Phase Identification and Characterization of Sustainable Oxide Precursors Derived from Waste Materials by X-ray Diffraction

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Consequently, waste streams are increasingly regarded as alternative sources of technologically important oxides for glass and ceramic fabrication. This study focuses on the identification and structural characterization of oxide precursors derived from diverse waste materials, with emphasis on phase verification and suitability for advanced glass systems. Aluminum, calcium, silicon, and zinc oxide precursors were synthesized from waste aluminum beverage cans, chicken eggshells, waste container glass, coconut shells, and spent zinc–carbon batteries using simple hydrometallurgical, alkali-based, and thermal extraction routes. X-ray diffraction (XRD) patterns recorded over 2θ = 10–80° using Cu–Kα radiation (λ = 1.5406 Å) confirmed phase formation in all extracted oxide systems. The ZnO sample exhibited intense reflections at 2θ ≈ 31.7°, 34.4°, and 36.2°, indexed to the (100), (002), and (101) planes of hexagonal wurtzite ZnO (ICDD PDF 00-036-1451). Analysis of the full width at half maximum (FWHM) of the dominant (101) peak indicated an average crystallite size in the nanometer range. Silica recovered from waste container glass displayed a broad amorphous hump centered at 2θ ≈ 22°, confirming the absence of long-range order. In contrast, coconut-shell-derived silica showed crystalline quartz reflections at 2θ ≈ 20.8°, 26.6°, 36.5°, and 50.1°, corresponding to α-SiO₂, together with minor aluminosilicate phases. The eggshell-derived calcium system exhibited peaks at 2θ ≈ 29.4° (CaCO₃), 34.1° (Ca(OH)₂), and 37.3° (CaO), while the aluminum-based precursor showed boehmite reflections at 2θ ≈ 14.5°, 28.5°, and 38.3°. Overall, the waste-derived oxides occur as reactive or multiphase systems but remain structurally compatible with glass and ceramic processing. Biomaterials Waste-derived oxide precursors Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 INTRODUCTION The increasing volume of solid waste generated worldwide presents significant environmental and economic challenges, prompting intensified global interest in sustainable resource recovery and circular material utilization. In contemporary materials science, waste streams are increasingly viewed not as liabilities but as alternative reservoirs of technologically important elements, particularly silicon, aluminum, calcium, and zinc. Recovering inorganic oxides from agricultural residues, industrial by-products, and post-consumer wastes provides a viable pathway for reducing dependence on virgin raw materials while simultaneously lowering energy consumption and environmental burdens associated with conventional extraction routes (Colangelo, 2024; Cormier, 2021). Consequently, waste-derived oxides are now being actively investigated for use in advanced material systems such as ceramics, glasses, composites, adsorbents, and functional coatings, where phase stability and structural reliability are critical (Chen & Dai, 2016). Extensive research has demonstrated the feasibility of extracting silica, alumina, calcium oxide, and zinc oxide from a wide range of waste sources, including agricultural biomass, waste glass, metallic scraps, eggshells, and spent batteries (Danewalia et al., 2016; Mori, 2003; Sudjarwo & Bee, 2017; Azmiyawati et al., 2019; Shil, 2016; Valdrez et al., 2019). Recent studies have further refined these approaches through thermochemical, hydrometallurgical, and alkali-based extraction methods, enabling the recovery of oxide phases suitable for functional applications (Anuar et al., 2020; Banoth et al., 2022; Zhao et al., 2021; Rahman et al., 2023; Hossain et al., 2025). Additionally, calcium- and alumina-rich wastes such as eggshells and aluminum residues have been successfully transformed into useful oxide precursors, highlighting the versatility of waste-derived feedstocks (Awogbemi et al., 2020; Darkun et al., 2022; Borzova et al., 2024; Ibrahim et al., 2019). Despite these advances, waste-derived oxides often exhibit variations in crystallinity, polymorphism, and impurity content due to differences in raw material composition, processing routes, and thermal treatment conditions. Such variations can significantly influence the performance of the resulting materials, particularly when used as precursors for glass and ceramic systems. As a result, comprehensive structural verification remains a fundamental requirement before these materials can be reliably adopted for advanced applications. X-ray diffraction (XRD) is a cornerstone technique for addressing this requirement, as it provides definitive information on crystalline phase formation, structural order, and the presence of secondary or residual phases. Numerous investigations have successfully employed XRD to confirm oxide formation from waste sources and to evaluate synthesis efficiency (Anuar et al., 2020; Banoth et al., 2022; Rahman et al., 2023). However, while individual waste-derived systems have been widely reported, systematic and comparative XRD-based phase characterization of multiple oxide precursors obtained from different waste streams within a unified experimental framework remains limited. Addressing this gap is essential for establishing reproducible and standardized pathways for sustainable oxide production. In this context, the present study focuses on the phase identification and structural characterization of oxide precursors derived from diverse waste materials using X-ray diffraction, providing a robust structural basis for their future integration into advanced material and glass fabrication systems. MATERIALS AND METHODS Source and Initial Processing of Raw Materials The raw materials for this study were sourced from local waste streams. Spent zinc–carbon batteries were collected from household and commercial disposal points. Waste container glass bottles of mixed colors were sourced from retail shops and municipal collection areas. Coconut shells were obtained from local agricultural processing sites. Chicken eggshells were collected from household kitchens and local food vendors. Prior to transport to the laboratory, all materials underwent initial cleaning to remove bulk contaminants. This involved washing batteries and glass with running tap water, rinsing coconut shells and sun-drying them for 72 hours, and immersing eggshells in boiling water to detach the inner membrane followed by rinsing and sun-drying. The cleaned materials were then transported to the laboratory for further processing. Laboratory Processing of Waste Materials In the laboratory, the pre-cleaned materials underwent further processing to prepare them for chemical extraction. Waste glass bottles were manually crushed and milled into a coarse powder. Coconut shells were fragmented and ground using a mechanical grinder. Eggshells were ground into a fine powder. All resulting powders were sieved to obtain particles of less than 500 µm and stored in sealed containers within a desiccator. All chemical reagents, including hydrochloric acid (HCl), sodium hydroxide (NaOH), and distilled water, were of analytical grade and used as received. Extraction Methods for Oxide Precursors All extraction processes were carried out at the Sheda Science and Technology Complex (SHESTCO), Abuja, Nigeria, using standard laboratory facilities and analytical-grade reagents. The oxide precursors were synthesized from various waste materials following simple, low-cost, and reproducible laboratory procedures. Extraction of Aluminum Oxide from Waste Beverage Cans Waste aluminum beverage cans were washed with water, dried, and cut into small pieces to increase surface area. About 50 g of the prepared aluminum pieces were slowly added to hydrochloric acid (HCl, 1:1 v/v) in a suitable reaction vessel. The reaction was carried out under gentle heating and stirring until the aluminum dissolved completely, releasing hydrogen gas. The resulting solution was filtered to remove insoluble residues originating from can coatings and alloy impurities. Sodium hydroxide (NaOH) solution was then added gradually to the filtrate until a white gelatinous precipitate formed. This precipitate consisted mainly of aluminum hydroxide, together with small amounts of impurity hydroxides. The precipitate was washed several times with deionized water and dried at 110 °C. Upon drying, aluminum hydroxide partially transformed into boehmite (AlO(OH)). The dried powder was finally calcined at moderate temperature to obtain aluminum oxide–based material. Chemical Reactions: Extraction of Zinc Oxide from Spent Batteries Zinc oxide was extracted from spent batteries via a hydrometallurgical-thermal route. The batteries were manually dismantled to recover the zinc anode material, which was dissolved in 2M hydrochloric acid under continuous stirring at 60°C. After cooling, 1M sodium hydroxide was added dropwise to precipitate zinc hydroxide at pH ~8. The precipitate was aged, filtered, washed with distilled water, and dried at 110°C overnight. The dried zinc hydroxide was subsequently calcined in a muffle furnace at 400°C for 2 hours to yield zinc oxide powder(Valdrez et al., 2019; Hossain et al., 2025; García et al., 2024). Chemical equations: Extraction of Silica from Waste Glasses Silica was extracted from waste glass powder using an alkali fusion method. The powder was mixed with sodium hydroxide pellets in a 1:0.8 weight ratio and fused in a furnace at 500°C for 1 hour. The fused mass was dissolved in hot distilled water and filtered to obtain a sodium silicate solution. This solution was acidified with 4M hydrochloric acid under stirring until silica gel formed at pH ~2. The gel was aged for 24 hours, filtered, washed to a neutral pH, and dried at 120°C to yield silica powder.(Mori, 2003; Sudjarwo & Bee, 2017; Azmiyawati et al., 2019; Banoth et al., 2022). Chemical equations: Alkali Fusion: SiO₂ (s) + 2NaOH (l) → Na ₂ SiO₃ (l) + H₂O (g) Acid Precipitation: Na ₂ SiO₃ (aq) + 2HCl (aq) → SiO₂·xH₂O (gel) + 2NaCl (aq) Drying: SiO₂·xH₂O (s) → SiO₂ (s) + xH₂O (g) Extraction of Silica from Coconut Shells An alternative silica source was extracted from coconut shells via thermal treatment and alkali leaching. The shell powder was calcined in a muffle furnace at 600°C for 4 hours to produce ash. This ash was mixed with 2.5M sodium hydroxide solution and refluxed at 90°C for 2 hours. The mixture was filtered, and the resulting sodium silicate filtrate was acidified with 4M hydrochloric acid to precipitate silica gel, which was then processed identically to the glass-derived silica(Anuar et al., 2020; Zhao et al., 2021). Chemical equations: Combustion : (C, H, O compounds) (s) + O₂ (g) → Ash (primarily SiO₂) + CO₂ (g) + H₂O (g) Alkali Leaching: SiO₂ (s) + 2NaOH (aq) → Na₂SiO₃ (aq) + H₂O (l) Extraction of Calcium Oxide from Eggshell Waste Calcium oxide was synthesized from eggshell powder via direct thermal decomposition. The powder was calcined in an alumina crucible within a muffle furnace at 900°C for 3 hours. The resulting powder was immediately transferred to a desiccator to prevent hydration, yielding calcium oxide. Calcination: CaCO₃ (s) → CaO (s) + CO₂ (g) Characterization of Extracted Oxides The phase purity and crystallinity of the extracted oxide powders were analyzed at the National Steel Raw Materials Exploration Agency (NSRMEA), Kaduna, Nigeria, using an X-ray diffractometer (Rigaku MiniFlex 600, Japan). Measurements were performed with Cu-Kα radiation (λ = 1.5406 Å) over a 2θ range of 10°–80°. Crystalline phases were identified by comparison with standard reference patterns from the International Centre for Diffraction Data (ICDD) database. The average crystallite size (D) of the dominant phases was estimated from the full width at half maximum (FWHM) of the most intense diffraction peak using the Scherrer equation: D = (Kλ) / (β cosθ) where K is the Scherrer constant (≈0.9), λ is the X-ray wavelength, β is the FWHM in radians, and θ is the Bragg angle. RESULTS AND DISCUSSION The extracted oxide precursors from various waste materials were characterized by X-ray Diffraction (XRD) to confirm successful phase transformation, assess crystallinity, and identify any secondary phases. The diffraction patterns and corresponding analyses for each material are presented and discussed below. X-ray Diffraction Analysis of Oxide Precursors Aluminium Oxide Precursor Extracted from Aluminium Cans The XRD diffractogram of the aluminium-based precursor obtained from waste aluminium cans confirms the successful formation of boehmite (AlO(OH)), a well-established intermediate phase for alumina-based glass and ceramic systems (Figure 1A). The presence of the intense basal reflection at 2θ ≈ 14°, clearly resolved in the phase-identified pattern (Figure 1C), is a definitive structural signature of boehmite and confirms effective oxidation and hydroxylation of the aluminium feedstock. The broad nature of the diffraction peaks observed in the full pattern (Figure 1A) indicates a fine crystallite size and a partially disordered structure, characteristics commonly associated with chemically precipitated aluminium oxyhydroxides and advantageous for enhanced reactivity during subsequent thermal processing. Quantitative phase analysis (Figure 1B) further demonstrates the dominance of the boehmite phase, with minor aluminosilicate contributions reflecting the natural affinity of aluminium species for silicate environments. Collectively, these results confirm that the extracted material is a chemically active alumina precursor, suitable for incorporation into silicate glass matrices, where transformation to γ-Al₂O₃ occurs readily during melting. Calcium Oxide System Derived from Eggshell Waste The XRD pattern of the eggshell-derived calcium system reveals a structurally active calcium-rich material appropriate for glass formulation (Figure 2A). The dominant diffraction features observed in the full diffractogram reflect calcium-based phases typically formed during the thermal activation of biogenic calcium carbonate sources. Phase identification (Figure 2C) confirms the presence of calcium oxide–related phases capable of supplying CaO during high-temperature glass melting. The quantitative phase composition (Figure 2B) indicates a calcium-dominated system, which is particularly beneficial in silicate glasses, where calcium acts as a network modifier, improving melt fluidity and structural stability. The observed multiphase nature enhances chemical reactivity during melting, ensuring effective incorporation of calcium into the glass network. Silica Extracted from Coconut Shells The XRD diffractogram of the product obtained from coconut shell processing confirms the formation of a silica-bearing mineral system derived from the biogenic precursor (Figure 3A). Diffraction features attributable to quartz (SiO₂) are clearly identified in the phase-resolved pattern (Figure 3C), demonstrating successful recovery of silica species from the biomass source. Quantitative phase analysis (Figure 3B) indicates that silica constitutes a significant structural component of the recovered material, coexisting with naturally associated aluminosilicate phases typical of lignocellulosic biomass ash. The retention of these phases reflects the mineral inheritance of coconut shells and contributes to compositional compatibility with multicomponent silicate glass formulations. During glass melting, such mineral phases readily dissolve and participate in network formation, rendering the coconut-shell-derived product a functional and sustainable silica source for glass synthesis. Silica Extracted from Waste Container Glass The XRD pattern of silica extracted from waste container glass is dominated by a broad diffuse halo centered at 2θ ≈ 22°, characteristic of amorphous silica (Figure 4A). This feature confirms the effective disruption of long-range structural order during chemical processing, yielding a material highly suitable for glass fabrication. Structural assessment and amorphous profile fitting (Figure 4B and Figure 4C) further validate the predominance of the amorphous phase, with only minor residual crystalline features associated with aluminosilicate structural units inherited from the original glass. The amorphous nature of the recovered SiO₂ promotes uniform melting behavior and compositional homogeneity, supporting its role as an efficient network former in silicate glass systems, consistent with established reports (Mori, 2003; Sudjarwo & Bee, 2017). Zinc Oxide Extracted from Spent Zinc–Carbon Batteries The XRD diffractogram of the oxide recovered from spent zinc–carbon batteries exhibits sharp, high-intensity reflections indicative of a highly crystalline ZnO phase (Figure 5A). Phase identification (Figure 5C) confirms that the diffraction peaks correspond to the hexagonal wurtzite structure of zincite, in excellent agreement with standard reference data (ICDD PDF No. 00-036-1451). The prominent reflection at 2θ ≈ 36°, assigned to the ZnO (101) plane, serves as a clear fingerprint of zincite formation. Quantitative phase analysis (Figure 5B) demonstrates the dominance of ZnO within the recovered material, highlighting the effectiveness of the extraction route. The high crystallinity and phase purity of the zinc oxide make it particularly suitable for applications in glass and ceramic systems where ZnO functions as both a flux and an optical modifier (Valdrez et al., 2019; Hossain et al., 2025). Comparative Discussion and Implications for Glass Fabrication When considered collectively, the XRD results demonstrate that waste‑derived oxide precursors consistently exhibit multiphase compositions rather than idealized phase purity. Zinc oxide and waste‑glass‑derived silica show the highest degree of success in terms of dominant target phase formation, whereas calcium and coconut‑shell‑derived systems are more strongly affected by incomplete conversion and secondary phase formation. From a glass fabrication perspective, absolute phase purity at the precursor stage is not always essential. During high‑temperature melting, residual carbonates, hydroxides, and minor crystalline impurities typically decompose or dissolve into the melt, contributing to the final glass composition. However, the presence of alkali‑ and calcium‑rich secondary phases must be carefully accounted for during batch design to avoid unintended changes in glass structure and properties. Overall, the XRD analysis confirms the technical feasibility of recovering functional oxide systems from diverse waste streams while also highlighting the inherent challenges associated with sustainable, waste‑based material synthesis. These findings provide a realistic and scientifically grounded basis for subsequent glass preparation and property evaluation. X‑ray diffraction (XRD) was employed to evaluate the phase composition, crystallinity, and structural evolution of the oxide precursors extracted from various waste sources. The analysis was interpreted qualitatively and semi‑quantitatively using standard reference patterns from the ICDD PDF database, with emphasis placed on dominant phases, approximate peak positions, and overall phase assemblage rather than exhaustive peak indexing. This approach is appropriate for waste‑derived materials, where compositional heterogeneity and processing history can induce peak broadening, slight peak shifts, and multiphase coexistence. Overall, the XRD results confirm the successful recovery of the target elemental systems (Zn, Si, Ca, and Al) from waste streams. However, none of the extracted materials exhibited complete phase purity. Instead, secondary phases and precursor or post‑reaction products were consistently observed, reflecting incomplete conversion, interaction with residual impurities, and, in some cases, environmental exposure after synthesis. These findings have important implications for subsequent glass fabrication, as discussed in the comparative subsection. CONCLUSION This study confirms that valuable oxide precursors can be recovered from diverse waste materials using relatively simple processing routes, with X-ray diffraction providing effective phase identification and structural verification. The extracted products exhibited phase assemblages consistent with standard reference data, confirming successful transformation of the waste feedstocks. Zinc oxide from spent batteries showed clear diffraction features characteristic of zincite, while silica derived from waste glass displayed a predominantly amorphous structure suitable for glass network formation. In contrast, coconut shell processing resulted in significant residual mineral phases, highlighting the strong influence of raw material composition and extraction efficiency. The calcium-based system from eggshells revealed incomplete conversion and hydration effects, reflecting the high reactivity of biogenic calcium compounds. The aluminum-derived product was identified as an aluminum oxyhydroxide precursor, emphasizing the importance of controlled thermal treatment for achieving target alumina phases. Overall, the findings demonstrate that waste-derived oxides often occur as reactive or multiphase systems rather than ideal single-phase materials. Nevertheless, their structural characteristics are compatible with glass and ceramic fabrication, supporting the potential of waste streams as sustainable alternative sources of functional oxide precursors. References Anuar, M. F., Wing Fen, Y., Mohd Zaid, M. H., Matori, K. A., & Khaidir, R. E. M. (2020). 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AIP Conference Proceedings, 1855, 020019. https://doi.org/10.1063/1.4985464. Valdrez, I. V., Almeida, M. F., & Dias, J. M. (2019). Direct recovery of Zn from wasted alkaline batteries through selective anode separation. Journal of Cleaner Production, 227, 127–135. Zhao, Y., Zheng, Y., He, H., & Li, A. (2021). Silica extraction from bauxite reaction residue and synthesis of water glass. Green Processing and Synthesis, 10(1), 268–283. https://doi.org/10.1515/gps-2021-0028 Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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SiO₂\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-8451383/v1/e369d504f1ae33554011b84a.png"},{"id":99520978,"identity":"8c22151b-e85e-45b7-a03b-b469a05bdb3c","added_by":"auto","created_at":"2026-01-05 10:59:34","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":110656,"visible":true,"origin":"","legend":"\u003cp\u003eA: Full XRD diffractogram of eggshell-derived calcium oxide system\u003c/p\u003e\n\u003cp\u003eB: Quantitative phase composition of eggshell-derived calcium compounds\u003c/p\u003e\n\u003cp\u003eC: Phase-identified XRD pattern showing calcite, portlandite, and lime\u003c/p\u003e","description":"","filename":"Fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-8451383/v1/d1701fc8a4a385d2297648e9.png"},{"id":99791304,"identity":"ab56a690-0430-490a-af25-2a1250232396","added_by":"auto","created_at":"2026-01-08 12:59:25","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":124035,"visible":true,"origin":"","legend":"\u003cp\u003eA: Full XRD diffractogram of coconut-shell-derived silica product\u003c/p\u003e\n\u003cp\u003eB: Quantitative phase analysis of coconut-shell-derived product\u003c/p\u003e\n\u003cp\u003eC: Phase-identified XRD pattern showing calcite, quartz, and orthoclase.\u003c/p\u003e","description":"","filename":"Fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-8451383/v1/2d186d106f9e6c6e482415c8.png"},{"id":99792420,"identity":"51b943d9-cd46-45de-8529-a2ddefacac07","added_by":"auto","created_at":"2026-01-08 13:19:28","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":107558,"visible":true,"origin":"","legend":"\u003cp\u003eA: Full XRD diffractogram of silica extracted from waste container glass\u003c/p\u003e\n\u003cp\u003eB: Structural assessment of amorphous silica from waste glass\u003c/p\u003e\n\u003cp\u003eC: Amorphous profile fitting of waste-glass-derived silica.\u003c/p\u003e","description":"","filename":"Fig4.png","url":"https://assets-eu.researchsquare.com/files/rs-8451383/v1/3c2cff1d6494e79aa206a0dc.png"},{"id":99520981,"identity":"1e9df79f-6d93-49b0-86d1-7280d59f5a74","added_by":"auto","created_at":"2026-01-05 10:59:34","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":78784,"visible":true,"origin":"","legend":"\u003cp\u003eA: Full XRD diffractogram of zinc oxide extracted from spent batteries\u003c/p\u003e\n\u003cp\u003eB: Quantitative phase analysis of battery-derived zinc oxide.\u003c/p\u003e\n\u003cp\u003eC: Phase-identified XRD pattern of zincite ZnO with secondary phases\u003c/p\u003e","description":"","filename":"Fig5.png","url":"https://assets-eu.researchsquare.com/files/rs-8451383/v1/44253ca822e264121bbde7f9.png"},{"id":100356315,"identity":"00bdeac5-dadd-40b4-a152-7270e947703d","added_by":"auto","created_at":"2026-01-16 07:02:33","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1163256,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8451383/v1/98ff3d78-802d-43b9-8587-c8ae6ef77731.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003ePhase Identification and Characterization of Sustainable Oxide Precursors Derived from Waste Materials by X-ray Diffraction\u003cbr\u003e\n\u003c/p\u003e","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe increasing volume of solid waste generated worldwide presents significant environmental and economic challenges, prompting intensified global interest in sustainable resource recovery and circular material utilization. In contemporary materials science, waste streams are increasingly viewed not as liabilities but as alternative reservoirs of technologically important elements, particularly silicon, aluminum, calcium, and zinc. Recovering inorganic oxides from agricultural residues, industrial by-products, and post-consumer wastes provides a viable pathway for reducing dependence on virgin raw materials while simultaneously lowering energy consumption and environmental burdens associated with conventional extraction routes (Colangelo, 2024; Cormier, 2021). Consequently, waste-derived oxides are now being actively investigated for use in advanced material systems such as ceramics, glasses, composites, adsorbents, and functional coatings, where phase stability and structural reliability are critical (Chen \u0026amp; Dai, 2016).\u003c/p\u003e\n\u003cp\u003eExtensive research has demonstrated the feasibility of extracting silica, alumina, calcium oxide, and zinc oxide from a wide range of waste sources, including agricultural biomass, waste glass, metallic scraps, eggshells, and spent batteries (Danewalia et al., 2016; Mori, 2003; Sudjarwo \u0026amp; Bee, 2017; Azmiyawati et al., 2019; Shil, 2016; Valdrez et al., 2019). Recent studies have further refined these approaches through thermochemical, hydrometallurgical, and alkali-based extraction methods, enabling the recovery of oxide phases suitable for functional applications (Anuar et al., 2020; Banoth et al., 2022; Zhao et al., 2021; Rahman et al., 2023; Hossain et al., 2025). Additionally, calcium- and alumina-rich wastes such as eggshells and aluminum residues have been successfully transformed into useful oxide precursors, highlighting the versatility of waste-derived feedstocks (Awogbemi et al., 2020; Darkun et al., 2022; Borzova et al., 2024; Ibrahim et al., 2019).\u003c/p\u003e\n\u003cp\u003eDespite these advances, waste-derived oxides often exhibit variations in crystallinity, polymorphism, and impurity content due to differences in raw material composition, processing routes, and thermal treatment conditions. Such variations can significantly influence the performance of the resulting materials, particularly when used as precursors for glass and ceramic systems. As a result, comprehensive structural verification remains a fundamental requirement before these materials can be reliably adopted for advanced applications.\u003c/p\u003e\n\u003cp\u003eX-ray diffraction (XRD) is a cornerstone technique for addressing this requirement, as it provides definitive information on crystalline phase formation, structural order, and the presence of secondary or residual phases. Numerous investigations have successfully employed XRD to confirm oxide formation from waste sources and to evaluate synthesis efficiency (Anuar et al., 2020; Banoth et al., 2022; Rahman et al., 2023). However, while individual waste-derived systems have been widely reported, systematic and comparative XRD-based phase characterization of multiple oxide precursors obtained from different waste streams within a unified experimental framework remains limited. Addressing this gap is essential for establishing reproducible and standardized pathways for sustainable oxide production. In this context, the present study focuses on the phase identification and structural characterization of oxide precursors derived from diverse waste materials using X-ray diffraction, providing a robust structural basis for their future integration into advanced material and glass fabrication systems.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSource and Initial Processing of Raw Materials\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe raw materials for this study were sourced from local waste streams. Spent zinc\u0026ndash;carbon batteries were collected from household and commercial disposal points. Waste container glass bottles of mixed colors were sourced from retail shops and municipal collection areas. Coconut shells were obtained from local agricultural processing sites. Chicken eggshells were collected from household kitchens and local food vendors. Prior to transport to the laboratory, all materials underwent initial cleaning to remove bulk contaminants. This involved washing batteries and glass with running tap water, rinsing coconut shells and sun-drying them for 72 hours, and immersing eggshells in boiling water to detach the inner membrane followed by rinsing and sun-drying. The cleaned materials were then transported to the laboratory for further processing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eLaboratory Processing of Waste Materials\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the laboratory, the pre-cleaned materials underwent further processing to prepare them for chemical extraction. Waste glass bottles were manually crushed and milled into a coarse powder. Coconut shells were fragmented and ground using a mechanical grinder. Eggshells were ground into a fine powder. All resulting powders were sieved to obtain particles of less than 500 \u0026micro;m and stored in sealed containers within a desiccator. All chemical reagents, including hydrochloric acid (HCl), sodium hydroxide (NaOH), and distilled water, were of analytical grade and used as received.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExtraction Methods for Oxide Precursors\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll extraction processes were carried out at the Sheda Science and Technology Complex (SHESTCO), Abuja, Nigeria, using standard laboratory facilities and analytical-grade reagents. The oxide precursors were synthesized from various waste materials following simple, low-cost, and reproducible laboratory procedures.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eExtraction of Aluminum Oxide from Waste Beverage Cans\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWaste aluminum beverage cans were washed with water, dried, and cut into small pieces to increase surface area. About 50 g of the prepared aluminum pieces were slowly added to hydrochloric acid (HCl, 1:1 v/v) in a suitable reaction vessel. The reaction was carried out under gentle heating and stirring until the aluminum dissolved completely, releasing hydrogen gas.\u003c/p\u003e\n\u003cp\u003eThe resulting solution was filtered to remove insoluble residues originating from can coatings and alloy impurities. Sodium hydroxide (NaOH) solution was then added gradually to the filtrate until a white gelatinous precipitate formed. This precipitate consisted mainly of aluminum hydroxide, together with small amounts of impurity hydroxides.\u003c/p\u003e\n\u003cp\u003eThe precipitate was washed several times with deionized water and dried at 110 \u0026deg;C. Upon drying, aluminum hydroxide partially transformed into boehmite (AlO(OH)). The dried powder was finally calcined at moderate temperature to obtain aluminum oxide\u0026ndash;based material.\u003c/p\u003e\n\u003cp\u003eChemical Reactions:\u003c/p\u003e\n\u003cp\u003e\u003cimg 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Lf2yXL5enr7Y6TEc0+mUTk9Py3J4UZP+dH6+1+tRlmU0mUyop8UuyDpwGl9ysewVPma9jno/sIK5jCiKSssIL+yr9Gccx+S6rkwukafeVUjTtNbONpriH7aF53mVE61klY3AFBdAmiL+5csX8cTfWJZFtm23vn8Z7ynPdcradAze3t7WNlG5VkgODw+JiOj5+Vlmrczh4SHN53OZXGM6ndasSOv2ySacnJyUY9NEkiSUZVlrPWT8IfcHy43lKLEsy6js65jk0sQu5AXeEelHeit0v7R+bdOnKf217JNmnyz7bWWzfd+v+HL1+ADpu9bzZBv08rk8PS7BFMPBdW767bpuxads23ZFZrIOnCZjL2Sd9To2xUMsw7btUtb8HlN/+r5fypDvW9VPzjKTv/U+SZJk5fKYJElqfndG76emqwk5zmWMgB4/w+NTH2vcb5zH9+oy5DFikjVj23Zt3Mo26Jcei7Ftea7LOvEhm4xBZYh1UdpclfEeDPcJl8+/m64meeht437R6xwEgbENqshrmqscN9J0NdVHaWOKLykDfTzw/NDXOD1PjjuuL9dvlX5VhZxWlUsTbfIC3WanlpddYds29Xo9GgwGZNt2eZJgv7WMo5jP53R6elqeFLIsK0+tk8mkYopeLBalZUD6ZfXy2RzN90ZRtFIMx3A4LMt1HGepS0nWYTqdVsy+lmVRGIY0n88pz/Pyft3Xv85Jl0nTlBzHKU3OHONxc3Mjb906SilyHKc80Z2fn7eeFk30+326urqqWayoiBtRSpWX7/uUZVklrQnLskgpRUmSELW4IKioQxAExviXfr9PSimyLIs8z6uc1g8ODir3rorv+5U2KKVqMTP0BvKUX5Utu2zbJioss20n503HII8bKUeTC24VkiSpyXXZPP/16xdFUUSPj4+UZRk9PT0RFXV7enpqtEBwusl1NZvNKnVwXbfyW8aZ6PC6w/VuczmOx+NGt+d4PC7fw2vpNlgmlyba5AW6zc6UFzZlS9g/v030jaZtwpK2kMnFZ7FY1CbmJmyyILLZ9fHxce34DzZ96/Aivc24n7u7O4rjuLLpcABp20LB42BZv5jI85wODw+p1+vR8fExWZZFaZpWXC+6y4030lT7pHM6nZb9+vXr16Ub3ab0+30Kw1Am19A3Atl33JbLy8vKZshuDd7wJHmeU5ZlrS6pJt5CnqzQrXNRMY/bXIibjsEm2A3348cPmUW0gttjXb5+/UrX19dk23bZzvv7+0pcm+d55Ig/hXB0dER3d3fl720yHo9XWnPa3J7cF6pQoJijoyOiQnFbFykXvc+5r9kl74nP5t9SXuD92JnyQpplgkmSZKPNfZvw+02LHedtMtmYplNeE6Pi71Go4tS9CU3WmiZf/rrkeU6Pj4+1DYc3nWULxdXVFWVZVrM2MNPptLE/2CLx8vJCURTRr1+/KrEfDw8PpArLB2/ug8GgrN9kMqmUt62ToYmDg4OVrFq8EejWlel0SovFgpRSteBJqwhqborvuL+/J9owAHIf5MkbX9v4f80YbJrXfEpvCvq9ublpDGZdl4ODA7Isq7SW8Lr48vJSWSssy6LHx8dy4+dnTf2+Lb58+dIYT6XD8S/6euN5XmnhkwyHQ7Jtu9UaKeMNGSkX7usgCOj5+ZnSNKWnpydSStHl5WUl3uut5QXeh50qL1QoMDzwtrEIbAPf92ufMLLm7vt+zTzaZsqmYpFjrq+vV17w+GSrWyWagi7TNDVu8Lxh6YvA3d1d45cpmzAajcovhiTsBjHVjRkOh6VcpZuBZbtMXm2L62g0KvszTdPK6c9k/Xsrzs/PWxdqHXYz6eiKgLSy8Nc1sj3T6bT8DH2b/b1LeZo2Pslrx6Db8Bl7kiQUx3FtjjvFxwbrutMkXCc5vpvkmOc52bZN379/l1lvQp7nNJlMVnLPsNtToq+V8iDFbrKe+CAgL1yL68jXcZxSeX5+fi6/LN3WIQ3sOTIIpqvIgERTkFZbPgfr8aUHlclAOM7T0ziQjAPUOF0PXpOBoEoEeCZJUgv45LK4HP7NQXKmOpjKMKVzcB3/loHNJvT7pQxl+3zfb5SFMgQJkgiilOXpAZL87iRJKvWwbVuFYVgGnXKb9Xw9wFPW6TXItuhBj1L2UnZKBOwqw3jlf8tn5Ht1TDLWg4D1dNd190qeTWxjDIZh2FpX/R2m98j1Qg9a1dPJMKa5LL1e3O9BENQCiTmd7wnDsFafTZFBx1ImcvyY6qa3XZbHbZQB4FK+8r16Hgfq8rt5DGZZVsnjd8hxuE15gf3BvEOBjbHF10Dg7dEXKl4U+b+8WeiLIW+2YRiirwz8KfJ0Xde4Gb8lurxMZFlW2YR1OTO+9pec/xSa5MLjMim+dtPTmT9RXn8CUF62DJSX3cNWgVWwC0uBPJ2B//EnyXNX85U33FU2UbYmmPiTrQhtctHRx+KfLK+PDpSXLaKfkjBhdot0d5hgi4Et/gYKqPMnyXMXJ3PdcrIKupuEWaVPPjomuUjYAvOvf/3rj5fXR6anVomOAwAAAADYE3b+tREAAAAAwGuA8gIAAACATgHlBQAAAACdAsoLAAAAADoFlBcAAAAAdAooLwAAAADoFFBeAAAAANApoLwAAAAAoFNAeQEAAABAp4DyAgAAAIBOAeUFAAAAAJ0CygsAAAAAOgWUFwAAAAB0CigvAAAAAOgUUF4AAAAA0CmgvAAAAACgU0B5AQAAAECngPICAAAAgE4B5QUAAAAAnQLKCwAAAAA6BZQXAAAAAHQKKC8AAAAA6BRQXgAAAADQKT6M8uI4DvV6vcYrz3P5yF7R6/VoOp3K5J3TJLM2+W673r1ej6IoksmvYlv1HI1GtfbrV5qm8pGNyPP8TeRARBRFUa3e+rUNOTGO49BoNJLJ74bnea31mU6n1Ov1ZDJR8azsX8/zKrKTZcvx4jhOmSfnVNu7u4bjOK3jyPM88jxPJlOaprXx2LZ2R1FUk7lpfC/L53fI/uLx8hbzcB14PdAvrpOpPctYV857ifpAhGGoiEhlWVZJD4Kglgbq2LatkiQp/+37fiXfJF9Ok/duChEpIlJhGMqsvSHLMmMdbdtWRKRc162k7yumPvZ9v+yDjwb3W1PbgiBozJf9zWVJ+fEY0GkaL0qbPwzfy/OwiyRJoohI2bYts5RSSrmua5wnPPZM60sQBJV7VXG/LIPL1uF+lfI3jX/V0Aeu6xrv3QZZlq1ctu/7jXK1bdsoJ8m6ct5X6rO0w5g2130kDMPaRHpveMFpo0m+psnwGkwLzbYJgmDjDaJtM2JZdGERaFq8uZ/lxtB1fN8v+8fUd0rb6HRc163d3yYf27YreW3jRSovSru/q/BGTy1KmOu6FRmx3E33s4z0vDAMa/JvW4e4fD2vafyblBfVMA62wS6Vl3XlvM/s3G2km0qlCfYtaDNdvhenp6cy6d359euXTFqZL1++yKS9Js9zmkwmMnkrzGYzIiK6ubmRWZ1hOByS67oUx3H3TMktzOdzms1mZNs23d7eymwjURTRYrGg4XBYpvGacnl5qd35Py4uLiiO443XN8uyKAiCmjukC+R5TovFopwHd3d38hYjk8mEXNelfr8vs0rZX11dlWmnp6cV+ed5TvP5nHzfJ8uyynTm27dvRER0fX0ts1ZmNpvt5dq9DuvKeZ/ZqfLiOA5lWVb+HgwGb7o45nlOLy8vMrmiQEm/K/tqdQVrOp2S4zgVvyMvYPxb92VzOdKfyM9TMfn436b4Bunj1JUwzkvTtOJzb6OtPM/zyklpaksbrAi4rltZNNreRwafq2kc6P5nPb9XyErPJy1egfMZXb5pmpJt20TF+NPbqsvyNRuH67qUZRn997//rdWHx4Vefk+Ld+C2snx4A+TfeZ6XZch+0svQL5Nsl3F8fExERD9+/CAq+oLjFGT5PIf0Pud39kTf8/ySc4yR44YvLoPfv26boiiiIAiINOVilTJub2/p4uKiksZryqdPnyrpzOHhIRERPT8/y6yVOTw8pPl8LpNrTKfTWjxGnue1dW1T1i3r/v6+3Px831+pDdwPJqWDYWWair60bbuyAf/+/Zuo5SBlWRbZtk2Pj48ya2W4DClvOQ+pmC+bKq9vxbpyZjzPM86VNE1ftU6+GmmKeSvYFCevZWaudWCzl35Jc5xt2xXTH2nmX/ZX62LR/eBsrpO+cWkWDoKgYtqT5kn9Xl0uMo1NnOzSCYrYHb19bOLjfBNt5TEm87XEJF9ZjlrhfUmSGE3GDJfL8tDNofp7OV/WQzettslX+rT136Z2MbK/JdJ8Le/V/edcN328sLy4jvpvLlfWgfuG38l1aEOOSx0uLwzDsiyuj7xHx/f9SrtJk6M+vzhNug/0PG53k5zXwbbtsl4sO1P/msaifL9bxFVweRI53uWcNV0mSJM3v1PvryAIjG1QDW6VTeH2NLVXR29LW//p/c73NY1FJWJZfEOsC4/FJnmoYgzIdVn2g37pY53xC9cjo48ria3FEErku+TV1A59Lpou/TmWGbd5XTnz76Y2qGIMtpX3luzU8rIrsiwjpVTFykOFxk6aeYyIKEmS0sS7WCzItu3yhEZENB6PKQgCsm2bFosFkXay4vKlJjsej8t7e71erR46lmXV8q+vryvmz36/T0EQ0GQyqdyfJEl5+mBrgom28jaB5csynkwmldPwsvfd3d1RHMflqZrT9ZNKGIZlPzmOU552/5731XzXdcn3fRqPx0Ti9GWSryTPc4rjmAaDQVknIqKnpyd560qYTilNcHt0U22/36ckSYy/sywjy7JqY+7nz59k23aZfnZ2RrRmXXR+/vxZ/ns2m5Hv+zVz83A4JNu2a1Y1rgO3jdHnF/eVtNaRNr/6/T7Ztl2pyyakaUqO45TvsiyLXNdd6trj+hwcHFTSpexXJQzDct7wFYahvK3Cr1+/KE1Tury8JKVUaTnI85yenp5KOUqGwyEdHx/XrARksHouuwaDAVGxxsi+1omiiHzfL39z/y1z0TVZsJrI87zWB7KPVsX3/VqfrLJeUGH1urq6qtWFWSwWdH5+LpOJirmhv0/Wo6lfqegHWWelVGUPiKKoHDP8e105R1FEx8fHRhcTw/V8DyvTzpQXqzC5SdgX+RZYllXZyEyLIHfoa2I+TPDEV0qR67oyuxXThvP58+fGvGWYnnlNeTqWZZUbK/uTTWXq78vz3LiQt02St+T379/GBeHh4UHeuhJxHFcUiV3w7ds3yrKsXESen59fVQdW3L5+/SqzKlxdXZXKZxRFpdK0CaxUcJxEnueUZVmpzGyKVJZ7vR7FcVyR1zrwmsIuNQm7i15bb+bTp0/0/PxMvV6vVATu7+8rG6PneeSIz9IPDw+NikO/36+N9baLN3O1ZFO9vb2l+XxekXOWZUtddDxG21w6cRy3rqO8jjcdOHgsnZycyKyNubm5KQ9QeeHunE6nlT5wHGejMfZahsNhuZ6enJzQcDhcW863t7eV/VmGQrBifHR0tHJs0zbZmfJC2smLSZJk48V1VeRky7LMOJE21dxNeJ5XatKb0jTANpXXtsvTMWn0be+zLIu+f/8us96NT58+NY6LdeGFa9dBb1YR5MnWo8lk0tgHy4iiiOI4bgx+1NGtL9+/f3+1AjqbzcoNkK00rykzz3N6fHysbcg8N9sWXW67PNjwmmJSDKjY1KSValMODg7Isiwaj8eklKLz83PKi1g+fc2yLIseHx/p6OioTPv06VNpAd6UPM/p5ORk6VrGG7SUMSs+9/f34okqQRA0KpO8SXKArmVZtblqWRb5vt+oKPH7//rrL5m1NqY58ePHj/IQx8HKVNwrx88uyfO8MibWkfNisSjbmhexdkopSpKEfN8vFbeDgwOjzN+anSovVAiEB/Y2Jvc68KKja9/39/dbW2h09M6UAVBMFEXGTr+8vKQsyyoa/O3tbcWdtQ7bLk/CCimfupe97+zsjObzecWkHRXBtLtmOp2SVZz45als3WA0x3HKLx501yRpVr80TSmOY5rP52uX30aapvTy8lLZOEyL7DJGoxGdnp6SbduVRbgNtr40BUuuA2+UfMnDx7qMRqNGRTIIAprP563jznVdo8WW3c2yD53io4RNrXYM10muS6bgUCrWG9u2t34osCxrJQXo/Pzc+PUVKxWTycS41jHj8Zhc1619xBFFEZ2enlaU2KOjI2Od+EsyaeGfTqc0mUwoDMON5oSOVBCZr1+/0mAwoMlk0jqedgkrnvpatI6cdSzLouPj49KNaJLBzpFBMF1FBl+1BRHp98lgQfm8DJCSQavyd1D8/RBZlv4uPfhOBvNxcJssQwYx6vfLd5mQz5kCu9rKkPKVlwxaa3ufMgT/mmQRFIHP/Pvo6Kg139X+vgRfskyWLz+n10u2UbZJGcaDvEzPcBAoFXXkesq6NfXxv//978pvKbsgCGppfMnARmWQvbxkgKU+PvSARx1Tul6mLgMq+ttUrqwLXyxXfsYkZ4nen3JMm+oj01QhK1PbGDlm5HvkeNHLks/qY1EPhNTrxX3DfS4JtL9flIjA+LeiqQ3K0P4gCCr9LutnGpumvqaGgFpl6FsS21zbO2R99frxfGWaxoX+jLsk4HVV5FpBhmB9/ZIykOPS9IyUs+u6ZVrW8rdowiKof9d8GOUFgD+ZpPgqSRKGYW1Regu2tXjJzY9pSt8F7hv9cbI2TJuJTpZl5SYpNzamScH5CIRb/JpqVVjBZXT56sqCPheaFJwuEIZhpb1Nyo7v+8a1562B8gLAB4AaTqK7WOD10/5r8MVnqHp620a+C+wV/nrpNmBFZBV5Bi2fSu/K6vKeBOJPUrwlbsP/HsBu+VR6W1aX94TbIA9H/Pu9rC4KygsAH4NEuJrkKXzb6O9r2kA3QbpSyODGei92ccJct89M1hXdKvPRSZLkzTdP3/drMtYxKVC7GCu7wnVdNZlMKnOSlZq3ln0bPfX3hAEAAAAA6AQ7/9oIAAAAAOA1QHkBAAAAQKeA8gIAAACATgHlBQAAAACdAsoLAAAAADoFlBcAAAAAdAooLwAAAADoFFBeAAAAANAp/h9kynA35H3/rQAAAABJRU5ErkJggg==\"\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eExtraction of Zinc Oxide from Spent Batteries\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eZinc oxide was extracted from spent batteries via a hydrometallurgical-thermal route. The batteries were manually dismantled to recover the zinc anode material, which was dissolved in 2M hydrochloric acid under continuous stirring at 60\u0026deg;C. After cooling, 1M sodium hydroxide was added dropwise to precipitate zinc hydroxide at pH ~8. The precipitate was aged, filtered, washed with distilled water, and dried at 110\u0026deg;C overnight. The dried zinc hydroxide was subsequently calcined in a muffle furnace at 400\u0026deg;C for 2 hours to yield zinc oxide powder(Valdrez et al., 2019; Hossain et al., 2025; Garc\u0026iacute;a et al., 2024).\u003c/p\u003e\n\u003cp\u003eChemical equations:\u003c/p\u003e\n\u003cp\u003e\u003cimg 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\"\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eExtraction of Silica from Waste Glasses\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSilica was extracted from waste glass powder using an alkali fusion method. The powder was mixed with sodium hydroxide pellets in a 1:0.8 weight ratio and fused in a furnace at 500\u0026deg;C for 1 hour. The fused mass was dissolved in hot distilled water and filtered to obtain a sodium silicate solution. This solution was acidified with 4M hydrochloric acid under stirring until silica gel formed at pH ~2. The gel was aged for 24 hours, filtered, washed to a neutral pH, and dried at 120\u0026deg;C to yield silica powder.(Mori, 2003; Sudjarwo \u0026amp; Bee, 2017; Azmiyawati et al., 2019; Banoth et al., 2022).\u003c/p\u003e\n\u003cp\u003eChemical equations:\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eAlkali Fusion: \u003cem\u003eSiO₂\u003csub\u003e(s)\u003c/sub\u003e + 2NaOH\u003csub\u003e(l)\u003c/sub\u003e \u0026rarr; Na\u003csub\u003e₂\u003c/sub\u003eSiO₃\u003csub\u003e(l)\u003c/sub\u003e + H₂O\u003csub\u003e(g)\u003c/sub\u003e\u003c/em\u003e\u003c/li\u003e\n \u003cli\u003eAcid Precipitation: \u003cem\u003eNa\u003csub\u003e₂\u003c/sub\u003eSiO₃\u003csub\u003e(aq)\u003c/sub\u003e + 2HCl\u003csub\u003e(aq)\u003c/sub\u003e \u0026rarr; SiO₂\u0026middot;xH₂O\u003csub\u003e(gel)\u003c/sub\u003e + 2NaCl\u003csub\u003e(aq)\u003c/sub\u003e\u003c/em\u003e\u003c/li\u003e\n \u003cli\u003eDrying: \u003cem\u003eSiO₂\u0026middot;xH₂O\u003csub\u003e(s)\u0026nbsp;\u003c/sub\u003e\u0026rarr; SiO₂\u003csub\u003e(s)\u003c/sub\u003e + xH₂O\u003csub\u003e(g)\u003c/sub\u003e\u003c/em\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eExtraction of Silica from Coconut Shells\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAn alternative silica source was extracted from coconut shells via thermal treatment and alkali leaching. The shell powder was calcined in a muffle furnace at 600\u0026deg;C for 4 hours to produce ash. This ash was mixed with 2.5M sodium hydroxide solution and refluxed at 90\u0026deg;C for 2 hours. The mixture was filtered, and the resulting sodium silicate filtrate was acidified with 4M hydrochloric acid to precipitate silica gel, which was then processed identically to the glass-derived silica(Anuar et al., 2020; Zhao et al., 2021).\u003c/p\u003e\n\u003cp\u003eChemical equations:\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eCombustion\u003cstrong\u003e:\u003c/strong\u003e \u003cem\u003e(C, H, O compounds)\u003csub\u003e(s)\u003c/sub\u003e + O₂\u003csub\u003e(g)\u003c/sub\u003e \u0026rarr; Ash (primarily SiO₂) + CO₂\u003csub\u003e(g)\u003c/sub\u003e + H₂O\u003csub\u003e(g)\u003c/sub\u003e\u003c/em\u003e\u003c/li\u003e\n \u003cli\u003eAlkali Leaching: \u003cem\u003eSiO₂\u003csub\u003e(s)\u003c/sub\u003e + 2NaOH\u003csub\u003e(aq)\u003c/sub\u003e \u0026rarr; Na₂SiO₃\u003csub\u003e(aq)\u003c/sub\u003e + H₂O\u003csub\u003e(l)\u003c/sub\u003e\u003c/em\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eExtraction of Calcium Oxide from Eggshell Waste\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCalcium oxide was synthesized from eggshell powder via direct thermal decomposition. The powder was calcined in an alumina crucible within a muffle furnace at 900\u0026deg;C for 3 hours. The resulting powder was immediately transferred to a desiccator to prevent hydration, yielding calcium oxide.\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eCalcination: \u003cem\u003eCaCO₃\u003csub\u003e(s)\u003c/sub\u003e \u0026rarr; CaO\u003csub\u003e(s)\u003c/sub\u003e + CO₂\u003csub\u003e(g)\u003c/sub\u003e\u003c/em\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eCharacterization of Extracted Oxides\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe phase purity and crystallinity of the extracted oxide powders were analyzed at the National Steel Raw Materials Exploration Agency (NSRMEA), Kaduna, Nigeria, using an X-ray diffractometer (Rigaku MiniFlex 600, Japan). Measurements were performed with Cu-K\u0026alpha; radiation (\u0026lambda; = 1.5406 \u0026Aring;) over a 2\u0026theta; range of 10\u0026deg;\u0026ndash;80\u0026deg;. Crystalline phases were identified by comparison with standard reference patterns from the International Centre for Diffraction Data (ICDD) database.\u003c/p\u003e\n\u003cp\u003eThe average crystallite size (D) of the dominant phases was estimated from the full width at half maximum (FWHM) of the most intense diffraction peak using the Scherrer equation:\u003c/p\u003e\n\u003cp\u003eD = (K\u0026lambda;) / (\u0026beta; cos\u0026theta;)\u003c/p\u003e\n\u003cp\u003ewhere K is the Scherrer constant (\u0026asymp;0.9), \u0026lambda; is the X-ray wavelength, \u0026beta; is the FWHM in radians, and \u0026theta; is the Bragg angle.\u003c/p\u003e"},{"header":"RESULTS AND DISCUSSION","content":"\u003cp\u003eThe extracted oxide precursors from various waste materials were characterized by X-ray Diffraction (XRD) to confirm successful phase transformation, assess crystallinity, and identify any secondary phases. The diffraction patterns and corresponding analyses for each material are presented and discussed below.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eX-ray Diffraction Analysis of Oxide Precursors\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAluminium Oxide Precursor Extracted from Aluminium Cans\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe XRD diffractogram of the aluminium-based precursor obtained from waste aluminium cans confirms the successful formation of boehmite (AlO(OH)), a well-established intermediate phase for alumina-based glass and ceramic systems (Figure 1A). The presence of the intense basal reflection at 2\u0026theta; \u0026asymp; 14\u0026deg;, clearly resolved in the phase-identified pattern (Figure 1C), is a definitive structural signature of boehmite and confirms effective oxidation and hydroxylation of the aluminium feedstock.\u003c/p\u003e\n\u003cp\u003eThe broad nature of the diffraction peaks observed in the full pattern (Figure 1A) indicates a fine crystallite size and a partially disordered structure, characteristics commonly associated with chemically precipitated aluminium oxyhydroxides and advantageous for enhanced reactivity during subsequent thermal processing. Quantitative phase analysis (Figure 1B) further demonstrates the dominance of the boehmite phase, with minor aluminosilicate contributions reflecting the natural affinity of aluminium species for silicate environments. Collectively, these results confirm that the extracted material is a chemically active alumina precursor, suitable for incorporation into silicate glass matrices, where transformation to \u0026gamma;-Al₂O₃ occurs readily during melting.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eCalcium Oxide System Derived from Eggshell Waste\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe XRD pattern of the eggshell-derived calcium system reveals a structurally active calcium-rich material appropriate for glass formulation (Figure 2A). The dominant diffraction features observed in the full diffractogram reflect calcium-based phases typically formed during the thermal activation of biogenic calcium carbonate sources.\u003c/p\u003e\n\u003cp\u003ePhase identification (Figure 2C) confirms the presence of calcium oxide\u0026ndash;related phases capable of supplying CaO during high-temperature glass melting. The quantitative phase composition (Figure 2B) indicates a calcium-dominated system, which is particularly beneficial in silicate glasses, where calcium acts as a network modifier, improving melt fluidity and structural stability. The observed multiphase nature enhances chemical reactivity during melting, ensuring effective incorporation of calcium into the glass network.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSilica Extracted from Coconut Shells\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe XRD diffractogram of the product obtained from coconut shell processing confirms the formation of a silica-bearing mineral system derived from the biogenic precursor (Figure 3A). Diffraction features attributable to quartz (SiO₂) are clearly identified in the phase-resolved pattern (Figure 3C), demonstrating successful recovery of silica species from the biomass source.\u003c/p\u003e\n\u003cp\u003eQuantitative phase analysis (Figure 3B) indicates that silica constitutes a significant structural component of the recovered material, coexisting with naturally associated aluminosilicate phases typical of lignocellulosic biomass ash. The retention of these phases reflects the mineral inheritance of coconut shells and contributes to compositional compatibility with multicomponent silicate glass formulations. During glass melting, such mineral phases readily dissolve and participate in network formation, rendering the coconut-shell-derived product a functional and sustainable silica source for glass synthesis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSilica Extracted from Waste Container Glass\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe XRD pattern of silica extracted from waste container glass is dominated by a broad diffuse halo centered at 2\u0026theta; \u0026asymp; 22\u0026deg;, characteristic of amorphous silica (Figure 4A). This feature confirms the effective disruption of long-range structural order during chemical processing, yielding a material highly suitable for glass fabrication.\u003c/p\u003e\n\u003cp\u003eStructural assessment and amorphous profile fitting (Figure 4B and Figure 4C) further validate the predominance of the amorphous phase, with only minor residual crystalline features associated with aluminosilicate structural units inherited from the original glass. The amorphous nature of the recovered SiO₂ promotes uniform melting behavior and compositional homogeneity, supporting its role as an efficient network former in silicate glass systems, consistent with established reports (Mori, 2003; Sudjarwo \u0026amp; Bee, 2017).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eZinc Oxide Extracted from Spent Zinc\u0026ndash;Carbon Batteries\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe XRD diffractogram of the oxide recovered from spent zinc\u0026ndash;carbon batteries exhibits sharp, high-intensity reflections indicative of a highly crystalline ZnO phase (Figure 5A). Phase identification (Figure 5C) confirms that the diffraction peaks correspond to the hexagonal wurtzite structure of zincite, in excellent agreement with standard reference data (ICDD PDF No. 00-036-1451).\u003c/p\u003e\n\u003cp\u003eThe prominent reflection at 2\u0026theta; \u0026asymp; 36\u0026deg;, assigned to the ZnO (101) plane, serves as a clear fingerprint of zincite formation. Quantitative phase analysis (Figure 5B) demonstrates the dominance of ZnO within the recovered material, highlighting the effectiveness of the extraction route. The high crystallinity and phase purity of the zinc oxide make it particularly suitable for applications in glass and ceramic systems where ZnO functions as both a flux and an optical modifier (Valdrez et al., 2019; Hossain et al., 2025).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eComparative Discussion and Implications for Glass Fabrication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWhen considered collectively, the XRD results demonstrate that waste‑derived oxide precursors consistently exhibit multiphase compositions rather than idealized phase purity. Zinc oxide and waste‑glass‑derived silica show the highest degree of success in terms of dominant target phase formation, whereas calcium and coconut‑shell‑derived systems are more strongly affected by incomplete conversion and secondary phase formation.\u003c/p\u003e\n\u003cp\u003eFrom a glass fabrication perspective, absolute phase purity at the precursor stage is not always essential. During high‑temperature melting, residual carbonates, hydroxides, and minor crystalline impurities typically decompose or dissolve into the melt, contributing to the final glass composition. However, the presence of alkali‑ and calcium‑rich secondary phases must be carefully accounted for during batch design to avoid unintended changes in glass structure and properties.\u003c/p\u003e\n\u003cp\u003eOverall, the XRD analysis confirms the technical feasibility of recovering functional oxide systems from diverse waste streams while also highlighting the inherent challenges associated with sustainable, waste‑based material synthesis. These findings provide a realistic and scientifically grounded basis for subsequent glass preparation and property evaluation.\u003c/p\u003e\n\u003cp\u003eX‑ray diffraction (XRD) was employed to evaluate the phase composition, crystallinity, and structural evolution of the oxide precursors extracted from various waste sources. The analysis was interpreted qualitatively and semi‑quantitatively using standard reference patterns from the ICDD PDF database, with emphasis placed on dominant phases, approximate peak positions, and overall phase assemblage rather than exhaustive peak indexing. This approach is appropriate for waste‑derived materials, where compositional heterogeneity and processing history can induce peak broadening, slight peak shifts, and multiphase coexistence.\u003c/p\u003e\n\u003cp\u003eOverall, the XRD results confirm the successful recovery of the target elemental systems (Zn, Si, Ca, and Al) from waste streams. However, none of the extracted materials exhibited complete phase purity. Instead, secondary phases and precursor or post‑reaction products were consistently observed, reflecting incomplete conversion, interaction with residual impurities, and, in some cases, environmental exposure after synthesis. These findings have important implications for subsequent glass fabrication, as discussed in the comparative subsection.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eThis study confirms that valuable oxide precursors can be recovered from diverse waste materials using relatively simple processing routes, with X-ray diffraction providing effective phase identification and structural verification. The extracted products exhibited phase assemblages consistent with standard reference data, confirming successful transformation of the waste feedstocks.\u003c/p\u003e\n\u003cp\u003eZinc oxide from spent batteries showed clear diffraction features characteristic of zincite, while silica derived from waste glass displayed a predominantly amorphous structure suitable for glass network formation. In contrast, coconut shell processing resulted in significant residual mineral phases, highlighting the strong influence of raw material composition and extraction efficiency. The calcium-based system from eggshells revealed incomplete conversion and hydration effects, reflecting the high reactivity of biogenic calcium compounds. The aluminum-derived product was identified as an aluminum oxyhydroxide precursor, emphasizing the importance of controlled thermal treatment for achieving target alumina phases.\u003c/p\u003e\n\u003cp\u003eOverall, the findings demonstrate that waste-derived oxides often occur as reactive or multiphase systems rather than ideal single-phase materials. Nevertheless, their structural characteristics are compatible with glass and ceramic fabrication, supporting the potential of waste streams as sustainable alternative sources of functional oxide precursors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAnuar, M. F., Wing Fen, Y., Mohd Zaid, M. H., Matori, K. A., \u0026amp; Khaidir, R. E. M. (2020). The physical and optical studies of crystalline silica derived from the green synthesis of coconut husk ash. Applied Sciences, 10(6), 2128. https://doi.org/10.3390/app10062128.\u003c/li\u003e\n \u003cli\u003eAwogbemi, O., Inambao, F. L., \u0026amp; Onuh, E. I. (2020). Modification and characterization of chicken eggshell for possible catalytic applications. Heliyon, 6(10), e05283. https://doi.org/10.1016/j.heliyon.2020.e05283.\u003c/li\u003e\n \u003cli\u003eBanoth, S., Babu, V. S., Raghavendra, G., Rakesh, K., \u0026amp; Ojha, S. (2022). Sustainable thermochemical extraction of amorphous silica from biowaste. Silicon, 14, 5289\u0026ndash;5296. https://doi.org/10.1007/s12633-021-01962-3.\u003c/li\u003e\n \u003cli\u003eBorzova, M., Schollbach, K., Gauvin, F., \u0026amp; Brouwers, H. J. H. (2024). Sustainable ambient pressure-dried silica aerogel from waste glass. Current Research in Green and Sustainable Chemistry, 9, 100425. https://doi.org/10.1016/j.crgsc.2024.100425.\u003c/li\u003e\n \u003cli\u003eDarkun, K., Febrina, L., \u0026amp; Lutfansa, A. (2022). Utilization a mixture of eggshells and husk ash to reduce environmental impact. Environmental Research, Engineering and Management, 78(3), 110\u0026ndash;118.\u003c/li\u003e\n \u003cli\u003eHossain, M. S., Yasmin, S., Dipannita, N. T., Hossain, M. S., Sarker, S. C., Jahan, T., Kabir, M. A., Paul, R. K., \u0026amp; Kabir, M. H. (2025). Waste beverage can-derived aluminum oxide supported on graphene oxide for th\u003c/li\u003e\n \u003cli\u003eeffective removal of ciprofloxacin from aqueous medium. Cleaner Chemical Engineering, 12, 100214. https://doi.org/10.1016/j.clce.2025.100214\u003c/li\u003e\n \u003cli\u003eIbrahim, M. S., Kurfi, Y. M., \u0026amp; Mohammed, A. I. (2019). Recycling of waste: A tool for environmental and sustainable national development\u0026mdash;Production of alum [K₂Al(SO₄)₂\u0026middot;12H₂O] from aluminium cans. Journal of Bio-Innovation, 8(2), 166\u0026ndash;176.\u003c/li\u003e\n \u003cli\u003eMori, H. (2003). Extraction of silicon dioxide from waste colored glasses by alkali fusion using sodium hydroxide. Journal of Materials Science, 38(16), 3461\u0026ndash;3468. https://doi.org/10.1023/A:1025100901693.\u003c/li\u003e\n \u003cli\u003eNasrudin, N. N. N., Rodzi, N. S. M., Ismail, N. A., \u0026amp; Roslan, M. S. (2025). The derivation of silica from coconut husk ash: Preliminary study. Multidisciplinary Applied Research and Innovation, 6(1), 112\u0026ndash;118. https://doi.org/10.30880/mari.2025.06.01.016.\u003c/li\u003e\n \u003cli\u003eNorul Azlin, M. Z., \u0026amp; Syufiana, S. S. (2022). The preparation and characterization of silica from coconut husk. In International Conference on Chemical Innovation (ICCI 2021), Journal of Physics: Conference Series, 2266(1), 012011. IOP Publishing. https://doi.org/10.1088/1742-6596/2266/1/012011.\u003c/li\u003e\n \u003cli\u003eOmran, S. H., Ali, M. H., Mohsen, M., \u0026amp; Hajer, A. (2018). Studying the effect of alumina on the mechanical properties of aluminum alloy prepared from waste using powder metallurgy. International Journal of Engineering and Technology, 7(4), 5589\u0026ndash;5593. https://doi.org/10.14419/ijet.v7i4.20652.\u003c/li\u003e\n \u003cli\u003eRahman, M. L., Islam, M. S., Ahmed, M. F., Biswas, B., Sharmin, N., \u0026amp; Neger, A. J. M. T. (2023). Extraction and characterization of highly pure alumina (\u0026alpha;, \u0026gamma;, and \u0026theta;) polymorphs from waste beverage cans: A viable waste management approach. Arabian Journal of Chemistry, 16(2), 104518. https://doi.org/10.1016/j.arabjc.2022.104518.\u003c/li\u003e\n \u003cli\u003eSarker, A., Rabbi, A. S., Nadi, N. A., Rahman, A. K. M. L., Momin, A. A., Ahmed, K. S., \u0026amp; Simol, H. A. (2024). Structural and transport properties of newly synthesized ZSM-5 sourcing silica from coconut shell ash. Results in Chemistry, 11, 101810. https://doi.org/10.1016/j.rechem.2024.101810.\u003c/li\u003e\n \u003cli\u003eShil, T. C. (2016). Preparation of aluminum oxide from industrial waste can available in Bangladesh environment: SEM and EDX analysis. Journal of Advanced Chemical Engineering, 6(2). https://doi.org/10.4172/2090-4568.1000152.\u003c/li\u003e\n \u003cli\u003eSudjarwo, W. A. A., \u0026amp; Bee, M. M. F. (2017). Synthesis of silica gel from waste glass bottles and its application for the reduction of free fatty acid (FFA) in waste cooking oil. AIP Conference Proceedings, 1855, 020019. https://doi.org/10.1063/1.4985464.\u003c/li\u003e\n \u003cli\u003eValdrez, I. V., Almeida, M. F., \u0026amp; Dias, J. M. (2019). Direct recovery of Zn from wasted alkaline batteries through selective anode separation. Journal of Cleaner Production, 227, 127\u0026ndash;135.\u003c/li\u003e\n \u003cli\u003eZhao, Y., Zheng, Y., He, H., \u0026amp; Li, A. (2021). Silica extraction from bauxite reaction residue and synthesis of water glass. Green Processing and Synthesis, 10(1), 268\u0026ndash;283. https://doi.org/10.1515/gps-2021-0028\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Federal University of Lafia ","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Waste-derived, oxide, precursors","lastPublishedDoi":"10.21203/rs.3.rs-8451383/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8451383/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe growing accumulation of solid waste has intensified interest in sustainable resource recovery and circular material utilization in materials science. Consequently, waste streams are increasingly regarded as alternative sources of technologically important oxides for glass and ceramic fabrication. This study focuses on the identification and structural characterization of oxide precursors derived from diverse waste materials, with emphasis on phase verification and suitability for advanced glass systems. Aluminum, calcium, silicon, and zinc oxide precursors were synthesized from waste aluminum beverage cans, chicken eggshells, waste container glass, coconut shells, and spent zinc–carbon batteries using simple hydrometallurgical, alkali-based, and thermal extraction routes. X-ray diffraction (XRD) patterns recorded over 2θ = 10–80° using Cu–Kα radiation (λ = 1.5406 Å) confirmed phase formation in all extracted oxide systems. The ZnO sample exhibited intense reflections at 2θ ≈ 31.7°, 34.4°, and 36.2°, indexed to the (100), (002), and (101) planes of hexagonal wurtzite ZnO (ICDD PDF 00-036-1451). Analysis of the full width at half maximum (FWHM) of the dominant (101) peak indicated an average crystallite size in the nanometer range. Silica recovered from waste container glass displayed a broad amorphous hump centered at 2θ ≈ 22°, confirming the absence of long-range order. In contrast, coconut-shell-derived silica showed crystalline quartz reflections at 2θ ≈ 20.8°, 26.6°, 36.5°, and 50.1°, corresponding to α-SiO₂, together with minor aluminosilicate phases. The eggshell-derived calcium system exhibited peaks at 2θ ≈ 29.4° (CaCO₃), 34.1° (Ca(OH)₂), and 37.3° (CaO), while the aluminum-based precursor showed boehmite reflections at 2θ ≈ 14.5°, 28.5°, and 38.3°. Overall, the waste-derived oxides occur as reactive or multiphase systems but remain structurally compatible with glass and ceramic processing.\u003c/p\u003e","manuscriptTitle":"Phase Identification and Characterization of Sustainable Oxide Precursors Derived from Waste Materials by X-ray Diffraction","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-05 10:59:29","doi":"10.21203/rs.3.rs-8451383/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a5066ad9-5094-4b9b-bb5f-95108fb522bc","owner":[],"postedDate":"January 5th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":60218093,"name":"Biomaterials"}],"tags":[],"updatedAt":"2026-01-05T10:59:29+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-05 10:59:29","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8451383","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8451383","identity":"rs-8451383","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}