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A novel strategy based on the sequential combination of UVC 254 nm -LED/H 2 O 2 and the Fenton process at neutral pH in continuous flow mode for wastewater reclamation has been assessed. The concentration of Escherichia coli (E. coli) reached water class A according to the European Union (EU) Regulation 2020/741 (≤10 CFU/100 mL) and a 87 ± 2 % of the contaminants of emerging concern (CECs) load was removed, complying with the new proposal regarding Urban Wastewater Treatment (Directive COM (2022) 541). To reach these results, initially the municipal wastewater secondary effluent was kept under UVC 254 nm -LED/H 2 O 2 process with a hydraulic residence time (HRT) of 5 min, a liquid depth of 5-cm and 1.8 mmol L−1 of H 2 O 2. In the sequence, addition of Fe2+ to the outside of the UVC 254 nm -LED reactor was added to acquire the desired concentration of 1.8 mmol L−1 Fe2+ (Fenton process). To obtain the same disinfection and CECs degradation by only UVC 254 nm -LED/H 2 O 2 process, 45 min-HRT were necessary. These results show that the coupled processes are the best strategy, given the reduction in HRT (from 45 to 5 min) and total cost (from 1.79 to 0.54 € m−3). In addition, new research on the application at pilot scale will encourage to evaluate the long-term toxicity of the reclaimed wastewater and to identify the main transformation products of the most abundant CECs. [Display omitted] • 45-min HRT to reach 87 ± 1 % CECs removal by UVC/H 2 O 2. • min-HRT to reach 87 ± 2 % CECs removal by coupling UVC/H 2 O 2 and Fenton processes. • Reductions of treatment time (89 %) and costs (70 %) coupling both processes. • Quality A of water reclaimed (EU2020/741) and 87 ± 2 % of CECs removal were reached. [ABSTRACT FROM AUTHOR]

Fast degradation and complete mineralization of herbicide dalapon (DPN) as the target pollutant has been investigated for the first time by the heterogeneous photoelectro-Fenton (hPEF) process using a nitrogen doped reduced graphene oxide (NrGO) modified carbon felt (CF) cathode (NrGO@CF) and a ternary nanocomposite catalyst (TNC) based on reduced graphene oxide (rGO), Fe 3 O 4 , and TiO 2 to maintain high yield generation of H 2 O 2 and •OH. The effects of main variables, including the catalyst composition and amount, applied current, and initial pH of the solution, were investigated. The as-synthesized nanomaterials exhibit significant improvements thanks to their high specific surface area, increased H 2 O 2 production, catalytic activity, and the possibility to work in a wide pH range. This system also promotes photoreduction and photooxidation reactions by increasing photon absorption. By combining highly conductive carbon materials and the photoexcited electrons from TiO 2 , redox cycling between ≡ F e I I and ≡ F e I I I was facilitated, thus improving the process performance. Catalytic stability measurements show that the use of a NrGO@CF cathode, an equimass rGO-Fe 3 O 4 -TiO 2 TNC and boron doped diamond (BDD) anode trio resulted in the fast degradation and complete mineralization of DPN within 30 and 60 minutes, respectively, after five consecutive cycles under UV light irradiation, 500 mA current intensity, 0.1 g L−1 catalyst concentration and pH 6 conditions. Moreover, intermediate products of DPN oxidation were identified. Therefore, this study highlights an efficient and stable cathode and catalyst duo for the removal of a short chain halogenated aliphatic herbicide from aqueous media. [Display omitted] [ABSTRACT FROM AUTHOR]

The production of petroleum involves significant water usage and generates substantial volumes of wastewater containing oil, grease, suspended particles, hydrocarbons, heavy metals, and other contaminants. This wastewater poses a serious challenge to global water resources, human health, and the environment. The complexity of petroleum wastewater, along with the limitations of traditional treatment methods, such as low efficiency, high costs, and potential secondary pollution risks, underscores the critical need for an efficient management strategy. Addressing the management of petroleum wastewater has become a pressing global issue, prompting the exploration of more effective treatment approaches. This paper provides a comprehensive overview of the sources and characteristics of petroleum wastewater while discussing current treatment processes. It also delves into advanced treatment technologies like adsorption, membrane technology, and advanced oxidation processes, highlighting their advantages, disadvantages, research progress, and future development trends in remediating petroleum wastewater. By focusing on these advanced treatment methods, aim to enhance the efficiency and sustainability of petroleum wastewater treatment, offering insights that can guide the development of more effective management strategies. Through ongoing research and innovation in this field, there is potential to significantly improve the remediation of petroleum wastewater, thereby contributing to environmental sustainability and the protection of water resources. [Display omitted] • Investigating the sources and characteristics of petroleum wastewater. • Summarize the established petroleum wastewater treatment process flow. • Investigating the progress of advanced technologies for treating oil wastewater. • Proposal for future research directions in petroleum wastewater treatment. [ABSTRACT FROM AUTHOR]

The contamination of water with antibiotics presents a critical challenge due to its adverse effects on the environment and public health. Advanced oxidation processes (AOPs), particularly sulfate radical-based AOPs (SR-AOPs), have emerged as promising technologies for antibiotic degradation due to their remarkable oxidative strength and selectivity. Sulfate radicals can produced through the activation of peroxymonosulfate (PMS). Metal-organic frameworks (MOFs), a class of highly porous materials, demonstrate exceptional potential in activating PMS for the production of either radical or non-radical reactive species, further enhancing pollutant degradation efficiency. A literature review is carried out on the activation of peroxymonosulfate by MOF materials for antibiotics degradation. By delving into the mechanisms of PMS activation by pristine MOFs, MOF composites, and their derivatives (including both radical and non-radical pathways), this review comprehensively evaluates various MOF/PMS systems to determine their effectiveness in antibiotic degradation. Furthermore, it examines the impact of environmental factors such as pH, temperature, and initial solution concentration on the degradation process. Finally, an overview of the degradation efficiency and mechanisms of MOFs/PMS systems towards antibiotics was provided and the challenges for such applications are proposed. The findings of this review article are expected to contribute significantly to the development of innovative approaches to address the problem of antibiotic degradation in water. [Display omitted] • Two activation pathways for peroxymonosulfate by metal-organic frameworks were analyzed. • Degradation efficiency and mechanisms of MOFs/PMS for antibiotics were studied. • Water stability and metal leaching challenges for MOFs were identified. [ABSTRACT FROM AUTHOR]

Microplastics (MPs), now considered as contaminants of emerging concern (CECs), have gained attention because of their widespread presence in the environment. Even though wastewater treatment plants (WWTPs) can reduce MPs concentrations by up to 99 %, a substantial amount is still released into the environment through sludge (1.69×105 MPs/g) and treated wastewater (447 MPs/L). What has not been widely discussed so far, is that the occurrence of MPs can affect process efficacy in WWTPs. This review critically examines the potential impact of MPs on wastewater treatment processes. The discussion first briefly addresses the removal of MPs from treatment trains implemented at WWTPs, to provide background information. Then, the review explores the effects of MPs on preliminary/primary, secondary, and tertiary/quaternary treatment stages, and processes. According to relevant studies, the presence of MPs adversely affects the performance of various treatment stages. Secondary treatment (biological treatment) performance in the presence of MPs is affected by changes occurring in the richness of microbial community, which ultimately affect the enzyme activity of microorganisms and degradation of nutrients. During some advanced oxidation processes, MPs may promote the removal of organic contaminants up to 29.2 %, while in contrast they may reduce bacteria and antibiotic resistant genes removal by up to 2.4 log unit and 18.6 %, respectively. Consequently, in many studies MPs were found to pose an additional burden on treatment. Therefore, the scientific community is urged to further explore the knowledge gap regarding the implications of MPs during wastewater treatment and provide effective and sustainable relevant solutions. [Display omitted] • MPs may interfere with wastewater treatment processes and reduce their efficacy. • MPs can reduce the removal of bacteria and genes during wastewater treatment. • MPs impact on AOPs is mostly studied under environmentally unrealistic conditions. • Treatment performance is affected by MPs concentration, type, and particle size. • Additives leaching from MPs may increase the toxicity of the treated wastewater. [ABSTRACT FROM AUTHOR]

As an organic pollutant difficult to be degraded in water bodies, phenol is toxic even at low concentrations. Therefore, studying the degradation technology of phenol is of great significance. In order to investigate the effect of transition metal doping on the performance of oxidative degradation of phenol by the persulfate activated by metal-organic frameworks, the different doping levels of Ce were tested based on the NH 2 -MIL-101(Fe). Then, NH 2 -MIL-101(Fe,Ce) with different Fe/Ce ratios was successfully prepared by solvothermal method. They were characterized by means of XRD, SEM, TEM, XPS and FT-IR. Selecting phenol as the target pollutant, the NH 2 -MIL-101(Fe,Ce)/PMS system was constructed to study the degradation rate. The factors of the different temperature, initial pH, anions, Ce doping ratios, catalyst dosage and PMS concentration were investigated. The mechanism of degradation of phenol for the above system was analyzed through free radical burst test, and the metal ion dissolution of catalytic materials in simulated wastewater treatment process was monitored by ICP-OES instrument. Finally, the intermediate products of phenol in the degradation process were inferred using LC-MS method. The results showed that when the molar ratio of Ce/(Ce+Fe) was 15 %, under the same reaction conditions, NH 2 -MIL-101(Fe,Ce)-15 % (referred to as NM-15 %) had the highest degradation rate for phenol. After the 50 min, phenol could be almostly completely removed, with K value of 0.059 min−1. This system could achieve the efficient degradation of phenol under the range of pH values (pH=3–9). The results of the free radical burst test and the free radical trapping test showed that the dominant oxidising groups were SO 4 •−, •OH, •O 2 − and non-free radical 1O 2. • NH 2 -MIL-101 (Fe,Ce) was successfully prepared and showed high performance on the removal of phenol. • The removal of phenol by the NH 2 -MIL-101 (Fe,Ce)/PMS system reached 100 % in 60 min. • Free radicals involved in degradation reactions include SO 4 •− and •OH. • •O2− and 1O 2 are also responsible for phenol degradation. • Two Phenol degradation pathways were proposed. [ABSTRACT FROM AUTHOR]

The ubiquitous existence of atrazine (ATZ) in aquatic environments has aroused intense concerns, regarding its potential harmful effects on human health and ecology safety. Ionizing radiation has now drawn increasing attention in wastewater treatment. However, its unsatisfactory mineralization performance has significantly hindered the practical applications. Herein, the gamma radiation combined with persulfate oxidation (gamma/PS) system has been innovatively engineered to facilitate the removal of ATZ. Results showed that ATZ (10 mg/L) can be completely removed by gamma radiation with 1.0 kGy dose, and the pseudo-first-order kinetic model provided an good fit for the degradation. Gamma radiation can effectively remove ATZ with initial concentrations ranging from 5–20 mg/L, over a broad pH range (3.2–10.5), with the co-existence of inorganic anions (including CO 3 2-, NO 3 -, and SO 4 2-) and humic acid, and in actual waters (tap water and surface water). Degradation pathways of ATZ were proposed according to density functional theory (DFT) calculation and LC-MS analysis, including alkylic-hydroxylation, alkylic-oxidation, and dechlorination-hydroxylation. Moreover, gamma radiation was promising to reduce the toxicity of ATZ. Compared with the gamma radiation alone process, the gamma/PS system exhibited satisfactory ATZ removal performance. The k value rose by 4.78 times when PS (1 mM) was added, and TOC removal efficiency increased from 6.48 % to 34.53 % when PS was 4 mM. •OH and SO 4 •- participated in ATZ degradation, with •OH dominating. These results demonstrated that gamma/PS is a potential approach to degrade ATZ. [Display omitted] • Atrazine could be effectively degraded by gamma irradiation. • Degradation pathway was proposed based on DFT calculation and LC-MS analysis. • Gamma irradiation could reduce the toxicity of atrazine. • Degradation and mineralization were improved in gamma/persulfate process. • •OH and SO 4 •- played roles for atrazine degradation in gamma/persulfate process. [ABSTRACT FROM AUTHOR]

Heterogeneous catalysts based on transition metal oxides are promising for activating peroxymonosulfate (PMS) for the degradation of organic pollutants and oxygen vacancy (V O) is often considered to be important in controlling catalytic performances. Herein, Cu-Mn-O/N-doped carbon catalysts were designed by changing the atomic ratio of Cu: Mn from 5:95 to 33.3:66.7, 50:50, and 95:5, resulting in the formation of V O or copper vacancy (V Cu). Unexpectedly, all these catalysts showed excellent catalytic behavior toward the oxidation of p-nitrophenol (PNP) by PMS, indicating that V O is not the main factor in determining the catalytic performance, and the synergistic effect between Cu and Mn species was suggested to be the main factor. The impact of initial pH, catalyst dosage, PMS concentration, the concentration of PNP, and inorganic anions on the removal of PNP were explored. Electron paramagnetic resonance (EPR) tests and radical scavenging experiments revealed that both radicals and non-radicals were involved in the degradation of PNP and single oxygen (1O 2) was the main reactive species. The intermediates were detected by using liquid chromatography mass spectrometry (LC-MS) in the degradation process, and a possible degradation mechanism was proposed. The developed catalysts also exhibited outstanding catalytic activities toward reduction reaction of PNP to P-aminophenol (PAP) by NaBH 4. These results exclude the consideration of designing high-performance Cu-Mn-O oxide catalysts with oxygen vacancies. [Display omitted] • Cu-Mn-O/N-doped carbon catalysts can be designed by the sol-gel method. • The catalysts have desired catalytic activity to the degradation of P-nitrophenol. • Synergistic effect is the main factor for excellent catalytic performance. • Oxygen vacancy isn't the determining factor in controlling the catalytic property. • The test results show that single oxygen (1O 2) is the main reactive species. [ABSTRACT FROM AUTHOR]

Nitrogen-doped carbon nanotubes (N-CNTs) have been considered as an excellent metal-free activator for persulfate-based advanced oxidation processes. However, the critical role of N-doping in the activation of peroxymonosulfate (PMS) and peroxydisulfate (PDS) remains a significant difference even opposed in scientific understanding. Herein, the CNTs and N-CNTs were used to active PMS and PDS for degradation of neonicotinoid insecticides (NNIs), one of the emerging refractory organic pollutants. The N-CNTs achieve 92.6% of nitenpyram (Nit) degradation within only 10 min under PMS system, much higher than that of CNTs/PMS system (∼10%). Moreover, the N-CNTs can active PMS to conduct degradation through a combined 1O 2 and electron transfer process with k of 4.94 × 10−2 L·mg−1·min−1, which was quite different from N-CNTs/PDS system (single electron transfer process, k = 1.84 × 10−3 L·mg−1·min−1). A positive correlation between degradation rates of five NNIs and their electron-donating ability is established, further verifying the importance of electron transfer in NNIs degradation. This study proves the superiority of N-CNTs/PMS over N-CNTs/PDS in Nit degradation and the underlying mechanisms, and reveals the importance of electron-donating ability of NNIs in their degradation by N-CNTs/PMS. These findings are of great significance for their removal from the environment. [Display omitted] • Nit degradation by N-CNTs/PMS was stronger and faster than that by N-CNTs/PDS. • 1O 2 was only detected from N-CNTs/PMS system, but not from N-CNTs/PDS system. • 1O 2 and electron transfer were involved in Nit degradation by N-CNTs-activated PMS. • Electron transfer from Nit to N-CNTs/PMS was stronger than that to N-CNTs/PDS. • NNIs degradation rates were positively related to their electron-donating ability. [ABSTRACT FROM AUTHOR]

This study aimed to investigate four photocatalysts, whether element-doped (g-C 3 N 4 /Cl) or through heterojunctions (g-C 3 N 4 /Nb 2 O 5 and g-C 3 N 4 /TiO 2), and compare against unmodified (bare) g-C 3 N 4 for diclofenac removal under artificial sunlight. The synthesis methodologies were deliberately chosen for simplicity to enable practical applications. Additionally, the potential phytotoxicity of the products was investigated. In this sense, the main novelty of the present work is to contribute to elucidate the performance of photocatalysts commonly employed in photocatalysis (such as Nb 2 O 5 and TiO 2), but combined with a material that allows them to be photoactive under visible irradiation. Under the experimental conditions of this study (C 0 = 20 mgL−1; C cat. = 600 mgL−1; pH = 6.0; artificial sunlight: 40 Wm−2 UVA, 245 Wm−2 VIS), the four photocatalysts displayed no statistically significant differences in diclofenac removal over the 240-minute evaluation period. However, the specific constant rate normalized by S BET indicated that bare g-C 3 N 4 demonstrated statistically superior efficacy in diclofenac removal. When exposed to natural sunlight, bare g-C 3 N 4 achieved a 68-minute normalized illumination time (t 30w) to remove over 67% of diclofenac. Assessing phytotoxicity involved 14 assays using the four photocatalysts and two seed types (cucumber and lettuce). With a few exceptions (g-C 3 N 4 , g-C 3 N 4 /Cl, and g-C 3 N 4 /TiO 2 , limited to cucumber seeds), experiments revealed non-phytotoxic byproducts after diclofenac photocatalysis, as indicated by germination indices exceeding 80%. [Display omitted] • Four photocatalysts based on g-C 3 N 4 were studied. • The average removal for the four photocatalysts under artificial light was 73%. • Phytotoxicity was studied using cucumber and lettuce seeds. • g-C 3 N 4 was able to remove over 67% of diclofenac under natural sunlight. • Most experiments revealed non-phytotoxic byproducts after diclofenac photocatalysis. [ABSTRACT FROM AUTHOR]

Currently, there are well-operated iron removal water plants in the northeast region of China. Among them, the backwash process produces a large amount of iron-containing sludge (IS) year by year, which can cause some harm to the environment if not treated. The main form of existence for IS is amorphous γ-FeOOH, and this work demonstrates that IS is a natural and highly active catalyst for periodate(PI). Moreover, IS showed strong stability in environmental factor effects and reproducibility experiments. EPR with quenching experiments proved that IS could activate PI to produce •OH, O 2 •−, 1O 2 , and IO 3 •. In the degradation experiments where methylene blue was chosen as the model pollutant, IO 3 •, and 1O 2 were the substances that served the prominent role in degradation. This work provides an inexpensive and feasible way to dispose of waste iron-containing sludge from water plants and provides fundamental insights into the degradation mechanism of organic pollutants through the activation of PI by IS. [Display omitted] • The IS from groundwater treatment plant is a natural, cheap, and accessible catalyst for PI activation. • IO 3 • and 1O 2 are found to play a vital role in IS/PI system. • IS is a promising catalyst with excellent catalytic performance, stability, and reusability. [ABSTRACT FROM AUTHOR]

The removal of contaminants through Advanced Oxidation Processes (AOPs) is a complex task that demands the simultaneous consideration of multiple operating parameters, such as type and concentration of oxidant and catalyst, type and intensity of radiation, composition of aqueous matrix, etc. Designing efficient AOPs often requires expensive and time-consuming laboratory experiments. To improve this process, this study proposes a Machine Learning approach based on a Random Forest (RF) model, to predict Enterococcus sp. concentration in wastewater treated with various AOPs, even when dealing with limited data. To assess our approach under diverse conditions, a data partitioning methodology is used to categorize the different AOPs into three distinct study cases of increasing complexity, from Case I to Case III. The evaluation of the RF model's performance, combined with the data partitioning methodology, demonstrated its usefulness in predicting missing or additional disinfection values at any instant during the AOPs. Specifically, in Case I, the model excels at generalizing predictions across various AOP treatments , followed by Case II and III, which achieve Root Mean Squared Error (RMSE) values below or comparable to the average RMSE of Case I (0.72) in 8 out of 15 and 2 out of 4 treatments , respectively. Moreover, the effects of imbalanced data on model performance are discussed. This highlights the potential of our approach to assess AOPs performance and facilitate the design of new experiments of the same treatment type without the need for additional laboratory trials, even in challenging conditions. • Random Forest predicts Enterococcus sp. disinfection in Advanced Oxidation Processes. • Improve of Advanced Oxidation Processes design using Machine Learning model. • Effect of data sample size and variability of parameters in Random Forest performance. • Challenges in the design of Advanced Oxidation Processes using Random Forest models. [ABSTRACT FROM AUTHOR]

The efficient elimination of ammonia nitrogen (NH 4 +-N) from the specific wastewater and selective oxidation to nitrogen gas are the most desirable purposes of wastewater treatment, but still remains a challenge. Herein, we presented a cobalt-based catalyst (Co-VB 12 -C) as a novel heterogeneous catalyst, which was fabricated via the co-pyrolysis of poly (2,6-diaminopyridine) and vitamin B 12. Co-VB 12 -C were successfully prepared to construct a facile heterogeneous Co-VB 12 -C/PMS/Cl system and achieve effective removal of NH 4 +-N and high selectivity to nitrogen gas in acidic and neutral pH. Co-VB 12 -C had superior catalytic capability, reusability, and stability. The role of catalyst, PMS, Cl-, and pH value was investigated and the corresponding mechanism was proposed, which revealed that Cl•-mediated oxidation reactions made predominant contribution to NH 4 +-N transformation. This system is a facile alternative technology for removing ammonium from high saline wastewater. [Display omitted] • Cobalt-based catalyst was prepared to activate PMS for NH 4 +-N oxidation. • Chlorine radical (Cl•)-mediated Co-SAC/PMS/Cl system was developed. • NH 4 +-N could be selectively oxidized to N 2 in Co-PMS/chloridion system. • The removal efficiency of NH 4 +-N and selectivity to N 2 were 96.47% and 97.23%. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNT) have been proposed to activate persulfate over the past decade, resulting in successful degradation performance for organic pollutants in wastewater treatment. However, there is debate over the reaction mechanism involving radical versus non-radical pathways, setting up a roadblock to further developing persulfate activation by carbonaceous materials. This work focused on the carbon nanotubes/peroxydisulfate (CNT/PDS) system, investigated its reaction mechanism, and unveiled the relationship from the aspect of molecular descriptors. The involvement of radicals (e.g., SO 4 •− and HO•) and 1O 2 was ruled out by the observation of quenching effect, oxidation products, chemical probes, solvent exchange, and electron paramagnetic resonance spectra. Then, mediated electron transfer was deemed as the primary reaction mechanism based on linear sweep voltammetry analysis, which was supported by the PDS consumption result. The substrate-dependent treatment capacity was found in the CNT/PDS for multiple contaminants degradation, and it turned out that E B3LYP was the most significant parameter in the relationship between degradation rates and molecular descriptors. Outstanding environmental application was exhibited based on the coexistence of various organic/inorganic substances and repeated degradation experiment. Therefore, the findings from this study would be helpful for both scientific research and technical development of persulfate activation by CNT. [Display omitted] • CNT/PDS exhibits highly effective degradation performance for pollutants. • Mediated electron transfer was the primary reaction mechanism. • E B3LYP was the most significant molecular descriptor for pollutants degradation. • PDS activation by CNT shows excellent environmental application. [ABSTRACT FROM AUTHOR]

The extensive use of parabens in various products in combination with the low removal when treated with conventional methods have resulted in their widespread environmental occurrence. Ethyl-paraben (EtP), methylparaben (MeP) and propylparaben (PrP) are characteristic compounds of this category. Over the last years, Sulfate Radical-based Advanced Oxidation Processes (SR-AOPs) have shown promising results for the removal of organic micropollutants. As parabens commonly coexist in mixtures in aquatic systems, this study investigates the efficiency of UV-C/PMS process to remove EtP, MeP and PrP as a mixture in ultrapure water (UPW) and wastewater (WW). UV-C/PMS process was found to be efficient and high removal percentages were observed for all the parabens. However, the removal was dependent on the complexity of the water matrix. Different ions, as well as the dissolved organic matter that exist in wastewater can significantly influence the degradation of the mixture of parabens in UV-C/PMS process. The transformation was found to proceed through hydroxylation, dealkylation, radical coupling and cleavage of the aromatic rings. Although the toxicity was increased at the first stages in both UPW and WW, almost complete detoxification was achieved after prolonged time accompanied by the degradation of all the generated TPs. UV-C/PMS was also found being able to significantly reduce the toxicity from the wastewater. [Display omitted] • UV-C/PMS was effective to remove ethyl-, methyl- and propyl- p-hydroxybenzoate ester. • The k app values were in the range of 6.27 × 10−2 − 10.51 × 10−2 min using 0.3 mM peroxymonosulfate. • The removal was found to be dependent on the complexity of the water matrix. • Hydroxylated, dealkylated, dimers and aliphatic transformation products were identified. • Low inhibitions 1.5% and 7.6% were achieved in ultrapure and wastewater after 60 and 180 min, respectively. [ABSTRACT FROM AUTHOR]

Persulfate (PS)-based advanced oxidation processes have attracted significant attention in the field of organic contaminant remediation. In this study, we developed a biochar-supported Fe nanoparticle catalyst (FeNPs@BC) characterized by a substantial quantity of Fe0, with the purpose of activating persulfate to facilitate the degradation of atrazine (ATZ) in soil. The results revealed that the 800 °C pyrolyzed FeNPs@BC-PS system, incorporating 2 wt% FeNPs@BC and 3 mmol/L PS, achieved rapid removal of ATZ (100%) within 10 min (k obs =0.19023 min−1). Active-species quenching experiments and electron spin resonance (ESR) demonstrated the presence of sulfate radicals (SO 4 •-), hydroxyl radicals (•OH), and singlet oxygen (1O 2) in the FeNPs@BC-PS system. Furthermore, FeNPs@BC maintained a high catalytic activity even after four cycles of recycling. And the catalyst exhibited efficiency in degrading three other triazine herbicides (simazine, terbuthylazine, and ametryn). Notably, toxicity prediction experiments on the degradation products indicated lower toxicity compared to that of the parent ATZ. In summary, this study presents a promising solution for the development of an economical, efficient, and environmentally friendly technology capable of rapidly degrading soil herbicides. • FeNPs@BC-PS achieved ultrafast degradation of atrazine in soil. • ATZ degradation involved both the free and non-free radical pathways. • DFT calculations proposed FeNPs@BC-PS system's possible ATZ decomposition pathway. • The toxicity of the intermediates was lower than that of ATZ. • FeNPs@BC-PS possesses universal applicability for triazine herbicide degradation. [ABSTRACT FROM AUTHOR]

In recent decades, natural mineral materials (NMMs) and NMMs-based materials as the emerging catalysts for advanced oxidation processes (AOPs) have progressively become a rising field of environmental research. Compared with chemically synthesized catalysts, NMMs are inexpensive and abundant, which makes them suitable to realize large-scale applications in practical production. This critical review classifies NMMs into five categories including Fe-based materials, Cu-based materials, Ti-based materials, other common metal materials and silicate mineral materials, whose crystallographic characteristics and applications in the field of AOPs for wastewater purification are systemically summarized. In addition, the catalytic degradation performance, catalytic mechanism and reusability of NMMs or NMMs-based materials are also briefly reviewed. We anticipate this review would highlight the strategy of using low-cost and abundant mineral resources as green materials for wastewater decontamination, and therefore broaden the application perspectives and values of NMMs. [Display omitted] • A comprehensive picture of natural minerals applied in AOPs are provided. • Catalysts based on both metallic and non-metallic natural minerals are reviewed. • Modification strategies to improve catalytic activity of natural minerals are summarized. • Pollutant removal performance of different kinds of minerals are compared. • Perspectives and future research directions for natural minerals are proposed. [ABSTRACT FROM AUTHOR]

Improper discharge of benzalkonium chlorides (BAC) to sewage and wastewater treatment plants can cause acute intoxication and chronic low-dose exposure, which can lead to changes in microbial communities and can promote the development of antibiotic resistance. The aim of this study was to develop a feasible treatment strategy based on the homogeneous Fenton oxidation to minimize the negative impact of BAC-containing wastewater on activated sludge systems. The effect of initial iron and oxidant concentrations was analyzed. After an initial Fenton oxidation stage (180 min), the solution needed to be stored at ambient temperature and in the dark for some time to remove residual oxidizing agents and promote further oxidation. The 0.1 % w/v-BAC solution treated at best operating conditions, i.e., homogeneous Fenton for 180 min at 30 °C, pH 0 = 3, stoichiometric oxidant dose, [Fe+2] 0 :[H 2 O 2 ] 0 = 0.011, and stored during 4 days, led to BAC conversion of 99.9 %, no residual H 2 O 2 , no sludge, and DOC conversion of 40.8 %. An increase in metabolic activity was observed when non-acclimated activated sludge was exposed to the treated solution. Treated solution showed biodegradation without increasing resistance to Ampicillin, Cephalexin, or Ciprofloxacin. Evaluation of the effect of water matrix (tap or distilled) showed that the composition of tap water enhanced the oxidation extent, resulting in a 15 % increase in mineralization and a further reduction of COD. This study provides insights into the treatment of wastewater containing BAC and its safe discharge to sewage systems or biological wastewater treatment plants. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, emerging advanced oxidation processes (AOPs), namely UVC photo-Fenton with two chelating agents at neutral pH, were compared for the first time to consolidated AOPs, namely, UVC/H 2 O 2 and Ozonation (O 3) in the degradation of three pharmaceuticals (PhCs) and pathogens inactivation, in real municipal wastewater (RMWW) at pilot scale. Conventional UVC based AOP (UVC/H 2 O 2 at 50 mg/L of H 2 O 2) was faster, being able to degrade 80% of the sum of PhCs in RMWW after 2.5 min, while the same treatment time was required to achieve 60% removal by photo-Fenton. 60% removal of the sum of PhCs in RMWW by O 3 was achieved only after 75 min, at the highest dose investigated (0.45 g O 3 / L h). The detection limit (1 CFU/100 mL) for pathogens inactivation was achieved after 120 min by O 3 for E. coli , while more time was required for Enterococcus (10 CFU/100 mL after 120 min). Faster inactivation was observed for UVC/H 2 O 2 (15 mg/L), the DL being achieved just within 5 and 10 min for E. coli and Enterococcus , respectively. Accordingly, UVC/H 2 O 2 at 15 mg/L would be an effective solution for simultaneous PhCs removal and bacteria inactivation, showing better performance compared to O 3 and UVC photo-Fenton like process. [Display omitted] • UVC AOPs and O 3 investigated as ternary and quaternary treatment of wastewater. • All the investigated processes removed pathogens and pharmaceuticals effectively. • UVC AOPs significantly faster (2.5 – 6.0 min) than O 3 treatment (75 min). • UVC photo-Fenton with EDDS and IDS resulted in similar efficiency. • UVC/H 2 O 2 (15 mg/L) can be recommended for full-scale application. [ABSTRACT FROM AUTHOR]

Wastewater treatment is an urgent challenge of the 21st century, and photocatalysis represents a promising approach. However, much of the research has focused on powdered photocatalysts and complex, costly methods, leading to limitations in practical applications. This study introduces an innovative approach to produce Cu:Co thin films with different weight ratios (70:30, 50:50, and 30:70) by the low-cost dip-coating technique. The photocatalytic activity of Cu:Co films was investigated through the photooxidation of alcohol (EtOH), degradation of dye (MB), antibiotic (AMX), and photoreduction of heavy material ions (Cr(VI)) under sunlight irradiation. The results clearly show that higher Cu concentration ratios (70:30%) resulted in smoother surfaces (49.7 nm), higher droplet contact angle (72.43 °), smaller particles (67 nm), lower film thickness (365 nm), narrower band gap (1.68 eV), higher transmittance (26.7%), and improved degradation of MB (78% for 4 h) and amoxicillin (43% for 45 min). Conversely, higher Co ratios may yield contrasting effects in most cases. The photoreduction of Cr(VI) showed similar results for Cu:Co films with 70:30 and 50:50 ratios, reaching 42.81% and 43.82% for 30 min, respectively. The effect of the ethanol photooxidation process significantly reduced the roughness, film thickness, and band gap in all Cu:Co films while enhancing transmittance, except for the 50:50 Cu:Co ratio. Cu:Co films are ideal for practical applications such as photoreaction processes due to their efficiency, sustainability, and stability. [Display omitted] • Innovative method for creating Cu:Co thin films with varying ratios (70:30, 50:50, and 30:70) using dip-coating technique. • Higher Cu concentration (70:30 ratio) yields non-rough surfaces, increased hydrophobicity, smaller particles. • Higher Cu reduced film thickness, narrowed the band gap, increased transmittance, and enhanced degradation of MB and AMX. • Comparable outcomes for photoreduction of Cr(VI) observed for Cu:Co films with ratios of 70:30 and 50:50. • Ethanol photo-oxidation significantly reduces roughness, film thickness, and band gap while enhancing transmittance. [ABSTRACT FROM AUTHOR]

This review presents a comprehensive review of recent advances in layered double hydroxide (LDHs) materials, with a focus on their synthesis, modification, and applications in wastewater treatment. We examine the structure and properties of LDHs materials, including aspects such as tunability, structural memory effect, thermal stability, acidity and alkalinity, stripability and assemblability. Various synthesis methods for LDHs materials are described, encompassing coprecipitation, urea hydrolysis, hydrothermal, sol-gel, and template. Additionally, we delve into diverse modification techniques, such as cation doping, anion exchange, reconstitution, delamination, and composite. Lastly, we discuss the potential applications of LDHs materials in wastewater treatment, specifically in the areas of adsorption and catalysis, with particular emphasis on the removal of heavy metal ions and dyes. In summary, This review provides a comprehensive overview of recent advances in LDHs materials and their potential for wastewater treatment. [Display omitted] • Excellent performance of LDHs materials in wastewater treatment. • LDHs are excellent adsorption and catalytic materials due to their unique structure and properties. • Multiple synthesis methods allow LDHs to meet the specific needs of wastewater treatment applications. • Future research and application of LDHs will continue to progress while encountering challenges. [ABSTRACT FROM AUTHOR]

The catalytic properties of low-cost ceramic aluminosilicate polymers (geopolymers) containing metakaolin and different amounts of magnetic mining waste, up to 75% w/w, were investigated for the degradation of the antibiotic drug trimethoprim (TMP) in water in the presence of ozone. In the presence of the geopolymers, the removal of TMP increased by up to 11% to reach 71% conversion, while its mineralization increased by 4% to reach 40%. Moreover, the catalyst also decreased the steady-state ozone saturation level of the solution. Reactive species (ROS) trapping experiments demonstrated that superoxide (O 2 •–) had the most significant impact on the removal rate (55% decrease), followed by singlet oxygen (1O 2) (30% decrease). The 20 intermediate reaction products identified by mass spectroscopy was consistent with a four-branch reaction mechanism by superoxide attack on the TMP molecule including i) the methylene bridge rupture, ii) the oxidation of the diaminopyrimidine amine with further hydroxylation and carbonylation, iii) the hydroxylation of diaminopyrimidine amines and iv) 1,2,3-trimethoxybenzene demethylation. XRF, FTIR, ss-NMR and XPS analyses of the geopolymers before and after the reaction also demonstrated the robustness of the geopolymers catalysts during the ozonation reaction. Overall, this study demonstrates that inexpensive geopolymers produced from mining waste could be used in catalytic ozonation reactions for water decontamination. [Display omitted] • Geopolymers with high magnetic mining waste levels were applied as catalysts. • Catalytic ozonation with these geopolymers attained 71% removal of Trimethoprim in 1 h. • A complex mechanistic route for trimethoprim degradation was proposed. • Chemical analyses showed that the as-prepared geopolymers were stable against ozone. [ABSTRACT FROM AUTHOR]

Highlights • We study the degradation of methyl orange by using hydrodynamic cavitation (HC) in the presence of ion metals. • We measure the effect of various operating parameters (pH, temperature, inlet pressure) on the decolourization efficiency. • A full factorial plan was carried out to determine the main effects and mutual interactions among the factors. • We find that the optimum operating conditions among those investigated are: 5 ppm of, pH = 2, 0.6 MPa and 1 h, independently of temperature. • The degradation process in the presence of ion metals increased of 5 times the efficiency of the HC performed in the absence of metals. Abstract The aim of this research was to investigate the methyl orange degradation using hydrodynamic cavitation. The synthetic solutions simulated a real textile effluent containing dye and metals (iron and nickel) as a consequence of the corrosion of nickel-plated metal components of the plant during the production of textile materials. In the first series of experiments, the hydrodynamic cavitation was studied in terms of operating inlet pressure and pH of solution. Subsequently, a full factorial plan was performed to determine the main effects and interactions among the investigated factors: inlet pressure (p in), temperature (T), initial dye concentration (c MO / 0), and treatment time (t). The results showed that inlet pressure, temperature and concentration had a significant positive effect on dye degradation, as well as the interactions temperature/dye concentration and pressure/time. The optimum operating conditions among those investigated were: c MO / 0 = 5 ppm, pH = 2, p in = 0.6 MPa and t = 1 h, independently of temperature (T). In the above conditions, the degradation yields were near to 75% and the final concentration was less than 1 ppm. On the contrary, at c MO / 0 = 20 ppm, pH = 2, p in = 0.6 MPa, T = 40 °C and t = 1 h, the degradation efficiency was about 56% and the final concentration was less than 9 ppm. A comparison among the experiments carried out in the absence and in the presence of iron and nickel showed that metals acted as catalysts and the energy required for the process with metal ions was 5 times smaller than that those required by the experiments conducted without the metals in solution, at the same operating conditions. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Advanced nanostructures of titanium dioxide are intensively investigated for environmental protection. The latest developments in the field pay special attention to innovative and highly performing titania materials (anatase/rutile mixed-phase nanocomposites, anion-doped core-shell nanostructures, self-organized nanotubes, photonic crystals and their modifications with graphene oxide and metal nanoparticles) with original functionalities and tailored properties (visible light activated photocatalysts-VLA), the elucidation of the corresponding mechanisms involving interaction of light with matter at the nanoscale and resulting photoinduced electron transfer reactions. These materials are also considered as key components for the design and fabrication of devices (photocatalytic reactors) for efficient degradation and/or transformation of emerging environmental contaminants. The presence of a TiO 2 photocatalyst on the asymmetric membrane surface and pores insures simultaneous pollutant retention and photodegradation, permitting continuous long-term device operation without fouling, practical absence of concentrated retentate and cost effective production of clean water. Focusing on recent investigations of our group concerning the use of innovative titania nanostructured photocatalysts, the present work attempts to explore novel trends and present perspectives of TiO 2 photocatalysis inside and outside the well-established frame of advanced oxidation processes (AOPs), expanding the field borders by including advanced reduction processes (ARPs) and relating technological applications (ARTs). [ABSTRACT FROM AUTHOR]

Fenton-like processes have gained widespread acceptance due to their high oxidative potential and environmental compatibility. In this study, a composite of graphitized carbon and nZVI (GC-nZVI) was synthesized and applied toward the degradation of bisphenol A (BPA) in water. The morphological structure and stability of GC-nZVI were evaluated using different characterization techniques including X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Our results showed that the catalytic graphitization of carbon occurred simultaneously with the carbothermal reduction of iron oxide, and ZVI was distributed uniformly on the carbon material. Excluding the adsorption effect, there was almost no degradation of BPA using GC-nZVI only. However, in the presence of H 2 O 2 and UVA radiation, BPA was rapidly degraded. The synergistic effect of the photo-Fenton process carried out in the presence of H 2 O 2 showed that 90% of BPA degradation was obtained after 60 min using only 50 mg L–1 of GC-nZVI and 0.5 mM of H 2 O 2 at pH 6. The generation of HO• has been demonstrated using chemical competition experiments and the photo-Fenton process, which could eliminate 66% of BPA within 15 min under the same conditions. Finally, recycling experiments have shown that after three cycles of BPA and H 2 O 2 addition, a degradation efficiency of 71% was achieved over 60 min. The GC-nZVI/H 2 O 2 /UVA system demonstrated great potential for advanced oxidation processes and had good application prospects in the treatment of actual wastewater. [Display omitted] • GC-nZVI was synthesized via a carbothermal reduction and metal-catalyzed graphitization process. • GC-nZVI mediated photo-Fenton degraded BPA under near-neutral conditions. • Multiple H 2 O 2 additions allowed for the continued degradation of BPA in our recycling experiments. • A proposed degradation pathway for BPA has been presented. [ABSTRACT FROM AUTHOR]

This study investigated an innovative and low-cost hybrid system that couples constructed wetland (CW) and solar photo-Fenton (SPF) to enhance the elimination of 17 different micropollutants (MPs) from urban wastewater. The CW unit explored two aquatic plants (Phragmites australis and Cyperus haspan) and two operational modes (with and without recirculation), resulting in four different microcosms. Photo-Fenton experiments were carried out in a bench solar simulator at natural pH using the commercial fertilizer DTPA as iron catalysts. The results showed that the constructed wetlands with recirculation obtained better MPs eliminations than microcosms without recirculation, with no significant difference between the two plants. The average removal of total MPs and different cycles was 67% and 41% in the unit planted with C. haspan , with recirculation and no recirculation, respectively. Additionally, the removal performance of total suspended solids (TSS) and dissolved organic carbon (DOC) from water was also high, reaching about 80% and 50% for TSS and DOC, respectively in the recirculation unit with no increase in nitrites content. The CWs performance resulted in a rise yields of overall MPs abatement in photo-Fenton process, from an average removal of 73% for the single process up to almost complete removal (95%) for the hybrid system. CW with recirculation combined with SPF would let to achieve the corresponding limits according the final use/fate of the effluent in a more economical, sustainable and green way. [Display omitted] [ABSTRACT FROM AUTHOR]

Wastewater treatment plants (WWTPs) have been identified as hotspots for the spread of micro(nano)plastics (MPs/NPs) in water. Advanced oxidation processes (AOPs) have emerged as promising alternatives for tackling MPs/NPs pollution, however, the number of studies on this topic remains quite limited and needs further research. In this study, the feasibility of the photo-Fenton process (UV/ H 2 O 2 / Fe3+) carried out at ambient conditions and using a broad-spectrum UV-Vis lamp was investigated for the degradation of polystyrene (PS) NPs in water. The impact of the main variables of the process, namely initial PS concentration, Fe3+ concentration, initial pH, H 2 O 2 dose and particle size, was evaluated. Under optimized operating conditions ([PS NPs] 0 = 20 mg L−1; [Fe3+] 0 = 1 mg L−1; [H 2 O 2 ] 0 = 130 mg L−1; pH 0 = 3 and T = 25 ºC), complete mineralization of PS NPs (140 nm) was achieved in 40 min. The outstanding performance of the process was mainly due to the wavelength and light intensity of the UV-lamp employed. To the best of our knowledge, this is the first study in the field of photoassisted AOPs reporting the complete and fast mineralization of PS NPs in water, under ambient conditions. According to our results, photo-Fenton process can be applied to higher loads and larger particle sizes by adjusting the supplied oxidant dose and extending the reaction time. Hence, the photo-Fenton process displays great potential for producing high-quality reclaimed water and/or to be combined with a conventional separation process to treat concentrate streams and mineralize NPs at WWTPs. [Display omitted] [ABSTRACT FROM AUTHOR]

The disposal of effluent and sludge containing emerging contaminants (ECs) are the main problems associated with most traditional treatment methods. Non-steroidal anti- inflammatory drugs (NSAIDs) require more complete treatments integrated with conventional processes to enable circular economy and the water-energy-food (WEF) nexus. Different options to traditional technologies have been employed in the treatment of effluents, such as advanced oxidation processes (AOPs). However, few studies use real scales integrated with existing technologies. This work evaluated the use of AOPs for the degradation of ketoprofen (KET), diclofenac (DCF), and the DCF+KET mixture in an anaerobic effluent matrix, post-treated by an Upflow Anaerobic Sludge Blanket Reactor (UASB) in a real-scale Sewage Treatment Plant (STP). A Factorial Experimental Design was proposed and after 2 h of treatment the efficiency was evaluated by the decrease in total organic carbon (TOC), decrease of drugs concentration, physicochemical and ecotoxicity parameters. As a result, the photo-Fenton process showed greater efficiency in the degradation of KET (97.2% ± 1.6), DCF (72.7% ± 4.9), and the mixture of the two drugs DCF+KET (66.0% ± 2.5), improved the quality of the effluent in the removal of COD, BOD, and turbidity, and reduced toxicity in tests performed with Artemia sp. and Lactuca sativa. The integration between AOPs and UASB as a sewage treatment technology widely used as primary and secondary treatment, allowed to optimize the sewage treatment system for an ideal arrangement. As a consequence, it possesses the capacity to eliminate conventional organic matter and efficiently degrade emerging pollutants. [Display omitted] [ABSTRACT FROM AUTHOR]

Microcontaminants present in environmental aqueous matrices represent an emerging concern due to their recalcitrance to conventional wastewater treatment. This study aimed to (i) investigate the degradation of a mixture containing benzophenone-3, fipronil and propylparaben in a tertiary municipal wastewater effluent (100 µg L−1 each) by UV-C, UV-C/H 2 O 2 , U V − C / S 2 O 8 2 − and U V − C / H S O 5 − , and (ii) compare the degradation profile of this mixture with that of naproxen (a compound that reacts preferentially by electron transfer). Regarding the mixture, degradation increased from 50% (UV-C) to 74–87% by coupling UV-C with peroxides under the best peroxide concentration (400 μmol L−1) due to the generation of hydroxyl (HO•) and sulfate ( S O 4 • − ) radicals. In addition, the degradation efficiency was strongly dependent on the structure of the target compound, pH and peroxide source. Although high pseudo-first-order rate constants (k obs) were obtained at pH 3.0 for all peroxides, higher k obs were obtained at pH 7.0 (natural matrix pH) in the presence of H 2 O 2. K obs calculated for mixture degradation using different peroxides at pH 7 showed the following order: UV-C/H 2 O 2 > U V − C / H S O 5 − > U V − C / S 2 O 8 2 − . In contrast, an opposite profile was observed for naproxen degradation (U V − C / S 2 O 8 2 − > U V − C / H S O 5 − > UV-C/H 2 O 2). Finally, the analysis of energy efficiency and treatment costs showed that UV-C/H 2 O 2 is highly cost-effective. [Display omitted] [ABSTRACT FROM AUTHOR]

The current study aims to develop a cost-effective and efficient treatment method for the remediation of amine-containing real industrial effluent. The method consists of a precipitation to remove chloride ions and TDS, followed by cavitation-based AOPs involving US and chemical oxidants as H 2 O 2 , O 3 , Fenton's reagent, NaClO, and nTiO 2. Different parameters including precipitating agent type and dosage, oxidant loading/flow rate, and time were assessed to determine optimal conditions for effective treatment. Treatment schemes were evaluated based on cavitational yield (mg/J), treatment cost (Rs/L), and COD reduction to select an industrially feasible design for amine-containing real effluent treatment. The optimum conditions elucidated were H 2 O 2 loading of 3 g/L, NaClO loading of 3 g/L, O 3 flowrate of 3 LPH, nTiO 2 loading of 3 g/L, and Fenton's reagent ratio (H 2 O 2 /Fe2+) as 6:1. Under the optimum conditions, US+nTiO 2 (70%) treatment schemes were the most efficient, achieving a maximum COD reduction compared to US+Fenton (65%), US+H 2 O 2 (36%), US+O 3 (49%) and US+NaClO (53%) schemes. Additionally, impact of chloride and TDS on the oxidation process in terms of COD reduction was assessed. Using Rotavap instead of precipitation, and subsequent use of the best oxidation method (US/HC+Fenton+CaO) achieved COD and TDS levels below 250 mg/L (discharge limit) at optimum conditions, with minimal operating costs of 0.23 $/L and 0.15 $/L, respectively. Overall, the study concluded that the sequential approach of precipitation/Rotavap and cavitation-assisted oxidation is an effective and sustainable method, providing a promising solution for the wastewater treatment in the metallurgical industry. [Display omitted] • Study proposes an economical method for treating REE effluent with high levels of TDS (130 g/L) and COD pollutants. • Rotavap pre-treatment was found to be more efficient than precipitation for removing TDS from REE effluent. • Parameter study included precipitating agent dosage, catalyst loading (nTiO 2), oxidant loading, and ozone flow rate. • Rotavap followed by cavitation+Fenton+CaO treatment scheme achieved dischargeable effluent • Proposed method can be a sustainable solution for treating metallurgical industry wastewater. [ABSTRACT FROM AUTHOR]

Continuous flow Electrochemical Peroxidation (EP) was studied as a method for wastewater treatment in the Mexican textile industry. Fe2+ was generated in a reactor by electrochemical cells in the presence of H 2 O 2. EP was combined with later stages of flocculation, sedimentation and vacuum filtration, in order to study the effects of pH, Fe dose, and H 2 O 2 concentration on overall process efficiency. Under optimal conditions (747 mg/L of Fe and 1226 mg/L of H 2 O 2 at pH 3.0, obtained by means of a central compound design, it was possible to remove 86.4% of the dissolved organic carbon (DOC) and 97.7% of the color. It was observed that electrocoagulation (EC) and chemical oxidation (CO) with H 2 O 2 have a synergistic effect when applied simultaneously during EP, compared to either effect on its own. EP was found to have an operating cost of 3.87 USD/m3, which accounts for energy consumption, chemical products, transport, and sludge disposal. This work is novel because it analyzes the effect of the main variables for EP in a continuous flow reactor with water from the textile industry, with competitive costs and treatment times applicable to real units. [Display omitted] [ABSTRACT FROM AUTHOR]

Prednisolone (PRD) is a popular synthetic corticosteroid medication that discharging it into wastewater raises potential environmental issues. In terms of treatment methods, advanced oxidation processes (AOPs), such as the electro-Fenton (EF) process, have been proposed as a potential option. This study investigates the removal of PRD from aqueous media using both homogeneous and heterogeneous EF processes. A reduced graphene oxide/Tin (IV) oxide/stainless steel mesh (rGO/SnO 2 /SSm) composite system was prepared as the cathode electrode, and a reduced graphene oxide/magnetite/cotton fabric (rGO/Fe 3 O 4 /CF) composite system was prepared as the heterogeneous catalyst. The optimization of process parameters for each system was carried out using response surface methodology (RSM). The removal efficiencies of PRD were determined under optimal conditions. The homogeneous EF process achieved an 83.79% removal efficiency, while the heterogeneous EF process achieved a 74.62% removal efficiency. The properties of the heterogeneous catalyst and the cathode electrode were investigated using SEM, XRD, FT-IR, CV and EDX analyses. GC-MS and TOC analyses were performed to evaluate degradation intermediates and mineralization efficiency. The stability and reusability of the heterogeneous catalyst and the synthesized cathode electrode were evaluated. These findings offer insightful information about the use of EF methods for PRD removal. [Display omitted] • Prednisolone was removed from water by the electro-Fenton process. • Homogeneous and heterogeneous catalysts were used in the electro-Fenton process. • A new cathode electrode was prepared using stainless steel mesh. • A new heterogeneous catalyst based on cotton fabric was prepared. [ABSTRACT FROM AUTHOR]

Highlights • Fe-MFI catalyzed wet peroxide oxidation of ibuprofen through free radical mechanism. • Very low catalyst leaching evidenced main contribution of surface iron species. • Reaction rate was improved by higher temperature, catalyst & oxidant concentrations. • Hydroxylated ibuprofen adducts were found as main oxidation intermediates. • Preliminary acidification maintained catalyst activity in WWTP effluent matrix. Abstract Heterogeneous Fenton oxidation using Fe-zeolite catalyst (of ZSM5 type) was investigated for the removal of ibuprofen (20 mg/L) in water. In particular, the effects of catalyst concentration, oxidant dosage, temperature, solution pH, and water matrix on pollutant conversion and mineralization were evaluated. The activity of leached iron species in solution was also measured to determine the contribution of the homogeneous reaction. Oxidation rate of ibuprofen obeyed a pseudo-first-order kinetics with respect to the pollutant concentration, and the apparent rate constant increased with catalyst and hydrogen peroxide concentrations in the investigated ranges (1-5 g/L of Fe-zeolite and 0.5-7 times the stoichiometric amount of oxidant). Energy activation of 53 kJ/mol was obtained from Arrhenius plot. However, the mineralization yield was not significantly improved by a too large excess of H 2 O 2 or increase of temperature. In the selected conditions (25 °C, 4.8 g/L of catalyst, 2 times the stoichiometric amount of H 2 O 2), 88% of ibuprofen and 27% of TOC were removed after 3 hours of reaction under "natural" pH conditions. Very low leaching (up to 0.2 mg/L) and negligible activity of leached iron in solution indicated that Fenton reaction was mainly induced by iron species on the catalyst surface. Degradation rate of ibuprofen was slower in wastewater effluent as compared to distilled water, mainly due to alkaline buffering and radical scavenging effects of organic and inorganic compounds present in the matrix. Mono- and multi-hydroxylated ibuprofen adducts were found as main oxidation intermediates -in line with free-radical mechanism- as well as 4-isobutylacetophenone from decarboxylation route. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • SMX removal by different oxidation processes under identical experimental conditions. • SMX degradation was faster in ozonation. • Combination of light and ozone presented synergistic effect in SMX decomposition. • SMX decomposition by AOPs leads intermediate compounds formation. • Treated solution presented toxicity. Abstract The degradation of the antibiotic sulfamethoxazole (SMX) was studied by several oxidation processes in the same reactor and under identical experimental conditions. The evolution of SMX concentration and mineralization degree, as well as toxicity of the treated solutions were the parameters considered to assess the efficiency of the different oxidation processes. The formation of molecular, radical and ion intermediates was also monitored. Ozonation was the most efficient process in SMX degradation, while photo–ozonation, with or without H 2 O 2 , led to the highest mineralization (83% after 3 h), confirming the synergistic effect when ozone and light were applied together. The results suggested that the first intermediate formed during the degradation of SMX was 3-amino-5-methylisoxazole, the direct O 3 attack being then the main responsible for its degradation. During the photolysis process p -benzoquinone was formed, although after 3 h of reaction this intermediate was no longer detected. The formation of two refractory acids, oxalic (OXL) and oxamic (OXM), was confirmed during SMX degradation and the presence of O 3 and radiation together was mandatory to remove these compounds. When O 3 and light were combined, all nitrogen and sulphur present in SMX molecule were converted into NH 4 +, NO 3 − and SO 4 2−, respectively. Although photo-ozonation was the most efficient process in converting SMX, a considerable toxicity was developed in the treated solution, suggesting the formation of intermediates more toxic than the parent molecule. [ABSTRACT FROM AUTHOR]

Natural materials were evaluated in the Catalytic Wet Peroxide Oxidation of a commonly used azo-compound, Orange II. Volcanic ash, black sand, pumice and Montanit300 ® were selected for evaluation. The materials were thoroughly characterized by several techniques (XRD, SEM/EDX, BET surface area and pore size distribution, TPD, Mössbauer spectroscopy, etc.). Peroxidation experiments were performed varying reaction temperatures (50–80 °C), catalyst loads and pH value (3–8). Complete decolouration was reached in most experiments; however, mineralization levels, peroxide consumptions and stabilities differed between materials. The activity of Fe leached during the reaction was evaluated and a combination of heterogeneous and homogeneous mechanism cannot be discarded. Thus, the materials may behave as Fe dispensers. Long-term stability experiments were also performed. While Montanit300 ® showed a decreased performance (20% activity reduction in 16 h) due to a higher leaching (20% Fe loss), ash and pumice performances remained almost steady at pH = 3 (Fe loss: 3% ash and 1.3% pumice). Mineralization levels obtained were outstanding (40–70%) and comparable to performances showed by more sophisticated catalysts. The use of these natural materials will optimize the Fenton process economics, since they are unexpensive, abundant and require only minimal modifications. [ABSTRACT FROM AUTHOR]

In this study, the degradation of a major pollutant present in terephthalic acid wastewater, benzoic acid, was investigated by several advanced oxidation methods using catalysts derived from walnut shells. The 10% Fe or 10% Fe-TiO 2 (wt/wt, 1:99 as Fe:TiO 2 ) catalysts were loaded on an AC prepared from walnut shells by physical activation or chemical activation methods with different chemical reagents. The effect of the activation method was investigated using catalyst screening tests. The most efficient catalyst for the Fenton-like oxidation and catalytic wet air oxidation was determined as B-FAC and for photocatalytic/photo-Fenton-like oxidation was the N-FTAC from the screening experiments. After the catalyst screening, the effect of operating conditions such as catalyst loading, temperature, initial pH, etc. on the catalytic activity were tested in terms of degradation efficiency by determining their optimum values. Maximum degradation efficiencies from parametric studies for each method were 40% for the Fenton-like oxidation, 70% for the catalytic wet air oxidation, and 90% for photocatalytic oxidation. The highest degradation efficiency was achieved by the photo-Fenton-like oxidation in the presence of the N-FTAC catalyst with a degradation efficiency of 95% at 0.5 g/L catalyst loading, 6 W UV light, 2 mM initial H 2 O 2 concentration, and an initial pH of 3 or 6, with a reaction time of 80 min. [ABSTRACT FROM AUTHOR]

This work aimed at comparing different UV and H 2 O 2 based advanced oxidation processes (AOPs) −photolysis, UV/H 2 O 2 , and photo-Fenton reaction- for the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D), a common ingredient of phytosanitary products. The influence of oxidant dose (H 2 O 2 ), catalyst type and concentration, pollutant concentration, water matrix and irradiation spectrum was also analyzed. Under reference conditions (25 mg/L of 2,4-D in osmosed water), photo-Fenton oxidation using Fe 2+ salt, initial pH value of 2.6 and a low-pressure mercury vapor lamp (10 W, λ = 254 nm) yielded more than 85% of pollutant mineralization in one hour, as compared to 60% and less than 10% for UV/H 2 O 2 and photolysis, respectively. Such a performance could be achieved in 10 min only when applying optimal concentration range for Fenton’s reagent (2 to 5 times the stoichiometric amount of H 2 O 2 and oxidant-to-catalyst molar ratio from 25 to 40). Conversely, addition of a ZSM-5 zeolite bearing iron active sites albeit catalyzing Fenton oxidation at natural pH – did not bring additional benefit to UV/H 2 O 2 process. Use of wastewater treatment plant effluent as aqueous matrix or irradiation in the UVA-visible range somewhat lowered the fficiency of the homogeneous photo-Fenton process. Nonetheless, bench scale experiments under sunlight gave promising results for 2,4 D remediation in wastewater, leading to over 80% conversion of the pollutant within ten minutes. [ABSTRACT FROM AUTHOR]

The production of domestic waste is increasing so much that waste disposal has become a serious problem in terms concern for the hazard to the human and environment. In Brazil, landfill is the most common method of municipal solid waste disposal. The present study aims to evaluate the efficiency of different advanced oxidation processes (ozonization (alkaline pH), electrochemical oxidation + ozonation (alkaline pH) and photo-electrochemical oxidation) and biological system as a treatment of leachate to remove acute-cyto-genotoxicity of municipal landfills. Toxicity assays were performed on Allium cepa , assessing root growth (acute toxicity), cell division (cytotoxicity), and chromosomal aberrations (genotoxicity). Results indicate high acute toxicity, cytotoxicity and genotoxicity of the raw leachate at nearly all collection times. The biological treatment proved to be inefficient in the improvement of physicochemical properties and in the reduction of genotoxicity. In general, all the advanced oxidation processes presented greater removal for physicochemical parameters as well as a reduction of the genotoxic potential. However, only the treatment with electrochemical oxidation + ozonation provided an effluent with physicochemical properties that are in line with the Brazilian legislation, being suitable for disposal in water bodies. On the other hand, electrochemical oxidation + ozonation and photo-electrochemical oxidation treatments were able in removing the genotoxicity though none managed to totally reduce the acute toxicity. [ABSTRACT FROM AUTHOR]

Ammonia nitrogen pollution is still a global concern, leading to eutrophication of aquatic ecosystems. Various technologies have been studied and applied for ammonium removal from water and wastewater, including physical, chemical and biological methods. For wastewater purification purposes, advanced oxidation processes (AOPs) are considered as promising approaches and potential alternatives for advanced treatment to further improving water quality. Although there are many reviews on AOPs for degradation of refractory pollutants, few reviews on the ammonia oxidation. In recent years, the selective oxidation of ammonia by AOPs has received increasing attention. In this review, the selective oxidation of ammonium to nitrogen gas (N 2) by various AOPs, such as photocatalytic process, electrochemical process, catalytic ozonation, sulfate radical-based process, and integrated processes were systematically summarized. Firstly, the formation, reactivity toward NH 4 +/NH 3 , and reactive species generated in AOPs were analyzed and compared; then, the radical mediated and non-radical mediated reaction mechanisms of NH 4 +/NH 3 oxidation were discussed in detail; thirdly, the selective oxidation of ammonia to nitrogen gas under specific operational conditions were summarized, and finally, various AOPs for selective oxidation of ammonia to nitrogen gas were discussed from the perspective of merits and demerits, influencing factors, key material development, integrated processes, current status, main challenges, and future research directions. This review will deepen to understand the selective oxidation of ammonia by various AOPs. [Display omitted] • The selective oxidation of NH 4 + to N 2 by various AOPs were critically reviewed. • The reactive species generated in AOPs for oxidizing NH 4 + were analyzed and compared. • The radical and non-radical mediated mechanisms of NH 4 + oxidation were discussed. • The strategies for improving the selectivity of NH 4 + oxidation were proposed. [ABSTRACT FROM AUTHOR]

This work demonstrates the suitability of employing carbon-based catalytic membranes for persulfate activation and water disinfection in continuous flow mode of operation for the first time. Poly(vinylidene fluoride) (PVDF) membranes with and without nitrogen-doped reduced graphene oxide (rGO-M) were prepared and tested. The cumulative effect of each membrane component was assessed based on the persulfate activation capacity and the retention and/or elimination of faecal contamination indicator microorganisms in a defined suspension of Escherichia coli and Enterococcus faecalis. In the absence of persulfate, the pristine PVDF membrane enabled retention of 1.98 ± 0.51 log, while the rGO-M–PVDF membrane removed 3.71 ± 0.66 log of the initial microbial abundance (3.87 ± 0.01 log) after 6 h of operation. The catalytic features of the rGO-M–PVDF membrane were then demonstrated by adding a persulfate precursor to the feed suspension. This treatment system was able to reduce the abundance of cultivable microorganisms (total heterotrophs, enterobacteria, enterococci) of the defined suspensions and river water samples to values below the limit of detection (< 0.5 CFU mL−1) up to 24 h operation. In addition, the reactivation capacity of the cultivable microorganisms and representative specific genes (16S rRNA, intl 1, bla TEM and sul 1) after 7-day storage of the treated river water was studied. Among the parameters analysed, only total cultivable heterotrophic cells were able to regrow to values similar to those found in the feed. Therefore, the proposed system can be considered as a promising technology for the removal of harmful microbiota during drinking water production in continuous flow mode. [Display omitted] • Nitrogen-doped reduced graphene oxide (rGO-M–PVDF) membranes were produced. • The rGO-M–PVDF membranes activated persulfate in a continuous flow mode treatment. • River water was disinfected to safe levels in continuous flow mode (24 h operation). • The treated river water maintained microbiological stability upon 7-day storage. [ABSTRACT FROM AUTHOR]

Xanthate is widely used in the flotation process of sulfide ores, and large amount of flotation wastewater with xanthate is produced and caused serious wastewater pollution due to its excessive usage. This study intensively studied ozonation and various ozone based advanced oxidation processes (AOPs) for alkyl xanthates (AXs) degradation and mineralization, including catalytic ozonation, peroxone and photocatalytic ozonation. The key operation parameters, such as ozone dosage, ratio of different oxidants and solution were studied. All integrated ozonation processes improved the mineralization efficiency of AXs, among which TiO 2 photocatalytic ozonation is the most efficient, and the chemical oxygen demand (COD) removal rate can reach 84.9% in 60 min. A quantitative structure-activity relationship (QSAR) model was also established for ozonation of xanthates for the first time, based on quantum chemical calculation of series of xanthate structures and their degradation rate constants in ozonation. It reveals that the main factor affecting the ozonation rate constant is the molecular volume, which is negatively linearly correlated with the length of carbon chain of alkyl substituent group. The degradation intermediates of potassium amyl xanthate were measured by ultraviolet-visible spectroscopy (UV-Vis) and gas chromatography-mass spectroscopy (GC-MS), based on which a degradation path of xanthate was proposed. This work provides deeper understanding of advanced oxidation and mineralization of AXs, and may guide the development of treating technology for flotation wastewater. • The degradation of AXs in O 3 -based AOPs was systematically studied, the mineralization rate of PEX by O 3 /UV/TiO 2 process is 84.9% • Degradation of AXs substrate is mainly due to O 3 molecule, QSAR model shows the Vm is negatively correlated with the k obs in ozonation • The oxidative degradation path of PAX was proposed, the main intermediate by-products of PAX based on ozonation are 1-pentanol and valeric acid. [ABSTRACT FROM AUTHOR]

This study proposes an efficient strategy for enhancing metallurgical copper slag (CS) performance, which has photodegradation properties for a photo-Fenton-like reaction. The addition of ascorbic acid in the reaction promotes the Fe(III)/Fe(II) redox cycle on the surface of copper slag due to its reducing and chelating properties, which help to produce Fe(II) species and avoid iron precipitation as hydroxides. Generally, in the reaction process, the values of salicylic acid (SA) degradation, H 2 O 2 decomposition, and •OH production increase as ascorbic acid (AA) increases. At the same time, the iron leaching remains below 1 mg/L. The system with the best result is CS 0.100 /AA 0.150 /H 2 O 2, where the percentage of SA degradation, •OH production, and H 2 O 2 degradation present twelve, thirty, and sixteen times more than that using the CS alone with H 2 O 2 , respectively. Also, the reusability experiments of CS in the CS 0.100 /AA 0.150 /H 2 O 2 system suggest their outstanding chemical stability. The CS 0.100 /AA 0.100 /H 2 O 2 system was used to degrade two antibiotics of the quinolones group, extensively used in respiratory diseases as a practical example of an application. The optimal system to photodegrade levofloxacin and ciprofloxacin was CS 0.100 /AA 0.100 /H 2 O 2, where the AA addition significantly affected the degradation speed of the levofloxacin than in the ciprofloxacin. It reaches 98.8 ± 0.4% of levofloxacin degradation at 60 min of reaction and 94.6 ± 1.2% for ciprofloxacin, with mineralization efficiencies higher than 60% and, in the reusability experiments, the percentage of antibiotics degradation stayed above 90%. [Display omitted] [ABSTRACT FROM AUTHOR]

In the present investigation, a sulfonamide drug named Sulfamerazine was degraded using the 5 L pilot scale hydrodynamic cavitation equipped with three different venturis namely circular (HC CV), slit (HC SV), and dual-slit venturi (HC DSV) operating at 4 bar inlet pressure. The novel HC DSV was successfully designed and applied for the first time to improve the cavitational activities and a subsequent increased ˙ OH radical generation. The SMZ degradation achieved using individual HC DSV was 41.54% in comparison to 27.69% and 21.54% for HC SV and HC CV respectively, clearly showing the benefits for intensification. The resistance coefficient (convergent and divergent sections of the venturi), number of passes, and cavitation number significantly influence the cavitational activities, and HC DSV was observed to be the most efficient design based on these parameters. A pilot scale US reactor (USR) was likewise used for the degradation of SMZ at a similar capacity. The combination of hydrodynamic and acoustic cavitation with H 2 O 2 , PS, PMS, Fenton and Fenton-like processes were successfully demonstrated on a pilot scale investigation. The combined approach of Fenton (Fe2+ at 0.75 mM and H 2 O 2 at 0.7 mM) coupled with hydrodynamic or acoustic cavitation was the most proficient approach, with maximum SMZ degradation of 96.92% and 97.25% achieved for HC DSV /Fe2+/H 2 O 2 and USR/Fe2+/H 2 O 2 (at 22 +44 kHz), respectively. The estimated cost of treatment for HC DSV /Fe2+/H 2 O 2 and USR/Fe2+/H 2 O 2 (at 22 +44 kHz) approaches were 0.1780 and 0.4583 ₹/L respectively, establishing HC DSV /Fe2+/H 2 O 2 as the most effective method in terms of SMZ degradation as well as cost of degradation. • SMZ degradation using hydrodynamic cavitation based on different devices. • Comparing the efficacy of hydrodynamic cavitation with ultrasound at pilot scale. • Elucidating the benefits of combined process with several oxidants. • Most effective treatment approach established as HC DSV /Fe2+/H 2 O 2 with over 96% SMZ degradation. [ABSTRACT FROM AUTHOR]

A tubular membrane photoreactor, operated in continuous mode and low residence times (τ from 3.9 to 12.2 s), was applied for the removal of 14 antibiotics (sulfonamides, fluoroquinolones, macrolides, cephalexin, and trimethoprim) in demineralized water (DW) and secondary-treated urban wastewater (UWW). In this setup, the oxidant (hydrogen peroxide (H 2 O 2), persulfate (S 2 O 8 2−) or ozone (O 3)) is permeated through the membrane pores and delivered to the catalyst (titanium dioxide (TiO 2) or silver molybdate (Ag 2 MoO 4)), embedded in the membrane shell side, and to the annular reaction zone (ARZ) where the DW or UWW fortified with the target antibiotics (50 µg L−1 each) flows. The antibiotics removal in the tested processes - photolysis (UVC), photocatalysis (UVC/TiO 2 or UVC/Ag 2 MoO 4), photochemical oxidation (UVC/H 2 O 2 or UVC/S 2 O 8 2−), their combinations (UVC/TiO 2 /H 2 O 2 , UVC/TiO 2 /S 2 O 8 2‾, UVC/Ag 2 MoO 4 /H 2 O 2 and UVC/Ag 2 MoO 4 /S 2 O 8 2‾) and O 3 - were evaluated at steady-state conditions by ultra-high performance liquid chromatography followed by quadrupole time-of-flight high-resolution mass spectrometry (UHPLC-QTOF-HRMS). In the DW, the treatment efficiency followed the sequence: UVC < UVC/TiO 2 ≈ UVC/Ag 2 MoO 4 < UVC/H 2 O 2 < UVC/TiO 2 /H 2 O 2 ≈ UVC/Ag 2 MoO 4 /H 2 O 2 < UVC/S 2 O 82 ‾ < UVC/TiO 2 /S 2 O 82 ‾ < UVC/Ag 2 MoO 4 /S 2 O 8 2‾ < O 3. In the UWW, the O 3 process proved again to be the most efficient (12 antibiotics removed >90%), followed by UVC/Ag 2 MoO 4 /S 2 O 8 2‾ (five antibiotics removed >60%). UHPLC-QTOF-HRMS tentatively identified seven by-products stemming from macrolides for O 3 treatment. This is a pioneer study on the application of Ag 2 MoO 4 combined with H 2 O 2 or S 2 O 8 2- for advanced treatment of UWW, laying the groundwork for future research. The membrane reactor proves to be an effective technological approach for the O 3 process. [Display omitted] [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysis such as ultraviolet/TiO 2 (UV/TiO 2 ) can be used in environmental remediation. It is an advanced oxidation process that can degrade organic contaminants through redox reactions. Unmodified TiO 2 can only generate electron-hole pairs in the UV range so it has limited efficiency. Highly efficient materials are required for this process to be implemented at a large scale. In this study, three methods were used to investigate and improve the efficiency of UV/TiO 2 slurry systems: (i) synthesizing one-dimensional TiO 2 , (ii) formation of Schottky junctions, and (iii) application of UV-light emitting diode (UV-LED) under controlled periodic illumination (CPI). These methods were quantified by measuring the formation of 2-hydroxyterephthalic acid (HTPA) as a probe molecule. In order to improve the charge separation in TiO 2 , one-dimensional TiO 2 nanobelts (TNB) were synthesized using a hydrothermal method and Ag nanoparticles were deposited on these nanobelts to form metal-semiconductor junctions. Ag-TNB was found to have HTPA formation rate greater than 1.33 and 2.59 times than that of P25 and TNB, respectively, under continuous illumination. UV-LED CPI was used to explore changes in photonic efficiencies by using duty cycles from 10% to 100%. At a duty cycle of 10%, normalized HTPA formation rate was 1.75, 1.40, and 0.70 times the HTPA formation rate at continuous illumination for commercial TiO 2 (P25), TNB, and Ag-TNB nanomaterials, respectively. The pulse frequency was varied from 0.05 Hz to 25 Hz. Under high frequencies, the HTPA formation rate was greater for Ag-TNB and P25 samples compared to the lowest frequency (0.05 Hz). Ag-TNB was determined to be an effective photocatalyst using CPI by demonstrating photon-limiting behaviour when lowering the duty cycle. [ABSTRACT FROM AUTHOR]

Two spinel-type oxides, CuMn 2 O 4 and CoMn 2 O 4 were synthesized by a simple combustion method. The oxides were characterized by X-ray Diffraction, infrared spectroscopy, scanning electron microscopy and atomic absorption spectroscopy. The structures of the obtained oxides were refined by the Rietveld method. The obtained samples were tested in the catalytic degradation of phenol and methyl orange. Two different oxidants were employed: potassium persulfate and peroxymonosulfate. The catalytic activity was tested, as well as the degradation efficiencies. The best results were obtained with the copper substituted oxides, using oxone as oxidant. With this system, mineralization of total organic carbon (TOC) reached more than 94% within 120 min of reaction. For cobalt mixed oxides, the TOC mineralization reached as much as 68% in the same condition. The activation mechanisms for the different systems studied in this work are discussed and two different pathways are proposed depending on the oxidant and/or the substitution metal. [ABSTRACT FROM AUTHOR]

In this study, the anti-depressant Venlafaxine, a new emerging contaminant of interest for the Swiss legislation, was subjected to systematic degradation. In order to develop an efficient framework for the treatment of emerging contaminants at industrial scale by AOPs, the photo-Fenton process was employed and the effect of the concentration of the Fenton’s reagents and the implication of the operating pH was assessed. Initially, in order to acquire a simple model that describes the process, a (general) full factorial experimental design was implemented. Generally, Venlafaxine degradation was achieved in minutes range at pH = 3 and increased with higher pH values. However, the changes in pH inflicted considerable modification in the treatment efficiency and imposed the subsequent use of higher order models, obtained by response surface methodology (3 pH-specific central composite designs). The improved, respective second degree models created for the 3 categories of response variables (kinetics, efficiency, Fenton evolution) were used as input for the desirability functions, towards the statistical optimization of the process. The composite desirability values obtained indicated the optimal operating regions (9 mg/L iron and 28 mg/L H 2 O 2 ), thus contributing to efficient application of the photo-Fenton process. The developed approach can be used as framework when the optimal treatment conditions of new, emerging contaminants are sought at production level, through well-established advanced oxidation processes and effective statistical methods. [ABSTRACT FROM AUTHOR]

Co-oxidation of trivalent chromium (Cr(III)) to hexavalent chromium (Cr(VI)) during ozonation of organic pollutants represents a common problem facing the implementation of in situ chemical oxidation (ISCO) for environmental remediation. A laboratory study was conducted by using groundwater and saturated soil samples from a field site in Sacramento, California, to determine optimal O 3 dosage to achieve satisfactory remediation of MTBE while minimizing co-oxidation of Cr(III) to Cr(VI). Total oxidant demand was determined (28.33 mg O 3 L −1 ) and used as the benchmark to establish a range of ozone dosages for the study. Concentration changes in MTBE and chromium were monitored at O 3 dosages less than and greater than the benchmark. The results indicate that MTBE is preferentially oxidized by ozone at and below the indicated benchmark dosage prior to the oxidation of Cr(III) to Cr(VI). The resultant O 3 dosage of 28.33 mg L −1 was applied in the field implementation, verifying that the O 3 can be applied in a controlled manner to remediate MTBE while minimizing the formation of Cr(VI). [ABSTRACT FROM AUTHOR]

Single-atom catalysts (SACs) are emerging heterogeneous catalysts, which have been shown to be promising for a wide range of applications. Herein, we report the fabrication of single-atom Co sites with regulated Co-N 3 coordination supported on waste paper-derived active carbon (WPAC). The high specific surface area (535.2 m2 g−1) and active Co-N 3 single sites endowed the Co-N 3 /WPAC with high adsorption capacity and excellent catalytic performance. The maximum adsorption capacity of sulfisoxazole (SIZ) onto Co-N 3 /WPAC reached 274.5 mg g−1, and the removal percentage of SIZ reached ∼93.0 % within 1.0 min in the Co-N 3 /WPAC+PS system. The bifunctional properties of Co-N 3 /WPAC led to the efficient preconcentration of organic pollutants from aqueous solution as well as in-situ oxidation of them via the catalytic oxidation process. In addition, the Co-N 3 /WPAC+PS system exhibited a wide operating pH range (3−11), high mineralization capacity (∼89.3 %) and excellent reusability for the degradation of SIZ. Mechanism studies suggested that the Co-N 3 active sites were responsible for enhanced generation of the reactive oxygen species via PS activation, and both radical and non-radical processes contributed to the oxidation of SIZ. This work provides new insights into the resourceful disposal of waste paper and the application of SACs for environmental remediation. • The waste paper-derived active carbon (WPAC) supported Co-N 3 single sites were fabricated. • Co-N 3 /WPAC exhibited high SIZ removal efficiency via adsorption and catalytic degradation. • Co-N 3 /WPAC/PS system had a satisfactory adaptability, stability, and reusability. • Radical pathway and non-radical pathway were proposed in Co-N 3 /WPAC/PS system. • The introduction of Co-N 3 sites accelerated the electron transfer process for PS activation. [ABSTRACT FROM AUTHOR]

The presence of pharmaceutical contaminants in aquatic environments has become an issue of huge concern worldwide due to their potential hazardous effects on the aquatic ecosystem, as well as on the health of humans. Bearing that in mind, in the last years we have seen an intense development of novel highly efficient, cost-effective, and sustainable treatment techniques for the degradation of these contaminants. Here, we present a comprehensive literature review on studies conducted over the past five years on pharmaceutical focusing on their ecotoxicological effects, as well as on the research efforts devoted to the development and application of sustainable technologies for the detoxification of a wide range of waters contaminated with these compounds. With these developments, this review look at the future perspectives on the subject and the constraints and challenges faced by researchers in terms of devising highly innovative techniques which can effectively contribute toward enhancing the efficiency of the treatment. According to the review, just a few studies worked in realistic scenarios (23.4%) including real water and contaminant concentrations close to levels detected in the environment. Regarding scale-up considerations, only 6% of studies applied the techniques on a large scale. The importance of economic considerations in the proposed techniques is also discussed in the following directions: (i) use of renewable energy sources; (ii) development of more cost-effective hybrid processes and (iii) simultaneous removal of other toxic inorganic species, by-products and microorganisms. [Display omitted] [ABSTRACT FROM AUTHOR]