Solar photo-Fenton optimization at neutral pH for microcontaminant removal at pilot plant scale

Solar photo-Fenton optimization at neutral pH for microcontaminant removal at pilot plant scale | 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 Solar photo-Fenton optimization at neutral pH for microcontaminant removal at pilot plant scale Mercedes Hinojosa, Isabel Oller, José María Quiroga, Sixto Malato, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2340059/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 11 Aug, 2023 Read the published version in Environmental Science and Pollution Research → Version 1 posted 5 You are reading this latest preprint version Abstract The increasing occurrence of micropollutants in natural water bodies has medium to long-term effects on both aquatic life and human health. The aim of this study is to optimize the degradation of two pharmaceutical pollutants of emerging concern: amoxicillin and acetaminophen in aqueous solution at laboratory and pilot scale, by solar photo-Fenton process carried out at neutral pH using EDDS as a complexing agent to maintain iron in solution. The initial concentration of each compound was set at 1 mg/L dissolved in a simulated effluent from a municipal wastewater treatment plant (MWTP). A factorial experimental design and its surface response analysis were used to optimise the operating parameters to achieve the highest initial degradation rate of each target. The evolution of the degradation process was measured by Ultra Performance Liquid Chromatography (UPLC/UV), obtaining elimination rates above 90% for both contaminants. Statistical study showed the optimum concentrations of Fe(III) at 3 mg/L at an Fe-EDDS ratio of 1:2 and 2.75 mg/L H2O2 for the almost complete removal of the target compounds by solar photo-Fenton process. Validation of the experimental design was successfully carried out with actual MWTP effluent spiked with 100µg/L of amoxicillin and acetaminophen at pilot plant scale. Antibiotics Contaminants of Emerging Concern Tertiary Treatment Fe-EDDS optimization solar photo-Fenton. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction The growing presence of microcontaminants in wastewater treatment plants (WWTPs), drinking water treatment plants (DWTPs), and even in the natural water bodies give an idea of the importance and great concern on what these emerging contaminants can potentially cause in the overall water cycle, as they may have medium- or long-term effects on both aquatic life and human health (Rogowska et al. 2020). Among the microcontaminants that can be currently found in waters, pharmaceutical drugs have been the focus of research studies in the recent years, both on account of their use and the risk, themselves or their degradation products, may suppose for the environment (Fatta-Kassinos et al. 2013; Patel et al. 2019; Krzeminski et al. 2019; Tran et a. 2018; Yang et al. 2020). The production and consumption of pharmaceutical drugs determine the amount that may reach water bodies such as Municipal Wastewater Treatment Plants (MWTPs). A study by Choi et al. (2008) showed that the concentration of acetaminophen, carbamazepine, cimetidine, diltiazem, sulfamethoxazole and trimethoprim in the environment followed the same order as the amount produced annually for each of these pharmaceuticals in Korea. High concentrations (above 10 g/L) of acetaminophen, tramadol, codeine, gabapentin and atenolol were also detected in raw wastewater in Wales (UK), which could be explained by the high-prescribed amounts of these drugs (Kasprzyk-Hordern et a. 2008). Although many types of drugs are produced worldwide, antibiotics and analgesics are the most important in terms of their volume of use due to the current high demand by consumers. In the case of antibiotics, there has been an increase of 36 % over the last ten years in 71 countries (Van Boeckel et al. 2014). Among the different types of antibiotics and analgesics, amoxicillin and acetaminophen are especially significant due to their high concentrations in the environment (Patel et al. 2019). Amoxicillin is a semi-synthetic antibiotic derived from penicillin. This aminopenicillin acts against a broad spectrum of bacteria, both Gram-positive and Gram-negative. Acetaminophen (paracetamol) is a drug with analgesic properties lacking clinically significant anti-inflammatory properties. It inhibits the synthesis of prostaglandins, i.e. the cellular mediators responsible for the onset of pain. It also has antipyretic effects (Zampronio et al. 2015). The different pathways via which these contaminants can appear in wastewater range from human excretion, as some of them are not completely assimilated by the human body when used for medicinal purposes (European Commission, 215), to veterinary applications, in addition to uncontrolled discharges of medicines by pharmaceutical companies and from household surpluses due to a lack of environmental awareness (Kaczala and Blum, 2016). There is clear evidence of their poor and inefficient removal in wastewater treatment plants using conventional technologies (Jelic et al. 2012; Petrovic et al. 2009; Petrie et al. 2015; Rizzo et al. 2019). Hence, the presence of these micro-contaminants in natural waters comes from MWTP effluents. It is therefore essential to remove them from the main source of entry into ecosystems. This requires the application of tertiary treatments to eliminate these pollutants before they reach the environment. Advanced oxidation processes are among the treatments that have been demonstrated to be highly efficient in the abatement of wide variety of microcontaminants and pharmaceuticals, specifically (Affam et al. 2014; Velo-Gala et al. 2014). Advanced oxidation processes (AOPs) comprise oxidative processes based on the generation of hydroxyl radicals (HO · ), which are highly oxidizing species (E 0 =2.8 V with respect to the standard hydrogen electrode) and non-selective, highly desirable characteristics when degrading highly persistent micro-contaminants (Wang and Zhuan 2020; Ribeiro et al. 2019). There is, however, a factor to consider in all AOPs, namely the presence in natural waters of potential scavengers of these hydroxyl radicals, which significantly reduce the efficiency of the pollutant degradation process (Pignatello et al. 2006). Worth highlighting, in this respect, the presence of species such as CO 3 2- , HCO 3 - , SO 4 2- , Cl - and humic acids. Within AOPs, Fenton process involves the reaction between iron ions and hydrogen peroxide to form reactive species capable of oxidizing different organic compounds. Additionally, photo-Fenton process could use sunlight as a source of radiation to increase the generation of HO · and hence reaction efficiency. In the presence of UV or UV-visible radiation, photo-reduction of ferric ions in solution also occurs via a metal-ligand charge transfer reaction. Studies in recent years on the application of solar photo-Fenton treatment to degrade low concentrations of micro-contaminants in Municipal Wastewater Treatment Plant (MWTP) effluents have concluded that the operating conditions of the process do not have to be as aggressive as those for the treatment of industrial wastewater or effluents with a high organic load. In this regard, studies carried out by different authors (Clarizia et al. 2017; Zhan and Zhou 2019; Oller et al. 2021) have shown that high degradation rates can be obtained using low concentrations of iron and hydrogen peroxide and so reducing process operating costs. The optimum pH for the photo-Fenton process is 2.8, because, under these conditions, the precipitation of hydroxides is avoided. This acidification in addition to the need for a neutralization step at the end of treatment, also supposes substantial treatment costs. Therefore, running the photo-Fenton process at near neutral pH by using iron complex agents can also mean major cost savings (De Luca et al. 2014). Consequently, the study of the photochemistry of Fe(III) complexes plays a very important role (Souza et al. 2014; Ungwanen et al. 2020; Min et al. 2020) in the removal of micro-contaminants when the aim is to determine the appropriate complexing agent that allows operating at neutral pH. Some of the Initial studies carried out in this field began working with Ethylenediamine-N,N'-disuccinic acid (EDDS) (a structural isomer of EDTA) as a complexing agent (Li et al. 2010; Wu et al. 2014). These studies showed that the complex of this compound with Fe 3+ is stable in aqueous solution under neutral pH conditions (demineralized water) and photochemically efficient. Three stereoisomers of EDDS exist, the most readily biodegradable stereoisomer being S, S‘]-EDDS (Schowanek et al. 1997; Metsarinne et al. 2001; Tandy et al. 2006; Huang et al. 2012; Lin et al. 2011). There are still few studies focused on the removal of micro-contaminants at low concentrations in MWTP effluents using the photo-Fenton processes with complexes such as citric acid, oxalate and EDDS. These include studies by (Li et al. 2010; Silva et al. 2007; Trovó et al. 2011; Huang et al. 2013; Klamerth et al. 2013) using EDDS as a complexing agent for the first time in MWTP effluents. At this point, it must be stressed that EDDS has been exhaustively studied by different authors up today (Ahmed et al. 2021; Soriano-Molina et al. 2021; Ahile et al. 2020). One of the key aspects when conducting these studies is the importance of the Fe(III):EDDS ratio, as it is crucial to determine the necessary ratio to obtain at least 90 % degradation of the contaminants and carry out the photo-Fenton process at neutral pH. Klamerth et al. (2012, 2013) and Miralles-Cuevas (2014) (Klamerth et al. 2013; Ahmed et al. 2021; Soriano-Molina et al. 2021; Ahile et al. 2020; Miralles-Cuevas et al. 2014) tested two different Fe(III):EDDS ratios, 1:1 and 1:2, concluding that an Fe(III) to EDDS ratio of 1:2 was slightly better than a ratio of 1:1 in terms of the degradation rate and hydrogen peroxide consumption. The present work addresses the application and optimization of solar photo-Fenton oxidation process at neutral pH (by using EDDS) for the removal of two drugs: an antibiotic, amoxicillin and an analgesic, acetaminophen (paracetamol) dissolved in simulated MWTP effluent for achieving degradation percentages higher than 90%. 2. Materials And Methods 2.1. Reagents and chemicals High purity (> 99 %) amoxicillin (AMX) and acetaminophen (ACT) were used (Main characteristics can be found in Supplementary Material, Table 1) for spiking simulated and actual MWTP effluents (characteristics shown in Supplementary Material, Table 2). Ethylenediamine disuccinic acid (EDDS 35 % w / v) (as complexing agent) and catalase for removing H 2 O 2 were supplied by Sigma Aldrich, as well as solvents used for liquid chromatography analysis (99.9 % grade). 75 % purity ferrous sulphate monohydrate (Fe 2 (SO 4 ) 3 H 2 O) and hydrogen peroxide H 2 O 2 35 % (w / v) were supplied by Panreac. 2.2. Sample analysis Target contaminants at low concentrations were measured by ultra-performance liquid chromatography (UPLC/UV) (Agilent Technologies, Series 1200) employing a Gemini C-18 column. Starting conditions were 100 % 10 mM KH 2 PO 4 buffer (mobile phase A) and 0% ACN (mobile phase B). A linear ramp was applied with the following sequence: 40% (phase A) to 60% (phase B) in 10 min and 0% (phase A) to 100% (phase B) in 13 min. The detection wavelengths and the limits of quantification (LOQ) and detection (LOD) for each contaminant are shown in Table 3 of Supplementary Material. Dissolved organic carbon (DOC) and inorganic carbon (IC) were determined on a Shimadzu TOC-VCSN analyser. The samples were filtered through 0.22 µm before analysis, so that only the dissolved organic carbon (DOC) was determined. DOC analysis was always performed immediately after collecting the sample. Total iron concentration was measured using the 1, 10-phentranoline method according to ISO 6332. Hydrogen peroxide was measured using titanium oxysulphate (IV) following DIN 38402H15. 2.3. Experimental design A series of preliminary experiments were performed to determine the level of each factor mostly affecting the degradation of the contaminants. A mixture of 1 mg/L of each amoxicillin and acetaminophen dissolved in simulated MWTP effluent was used in these trials. The experiments were run using a solar simulator (Suntest, XLS + Heraeus, Germany) equipped with a 2.2 kW xenon arc lamp and a special glass filter (Daylight) that cuts off UV irradiation at 290 nm, the source of radiation being artificial light which simulates sunlight on a sunny day. The radiation from the lamp was measured using a pyranometer (SOLAR LIGHT PM A2100). Initially, a total volume of 1.5 L of simulated MWTP effluent was spiked with 1 mg/L of each pharmaceutical and then stirred for several minutes to ensure a suitable degree of homogeneity in the samples. Subsequently, the concentration of Fe 3+ -EDDS was added to the mixture and an initial sample was taken to ensure that complex formation had taken place and for checking the pH. The reason for using Fe 2 (SO 4 ) 3 H 2 O as a source of Fe 3+ in this paper is that previous studies showed that the iron source can strongly influence the degradation of pollutants 44 , in addition to the possibility of working with the Fe 3+ -EDDS complex at neutral pH and minimizing operating expenses, as regent costs are thus reduced considerably. The complex was previously prepared in the laboratory immediately before used by dissolving the required iron quantity (depending on the concentration to be tested) in demineralized water at pH 3 and adding the corresponding EDDS in the dark, as the complex is affected by light. The mixture was then left to homogenize for 5-10 minutes, the solution turned bright yellow in colour, indicative of the correct formation of the complex. Required hydrogen peroxide concentration (depending on the experiment) was then added and the photo-Fenton reaction commenced. The hydraulic residence time (HRT) was 30 minutes, taking samples every 2 minutes. Catalase was used to stop the reaction. This enzyme is able to neutralize oxygen-derived toxic forms (such as H 2 O 2 ) which form in aqueous media containing dissolved oxygen. Catalase converts hydrogen peroxide into water and molecular oxygen. The amount of Catalase was added as function of the initial concentration of H 2 O 2 employed. Experiments were performed in a borosilicate glass beaker under constant stirring. The beaker was 19 cm diameter, providing an irradiated surface of 0.0284 m 2 , and the entire volume was illuminated 1.5 L. The variables studied to degrade 90 % of the contaminants, were the hydraulic residence time (HRT), initial degradation rate, accumulated energy ( Quv ), Fe 3+ -EDDS (1:2) complex concentration, H 2 O 2 concentration and Dissolved Organic Carbon (DOC). The pH was around 7 throughout the reaction. Once the initial starting conditions had been determined, a fractional factorial design was performed involving a set of 14 experiments to optimize which variables were more significant and the optimum values of these variables for the degradation of the drugs. The procedure for these experiments was the same as for the previous trials. After completing the experimental design, two tests were developed with the main goal of validating the values of each parameter defined as optimal to maximize the initial degradation rate for each contaminant. Two different aqueous matrices were used in those validation experiments, simulated water from the MWTP (see Table 2) and actual effluent from El Ejido MWTP (South-East of Spain), to which the content of HCO 3 - / CO 3 2- (hydroxyl radical scavengers 21 ) was eliminated by the addition of concentrated H 2 SO 4 just in a sufficient amount to avoid a significant drop in pH. For the performance of these experiments a photoreactor based on CPC (Compound Parabolic Collectors) was used at the Plataforma Solar de Almería (PSA, latitude 37ºN, length 2.4 W) using natural solar radiation. The initial concentration of drugs, AMX and ACT was 1 mg/L of each. After 12 minutes of homogenization of the aqueous matrix together with the drugs in the CPC photoreactor, an initial sample was taken to ensure the starting concentration of both contaminants. The Fe 3+ -EDDS complex was then added again leaving a time for homogenization and then, the first dose of hydrogen peroxide was added. The photoreactor was then uncovered and the solar photo-Fenton reaction started. Samples were taken every 3 min during the first hour in the simulated effluent from the MWTP and every 5 min for the first 60 min of reaction in the actual MWTP effluent assay and thereafter every 15 min to complete three hours of treatment. 3. Results And Discussion A series of preliminary studies were conducted with the aim of selecting the best operation range of affecting parameters for the experimental design, stablishing upper concentration limits on 5.5 mg/L Fe 3+ and 5 mg/L H 2 O 2 (added as consumed) according to previous published works (Klamerth et al. 2013; Ahmed et al. 2021; Soriano-Molina et al. 2021; Ahile et al. 2020; Miralles-Cuevas et al. 2014; Nogueira et al. 2005; Prieto-Rodríguez et al 2013). This concentration of H 2 O 2 was chosen because previous studies by Huang (Huang et al. 2013) showed that higher concentrations involve loss of the positive effect of the addition of EDDS over the process, because hydrogen peroxide in excess also acts as a scavenger of hydroxyl radicals, thereby decreasing the efficiency of the system. The results of these preliminary tests gave high degradation rates of both compounds (above 90 %) in only nine minutes of exposure. Based on these results and previous published studies (Prieto-Rodríguez et al. 2013; Klamerth et al. 2011) which showed that high degradation rates can be obtained using low concentrations of iron and hydrogen peroxide, four tests were carried out setting the concentration of Fe 3+ at 5.5 mg/L and doing additions of 5 mg/L of H 2 O 2 as consumed. First, it should be noted that the concentration of Fe 3+ was almost constant throughout the reaction time so Fe-EDDS complex was stable along the whole process. More than 94% of both contaminants degradation was attained after only 3.6 mg/L of H 2 O 2 consumed and six minutes of reaction time. According to these previous results, the range of affecting parameters selected for the experimental design was 0.5 - 5.5 mg/L for Fe 3+ -EDDS complex and 2.75 - 5 mg/L for H 2 O 2 with the aim of maximizing the initial degradation rate of both target contaminants with the minimum accumulated energy required, which was calculated according the following expression: 3.1. Key parameters optimization Once the range of each key parameter had been selected, a full factorial experimental design was applied with the aim of optimizing the operational parameters to maximize pharmaceuticals degradation rate through a solar photo-Fenton process at neutral pH. A 2-level full factorial design with six central points has been applied by using the statistical program MINITAB, Version 3.11. The experimental design established the necessity of perform 14 experiments in which both drugs initial concentration was stated at 1 mg/L. The pH remained constant in all trials between 7 and 8. The wastewater matrix used for tests at laboratory scale was simulated effluent from a MWTP (characterization shown in Table 2). Irradiation was set at 30 W/m 2 in the solar box according to the irradiation obtained in the mid-day of a sunny day. Both the irradiated area and the reactor volume were kept constant, so Quv was only function of the sampling time interval, reaching values of 1.02 (kJ/L) at the end of each test (HRT = 30 min). In consequence, in trials using the maximum concentrations of Fe 3+ and H 2 O 2 (5.5 mg/L and 5 mg/L, respectively), drug degradation rates of 50% were achieved without irradiation that is thanks to Fenton reaction. However, Quv values of 0.75 kJ/L were required to obtain this same degradation percentage in trials employing low concentrations of Fe 3+ and H 2 O 2 . Table 4 shows the experimental conditions and results obtained in the 14 experiments designed. It is also shown the degradation rates of both compounds obtained by representing the evolution of the concentration of the drugs versus time corresponding to kinetics of order 1. Table 4. Results of the full factorial design with 14 experiments Experiments Fe(III) mg/L H 2 O 2 mg/L Degradation % AMX Degradation % ACT Initial degradation rate AMX (mg/L min) Initial degradation rate ACT (mg/L min) 1 0.5 0.5 76 48 0.184 0.108 2 5.5 0.5 66 61 0.143 0.125 3 0.5 5.0 70 70 0.205 0.126 4 5.5 5.0 96 91 0.300 0.289 5 3.0 2.75 93 91 0.307 0.305 6 3.0 2.75 95 94 0.290 0.276 7 3.0 2.75 91 87 0.308 0.324 8 0.5 0.5 71 35 0.173 0.107 9 5.5 0.5 68 61 0.119 0.134 10 0.5 5.0 70 60 0.244 0.196 11 5.5 5.0 98 98 0.350 0.352 12 3.0 2.75 92 90 0.308 0.319 13 3.0 2.75 93 92 0.294 0.305 14 3.0 2.75 94 93 0.306 0.326 It can be seen that the higher the concentrations of Fe 3+ -EDDS and H 2 O 2 (experiments 4 and 11), the greater the degradation percentages obtained, which corresponds with a higher initial degradation rates for both contaminants. Values close to those reported above are also achieved for intermediate values of Fe 3+ -EDDS and H 2 O 2 concentrations (3 mg/L and 2.75 mg/L, experiments 5, 6, 7, 12, 13 and 14). Although 100% removal was not achieved in any of these cases, even when increasing the concentration of iron and peroxide, high primary degradation of contaminants did occur. These degradation results are consistent with those reported by Trovo et al., 2008, who studied the degradation of amoxicillin (AMX), paracetamol o acetaminophen (ACT) and bezafibrate (BZF). Working with concentrations of 1.0 to 5.0 mM H 2 O 2 and using potassium ferrioxalate (K 3 Fe (C 2 O 4 ) 3 3H 2 O) or Fe(NO 3 ) 3 as a source of Fe 3+ at optimum pH for the photo-Fenton reaction (2.8), these authors found that degradation is favoured by (K 3 Fe (C 2 O 4 ) 3 · 3H 2 O), achieving 98 % removal of BZF and ACT after 5 minutes of irradiation. However, no difference was observed in the oxidation of AMX, for which complete degradation was achieved after 0.5 min of irradiation time for both iron sources. Nonetheless, it should be noted that the pH employed in the present study was close to neutral, while Trovó et al. studies were carried out at optimal pH of 2.8 for photo-Fenton applications to avoid iron precipitation. The DOC measurement showed that the value remained practically constant throughout the experiments, thus demonstrating that the complex was still active and the EDDS was not yet degrading. Initial degradation rate for each target contaminant is considered in the proposed experimental design as the response factor. A statistical study was carried out to obtain the equations, which model the initial degradation rate for each contaminant as function of the concentrations of the influence parameters (Fe-EDDS and H 2 O 2 ). Such equations are shown in Table 5. Table 5. Summary of the model of the sum of degradation rates of both contaminants Variables Effects Student-t P Value Fe(III) 0.1214 3.43 0.009 H 2 O 2 0.2384 6.73 0.000 Fe(III)*H 2 O 2 0.1606 4.54 0.002 Central Point 8.18 0.002 Based on these results, an analysis of variance was carried out using the statistical program MINITAB to study how the different process variables and the interaction between these affected the percentage degradation of the contaminants. Although both variables influence the process, presenting a p-value < 0.05, Fe 3+ affects the photo-Fenton process less than H 2 O 2 , as evidenced by the values of the effects and the Student-t values shown in Table 6. The statistical study carried out by MINITAB software gave different graphics allowing the analysis of the influence rate of each parameter on the initial degradation rate for each target drug. The rate of degradation of these compounds under the experimental conditions in which the experiments were carried out is a first-order reaction: -d(C Contaminants)/d HRT = K*C contaminants The optimization of both contaminants degradation by solar photo-Fenton process accordingly to the selected experimental design, gave the following common initial degradation rate (r 0 ) equation: r 0 = 0.2846 – 0.0150 Fe 3+ + 0.0101 H 2 O 2 + 0.01428 Fe 3+ H 2 O 2 + 0.2213 Central Pt, (R 2 94.81%) Table 6 shows the degradation rates (r 0 ) for each of the contaminants separately and for the sum of both. These results coincide with those obtained by other authors (Rodriguez et al. 2005). Table 6. Degradation rate equations for each contaminant studied Predictive model equation: Factorial regression R 2 Degradation rate AMX r0 = 0.413 + 0.07113 Fe(III) + 0.00693 H 2 O 2 – 0.01399 Fe(III)*Fe(III) + 0.00658 Fe(III)*H 2 O 2 96 % Degradation rate ACT r0 = 0.0439 + 0.1257 Fe(III) + 0,00883 H 2 O 2 – 0.02073 Fe(III)*Fe(III) + 0.00611 Fe(III)* H 2 O 2 94 % High accuracy of the proposed statistic models are demonstrated thanks to R 2 values between 94 and 96%. The Pareto chart (Figure 1) was used to decide which of the variables or the interaction between them was more significant. This type of chart shows both the magnitude and the significance of the effects. The vertical axis represents the two variables and the interaction between both, while the horizontal axis represents the standardized effects. In this case, the effects of the variables are specified in the model equation and show the difference between the maximum and minimum for each value. The vertical reference line indicates that any effect that extends beyond this line is significant. The Pareto chart for this study confirms that the most important variable is the concentration of hydrogen peroxide and the interaction of this reagent with Fe. Figure 2 shows the individual effects of each variable (Fe 3+ and H 2 O 2 ) on the degradation rate of the studied contaminants. It can be seen that the influence of both parameters is positive as their concentration is increasing. That means that no limitation was observed and, initially, higher initial degradation rates for both contaminants should be attained as increasing both Fe 3+ and H 2 O 2 concentrations. The response surface graphics have been obtained in the experimental design (Figure 3). It must be highlighted the maximum response observed in the central points (at 3 mg/L of Fe 3+ and 2.75 mg/L of H 2 O 2 ) similar to that shown at the maximum values of both parameters. As maximum degradation rates were not significantly improved at the maximum concentration of both parameters, it was decided to choose the central point values as the optimal operation conditions for the degradation of such contaminants. Indeed, this is what it was obtained in the system optimization represented by Figure 3. It is clear from the contour plot (Figure 4) that, although the optimal degradation value is also obtained in the experiment with the highest concentration of Fe and H 2 O 2 , the maximum degradation rate actually appears at the central points (darker area in the figure). Given that 90% degradation rates were obtained using the reagent concentrations corresponding to these central points within the same reaction time as that achieved when using the maximum reagent concentrations, as previously mentioned, it was decided to consider these central point as optimal to validate the predictive model equations mathematically obtained, as reagent costs would be minimized. 3.2. Validation tests with actual wastewater Once the optimum concentration conditions for the Fe 3+ -EDDS complex and H 2 O 2 were selected according to the experimental design results, two validation tests were carried out at pilot plant scale. Firstly, the elimination of both drugs spiked at 1 mg/L each one in actual MWTP effluent (see table 2 for physic-chemical characterization) was carried out, initial degradation rates obtained were 0.021 mg/Lmin for AMX and 0.015 mg/Lmin for ACT, respectively, attaining global degradation rates of 47% for AMX and 20% for ACT after 5 minutes of irradiation time. After the first 5 minutes of treatment, three extra additions of H 2 O 2 (5 mg/L each) were made in order to determine the maximum percentage of degradation that could be reached for both drugs, which was around 60% for both after 180 minutes of treatment and a total H 2 O 2 consumption of 13.4 mg/L. pH remained constant throughout the reaction between 7.6 and 7.9. DOC remained also constant along the 180 min of complete treatment. Iron concentration decreased till around 1.7 mg/L at the end of the treatment. These results showed that the greater physic-chemical complexity of the actual effluent from the MWTP causes a reduction in the efficiency of the treatment and the necessity of a greater consumption of H 2 O 2 and higher treatment times to attain quite lower degradation rates than those obtained with simulated effluent from the MWTP (Figure 5). Specifically after 5 min of solar photo-Fenton treatment at neutral pH, 90% of degradation was obtained for both drugs with an initial degradation rate around 0.3 mg/L min (15 times higher) in simulated MWTP effluent (table 4). Finally and with the main objective of checking the performance of solar photo-Fenton optimum parameters at pilot scale (3 mg/L Fe 3+ (1:2 Fe: EDDS) and 2.75 mg/L H 2 O 2 ) and under more realistic conditions considering lower target contaminants concentration, experiment with actual effluent of MWTP was repeated by spiking 100 µg/L of ACT and AMX, each. 91% of AMX degradation was achieved after 105 min of treatment and 11 mg/L of H 2 O 2 consumption. However, at that time, only 17% of ACT was eliminated, so solar photo-Fenton process was maintained till achieving 70% of ACT degradation after 210 min and 13.1 mg/L of H 2 O 2 consumption. As already commented, the more complex water matrix provoked the requirement of higher doses of H 2 O 2 to achieved contaminant degradation targets, that was, five additions of 2.75 mg/L of H 2 O 2 for maintaining the reaction till maximum ACT elimination (most unfavorable condition). 4. Conclusions The results obtained in this study show that solar photo-Fenton oxidation operated with Fe 3+ -EDDS complex at neutral pH (low initial concentration of iron and low hydrogen peroxide consumption) is a viable alternative as tertiary treatment for the removal of emerging contaminants present in MWTPs. This enables a reduction in the consumption of reagents and, consequently, a reduction of associated operating costs. The use of the Fe(III)-EDDS complex allows operating at both neutral pH and low reagent concentrations. The reagent concentrations considered optimal for maximizing initial degradation rate of both target drugs were 3 ppm for the Fe 3+ complex and 2.75 ppm for H 2 O 2 according to the experimental design performed. In addition, mathematical model equations have been obtained for predicting the behaviour of the system. When the optimum concentrations of the variables obtained in the experimental design for the treatment of actual effluent with the added pollutants are applied, the consumption of H 2 O 2 is always higher than the optimum to reach the same point obtained with simulated water due to the presence of other substances that consume hydroxyl radicals, such as organic matter as humic acids, carbonates and bicarbonates and more complex ionic characterization. It was found that, when operating at the aforementioned reagent concentrations using solar photo-Fenton at neutral pH, primary degradation rates of 90% and 70% of target contaminants under more realistic conditions (100 µg/L, each, spiked in real MWTP effluent), were achieved, though higher final doses of H 2 O 2 and long treatment times were required. These results confirm some previous studies that suggest, as the best strategy, complete addition of the required oxidant concentration to achieve a specific target, at the beginning of the treatment. It is also very important to highlight the importance of using water matrices as close to the actual situation as possible to better adjust oxidant concentrations. Declarations Ethical Approval This manuscript complies with ethical standards. Consent to Participate and Consent to Publish All authors whose names appear on the submission approved the version to be published; and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Funding The Spanish Ministry of Science and Innovation, AEI, and FEDER (NAVIA Project, reference PID2019-110441RB-C32) is gratefully acknowledged for financial support. Competing interests The authors have no relevant financial or non-financial interests to disclose. Author contributions Conceptualization: Isabel Oller; Methodology: Mercedes Hinojosa; Formal analysis and investigation: Mercedes Hinojosa; Writing - original draft preparation: Mercedes Hinojosa; Writing - review and editing: Mercedes Hinojosa, Agata Egea-Corbacho; Funding acquisition: Isabel Oller; Resources: Sixto Malato, Jose Maria Quiroga; Supervision: Isabel Oller, Asunción Acevedo-Merino. Availability of data and materials We ensure that all data and materials as well as software application or custom code support their published claims and comply with field standards. References Affam, AC, Chaudhuri M (2014) Optimization of Fenton treatment of amoxicillin and cloxacillin antibiotic aqueous solution. Desal Water Treat 52:1878-1884. https://doi.org/10.1080/19443994.2013.794015. Ahile UJ, Wuana RA, Itodo AU, Sha'Ato R, Dantas RF (2020) A review on the use of chelating agents as an alternative to promote photo-Fenton at neutral pH: Current trends, knowledge gap and future studies. Sci Total Environ 710:134872. doi: 10.1016/j.scitotenv.2019.134872. Ahmed Y, Zhong J, Yuan Z, Guo J (2021) Simultaneous removal of antibiotic resistant bacteria, antibiotic resistance genes, and micropollutants by a modified photo-Fenton process. Wat Res 197: 117075. doi: 10.1016/j.watres.2021.117075 Choi K, Kim Y, Park J, Park CK, Kim M, Kim HS (2008) Seasonal variations of several pharmaceutical residues in surface water and sewage treatment plants of Han River, Korea. Sci Total Environ 405:0–8. DOI: 10.1016/j.scitotenv.2008.06.038. Clarizia L, Russo D, Di Somma I, Marotta R, Andreozzi R (2017) Homogeneous photo-Fenton processes at near neutral pH: A review. Appl Catal B-Environ 209:358-371. https://doi.org/10.1016/j.apcatb.2017.03.011. De Luca A, Dantas RF, Esplugas S (2014) Assessment of iron chelates efficiency for photo-Fenton at neutral pH. Wat Res 61:232-242. DOI: 10.1016/j.watres.2014.05.033. Fatta-Kassinos D, Michael C (2013) Wastewater reuse applications and contaminants of emerging concern. Environ Sci Pollut Res Int 20:3493-3495. doi: 10.1007/s11356-013-1699-5. Huang W, Brigante M, Wu F, Hanna K, Mailhot G (2012) Development of a new homogenous photo-Fenton process using Fe(III)-EDDS complexes. J Photochem Photobiol A: Chem 239:17-23. DOI: 10.1016/j.jphotochem.2012.04.018. Huang W, Brigante M, Wu F, Mousty C, Hanna K, Mailhot G (2013) Assessment of the Fe(III)- EDDS complex in Fenton-like processes: From the radical formation to the degradation of bisphenol A. Environ Sci Technol 47:1952-1959. https://doi.org/10.1021/es304502y. Jelic, A et al. (2012) Occurrence and elimination of pharmaceuticals during conventional wastewater treatment. In: Guasch H, Ginebreda A, Geiszinger A (eds) Emerging and priority pollutants in rivers Springer: Berlin, pp. 1–24. Kaczala, F.; Blum, S.E. The Occurrence of Veterinary Pharmaceuticals in the Environment: A Review. Current Anal. Chem. 2016 , 12, 169–182. https://doi.org/10.2174/1573411012666151009193108. Kasprzyk-Hordern, B.; Dinsdale, R.M.; Guwy, A.J. The removal of pharmaceuticals, personal care products, endocrine disruptors and illicit drugs during wastewater treatment and its impact on the quality of receiving waters. Water Res. 2009 , 43, 63–80. doi: 10.1016/j.watres.2008.10.047. Klamerth N, Malato S, Agüera A, Fernández-Alba A (2013) Photo-Fenton and modified photoFenton at neutral pH for the treatment of emerging contaminants in wastewater treatment plant effluents: A comparison. Water Res 47:833-840. doi: 10.1016/j.watres.2012.11.008. Klamerth N, Malato S, Maldonado MI, Agüera A, Fernández-Alba A (2011) Modified photo-Fenton for degradation of emerging contaminants in municipal wastewater effluents. Catal Today 161:241–246. doi:10.1016/j.cattod.2010.10.074. Krzeminski P, Tomei MC, Karaolia P, Langenhoff A, Almeida CMR, Felis E, Gritten F, Andersen HR, Fernandes T, Manaia CM, Rizzo L, Fatta-Kassinos D (2019) Performance of secondary wastewater treatment methods for the removal of contaminants of emerging concern implicated in crop uptake and antibiotic resistance spread: A review. Sci Total Environ 648:1052–1081. doi:10.1016/j.scitotenv.2018.08.130. Li J, Mailhot G, Wu F, Deng N (2010) Photochemical efficiency of Fe(III)-EDDS complex: OH radical production and 17β-estradiol degradation. J Photochem Photobiol A: Chem 212:1-7. DOI:10.1016/j.jphotochem.2010.03.001. Lin AY-C, Tsai Y-T, Yu T-H, Wang X-H, Lin C-F (2011) Occurrence and fate of pharmaceuticals and personal care products in Taiwan's aquatic environment. Desal Water Treat 3:57–64. DOI: 10.5004/dwt.2011.2678. Metsarinne S, Tuhkanen T, Aksela R (2001) Photodegradation of ethylenediaminetetraacetic acid (EDTA) and ethylenediamine disuccinic acid (EDDS) within natural UV radiation range. Chemosphere 45:949-955. doi: 10.1016/s0045-6535(01)00022-4. Min X, et.al (2020) Advancements in the Fenton Process for Wastewater Treatment. In: Bustillo-Lecompte C (ed) Advanced Oxidation Processes - Applications, Trends, and Prospects, pp 61-79. DOI: 10.5772/intechopen.90256 Miralles-Cuevas S, Oller I, Sanchez Perez JA, Malato S (2014) Removal of pharmaceuticals from MWTP effluent by nanofiltration and solar photo-Fenton using two different iron complexes at neutral pH. Wat. Res 64:23-31. doi: 10.1016/j.watres.2014.06.032. Nogueira RFP, Silva MRA, Trovó AG (2005) Influence of the iron source on the solar photo-Fenton degradation of different classes of organic compounds. Solar Energy 79:384-392. https://doi.org/10.1016/j.solener.2005.02.019. Oller I, Malato S (2021) Photo-Fenton applied to the removal of pharmaceutical and other pollutants of emerging concern. Current Opinion in Green and Sustainable Chemistry 29:100458. https://doi.org/10.1016/j.cogsc.2021.100458. Patel M, Kumar R, Kishor K, Mlsna T, Pittman JrCJ, Mohan D (2019) Pharmaceuticals of Emerging Concern in Aquatic Systems: Chemistry, Occurrence, Effects, and Removal Methods. Chem Rev 119:3510–3673. https://doi.org/10.1021/acs.chemrev.8b00299. Petrie B, Barden R, Kasprzyk-Hordern B (2015) A review on emerging contaminants in wastewaters and the environment: Current knowledge, understudied areas and recommendations for future monitoring. Water Res 72:3-27. https://doi.org/10.1016/j.watres.2014.08.053. Petrovic M, De Alda MJL, Diaz-Cruz S, Postigo C, Radjenovic J, Gros M, Barceló D (2009) Fate and removal of pharmaceuticals and illicit drugs in conventional and membrane bioreactor wastewater treatment plants and by riverbank filtration. Phil Trans R Soc A 367:3979-4003. https://doi.org/10.1098/rsta.2009.0105. Pignatello JJ, Oliveros E, MacKay A (2006) Advanced Oxidation Processes for Organic Contaminant Destruction Based on the Fenton Reaction and Related Chemistry. Crit Rev Env Sci Tech 36:1-84. https://doi.org/10.1080/10643380500326564. Prieto-Rodríguez L, Oller I, Klamerth N, Agüera A, Rodríguez EM, Malato S (2013) Application of solar AOPs and ozonation for elimination of micropollutants in municipal wastewater treatment plant effluents. Wat Res 47:1521–1528. doi: 10.1016/j.watres.2012.11.002. Ribeiro L, Moreira NFF, Li Puma G, Silva AMT (2019) Impact of water matrix on the removal of micropollutants by advanced oxidation technologies. Chem Eng J 363:155-173. DOI: 10.1016/j.cej.2019.01.080. Rizzo L, Malato S, Antakyali D, Beretsou VG, Đolić MB, Gernjak W, Heath E, Ivancev-Tumbas I, Karaolia P, Lado Ribeiro AR, Mascolo G, McArdell CS, Schaar H, Silva AMT, Fatta-Kassinos D (2019) Consolidated vs new advanced treatment methods for the removal of contaminants of emerging concern from urban wastewater. Sci Total Env 655:986-1008. doi: 10.1016/j.scitotenv.2018.11.265. Rogowska, J.; Cieszynska-Semenowicz, M.; Ratajczyk, W.; Ratjczyk, W.; Wolska, L. Micropollutants in treated wastewater. Ambio 2020 , 49, 487–503. https://doi.org/10.1007/s13280-019-01219-5. Schowanek D, Feijtel TCJ, Perkins CM, Hartman FA, Federle TW, Larson RJ (1997) Biodegradation of [S,S], [R,R] and mixed stereoisomers of ethylenediaminedisuccinic acid (EDDS), a transition metal chelator. Chemosphere 34:2375-2391. doi: 10.1016/s0045-6535(97)00082-9. Silva MRA, Trovó AG, Nogueira RFP (2007) Degradation of the herbicide tebuthiuron using solar photo-Fenton process and ferric citrate complex at circumneutral pH. J Photochem Photobiol A: Chem 191:187-192. http://dx.doi.org/10.1016/j.jphotochem.2007.04.022. Soriano-Molina P, Miralles-Cuevas S, Esteban García B, Plaza-Bolaños P, Sánchez Pérez JA (2021) Two strategies of solar photo-Fenton at neutral pH for the simultaneous disinfection and removal of contaminants of emerging concern. Comparative assessment in raceway pond reactors. Catal Today 361:17-23. https://doi.org/10.1016/j.cattod.2019.11.028. Souza BM, Dezotti MWC, Boaventura RAR, Vilar VJP (2014) Intensification of a solar photoFenton reaction at near neutral pH with ferrioxalate complexes: A case study on diclofenac removal from aqueous solutions. Chem Eng J 256:448-457. https://doi.org/10.1016/j.cej.2014.06.111. Tran NH, Reinhard M, Gin KY-H (2018) Occurrence and fate of emerging contaminants in municipal wastewater treatment plants from different geographical regions-a review. Water Res 133:182–207. doi:10.1016/j.watres.2017.12.029. Tandy S, Ammann A, Schulin R, Nowack B (2006) Biodegradation and speciation of residual SSethylenediaminedisuccinic acid (EDDS) in soil solution left after soil washing. Environ Pol 142:191-199. DOI: 10.1016/j.envpol.2005.10.013. Trovó AG, Nogueira RFP (2011) Diclofenac abatement using modified solar photo-Fenton process with ammonium iron(III) citrate. J Braz Chem Soc 22:1033-1039. https://doi.org/10.1590/S0103-50532011000600005. Trovó AG, Santos SA, Nogueira MRFP (2008) Photodegradation of the pharmaceuticals amoxicillin, bezafibrate and paracetamol by the photo-Fenton process—Application to sewage treatment plant effluent. J Photochem Photobiol A: Chem 198:215-220. https://doi.org/10.1016/j.jphotochem.2008.03.011. Ungwanen JA, Raymond AW, Adams UI, Rufus S, Renato FD (2020) A review on the use of chelating agents as an alternative to promote photo-Fenton at neutral pH: Current trends, knowledge gap and future studies. Sci Tot Environ 710:134872. doi: 10.1016/j.scitotenv.2019.134872. Van Boeckel TP, Gandra S, Ashok A, Caudron Q, Grenfell BT, Levin SA, Laxminarayan R (2014) Global antibiotic consumption 2000 to 2010: an analysis of national pharmaceutical sales data. The Lancet Infectious Diseases 14:742-750. https://doi.org/10.1016/S1473-3099(14)70780-7. Velo-Gala I, López-Peñalver JJ, Sánchez-Polo M, Rivera-Utrilla J (2014) Comparative study of oxidative degradation of sodium diatrizoate in aqueous solution by H 2 O 2 /Fe 2+ , H 2 O 2 /Fe 3+ , Fe (VI) and UV, H 2 O 2 /UV, K 2 S 2 O 8 /UV. Chem Eng J 241:504-512. http://dx.doi.org/10.1016/j.cej.2013.10.036. Wang J, Zhuan R (2020) Degradation of antibiotics by advanced oxidation processes: An overview. Sci Total Env 701:135023. https://doi.org/10.1016/j.scitotenv.2019.135023. Wu Y, Passanti M, Brigante M, Dong W, Mailhot G (2014) Fe (III)-EDDS complex in Fenton and photo-Fenton processes: from the radical formation to the degradation of a target compound. Env Sci Pol Res 21:12154–12162. https://doi.org/10.1007/s11356-014-2945-1. Yang C, Song G, Lim W (2020) A review of the toxicity in fish exposed to antibiotics. Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology 237:108840. https://doi.org/10.1016/j.cbpc.2020.108840]. Zampronio AR, Soares DM, Souza GE (2015) Central mediators involved in the febrile response: effects of antipyretic drugs. Temperature (Austin, Tex.) 2:506–521. https://doi.org/10.1080/23328940.2015.1102802. Zhan Y, Zhou MA (2019) Critical review of the application of chelating agents to enable Fenton and Fenton-like reactions at high pH values. J Haz Mat 362:436–450. doi: 10.1016/j.jhazmat.2018.09.035. Supplementary Materials Supplementary Material, Tables 1-3 are not available with this version. Cite Share Download PDF Status: Published Journal Publication published 11 Aug, 2023 Read the published version in Environmental Science and Pollution Research → Version 1 posted Reviewers agreed at journal 03 Feb, 2023 Reviewers invited by journal 02 Feb, 2023 Editor invited by journal 23 Dec, 2022 Editor assigned by journal 14 Dec, 2022 First submitted to journal 08 Dec, 2022 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-2340059","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":172899187,"identity":"f1d9ee26-df12-42df-99b6-11bc68d4a208","order_by":0,"name":"Mercedes Hinojosa","email":"","orcid":"","institution":"Universidad de Cádiz: Universidad de Cadiz","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Mercedes","middleName":"","lastName":"Hinojosa","suffix":""},{"id":172899188,"identity":"2f5d98a5-8495-4fd5-a0f4-f1286ec9f4a7","order_by":1,"name":"Isabel Oller","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3UlEQVRIiWNgGAWjYBACNjAqYGDgYwfyPhCvxQBIMjMwMM4g3iKoFmYeYtTz8R9+9uCDAYMcGzPzsc+2O+rkGdjbH+C3QiLN3HCGAYMxGzNb8uzcM4cNG3jOGBDQwmAmzWPAkNjGzGPMnNt2gLFBIoeAR/iPf5P+A9bC/5nZsq3OvkH+OQGHMeSYSTNAbGFmZmxjTmyQYCDksJxywx4DCZBfjBl7zxxObuPJwa9Fvv/4tgc/Kmzk+NmbHzP83FFn289+HL/DoEACQjE2gKOJFADSMgpGwSgYBaMAHQAAyBY1XmyBhVAAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-9893-6207","institution":"CIEMAT: Centro de Investigaciones Energeticas Medioambientales y Tecnologicas","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Isabel","middleName":"","lastName":"Oller","suffix":""},{"id":172899189,"identity":"c0599de9-c2b1-4659-9d3b-2be8f9373263","order_by":2,"name":"José María Quiroga","email":"","orcid":"","institution":"Universidad de Cádiz: Universidad de Cadiz","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"José","middleName":"María","lastName":"Quiroga","suffix":""},{"id":172899190,"identity":"7c7086c9-8705-4c0e-a5dc-ebbd69a48a7e","order_by":3,"name":"Sixto Malato","email":"","orcid":"","institution":"CIEMAT: Centro de Investigaciones Energeticas Medioambientales y Tecnologicas","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Sixto","middleName":"","lastName":"Malato","suffix":""},{"id":172899191,"identity":"9926d913-3854-4c78-8f1f-466f5eb723ef","order_by":4,"name":"Agata Egea-Corbacho","email":"","orcid":"","institution":"Universidad de Cádiz: Universidad de Cadiz","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Agata","middleName":"","lastName":"Egea-Corbacho","suffix":""},{"id":172899192,"identity":"993a6df9-846d-4d0c-b5d4-70ea2fec7b74","order_by":5,"name":"Asunción Acevedo-Merino","email":"","orcid":"","institution":"Universidad de Cádiz: Universidad de Cadiz","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Asunción","middleName":"","lastName":"Acevedo-Merino","suffix":""}],"badges":[],"createdAt":"2022-12-03 09:58:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2340059/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2340059/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11356-023-28988-7","type":"published","date":"2023-08-11T21:56:01+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":32540793,"identity":"261f673a-2d99-4d30-84ed-d04e68446fa4","added_by":"auto","created_at":"2023-02-06 16:36:43","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":43052,"visible":true,"origin":"","legend":"\u003cp\u003ePareto chart.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-2340059/v1/083e9d1785d24b9e6e208f8b.png"},{"id":32540790,"identity":"bcc2df5a-bc71-44e4-bc52-22149c3e9244","added_by":"auto","created_at":"2023-02-06 16:36:43","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":40478,"visible":true,"origin":"","legend":"\u003cp\u003eMain effects graph for the degradation rate\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-2340059/v1/1fd31cc3d68cd5b4e1fa3093.png"},{"id":32540794,"identity":"e51ac2f7-c1aa-4a66-95c9-ef9ae4506d3d","added_by":"auto","created_at":"2023-02-06 16:36:43","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":290510,"visible":true,"origin":"","legend":"\u003cp\u003eA) Response surface graph AMX; B) Response surface graph ACT\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-2340059/v1/c7f5a5272952b2829ef521fb.png"},{"id":32540792,"identity":"6555daa8-e380-4b5b-9581-aa86cf30762f","added_by":"auto","created_at":"2023-02-06 16:36:43","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":43575,"visible":true,"origin":"","legend":"\u003cp\u003eContour graph for initial degradation rate vs. concentrations of Fe (III) and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-2340059/v1/d3ceb6d76ccdd66d40e37ce7.png"},{"id":32540791,"identity":"0461280e-b1a8-4b19-bebc-3a18fd33a6b0","added_by":"auto","created_at":"2023-02-06 16:36:43","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":4493,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-2340059/v1/70b00d9872e377e1baa6c7d8.png"},{"id":44735113,"identity":"41a3698b-112c-425c-ae54-a73de26cbd68","added_by":"auto","created_at":"2023-10-16 22:23:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":833746,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2340059/v1/b3835390-b76f-48cb-9184-100cd55ea051.pdf"}],"financialInterests":"","formattedTitle":"Solar photo-Fenton optimization at neutral pH for microcontaminant removal at pilot plant scale","fulltext":[{"header":"1. Introduction ","content":"\u003cp\u003eThe growing presence of microcontaminants in wastewater treatment plants (WWTPs), drinking water treatment plants (DWTPs), and even in the natural water bodies give an idea of the importance and great concern on what these emerging contaminants can potentially cause in the overall water cycle, as they may have medium- or long-term effects on both aquatic life and human health\u003csup\u003e\u0026nbsp;\u003c/sup\u003e(Rogowska et al. 2020).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAmong the microcontaminants that can be currently found in waters, pharmaceutical drugs have been the focus of research studies in the recent years, both on account of their use and the risk, themselves or their degradation products, may suppose for the environment (Fatta-Kassinos et al. 2013; Patel et al. 2019; Krzeminski et al. 2019; Tran et a. 2018; Yang et al. 2020).\u003c/p\u003e\n\u003cp\u003eThe production and consumption of pharmaceutical drugs determine the amount that may reach water bodies such as Municipal Wastewater Treatment Plants (MWTPs). A study by Choi et al. (2008) showed that the concentration of acetaminophen, carbamazepine, cimetidine, diltiazem, sulfamethoxazole and trimethoprim in the environment followed the same order as the amount produced annually for each of these pharmaceuticals in Korea. High concentrations (above 10 g/L) of acetaminophen, tramadol, codeine, gabapentin and atenolol were also detected in raw wastewater in Wales (UK), which could be explained by the high-prescribed amounts of these drugs (Kasprzyk-Hordern et a. 2008).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAlthough many types of drugs are produced worldwide, antibiotics and analgesics are the most important in terms of their volume of use due to the current high demand by consumers. In the case of antibiotics, there has been an increase of 36 % over the last ten years in 71 countries (Van Boeckel et al. 2014). Among the different types of antibiotics and analgesics, amoxicillin and acetaminophen are especially significant due to their high concentrations in the environment (Patel et al. 2019). Amoxicillin is a semi-synthetic antibiotic derived from penicillin. This aminopenicillin acts against a broad spectrum of bacteria, both Gram-positive and Gram-negative. Acetaminophen (paracetamol) is a drug with analgesic properties lacking clinically significant anti-inflammatory properties. It inhibits the synthesis of prostaglandins, i.e. the cellular mediators responsible for the onset of pain. It also has antipyretic effects (Zampronio et al. 2015).\u003c/p\u003e\n\u003cp\u003eThe different pathways via which these contaminants can appear in wastewater range from human excretion, as some of them are not completely assimilated by the human body when used for medicinal purposes (European Commission, 215), to veterinary applications, in addition to uncontrolled discharges of medicines by pharmaceutical companies and from household surpluses due to a lack of environmental awareness (Kaczala and Blum, 2016).\u003c/p\u003e\n\u003cp\u003eThere is clear evidence of their poor and inefficient removal in wastewater treatment plants using conventional technologies (Jelic et al. 2012; Petrovic et al. 2009; Petrie et al. 2015; Rizzo et al. 2019). Hence, the presence of these micro-contaminants in natural waters comes from MWTP effluents. It is therefore essential to remove them from the main source of entry into ecosystems. This requires the application of tertiary treatments to eliminate these pollutants before they reach the environment. Advanced oxidation processes are among the treatments that have been demonstrated to be highly efficient in the abatement of wide variety of microcontaminants and pharmaceuticals, specifically (Affam et al. 2014; Velo-Gala et al. 2014).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAdvanced oxidation processes (AOPs) comprise oxidative processes based on the generation of hydroxyl radicals (HO\u003cstrong\u003e\u003csup\u003e\u0026middot;\u003c/sup\u003e\u003c/strong\u003e), which are highly oxidizing species (E\u003csub\u003e0\u003c/sub\u003e=2.8 V with respect to the standard hydrogen electrode) and non-selective, highly desirable characteristics when degrading highly persistent micro-contaminants (Wang and Zhuan 2020; Ribeiro et al. 2019).\u003c/p\u003e\n\u003cp\u003eThere is, however, a factor to consider in all AOPs, namely the presence in natural waters of potential scavengers of these hydroxyl radicals, which significantly reduce the efficiency of the pollutant degradation process (Pignatello et al. 2006). Worth highlighting, in this respect, the presence of species such as CO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e2-\u003c/sup\u003e, HCO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e, SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2-\u003c/sup\u003e, Cl\u003csup\u003e-\u003c/sup\u003e and humic acids. Within AOPs, Fenton process involves the reaction between iron ions and hydrogen peroxide to form reactive species capable of oxidizing different organic compounds. Additionally, photo-Fenton process could use sunlight as a source of radiation to increase the generation of HO\u003cstrong\u003e\u003csup\u003e\u0026middot;\u003c/sup\u003e\u003c/strong\u003e and hence reaction efficiency. In the presence of UV or UV-visible radiation, photo-reduction of ferric ions in solution also occurs via a metal-ligand charge transfer reaction.\u003c/p\u003e\n\u003cp\u003eStudies in recent years on the application of solar photo-Fenton treatment to degrade low concentrations of micro-contaminants in Municipal Wastewater Treatment Plant (MWTP) effluents have concluded that the operating conditions of the process do not have to be as aggressive as those for the treatment of industrial wastewater or effluents with a high organic load. In this regard, studies carried out by different authors (Clarizia et al. 2017; Zhan and Zhou 2019; Oller et al. 2021) have shown that high degradation rates can be obtained using low concentrations of iron and hydrogen peroxide and so reducing process operating costs.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe optimum pH for the photo-Fenton process is 2.8, because, under these conditions, the precipitation of hydroxides is avoided. This acidification in addition to the need for a neutralization step at the end of treatment, also supposes substantial treatment costs. Therefore, running the photo-Fenton process at near neutral pH by using iron complex agents can also mean major cost savings (De Luca et al. 2014). Consequently, the study of the photochemistry of Fe(III) complexes plays a very important role (Souza et al. 2014; Ungwanen et al. 2020; Min et al. 2020) in the removal of micro-contaminants when the aim is to determine the appropriate complexing agent that allows operating at neutral pH. Some of the Initial studies carried out in this field began working with Ethylenediamine-N,N\u0026apos;-disuccinic acid (EDDS) (a structural isomer of EDTA) as a complexing\u0026nbsp;agent (Li et al. 2010; Wu et al. 2014). These studies showed that the complex of this compound with Fe\u003csup\u003e3+\u003c/sup\u003e is stable in aqueous solution under neutral pH conditions (demineralized water) and photochemically efficient. Three stereoisomers of EDDS exist, the most readily biodegradable stereoisomer being S, S\u0026lsquo;]-EDDS (Schowanek et al. 1997; Metsarinne et al. 2001; Tandy et al. 2006; Huang et al. 2012; Lin et al. 2011).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThere are still few studies focused on the removal of micro-contaminants at low concentrations in MWTP effluents using the photo-Fenton processes with complexes such as citric acid, oxalate and EDDS. These include studies by (Li et al. 2010; Silva et al. 2007; Trov\u0026oacute; et al. 2011; Huang et al. 2013; Klamerth et al. 2013)\u003csup\u003e\u0026nbsp;\u003c/sup\u003eusing EDDS as a complexing agent for the first time in MWTP effluents. At this point, it must be stressed that EDDS has been exhaustively studied by different authors up today (Ahmed et al. 2021; Soriano-Molina et al. 2021; Ahile et al. 2020). One of the key aspects when conducting these studies is the importance of the Fe(III):EDDS ratio, as it is crucial to determine the necessary ratio to obtain at least 90 % degradation of the contaminants and carry out the photo-Fenton process at neutral pH. Klamerth et al. (2012, 2013) and Miralles-Cuevas (2014) (Klamerth et al. 2013; Ahmed et al. 2021; Soriano-Molina et al. 2021; Ahile et al. 2020; Miralles-Cuevas et al. 2014) tested two different Fe(III):EDDS ratios, 1:1 and 1:2, concluding that an Fe(III) to EDDS ratio of 1:2 was slightly better than a ratio of 1:1 in terms of the degradation rate and hydrogen peroxide consumption.\u003c/p\u003e\n\u003cp\u003eThe present work addresses the application and optimization of solar photo-Fenton oxidation process at neutral pH (by using EDDS) for the removal of two drugs: an antibiotic, amoxicillin and an analgesic, acetaminophen (paracetamol) dissolved in simulated MWTP effluent for achieving degradation percentages higher than 90%.\u003c/p\u003e"},{"header":"2. Materials And Methods","content":"\u003cp\u003e\u003cstrong\u003e2.1. Reagents and chemicals\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHigh purity (\u0026gt; 99 %) amoxicillin (AMX) and acetaminophen (ACT) were used (Main characteristics can be found in Supplementary Material, Table 1) for spiking simulated and actual MWTP effluents (characteristics shown in Supplementary Material, Table 2). Ethylenediamine disuccinic acid (EDDS 35 % w / v) (as complexing agent) and catalase for removing H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e were supplied by Sigma Aldrich, as well as solvents used for liquid chromatography analysis (99.9 % grade). 75 % purity ferrous sulphate monohydrate (Fe\u003csub\u003e2\u003c/sub\u003e (SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e H\u003csub\u003e2\u003c/sub\u003eO) and hydrogen peroxide H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e 35 % (w / v) were supplied by Panreac.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2. Sample analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTarget contaminants at low concentrations were measured by ultra-performance liquid chromatography (UPLC/UV) (Agilent Technologies, Series 1200) employing a Gemini C-18 column. Starting conditions were 100 % 10 mM KH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e4\u003c/sub\u003e buffer (mobile phase A) and 0% ACN (mobile phase B). A linear ramp was applied with the following sequence: 40% (phase A) to 60% (phase B) in 10 min and 0% (phase A) to 100% (phase B) in 13 min. The detection wavelengths and the limits of quantification (LOQ) and detection (LOD) for each contaminant are shown in Table 3 of Supplementary Material.\u003c/p\u003e\n\u003cp\u003eDissolved organic carbon (DOC) and inorganic carbon (IC) were determined on a Shimadzu TOC-VCSN analyser. The samples were filtered through 0.22 \u0026micro;m before analysis, so that only the dissolved organic carbon (DOC) was determined. DOC analysis was always performed immediately after collecting the sample.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTotal iron concentration was measured using the 1, 10-phentranoline method according to ISO 6332. Hydrogen peroxide was measured using titanium oxysulphate (IV) following DIN 38402H15.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3. Experimental design\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA series of preliminary experiments were performed to determine the level of each factor mostly affecting the degradation of the contaminants.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eA mixture of 1 mg/L of each amoxicillin and acetaminophen dissolved in simulated MWTP effluent was used in these trials.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe experiments were run using a solar simulator (Suntest, XLS + Heraeus, Germany) equipped with a 2.2 kW xenon arc lamp and a special glass filter (Daylight) that cuts off UV irradiation at 290 nm, the source of radiation being artificial light which simulates sunlight on a sunny day. The radiation from the lamp was measured using a pyranometer (SOLAR LIGHT PM A2100).\u003c/p\u003e\n\u003cp\u003eInitially, a total volume of 1.5 L of simulated MWTP effluent was spiked with 1 mg/L of each pharmaceutical and then stirred for several minutes to ensure a suitable degree of homogeneity in the samples. Subsequently, the concentration of Fe\u003csup\u003e3+\u003c/sup\u003e-EDDS was added to the mixture and an initial sample was taken to ensure that complex formation had taken place and for checking the pH. The reason for using Fe\u003csub\u003e2\u003c/sub\u003e (SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e H\u003csub\u003e2\u003c/sub\u003eO as a source of Fe\u003csup\u003e3+\u003c/sup\u003e in this paper is that previous studies showed that the iron source can strongly influence the degradation of pollutants\u003csup\u003e44\u003c/sup\u003e, in addition to the possibility of working with the Fe\u003csup\u003e3+\u003c/sup\u003e-EDDS complex at neutral pH and minimizing operating expenses, as regent costs are thus reduced considerably.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe complex was previously prepared in the laboratory immediately before used by dissolving the required iron quantity (depending on the concentration to be tested) in demineralized water at pH 3 and adding the corresponding EDDS in the dark, as the complex is affected by light. The mixture was then left to homogenize for 5-10 minutes, the solution turned bright yellow in colour, indicative of the correct formation of the complex.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eRequired hydrogen peroxide concentration (depending on the experiment) was then added and the photo-Fenton reaction commenced. The hydraulic residence time (HRT) was 30 minutes, taking samples every 2 minutes. Catalase was used to stop the reaction. This enzyme is able to neutralize oxygen-derived toxic forms (such as H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) which form in aqueous media containing dissolved oxygen. Catalase converts hydrogen peroxide into water and molecular oxygen. The amount of Catalase was added as function of the initial concentration of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e employed.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eExperiments were performed in a borosilicate glass beaker under constant stirring. The beaker was 19 cm diameter, providing an irradiated surface of 0.0284 m\u003csup\u003e2\u003c/sup\u003e, and the entire volume was illuminated 1.5 L.\u003c/p\u003e\n\u003cp\u003eThe variables studied to degrade 90 % of the contaminants, were the hydraulic residence time (HRT), initial degradation rate, accumulated energy (\u003cem\u003eQuv\u003c/em\u003e), Fe\u003csup\u003e3+\u003c/sup\u003e-EDDS (1:2) complex concentration, H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e concentration and Dissolved Organic Carbon (DOC). The pH was around 7 throughout the reaction.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOnce the initial starting conditions had been determined, a fractional factorial design was performed involving a set of 14 experiments to optimize which variables were more significant and the optimum values of these variables for the degradation of the drugs. The procedure for these experiments was the same as for the previous trials.\u003c/p\u003e\n\u003cp\u003eAfter completing the experimental design, two tests were developed with the main goal of validating the values of each parameter defined as optimal to maximize the initial degradation rate for each contaminant. Two different aqueous matrices were used in those validation experiments, simulated water from the MWTP (see Table 2) and actual effluent from El Ejido MWTP (South-East of Spain), to which the content of HCO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e / CO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e2-\u003c/sup\u003e (hydroxyl radical scavengers\u003csup\u003e21\u003c/sup\u003e) was eliminated by the addition of concentrated H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e just in a sufficient amount to avoid a significant drop in pH.\u003c/p\u003e\n\u003cp\u003eFor the performance of these experiments a photoreactor based on CPC (Compound Parabolic Collectors) was used at the Plataforma Solar de Almer\u0026iacute;a (PSA, latitude 37\u0026ordm;N, length 2.4 W) using natural solar radiation. The initial concentration of drugs, AMX and ACT was 1 mg/L of each. After 12 minutes of homogenization of the aqueous matrix together with the drugs in the CPC photoreactor, an initial sample was taken to ensure the starting concentration of both contaminants. The Fe\u003csup\u003e3+\u003c/sup\u003e -EDDS complex was then added again leaving a time for homogenization and then, the first dose of hydrogen peroxide was added. The photoreactor was then uncovered and the solar photo-Fenton reaction started. Samples were taken every 3 min during the first hour in the simulated effluent from the MWTP and every 5 min for the first 60 min of reaction in the actual MWTP effluent assay and thereafter every 15 min to complete three hours of treatment.\u003c/p\u003e"},{"header":"3. Results And Discussion","content":"\u003cp\u003eA series of preliminary studies were conducted with the aim of selecting the best operation range of affecting parameters for the experimental design, stablishing upper concentration limits on 5.5\u0026nbsp;mg/L Fe\u003csup\u003e3+\u003c/sup\u003e and 5 mg/L H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(added as consumed)\u003csub\u003e\u0026nbsp;\u003c/sub\u003eaccording to previous published works (Klamerth et al. 2013; Ahmed et al. 2021; Soriano-Molina et al. 2021; Ahile et al. 2020; Miralles-Cuevas et al. 2014; Nogueira et al. 2005; Prieto-Rodr\u0026iacute;guez et al 2013). This concentration of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e was chosen because previous studies by Huang (Huang et al. 2013) showed that higher concentrations involve loss of the positive effect of the addition of EDDS over the process, because hydrogen peroxide in excess also acts as a scavenger of hydroxyl radicals, thereby decreasing the efficiency of the system. The results of these preliminary tests gave high degradation rates of both compounds (above 90 %) in only nine minutes of exposure.\u003c/p\u003e\n\u003cp\u003eBased on these results and previous published studies (Prieto-Rodr\u0026iacute;guez et al. 2013; Klamerth et al. 2011) which showed that high degradation rates can be obtained using low concentrations of iron and hydrogen peroxide, four tests were carried out setting the concentration of Fe\u003csup\u003e3+\u003c/sup\u003e at 5.5 mg/L and doing additions of 5 mg/L of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e as consumed.\u003c/p\u003e\n\u003cp\u003eFirst, it should be noted that the concentration of Fe\u003csup\u003e3+\u003c/sup\u003e was almost constant throughout the reaction time so Fe-EDDS complex was stable along the whole process. More than 94% of both contaminants degradation was attained after only 3.6 mg/L of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e consumed and six minutes of reaction time.\u003c/p\u003e\n\u003cp\u003eAccording to these previous results, the range of affecting parameters selected for the experimental design was 0.5 - 5.5 mg/L for Fe\u003csup\u003e3+\u003c/sup\u003e-EDDS complex and 2.75 - 5\u0026nbsp;mg/L for H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003ewith the aim of maximizing the initial degradation rate of both target contaminants with the minimum accumulated energy required, which was calculated according the following expression:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"471\" height=\"317\"\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.1. Key parameters optimization\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOnce the range of each key parameter had been selected, a full factorial experimental design was applied with the aim of optimizing the operational parameters to maximize pharmaceuticals degradation rate through a solar photo-Fenton process at neutral pH. A 2-level full factorial design with six central points has been applied by using the statistical program MINITAB, Version 3.11.\u003c/p\u003e\n\u003cp\u003eThe experimental design established the necessity of perform 14 experiments in which both drugs initial concentration was stated at 1 mg/L. The pH remained constant in all trials between 7 and 8. The wastewater matrix used for tests at laboratory scale was simulated effluent from a MWTP (characterization shown in Table 2).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIrradiation was set at 30 W/m\u003csup\u003e2\u003c/sup\u003e in the solar box according to the irradiation obtained in the mid-day of a sunny day. Both the irradiated area and the reactor volume were kept constant, so \u003cem\u003eQuv\u003c/em\u003e was only function of the sampling time interval, reaching values of 1.02 (kJ/L) at the end of each test (HRT = 30 min). In consequence, in trials using the maximum concentrations of Fe\u003csup\u003e3+\u003c/sup\u003e and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(5.5 mg/L and 5 mg/L, respectively), drug degradation rates of 50% were achieved without irradiation that is thanks to Fenton reaction. However, \u003cem\u003eQuv\u0026nbsp;\u003c/em\u003evalues of 0.75 kJ/L were required to obtain this same degradation percentage in trials employing low concentrations of Fe\u003csup\u003e3+\u003c/sup\u003e and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e. Table 4 shows the experimental conditions and results obtained in the 14 experiments designed. It is also shown the degradation rates of both compounds obtained by representing the evolution of the concentration of the drugs versus time corresponding to kinetics of order 1.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 4. Results of the full factorial design with 14 experiments\u0026nbsp;\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e\u003cstrong\u003eExperiments\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e\u003cstrong\u003eFe(III) mg/L\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e\u003cstrong\u003eH\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e mg/L\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e\u003cstrong\u003eDegradation % AMX\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e\u003cstrong\u003eDegradation % ACT\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e\u003cstrong\u003eInitial degradation rate AMX\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(mg/L min)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e\u003cstrong\u003eInitial degradation rate ACT\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(mg/L min)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.184\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.108\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.143\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.125\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.205\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.126\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.300\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.289\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e2.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.307\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.305\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e2.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.290\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.276\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e2.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.308\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.324\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.173\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.107\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.119\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.134\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.244\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.196\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.350\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.352\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e2.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.308\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.319\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e2.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.294\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.305\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.07773851590106%\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.307420494699647%\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.424028268551236%\"\u003e\n \u003cp\u003e2.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.724381625441696%\"\u003e\n \u003cp\u003e93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.306\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.371024734982333%\"\u003e\n \u003cp\u003e0.326\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eIt can be seen that the higher the concentrations of Fe\u003csup\u003e3+\u003c/sup\u003e-EDDS and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e (experiments 4 and 11), the greater the degradation percentages obtained, which corresponds with a higher initial degradation rates for both contaminants. Values close to those reported above are also achieved for intermediate values of Fe\u003csup\u003e3+\u003c/sup\u003e-EDDS and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e concentrations (3 mg/L and 2.75 mg/L, experiments 5, 6, 7, 12, 13 and 14). Although 100% removal was not achieved in any of these cases, even when increasing the concentration of iron and peroxide, high primary degradation of contaminants did occur. These degradation results are consistent with those reported by Trovo et al., 2008, who studied the degradation of amoxicillin (AMX), paracetamol o acetaminophen (ACT) and bezafibrate (BZF). Working with concentrations of 1.0 to 5.0 mM H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e and using potassium ferrioxalate (K\u003csub\u003e3\u003c/sub\u003eFe (C\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e 3H\u003csub\u003e2\u003c/sub\u003eO) or Fe(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e as a source of Fe\u003csup\u003e3+\u003c/sup\u003e at optimum pH for the photo-Fenton reaction (2.8), these authors found that degradation is favoured by (K\u003csub\u003e3\u003c/sub\u003eFe (C\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e \u0026middot; 3H\u003csub\u003e2\u003c/sub\u003eO), achieving 98 % removal of BZF and ACT after 5 minutes of irradiation. However, no difference was observed in the oxidation of AMX, for which complete degradation was achieved after 0.5 min of irradiation time for both iron sources. Nonetheless, it should be noted that the pH employed in the present study was close to neutral, while Trov\u0026oacute; et al. studies were carried out at optimal pH of 2.8 for photo-Fenton applications to avoid iron precipitation.\u003c/p\u003e\n\u003cp\u003eThe DOC measurement showed that the value remained practically constant throughout the experiments, thus demonstrating that the complex was still active and the EDDS was not yet degrading.\u003c/p\u003e\n\u003cp\u003eInitial degradation rate for each target contaminant is considered in the proposed experimental design as the response factor. A statistical study was carried out to obtain the equations, which model the initial degradation rate for each contaminant as function of the concentrations of the influence parameters (Fe-EDDS and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e). Such equations are shown in Table 5.\u003c/p\u003e\n\u003cp\u003eTable 5. Summary of the model of the sum of degradation rates of both contaminants\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"28.345070422535212%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eVariables\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.654929577464788%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eEffects\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eStudent-t\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP Value\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"28.345070422535212%\"\u003e\n \u003cp\u003eFe(III)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.654929577464788%\"\u003e\n \u003cp\u003e0.1214\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25%\"\u003e\n \u003cp\u003e3.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25%\"\u003e\n \u003cp\u003e0.009\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"28.345070422535212%\"\u003e\n \u003cp\u003eH\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.654929577464788%\"\u003e\n \u003cp\u003e0.2384\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25%\"\u003e\n \u003cp\u003e6.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25%\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"28.345070422535212%\"\u003e\n \u003cp\u003eFe(III)*H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.654929577464788%\"\u003e\n \u003cp\u003e0.1606\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25%\"\u003e\n \u003cp\u003e4.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25%\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"28.345070422535212%\"\u003e\n \u003cp\u003eCentral Point\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.654929577464788%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25%\"\u003e\n \u003cp\u003e8.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25%\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eBased on these results, an analysis of variance was carried out using the statistical program MINITAB to study how the different process variables and the interaction between these affected the percentage degradation of the contaminants. Although both variables influence the process, presenting a p-value \u0026lt; 0.05, Fe\u003csup\u003e3+\u003c/sup\u003e affects the photo-Fenton process less than H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, as evidenced by the values of the effects and the Student-t values shown in Table 6.\u003c/p\u003e\n\u003cp\u003eThe statistical study carried out by MINITAB software gave different graphics allowing the analysis of the influence rate of each parameter on the initial degradation rate for each target drug.\u003c/p\u003e\n\u003cp\u003eThe rate of degradation of these compounds under the experimental conditions in which the experiments were carried out is a first-order reaction:\u003c/p\u003e\n\u003cp\u003e-d(C Contaminants)/d HRT = K*C contaminants\u003c/p\u003e\n\u003cp\u003eThe optimization of both contaminants degradation by solar photo-Fenton process accordingly to the selected experimental design, gave the following common initial degradation rate (r\u003csub\u003e0\u003c/sub\u003e) equation:\u003c/p\u003e\n\u003cp\u003er\u003csub\u003e0\u003c/sub\u003e = 0.2846 \u0026ndash; 0.0150 Fe\u003csup\u003e3+\u003c/sup\u003e + 0.0101 H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e + 0.01428 Fe\u003csup\u003e3+\u003c/sup\u003e H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e + 0.2213 Central Pt, (R\u003csup\u003e2\u0026nbsp;\u003c/sup\u003e94.81%)\u003c/p\u003e\n\u003cp\u003eTable 6 shows the degradation rates (r\u003csub\u003e0\u003c/sub\u003e) for each of the contaminants separately and for the sum of both. These results coincide with those obtained by other authors (Rodriguez et al. 2005).\u003c/p\u003e\n\u003cp\u003eTable 6. Degradation rate equations for each contaminant studied\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"33.333333333333336%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"51.499118165784836%\"\u003e\n \u003cp\u003e\u003cstrong\u003ePredictive model equation: Factorial regression\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.167548500881834%\"\u003e\n \u003cp\u003e\u003cstrong\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.333333333333336%\"\u003e\n \u003cp\u003e\u003cstrong\u003eDegradation rate AMX\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"51.499118165784836%\"\u003e\n \u003cp\u003er0 = 0.413 + 0.07113 Fe(III) + 0.00693 H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e \u0026ndash; 0.01399 Fe(III)*Fe(III) + 0.00658 Fe(III)*H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.167548500881834%\"\u003e\n \u003cp\u003e96 %\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.333333333333336%\"\u003e\n \u003cp\u003e\u003cstrong\u003eDegradation rate ACT\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"51.499118165784836%\"\u003e\n \u003cp\u003er0 = 0.0439 + 0.1257 Fe(III) + 0,00883 H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e \u0026ndash; 0.02073 Fe(III)*Fe(III) + 0.00611 Fe(III)* H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.167548500881834%\"\u003e\n \u003cp\u003e94 %\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eHigh accuracy of the proposed statistic models are demonstrated thanks to R\u003csup\u003e2\u003c/sup\u003e values between 94 and 96%.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe Pareto chart (Figure 1) was used to decide which of the variables or the interaction between them was more significant. This type of chart shows both the magnitude and the significance of the effects. The vertical axis represents the two variables and the interaction between both, while the horizontal axis represents the standardized effects. In this case, the effects of the variables are specified in the model equation and show the difference between the maximum and minimum for each value. The vertical reference line indicates that any effect that extends beyond this line is significant. The Pareto chart for this study confirms that the most important variable is the concentration of hydrogen peroxide and the interaction of this reagent with Fe.\u003c/p\u003e\n\u003cp\u003eFigure 2 shows the individual effects of each variable (Fe\u003csup\u003e3+\u003c/sup\u003e and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) on the degradation rate of the studied contaminants. It can be seen that the influence of both parameters is positive as their concentration is increasing. That means that no limitation was observed and, initially, higher initial degradation rates for both contaminants should be attained as increasing both Fe\u003csup\u003e3+\u003c/sup\u003e and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e concentrations.\u003c/p\u003e\n\u003cp\u003eThe response surface graphics have been obtained in the experimental design (Figure 3). It must be highlighted the maximum response observed in the central points (at 3 mg/L of Fe\u003csup\u003e3+\u003c/sup\u003e and 2.75 mg/L of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) similar to that shown at the maximum values of both parameters. As maximum degradation rates were not significantly improved at the maximum concentration of both parameters, it was decided to choose the central point values as the optimal operation conditions for the degradation of such contaminants. Indeed, this is what it was obtained in the system optimization represented by Figure 3.\u003c/p\u003e\n\u003cp\u003eIt is clear from the contour plot (Figure 4) that, although the optimal degradation value is also obtained in the experiment with the highest concentration of Fe and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, the maximum degradation rate actually appears at the central points (darker area in the figure). Given that 90% degradation rates were obtained using the reagent concentrations corresponding to these central points within the same reaction time as that achieved when using the maximum reagent concentrations, as previously mentioned, it was decided to consider these central point as optimal to validate the predictive model equations mathematically obtained, as reagent costs would be minimized.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2. Validation tests with actual wastewater\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOnce the optimum concentration conditions for the Fe\u003csup\u003e3+\u003c/sup\u003e-EDDS complex and H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e were selected according to the experimental design results, two validation tests were carried out at pilot plant scale. Firstly, the elimination of both drugs spiked at 1 mg/L each one in actual MWTP effluent (see table 2 for physic-chemical characterization) was carried out, initial degradation rates obtained were 0.021 mg/Lmin for AMX and 0.015 mg/Lmin for ACT, respectively, attaining global degradation rates of 47% for AMX and 20% for ACT after 5 minutes of irradiation time. After the first 5 minutes of treatment, three extra additions of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e (5 mg/L each) were made in order to determine the maximum percentage of degradation that could be reached for both drugs, which was around 60% for both after 180 minutes of treatment and a total H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e consumption of 13.4 mg/L. pH remained constant throughout the reaction between 7.6 and 7.9. DOC remained also constant along the 180 min of complete treatment. Iron concentration decreased till around 1.7 mg/L at the end of the treatment.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThese results showed that the greater physic-chemical complexity of the actual effluent from the MWTP causes a reduction in the efficiency of the treatment and the necessity of a greater consumption of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e and higher treatment times to attain quite lower degradation rates than those obtained with simulated effluent from the MWTP (Figure 5). Specifically after 5 min of solar photo-Fenton treatment at neutral pH, 90% of degradation was obtained for both drugs with an initial degradation rate around 0.3 mg/L min (15 times higher) in simulated MWTP effluent (table 4).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFinally and with the main objective of checking the performance of solar photo-Fenton optimum parameters at pilot scale (3 mg/L Fe\u003csup\u003e3+\u003c/sup\u003e (1:2 Fe: EDDS) and 2.75 mg/L H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) and under more realistic conditions considering lower target contaminants concentration, experiment with actual effluent of MWTP was repeated by spiking 100\u0026nbsp;\u0026micro;g/L of ACT and AMX, each. 91% of AMX degradation was achieved after 105 min of treatment and 11 mg/L of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e consumption. However, at that time, only 17% of ACT was eliminated, so solar photo-Fenton process was maintained till achieving 70% of ACT degradation after 210 min and 13.1 mg/L of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e consumption. As already commented, the more complex water matrix provoked the requirement of higher doses of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e to achieved contaminant degradation targets, that was, five additions of 2.75 mg/L of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e for maintaining the reaction till maximum ACT elimination (most unfavorable condition).\u0026nbsp;\u003c/p\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eThe results obtained in this study show that solar photo-Fenton oxidation operated with Fe\u003csup\u003e3+\u003c/sup\u003e-EDDS complex at neutral pH (low initial concentration of iron and low hydrogen peroxide consumption) is a viable alternative as tertiary treatment for the removal of emerging contaminants present in MWTPs. This enables a reduction in the consumption of reagents and, consequently, a reduction of associated operating costs.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe use of the Fe(III)-EDDS complex allows operating at both neutral pH and low reagent concentrations. The reagent concentrations considered optimal for maximizing initial degradation rate of both target drugs were 3 ppm for the Fe\u003csup\u003e3+\u003c/sup\u003e complex and 2.75 ppm for H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e according to the experimental design performed. In addition, mathematical model equations have been obtained for predicting the behaviour of the system.\u003c/p\u003e\n\u003cp\u003eWhen the optimum concentrations of the variables obtained in the experimental design for the treatment of actual effluent with the added pollutants are applied, the consumption of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e is always higher than the optimum to reach the same point obtained with simulated water due to the presence of other substances that consume hydroxyl radicals, such as organic matter as humic acids, carbonates and bicarbonates and more complex ionic characterization.\u003c/p\u003e\n\u003cp\u003eIt was found that, when operating at the aforementioned reagent concentrations using solar photo-Fenton at neutral pH, primary degradation rates of 90% and 70% of target contaminants under more realistic conditions (100 \u0026micro;g/L, each, spiked in real MWTP effluent), were achieved, though higher final doses of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003eand long treatment times were required. These results confirm some previous studies that suggest, as the best strategy, complete addition of the required oxidant concentration to achieve a specific target, at the beginning of the treatment. It is also very important to highlight the importance of using water matrices as close to the actual situation as possible to better adjust oxidant concentrations.\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical Approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis manuscript complies with ethical standards.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate and Consent to Publish\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors whose names appear on the submission approved the version to be published; and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Spanish Ministry of Science and Innovation, AEI, and FEDER (NAVIA Project, reference PID2019-110441RB-C32) is gratefully acknowledged for financial support.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization: Isabel Oller; Methodology: Mercedes Hinojosa; Formal analysis and investigation: Mercedes Hinojosa; Writing - original draft preparation: Mercedes Hinojosa; Writing - review and editing: Mercedes Hinojosa, Agata Egea-Corbacho; Funding acquisition: Isabel Oller; Resources: Sixto Malato, Jose Maria Quiroga; Supervision: Isabel Oller, Asunci\u0026oacute;n Acevedo-Merino.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe ensure that all data and materials as well as software application or custom code support their published claims and comply with field standards.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAffam, AC, Chaudhuri M (2014) Optimization of Fenton treatment of amoxicillin and cloxacillin antibiotic aqueous solution. Desal Water Treat\u003cstrong\u003e \u003c/strong\u003e 52:1878-1884. https://doi.org/10.1080/19443994.2013.794015.\u003c/li\u003e\n\u003cli\u003eAhile UJ, Wuana RA, Itodo AU, Sha\u0026apos;Ato R, Dantas RF (2020) A review on the use of chelating agents as an alternative to promote photo-Fenton at neutral pH: Current trends, knowledge gap and future studies. Sci Total Environ 710:134872. doi: 10.1016/j.scitotenv.2019.134872.\u003c/li\u003e\n\u003cli\u003eAhmed Y, Zhong J, Yuan Z, Guo J (2021) Simultaneous removal of antibiotic resistant bacteria, antibiotic resistance genes, and micropollutants by a modified photo-Fenton process. Wat Res 197: 117075. doi: 10.1016/j.watres.2021.117075\u003c/li\u003e\n\u003cli\u003eChoi K, Kim Y, Park J, Park CK, Kim M, Kim HS (2008) Seasonal variations of several pharmaceutical residues in surface water and sewage treatment plants of Han River, Korea. Sci Total Environ 405:0\u0026ndash;8. DOI: 10.1016/j.scitotenv.2008.06.038.\u003c/li\u003e\n\u003cli\u003eClarizia L, Russo D, Di Somma I, Marotta R, Andreozzi R (2017) Homogeneous photo-Fenton processes at near neutral pH: A review. Appl Catal B-Environ 209:358-371. https://doi.org/10.1016/j.apcatb.2017.03.011.\u003c/li\u003e\n\u003cli\u003eDe Luca A, Dantas RF, Esplugas S (2014) Assessment of iron chelates efficiency for photo-Fenton at neutral pH. Wat Res 61:232-242. DOI: 10.1016/j.watres.2014.05.033.\u003c/li\u003e\n\u003cli\u003eFatta-Kassinos D, Michael C (2013) Wastewater reuse applications and contaminants of emerging concern. Environ Sci Pollut Res Int 20:3493-3495. doi: 10.1007/s11356-013-1699-5.\u003c/li\u003e\n\u003cli\u003eHuang W, Brigante M, Wu F, Hanna K, Mailhot G (2012) Development of a new homogenous photo-Fenton process using Fe(III)-EDDS complexes. J Photochem Photobiol A: Chem 239:17-23. DOI: 10.1016/j.jphotochem.2012.04.018.\u003c/li\u003e\n\u003cli\u003eHuang W, Brigante M, Wu F, Mousty C, Hanna K, Mailhot G (2013) Assessment of the Fe(III)- EDDS complex in Fenton-like processes: From the radical formation to the degradation of bisphenol A. Environ Sci Technol 47:1952-1959. https://doi.org/10.1021/es304502y.\u003c/li\u003e\n\u003cli\u003eJelic, A et al. (2012) Occurrence and elimination of pharmaceuticals during conventional wastewater treatment. In: Guasch H, Ginebreda A, Geiszinger A (eds) Emerging and priority pollutants in rivers Springer: Berlin, pp. 1\u0026ndash;24.\u003c/li\u003e\n\u003cli\u003eKaczala, F.; Blum, S.E. The Occurrence of Veterinary Pharmaceuticals in the Environment: A Review. \u003cem\u003eCurrent Anal. Chem.\u003c/em\u003e \u003cstrong\u003e2016\u003c/strong\u003e, 12, 169\u0026ndash;182. https://doi.org/10.2174/1573411012666151009193108.\u003c/li\u003e\n\u003cli\u003eKasprzyk-Hordern, B.; Dinsdale, R.M.; Guwy, A.J. The removal of pharmaceuticals, personal care products, endocrine disruptors and illicit drugs during wastewater treatment and its impact on the quality of receiving waters. \u003cem\u003eWater Res.\u003c/em\u003e \u003cstrong\u003e2009\u003c/strong\u003e, 43, 63\u0026ndash;80. doi: 10.1016/j.watres.2008.10.047.\u003c/li\u003e\n\u003cli\u003eKlamerth N, Malato S, Ag\u0026uuml;era A, Fern\u0026aacute;ndez-Alba A (2013) Photo-Fenton and modified photoFenton at neutral pH for the treatment of emerging contaminants in wastewater treatment plant effluents: A comparison. Water Res 47:833-840. doi: 10.1016/j.watres.2012.11.008.\u003c/li\u003e\n\u003cli\u003eKlamerth N, Malato S, Maldonado MI, Ag\u0026uuml;era A, Fern\u0026aacute;ndez-Alba A (2011) Modified photo-Fenton for degradation of emerging contaminants in municipal wastewater effluents. Catal Today 161:241\u0026ndash;246. doi:10.1016/j.cattod.2010.10.074.\u003c/li\u003e\n\u003cli\u003eKrzeminski P, Tomei MC, Karaolia P, Langenhoff A, Almeida CMR, Felis E, Gritten F, Andersen HR, Fernandes T, Manaia CM, Rizzo L, Fatta-Kassinos D (2019) Performance of secondary wastewater treatment methods for the removal of contaminants of emerging concern implicated in crop uptake and antibiotic resistance spread: A review. Sci Total Environ 648:1052\u0026ndash;1081. doi:10.1016/j.scitotenv.2018.08.130.\u003c/li\u003e\n\u003cli\u003eLi J, Mailhot G, Wu F, Deng N (2010) Photochemical efficiency of Fe(III)-EDDS complex: OH radical production and 17\u0026beta;-estradiol degradation. J Photochem Photobiol A: Chem 212:1-7. DOI:10.1016/j.jphotochem.2010.03.001.\u003c/li\u003e\n\u003cli\u003eLin AY-C, Tsai Y-T, Yu T-H, Wang X-H, Lin C-F (2011) Occurrence and fate of pharmaceuticals and personal care products in Taiwan\u0026apos;s aquatic environment. Desal Water Treat 3:57\u0026ndash;64. DOI: 10.5004/dwt.2011.2678.\u003c/li\u003e\n\u003cli\u003eMetsarinne S, Tuhkanen T, Aksela R (2001) Photodegradation of ethylenediaminetetraacetic acid (EDTA) and ethylenediamine disuccinic acid (EDDS) within natural UV radiation range. Chemosphere 45:949-955. doi: 10.1016/s0045-6535(01)00022-4.\u003c/li\u003e\n\u003cli\u003eMin X, et.al (2020) Advancements in the Fenton Process for Wastewater Treatment. In: Bustillo-Lecompte C (ed) Advanced Oxidation Processes - Applications, Trends, and Prospects, pp 61-79. DOI: 10.5772/intechopen.90256\u003c/li\u003e\n\u003cli\u003eMiralles-Cuevas S, Oller I, Sanchez Perez JA, Malato S (2014) Removal of pharmaceuticals from MWTP effluent by nanofiltration and solar photo-Fenton using two different iron complexes at neutral pH. Wat. Res 64:23-31. doi: 10.1016/j.watres.2014.06.032.\u003c/li\u003e\n\u003cli\u003eNogueira RFP, Silva MRA, Trov\u0026oacute; AG (2005) Influence of the iron source on the solar photo-Fenton degradation of different classes of organic compounds. Solar Energy 79:384-392. https://doi.org/10.1016/j.solener.2005.02.019.\u003c/li\u003e\n\u003cli\u003eOller I, Malato S (2021) Photo-Fenton applied to the removal of pharmaceutical and other pollutants of emerging concern. Current Opinion in Green and Sustainable Chemistry 29:100458. https://doi.org/10.1016/j.cogsc.2021.100458.\u003c/li\u003e\n\u003cli\u003ePatel M, Kumar R, Kishor K, Mlsna T, Pittman JrCJ, Mohan D (2019) Pharmaceuticals of Emerging Concern in Aquatic Systems: Chemistry, Occurrence, Effects, and Removal Methods. Chem Rev 119:3510\u0026ndash;3673. https://doi.org/10.1021/acs.chemrev.8b00299.\u003c/li\u003e\n\u003cli\u003ePetrie B, Barden R, Kasprzyk-Hordern B (2015) A review on emerging contaminants in wastewaters and the environment: Current knowledge, understudied areas and recommendations for future monitoring. Water Res\u003cstrong\u003e \u003c/strong\u003e72:3-27. https://doi.org/10.1016/j.watres.2014.08.053.\u003c/li\u003e\n\u003cli\u003ePetrovic M, De Alda MJL, Diaz-Cruz S, Postigo C, Radjenovic J, Gros M, Barcel\u0026oacute; D (2009) Fate and removal of pharmaceuticals and illicit drugs in conventional and membrane bioreactor wastewater treatment plants and by riverbank filtration. Phil Trans R Soc A 367:3979-4003. https://doi.org/10.1098/rsta.2009.0105.\u003c/li\u003e\n\u003cli\u003ePignatello JJ, Oliveros E, MacKay A (2006) Advanced Oxidation Processes for Organic Contaminant Destruction Based on the Fenton Reaction and Related Chemistry. Crit Rev Env Sci Tech 36:1-84. https://doi.org/10.1080/10643380500326564.\u003c/li\u003e\n\u003cli\u003ePrieto-Rodr\u0026iacute;guez L, Oller I, Klamerth N, Ag\u0026uuml;era A, Rodr\u0026iacute;guez EM, Malato S (2013) Application of solar AOPs and ozonation for elimination of micropollutants in municipal wastewater treatment plant effluents. Wat Res 47:1521\u0026ndash;1528. doi: 10.1016/j.watres.2012.11.002.\u003c/li\u003e\n\u003cli\u003eRibeiro L, Moreira NFF, Li Puma G, Silva AMT (2019) Impact of water matrix on the removal of micropollutants by advanced oxidation technologies. Chem Eng J 363:155-173. DOI: 10.1016/j.cej.2019.01.080.\u003c/li\u003e\n\u003cli\u003eRizzo L, Malato S, Antakyali D, Beretsou VG, Đolić MB, Gernjak W, Heath E, Ivancev-Tumbas I, Karaolia P, Lado Ribeiro AR, Mascolo G, McArdell CS, Schaar H, Silva AMT, Fatta-Kassinos D (2019) Consolidated vs new advanced treatment methods for the removal of contaminants of emerging concern from urban wastewater. Sci Total Env 655:986-1008. doi: 10.1016/j.scitotenv.2018.11.265.\u003c/li\u003e\n\u003cli\u003eRogowska, J.; Cieszynska-Semenowicz, M.; Ratajczyk, W.; Ratjczyk, W.; Wolska, L. Micropollutants in treated wastewater. \u003cem\u003eAmbio\u003c/em\u003e \u003cstrong\u003e2020\u003c/strong\u003e, 49, 487\u0026ndash;503. https://doi.org/10.1007/s13280-019-01219-5.\u003c/li\u003e\n\u003cli\u003eSchowanek D, Feijtel TCJ, Perkins CM, Hartman FA, Federle TW, Larson RJ (1997) Biodegradation of [S,S], [R,R] and mixed stereoisomers of ethylenediaminedisuccinic acid (EDDS), a transition metal chelator. Chemosphere 34:2375-2391. doi: 10.1016/s0045-6535(97)00082-9.\u003c/li\u003e\n\u003cli\u003eSilva MRA, Trov\u0026oacute; AG, Nogueira RFP (2007) Degradation of the herbicide tebuthiuron using solar photo-Fenton process and ferric citrate complex at circumneutral pH. J Photochem Photobiol A: Chem 191:187-192. http://dx.doi.org/10.1016/j.jphotochem.2007.04.022.\u003c/li\u003e\n\u003cli\u003eSoriano-Molina P, Miralles-Cuevas S, Esteban Garc\u0026iacute;a B, Plaza-Bola\u0026ntilde;os P, S\u0026aacute;nchez P\u0026eacute;rez JA (2021) Two strategies of solar photo-Fenton at neutral pH for the simultaneous disinfection and removal of contaminants of emerging concern. Comparative assessment in raceway pond reactors. Catal Today 361:17-23. https://doi.org/10.1016/j.cattod.2019.11.028.\u003c/li\u003e\n\u003cli\u003eSouza BM, Dezotti MWC, Boaventura RAR, Vilar VJP (2014) Intensification of a solar photoFenton reaction at near neutral pH with ferrioxalate complexes: A case study on diclofenac removal from aqueous solutions. Chem Eng J 256:448-457. https://doi.org/10.1016/j.cej.2014.06.111.\u003c/li\u003e\n\u003cli\u003eTran NH, Reinhard M, Gin KY-H (2018) Occurrence and fate of emerging contaminants in municipal wastewater treatment plants from different geographical regions-a review. Water Res 133:182\u0026ndash;207. doi:10.1016/j.watres.2017.12.029. \u003c/li\u003e\n\u003cli\u003eTandy S, Ammann A, Schulin R, Nowack B (2006) Biodegradation and speciation of residual SSethylenediaminedisuccinic acid (EDDS) in soil solution left after soil washing. Environ Pol 142:191-199. DOI: 10.1016/j.envpol.2005.10.013.\u003c/li\u003e\n\u003cli\u003eTrov\u0026oacute; AG, Nogueira RFP (2011) Diclofenac abatement using modified solar photo-Fenton process with ammonium iron(III) citrate. J Braz Chem Soc 22:1033-1039. https://doi.org/10.1590/S0103-50532011000600005.\u003c/li\u003e\n\u003cli\u003eTrov\u0026oacute; AG, Santos SA, Nogueira MRFP (2008) Photodegradation of the pharmaceuticals amoxicillin, bezafibrate and paracetamol by the photo-Fenton process\u0026mdash;Application to sewage treatment plant effluent. J Photochem Photobiol A: Chem 198:215-220. https://doi.org/10.1016/j.jphotochem.2008.03.011.\u003c/li\u003e\n\u003cli\u003eUngwanen JA, Raymond AW, Adams UI, Rufus S, Renato FD (2020) A review on the use of chelating agents as an alternative to promote photo-Fenton at neutral pH: Current trends, knowledge gap and future studies. Sci Tot Environ 710:134872. doi: 10.1016/j.scitotenv.2019.134872.\u003c/li\u003e\n\u003cli\u003eVan Boeckel TP, Gandra S, Ashok A, Caudron Q, Grenfell BT, Levin SA, Laxminarayan R (2014) Global antibiotic consumption 2000 to 2010: an analysis of national pharmaceutical sales data. The Lancet Infectious Diseases 14:742-750. https://doi.org/10.1016/S1473-3099(14)70780-7.\u003c/li\u003e\n\u003cli\u003eVelo-Gala I, L\u0026oacute;pez-Pe\u0026ntilde;alver JJ, S\u0026aacute;nchez-Polo M, Rivera-Utrilla J (2014) Comparative study of oxidative degradation of sodium diatrizoate in aqueous solution by H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e/Fe\u003csup\u003e2+\u003c/sup\u003e, H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e/Fe\u003csup\u003e3+ \u003c/sup\u003e, Fe (VI) and UV, H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e/UV, K\u003csub\u003e2\u003c/sub\u003eS\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e8\u003c/sub\u003e/UV. Chem Eng J 241:504-512. http://dx.doi.org/10.1016/j.cej.2013.10.036.\u003c/li\u003e\n\u003cli\u003eWang J, Zhuan R (2020) Degradation of antibiotics by advanced oxidation processes: An overview. Sci Total Env 701:135023. https://doi.org/10.1016/j.scitotenv.2019.135023.\u003c/li\u003e\n\u003cli\u003eWu Y, Passanti M, Brigante M, Dong W, Mailhot G (2014) Fe (III)-EDDS complex in Fenton and photo-Fenton processes: from the radical formation to the degradation of a target compound. Env Sci Pol Res 21:12154\u0026ndash;12162. https://doi.org/10.1007/s11356-014-2945-1.\u003c/li\u003e\n\u003cli\u003eYang C, Song G, Lim W (2020) A review of the toxicity in fish exposed to antibiotics. Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology 237:108840. https://doi.org/10.1016/j.cbpc.2020.108840].\u003c/li\u003e\n\u003cli\u003eZampronio AR, Soares DM, Souza GE (2015) Central mediators involved in the febrile response: effects of antipyretic drugs. Temperature (Austin, Tex.) 2:506\u0026ndash;521. https://doi.org/10.1080/23328940.2015.1102802.\u003c/li\u003e\n\u003cli\u003eZhan Y, Zhou MA (2019) Critical review of the application of chelating agents to enable Fenton and Fenton-like reactions at high pH values. J Haz Mat 362:436\u0026ndash;450. doi: 10.1016/j.jhazmat.2018.09.035.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Supplementary Materials","content":"\u003cp\u003eSupplementary Material, Tables 1-3 are not available with this version.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Antibiotics, Contaminants of Emerging Concern, Tertiary Treatment, Fe-EDDS, optimization, solar photo-Fenton.","lastPublishedDoi":"10.21203/rs.3.rs-2340059/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2340059/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"The increasing occurrence of micropollutants in natural water bodies has medium to long-term effects on both aquatic life and human health. The aim of this study is to optimize the degradation of two pharmaceutical pollutants of emerging concern: amoxicillin and acetaminophen in aqueous solution at laboratory and pilot scale, by solar photo-Fenton process carried out at neutral pH using EDDS as a complexing agent to maintain iron in solution. The initial concentration of each compound was set at 1 mg/L dissolved in a simulated effluent from a municipal wastewater treatment plant (MWTP). A factorial experimental design and its surface response analysis were used to optimise the operating parameters to achieve the highest initial degradation rate of each target. The evolution of the degradation process was measured by Ultra Performance Liquid Chromatography (UPLC/UV), obtaining elimination rates above 90% for both contaminants. Statistical study showed the optimum concentrations of Fe(III) at 3 mg/L at an Fe-EDDS ratio of 1:2 and 2.75 mg/L H2O2 for the almost complete removal of the target compounds by solar photo-Fenton process. Validation of the experimental design was successfully carried out with actual MWTP effluent spiked with 100µg/L of amoxicillin and acetaminophen at pilot plant scale.","manuscriptTitle":"Solar photo-Fenton optimization at neutral pH for microcontaminant removal at pilot plant scale","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-02-06 16:36:38","doi":"10.21203/rs.3.rs-2340059/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2023-02-03T08:41:44+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2023-02-02T19:55:58+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Environmental Science and Pollution Research","date":"2022-12-23T15:46:04+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-12-15T04:39:49+00:00","index":"","fulltext":""},{"type":"submitted","content":"Environmental Science and Pollution Research","date":"2022-12-09T01:04:58+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"034501a2-0ca4-44b1-97be-528da4ad9aed","owner":[],"postedDate":"February 6th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T22:07:51+00:00","versionOfRecord":{"articleIdentity":"rs-2340059","link":"https://doi.org/10.1007/s11356-023-28988-7","journal":{"identity":"environmental-science-and-pollution-research","isVorOnly":false,"title":"Environmental Science and Pollution Research"},"publishedOn":"2023-08-11 21:56:01","publishedOnDateReadable":"August 11th, 2023"},"versionCreatedAt":"2023-02-06 16:36:38","video":"","vorDoi":"10.1007/s11356-023-28988-7","vorDoiUrl":"https://doi.org/10.1007/s11356-023-28988-7","workflowStages":[]},"version":"v1","identity":"rs-2340059","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2340059","identity":"rs-2340059","version":["v1"]},"buildId":"cBFmMYwuxLRRLfASyISRj","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}