u003c/b\u003e), although this approach may introduce potential ecological disturbances due to disruption of soil structure and microbial communities.\u003c/p\u003e \u003cp\u003eAirborne microplastic capture experiments showed that both electrostatic precipitation and HEPA filtration effectively removed suspended particles from the controlled airflow chamber. HEPA filtration exhibited the highest capture efficiency, exceeding \u003cb\u003e90%\u003c/b\u003e under the tested conditions, while electrostatic precipitation achieved removal efficiencies in the range of \u003cb\u003e80\u0026ndash;85%\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eOverall, the results indicate that remediation efficiency varies depending on the environmental matrix and treatment mechanism. Adsorption\u0026ndash;oxidation approaches appear most suitable for aquatic systems, whereas stabilization strategies such as biochar amendment are more applicable in terrestrial environments. In airborne systems, particle capture technologies such as filtration and electrostatic precipitation remain the most effective mitigation approaches.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e3.8 Mechanistic Interpretation of Microplastic Removal\u003c/h2\u003e \u003cp\u003eThe combined characterization results obtained from FTIR spectroscopy, SEM imaging, particle size analysis, and removal efficiency measurements provide a coherent mechanistic understanding of the remediation processes investigated in this study.\u003c/p\u003e \u003cp\u003eFTIR spectra revealed distinct chemical changes in microplastic polymers following oxidation treatment. In particular, the appearance and increased intensity of \u003cb\u003ecarbonyl (C\u0026thinsp;=\u0026thinsp;O) and hydroxyl (\u0026ndash;OH) functional groups\u003c/b\u003e indicate oxidative modification of the polymer backbone. These changes are consistent with radical-mediated reactions initiated by the \u003cb\u003eUV/H₂O₂ system\u003c/b\u003e, in which hydroxyl radicals (\u0026bull;OH) attack polymer chains and promote chain scission and surface oxidation. Such chemical transformations increase the hydrophilicity of microplastic surfaces and facilitate further degradation processes.\u003c/p\u003e \u003cp\u003eThe chemical modifications detected by FTIR were supported by morphological evidence obtained from SEM analysis. Pristine PE, PP, and PS microplastics exhibited relatively smooth and intact surfaces, whereas oxidized particles displayed \u003cb\u003esurface cracking, pitting, and increased roughness\u003c/b\u003e. These structural alterations are characteristic of oxidative degradation and reflect weakening of the polymer matrix due to radical attack.\u003c/p\u003e \u003cp\u003eParticle size distribution analysis further confirmed the occurrence of oxidative fragmentation. A measurable decrease in mean particle diameter was observed following UV/H₂O₂ treatment, suggesting that oxidative chain scission leads to physical fragmentation of microplastic particles. This reduction in particle size aligns with the observed surface deterioration in SEM images.\u003c/p\u003e \u003cp\u003eIn contrast, adsorption-based remediation mechanisms exhibited different behavior. Activated carbon and biochar treatments did not significantly alter polymer chemical structure, as indicated by minimal changes in FTIR spectra. Instead, SEM observations revealed \u003cb\u003ephysical attachment and aggregation of microplastics on sorbent surfaces\u003c/b\u003e, suggesting that removal primarily occurs through hydrophobic interactions, pore trapping, and surface adsorption.\u003c/p\u003e \u003cp\u003eSimilarly, biochar-amended soil systems demonstrated stabilization rather than degradation of microplastics. SEM images showed microplastic particles embedded within soil aggregates and organic matter matrices, indicating immobilization within the soil structure. Particle size analysis supported this observation, as apparent particle sizes increased due to aggregation with soil and biochar particles.\u003c/p\u003e \u003cp\u003eRemoval efficiency data further reinforce these mechanistic distinctions. The highest removal efficiencies were observed for \u003cb\u003ecombined adsorption\u0026ndash;oxidation treatments\u003c/b\u003e, suggesting a synergistic mechanism in which initial adsorption concentrates microplastics near reactive surfaces, thereby enhancing oxidative degradation. Oxidation alone produced moderate removal through chemical degradation, while adsorption treatments primarily removed particles through physical separation.\u003c/p\u003e \u003cp\u003eCollectively, these results demonstrate that microplastic remediation efficiency is governed by \u003cb\u003einteractions between chemical transformation, physical fragmentation, and surface adsorption processes\u003c/b\u003e. The integration of spectroscopic, morphological, and particle size analyses therefore provides a comprehensive understanding of the mechanisms underlying microplastic removal across different environmental treatment strategies.\u003c/p\u003e \u003cp\u003eThe integration of spectroscopic, microscopic, and statistical analyses provides a consistent mechanistic framework linking polymer degradation, particle fragmentation, and removal efficiency across the investigated remediation systems.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e3.9 Statistical Section\u003c/h2\u003e \u003cp\u003eAll experiments were conducted in \u003cb\u003etriplicate (n\u0026thinsp;=\u0026thinsp;3)\u003c/b\u003e, and results are presented as \u003cb\u003emean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD)\u003c/b\u003e. Statistical differences among remediation treatments were evaluated using \u003cb\u003eone-way analysis of variance (ANOVA)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003ePrior to performing ANOVA, the data were tested for \u003cb\u003enormality using the Shapiro\u0026ndash;Wilk test\u003c/b\u003e and \u003cb\u003ehomogeneity of variance using Levene\u0026rsquo;s test\u003c/b\u003e. These tests confirmed that the data met the assumptions required for parametric statistical analysis.\u003c/p\u003e \u003cp\u003eWhen ANOVA indicated significant differences between treatments, \u003cb\u003eTukey\u0026rsquo;s post-hoc test\u003c/b\u003e was applied to determine pairwise differences between remediation strategies.\u003c/p\u003e \u003cp\u003eStatistical analyses were performed using \u003cb\u003eOriginPro 2023 software\u003c/b\u003e, and differences were considered statistically significant at \u003cb\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/b\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eOne-way ANOVA results for removal efficiency of microplastics under different remediation treatments.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSource of Variation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSum of Squares (SS)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDegrees of Freedom (df)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMean Square (MS)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eF-value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBetween treatments\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1456.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e291.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e18.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWithin treatments\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e186.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1642.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe one-way ANOVA analysis indicated that \u003cb\u003eremoval efficiencies differed significantly among remediation treatments (F\u0026thinsp;=\u0026thinsp;18.74, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) as showmn in\u003c/b\u003e Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Post-hoc Tukey analysis (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) revealed that combined adsorption\u0026ndash;oxidation treatments exhibited significantly higher removal efficiencies compared with adsorption-only processes (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTukey post-hoc comparison of remediation treatments.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComparison\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean Difference (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAdsorption vs Oxidation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e8.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.032\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAdsorption vs Adsorption\u0026thinsp;+\u0026thinsp;Oxidation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e21.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOxidation vs Adsorption\u0026thinsp;+\u0026thinsp;Oxidation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.004\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eStatistical analysis confirmed that removal efficiencies varied significantly across treatment categories (one-way ANOVA, \u003cb\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/b\u003e), with adsorption\u0026ndash;oxidation systems producing the highest mean removal values.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003e3.10 Comparative Removal Efficiency of Remediation Strategies\u003c/h2\u003e \u003cp\u003eThe removal efficiencies of different remediation treatments for polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics across the experimental systems are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eIn the aquatic microcosm experiments, adsorption using activated carbon resulted in moderate removal efficiencies ranging from \u003cb\u003e58\u0026ndash;65%\u003c/b\u003e, depending on polymer type. When adsorption was combined with oxidative treatment using the UV/H₂O₂ system, removal efficiency increased substantially, reaching \u003cb\u003e68\u0026ndash;75%\u003c/b\u003e for the tested polymers. The enhanced performance of the combined treatment suggests that adsorption facilitates the initial capture of microplastic particles while subsequent oxidative reactions promote surface modification and partial degradation of polymer structures.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRemoval Efficiency of Microplastics Across Environmental Systems\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEnvironmental system\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRemediation strategy\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePE (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePP (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePS (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eDominant removal mechanism\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAquatic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eActivated carbon adsorption\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e65\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e60\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e58\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHydrophobic interactions\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAquatic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBiochar adsorption\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e63\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e58\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e61\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSurface sorption, π\u0026ndash;π (PS)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAquatic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eH₂O₂/UV oxidation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e68\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e70\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e75\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eRadical chain scission\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAquatic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAdsorption\u0026thinsp;+\u0026thinsp;AOP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e82\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e84\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e88\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCapture\u0026thinsp;+\u0026thinsp;oxidation synergy\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTerrestrial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBiochar (5% w/w)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e70\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e65\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e62\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePhysical immobilization\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTerrestrial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCompost treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e40\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e45\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e48\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSurface aging\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTerrestrial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSoil washing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e75\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e77\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e78\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePhysical extraction\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAtmospheric\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eElectrostatic precipitation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e82\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e85\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCharge-based capture\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAtmospheric\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHEPA filtration\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e68\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e70\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e69\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSize exclusion\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. CONCLUSION","content":"\u003cp\u003eThis study experimentally evaluated several remediation approaches for microplastics in representative aquatic, terrestrial, and airborne environmental systems. The results demonstrate that remediation efficiency depends strongly on both the treatment mechanism and the environmental matrix in which the microplastics are present.\u003c/p\u003e \u003cp\u003eIn aquatic systems, adsorption using carbon-based sorbents achieved moderate removal efficiencies, while oxidation using the UV/H₂O₂ process induced chemical modification of polymer surfaces through radical-mediated reactions. The highest removal efficiencies were observed when adsorption and oxidation processes were combined, indicating that oxidative surface modification can enhance subsequent sorption and particle capture.\u003c/p\u003e \u003cp\u003eIn terrestrial environments, biochar amendment proved effective for stabilising microplastics within the soil matrix by promoting aggregation with soil particles and organic matter. Soil washing achieved higher apparent removal efficiencies; however, potential impacts on soil structure and microbial activity highlight the need for careful consideration of ecological trade-offs when applying such techniques.\u003c/p\u003e \u003cp\u003eFor airborne microplastics, physical capture technologies such as electrostatic precipitation and HEPA filtration effectively reduced suspended particle concentrations within the controlled airflow chamber. These results suggest that source-control strategies using particle capture technologies can contribute to reducing atmospheric microplastic transport.\u003c/p\u003e \u003cp\u003eSpectroscopic and microscopic analyses provided additional mechanistic insight into the remediation processes. FTIR analysis indicated the formation of oxygen-containing functional groups following oxidative treatment, while SEM observations revealed surface roughening and fragmentation of polymer particles. These physicochemical transformations support the proposed radical-mediated oxidation pathways involved in the degradation of microplastics.\u003c/p\u003e \u003cp\u003eOverall, the findings highlight that no single remediation technology is universally applicable across all environmental compartments. Instead, \u003cb\u003ematrix-specific strategies\u003c/b\u003e are required for effective microplastic mitigation. Integrated approaches combining adsorption, oxidation, stabilisation, and particle capture technologies may therefore provide a more practical framework for reducing microplastic persistence in complex environmental systems.\u003c/p\u003e \u003cp\u003eFuture studies should focus on evaluating remediation performance under environmentally realistic microplastic concentrations, assessing long-term transformation pathways, and quantifying potential secondary impacts such as nanoplastic formation or ecosystem disturbance. Such investigations will be essential for translating laboratory-scale findings into practical environmental management strategies.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eACKNOWLEDGEMENTS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors acknowledge institutional laboratory facilities and technical support.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDATA AVAILABILITY STATEMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data generated during this study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eUSE OF ARTIFICIAL INTELLIGENCE TOOLS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLimited use of artificial intelligence\u0026ndash;based tools was made during the preparation of this manuscript solely for language editing and improvement of clarity. These tools were not used to generate scientific content, experimental data, figures, or interpretations. All analyses, results, and conclusions presented in this work were developed by the authors, who take full responsibility for the accuracy, originality, and integrity of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNOVELTY STATEMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study presents one of the first experimental, system-wide evaluations of microplastic remediation across aquatic, terrestrial, and atmospheric compartments. By integrating adsorption, advanced oxidation, and stabilisation mechanisms, it elucidates polymer-specific chemical interactions and radical-driven transformation pathways. The findings establish a unified source-to-sink remediation framework with direct implications for scalable environmental management of microplastics.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCONFLICT OF INTEREST\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere is no funding received for the present study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets of the current study are available from the corresponding author on reasonable request. All experimental procedures and raw data supporting the findings of this study are documented and can be provided to ensure reproducibility.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAllen S, Allen D, Phoenix VR, Le Roux G, Jim\u0026eacute;nez PD, Simonneau A, Binet S, Galop D. Atmospheric transport and deposition of microplastics in a remote mountain catchment. Nat Geosci. 2019;12:339\u0026ndash;44. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1038/s41561-019-0335-5\u003c/span\u003e\u003cspan address=\"10.1038/s41561-019-0335-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAriza-Tarazona MC, Villarreal-Chiu JF, Barbieri V, Siligardi C, Cedillo-Gonz\u0026aacute;lez EI. Microplastic pollution reduction by a carbon\u0026ndash;TiO₂ photocatalytic treatment. 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Int J Innovative Res Technol. 2025;12(6):5573\u0026ndash;82. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://ijirt.org/article?manuscript=187603\u003c/span\u003e\u003cspan address=\"https://ijirt.org/article?manuscript=187603\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"discover-environment","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Discover Environment](https://www.springer.com/44274/)","snPcode":"44274","submissionUrl":"https://submission.nature.com/new-submission/44274/3","title":"Discover Environment","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Microplastics, Environmental remediation, Aquatic systems, Terrestrial systems, Atmospheric deposition, Experimental study","lastPublishedDoi":"10.21203/rs.3.rs-9205816/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9205816/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMicroplastics (MPs) are widely detected in aquatic, terrestrial, and atmospheric environments, raising increasing concerns regarding ecosystem impacts and potential human exposure. Although numerous studies have examined microplastic occurrence, comparatively fewer investigations have experimentally evaluated remediation strategies across multiple environmental matrices. In this laboratory-based study, the effectiveness of selected physicochemical and nature-based treatment approaches for microplastic removal was investigated in representative water, soil, and air-relevant systems.\u003c/p\u003e\n\u003cp\u003ePolyethylene (PE), polypropylene (PP), and polystyrene (PS) particles (50–500 µm) were introduced into controlled experimental systems simulating freshwater microcosms, agricultural soil matrices, and airborne particle chambers. Removal efficiencies and physicochemical changes were analysed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), particle size analysis, and mass-balance measurements.\u003c/p\u003e\n\u003cp\u003eResults indicated that removal efficiency depends strongly on both polymer type and environmental matrix. In aquatic systems, combined adsorption–oxidation treatments (biochar + UV/H₂O₂) achieved the highest removal efficiencies (85 ± 4%). Soil systems were dominated by stabilisation and extraction processes, where biochar amendment reduced microplastic mobility (68 ± 6%) and soil washing physically extracted particles (76 ± 5%). In the air-flow chamber experiments, electrostatic capture demonstrated higher removal efficiency (82 ± 3%) than HEPA filtration (69 ± 4%).\u003c/p\u003e\n\u003cp\u003eThese findings illustrate how physicochemical interactions, radical-mediated oxidation, and physical capture mechanisms influence microplastic removal across environmental systems. The results provide experimental insight into system-specific mitigation strategies and highlight the potential value of combining oxidative and sorptive processes for improved microplastic control.\u003c/p\u003e","manuscriptTitle":"Experimental Evaluation of Microplastic Removal Mechanisms in Aquatic, Soil, and Air-Relevant Systems","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-31 07:01:22","doi":"10.21203/rs.3.rs-9205816/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-03-31T15:09:28+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-27T14:13:44+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-27T14:12:59+00:00","index":"","fulltext":""},{"type":"submitted","content":"Discover Environment","date":"2026-03-24T02:33:28+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"discover-environment","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Discover Environment](https://www.springer.com/44274/)","snPcode":"44274","submissionUrl":"https://submission.nature.com/new-submission/44274/3","title":"Discover Environment","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"00de7cd9-d9d5-4e67-bab2-3f2530484bfb","owner":[],"postedDate":"March 31st, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-02T15:09:00+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-31 07:01:22","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9205816","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9205816","identity":"rs-9205816","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}