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Greigite (Fe3S4) and millerite (NiS) are important transition metal sulfides that exhibit light‐driven Fenton catalytic activity. In absence of light, they show limited activity. To utilize these properties without relying on light, we synergized these sulfides to prepare a composite Fe3S4–NiS (FSNS). Under fixed reaction conditions, the composite demonstrated excellent Fenton activity, degrading 93% of fast green dye (FG) and 98.1% of eriochrome black T dye (EBT) within a short reaction time. The mechanism involves electron transfer from the reduced sulfur state (S2−) in both NiS and Fe3S4 to the higher oxidation states of the metal ions viz. Fe3+and Ni3+ to facilitate the redox cyclization in the Fenton process. The catalyst showed high stability for five cyclical tests by recovering it from solution with an external magnet. [ABSTRACT FROM AUTHOR]

The chlorination of surface waters leads to the formation of thrihalomethans (THMs) and haloaceticacids (HAAs) due to the presence of natural organic matters. Thus, the removal of fulvic acid (FA) as one of the most prominent natural organic matters in water is necessary. Therefore, this study was aimed to evaluate the efficiency of catalytic ozonation of FA in the presence of the local montmorillonite (Mnt). The soils were collected from the Ardabil Sarcham area and used as a catalyst, after the required preparation. The variables in this study including initial solution pH, catalyst dosage, reaction time, and initial pollutant concentration were examined. For the ozonation of the samples, an ozone generator with a capacity of 5 g/h was used. It was found that, with increasing contact time, pH, and catalysts dosage, as well as decreasing initial FA concentration, the performance of the catalytic ozonation process increased significantly. The results demonstrated that radical scavengers like nitrate, chloride, sulfate, and carbonate a high concentration had very low effect on the efficiency of this process compared to conventional ozonation. The kinetic data was found to fit into the pseudo-first-order kinetic model (R2 = 0.98) than the zero and pseudo-second-order model. The Green Mnt was more effectual than the Red Mnt at pH: pH = 7, FA concentration = 25 mg/L, time = 30 min, catalyst dosage = 1.25 g/L, inlet ozone concentration = 2.2 mg/L-min; which gave COD removals of 84.68 and 78.25%, respectively. As a whole, green and red soils increase highly the efficiency of FA removal in the catalytic ozonation process, because of low costs and availability of these soils. [ABSTRACT FROM AUTHOR]

Wastewater generated by the textile industry contains a variety of harmful and complex substances. These effluents can negatively impact aquatic ecosystems and human health if not managed properly. The textile industry relies on various chemicals and water to dye and wash fabric. The textile effluent exhibits vibrant colours, elevated pH levels, increased temperature, and higher COD levels. Various factors contribute to the increased pollutant load in effluents, including diluted solids, suspended particles, colours, and toxic metals. Various techniques are used to address textile wastewater, including mechanical, chemical, biological, hybrid, and advanced oxidation methods. This study offers a thorough examination of the dyes and chemicals utilized in the textile industry. It specifically looks at various treatment methods for removing pollutants from industrial wastewater, including chemical, biological, physical, AOPs, and hybrid systems. The findings suggest that photocatalytic techniques are the most effective in terms of rapid dye removal, cost-effectiveness, timeliness, and environmental friendliness. This review also offers a detailed analysis of the past decade and explores the challenges and potential of this innovative approach in the context of sustainable development. [ABSTRACT FROM AUTHOR]

The development of efficient photocatalysts is crucial in addressing water pollution concerns, specifically in the removal of organic dyes from wastewater. In this context, the use of silver nanoparticles (Ag NPs) might represent a method to achieve high dye degradation efficiencies. On the other hand, the classical Ag NP production process involves several reactants and operating conditions, which make it poorly sustainable. In the present work, Ag NPs were synthesized according to a new sustainable process involving the use of natural extracts of Spirulina platensis and milder operating conditions. The material was also calcined to determine the influence of organic content on the properties of Ag NPs. The X-ray diffraction (XRD) analysis displayed the AgCl and Ag phases with a crystalline size of 11.79 nm before calcination. After calcination, only the Ag phase was present with an increased crystalline size of 24.60 nm. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the capping role of the metabolites from the extract. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed the spherical or quasi-spherical morphologies with agglomeration due to the calcination. Energy-dispersive X-ray spectroscopy (EDX) and Thermogravimetric (TGA) analyses further confirmed the involvement of metabolites in the synthesis of Ag NPs. The optical changes in the products were observed in a UV-Vis analysis. The Ag NPs were tested for their photocatalytic activity against the laboratory dye brilliant blue r in visible light in various conditions. The highest degradation efficiency of 81.9%, with a kapp value of 0.00595 min−1, was observed in alkaline medium after 90 min of light irradiation. [ABSTRACT FROM AUTHOR]

This study focuses on utilization of a zero-valent metal (zero-valent iron, zero-valent aluminum, and nanoscale zerovalent copper) in conjunction with H2O2 conducted to treat real dye wastewater. Box-Behnken methodology was applied to describe effects of five independent factors involved in optimization of advanced oxidation system, which was type of zero-valent metals, dosage of zero-valent metals, pH, time and dosage of H2O2, for treating dye wastewater. Correlation coefficients for model, shown by the value R², were 0.9996 for removing color and 0.9708 for reducing COD. Mass of nZVC equaled 1.09 g/L, H2O2 equaled 5.39 mg/L were found to be the optimal reaction conditions when the pH was equal to 3.71. After 120 minutes of optimal settings, there was a reduction of 87.3% in COD and 98.72% in color of dye wastewater after heterogeneous treatments (nZVC/H2O2). The reusability of nZVC for degrading dye wastewater has been tested in four cycles and showed up to 70% COD removal. Ecotoxicological testing indicated that the raw textile effluent was extremely toxic to Chlorella sp. and V. fischeri. Even while wastewater after treatment collected definitely had a lower toxicity level with both V. fischeri and Chlorella sp. This research findings highlight the nZVC/H2O2 process as a feasible and effective method for real dye wastewater treatment and detoxification, positioning it as a valuable alternative oxidation process for treating organic contaminants. [ABSTRACT FROM AUTHOR]

This study discussed the effect of ferric salt addition on UV/electro-chlorine advanced oxidation process using a train of electrolytic and UV flow cells with an ozone-free low-pressure mercury vapour lamp (total irradiance:0.60 W at 254 nm). Ferric salt addition enhanced 1,4-dioxane degradation at an electrolytic current of 0.100 A. By contrast, an inhibitory effect of ferric salt addition was observed at a current of 0.500 A. The enhanced accumulation of free chlorine at a current of 0.500 A directly decreased the 1,4-dioxane degradation rate by scavenging reactive radicals like HO˙ and Cl˙. However, at an electrolytic current of 0.100 A, UV irradiance was relatively excessive for electrochemical chlorine production. The excess UV energy enhanced the photoreduction of FeOH2+, followed by the Fenton-type reaction of Fe2+ and HOCl, which produced HO˙ and consumed free chlorine. As a result, the free chlorine concentration decreased, and the reaction efficiency between the reactive radicals and 1,4-dioxane improved. Thus, the addition of ferric salt to a UV/electro-chlorine system is recommended when the UV irradiance in the system is excessive compared to the electrochemical chlorine supply. [ABSTRACT FROM AUTHOR]

Using cheap and readily available pomelo peel-flesh biomass as raw material to construct ultra-fine and highly dispersed nano-cobalt biochar material, further realizing the efficient activation of peroxymonosulfate to active oxygen species that can effectively degrade organic pollutants, which provides a low-cost way for the elimination of organic pollutants and the continuous purification of sewage. [Display omitted] • A highly dispersed ultrafine nano-Co material was constructed based on pomelo peel-flesh biomass. • Co/BDPPF combined with PMS nearly 100% degradation of tetracycline, and has lasting stability. • Co/BDPPF can efficiently degrade organic pollutants in complex water environments. • The integrated device built by Co/BDPPF can realize the continuous purification of organic sewage. The advanced oxidation process (AOPs) is playing an important role in the elimination of hazardous organic pollutants, but the development of inexpensive and highly active advanced catalysts is facing challenges. In this study, a low-cost and readily available agricultural waste resource pomelo peel-flesh (PPF) biomass was used as the basic raw material, and the uniformly dispersed small cobalt nanoparticles were effectively anchored in the biochar derived from pomelo peel-flesh (BDPPF) by impregnation adsorption/complexation combined with heat treatment. Co/BDPPF (BDPPF embedded with Co) can effectively activate peroxymonosulfate (PMS) to SO 4 ·-, ·OH and 1O 2 reactive oxygen species, and achieve nearly 100% degradation of tetracycline persistent organic pollutant. Co/BDPPF can not only degrade tetracycline efficiently in complex water environment, but also degrade most organic pollutants universally, and has long-term stability, which solves the problem of poor universality and stability of heterogeneous catalysts to a certain extent. Importantly, Co/BDPPF derived from waste biomass was also innovatively designed as the core of an integrated continuous purification device to achieve continuous purification of organic wastewater. In this study, agricultural waste resources were selected as biomass raw materials to achieve efficient capture of Co2+, and finally developed advanced AOPs catalyst with excellent performance to achieve the purification of organic wastewater. It also provides a promising solution for the preparation of simple, low-cost, large-scale production of AOPs catalysts that can be put into actual production. [ABSTRACT FROM AUTHOR]

This study developed a new system for removing antibiotics using UV/ZIF-67 (Co)-activated peroxymonosulfate. The presence of antibiotic organic pollutants in urban sewage presents a substantial challenge for sewage treatment technologies. Due to the persistent chemical stability of antibiotics, their low environmental concentrations, and their resistance to degradation, effectively removing residual antibiotics remains a significant issue in urban wastewater treatment. This study introduces an eco-friendly photocatalytic technology designed to enhance the removal of oxytetracycline (OTC) from municipal wastewater using a UV/ZIF-67 (Co)/PMS system. The results showed that compared with UV, UV/PMS, ZIF-67 (Co), ZIF-67 (Co)/PMS, and UV/ZIF-67 (Co) systems, the UV/ZIF-67 (Co)/PMS system had the highest OTC removal rate. When 10 mg ZIF-67 (Co) and 1 mM PMS were applied to 100 mL 30 mg/L OTC solution, the degradation efficiency reached 87.73% under 400 W ultraviolet light. Increasing the dosage of ZIF-67 (Co) and PMS can improve the removal rate of OTC, but the marginal benefit of additional dosage is reduced. The highest degradation efficiency was observed at weakly acidic pH, which may be due to potential damage to the internal structure of the catalyst and reduced performance under extreme pH conditions. The influence of chloride ions and nitrate ions on the reaction system is minimal, while bicarbonate ions exhibit a significant inhibitory effect on the removal of OTC. The UV/ZIF-67 (Co)/PMS system exhibits adaptability to various water sources, including tap water, Guitang River water, and pure water. The results of free radical identification indicate the presence of hydroxyl and sulfate groups in the UV/ZIF-67 (Co)/PMS system, both of which play important roles in the degradation of OTC. This study offers valuable insights and technical support for the green, efficient, and environmentally friendly removal of antibiotics from urban wastewater. [ABSTRACT FROM AUTHOR]

In this study, an anionic dye, Reactive Black 5 (RB5), was subjected to sonophotocatalytic treatment process with the aim of establishing the effectiveness of the prepared ZnO incorporated activated red mud (ZnO/ARM) as a viable sonophotocatalyst. ZnO/ARM was prepared by impregnation method at different weight ratios (0.25:1, 0.5:1, 0.75:1 and 1:1) with the ZnO/ARM at weight ratio of 0.75:1 proving to be the best sonophotocatalyst. The prepared sonophotocatalysts were characterized by X-ray diffractometer for crystal phase studies, Brunauer–Emmett–Teller for surface area studies, Fourier transform infrared for surface functional groups studies, SEM–EDX for surface morphological and elemental studies, diffuse reflectance spectroscopy and photoluminescence for sonophotocatalyst band-gap studies while parametric and kinetic studies of the removal of RB5 from the simulated wastewater were conducted to confirm its effectiveness under simultaneous application of a transducer bath-type sonicator (35 kHz) and a UV-C (254 nm) lamp. The influence of the solution pH, concentration and catalyst dosage were manipulated throughout this study to investigate the sonophotodegradation kinetics and synergistic effects on the RB5 degradation. Experimental results confirmed that the sonophotocatalytic degradation rate of 20 ppm RB5 was most effective under acidic medium (66.7%) as compared to alkaline medium (46.1%) due to an excess of positive charge in the ZnO/ARM surface which favours a strong electrostatic interaction with SO3− groups of the dye resulting in a higher degradation rate (0.0156 min−1). Under alkaline conditions, the catalytic activity of ZnO/ARM was attenuated by the higher negative charge which promoted the repulsion of the dye from ZnO/ARM surfaces leading to a lower degradation rate of 0.01 min−1. The accelerated photo induced electron–hole transfer and separation, decreased recombination rate and band energy matching, enhancing the photocatalytic performance of ZnO/ARM composite. [ABSTRACT FROM AUTHOR]

Drugs and related goods are widely used in order to promote public health and the quality of life. One of the most serious environmental challenges affecting public health is the ongoing presence of antibiotics in the effluents generated by pharmaceutical industries and hospitals. Antibiotics cannot be entirely removed from wastewater using the traditional wastewater treatment methods. Unmetabolized antibiotics generated by humans can be found in urban and livestock effluent. The antibiotic present in effluent contributes to issues with resistance to antibiotics and the creation of superbugs. Over the recent 2 years, the coronavirus disease 2019 pandemic has substantially boosted hospital waste volume. In this situation, a detailed literature review was conducted to highlight the harmful effects of untreated hospital waste and outline the best approaches to manage it. Approximately 50 to 70% of the emerging contaminants prevalent in the hospital wastewater can be removed using traditional treatment strategies. This paper emphasizes the numerous treatment approaches for effectively eliminating emerging contaminants and antibiotics from hospital wastewater and provides an overview of global hospital wastewater legislation and guidelines on hospital wastewater administration. Around 90% of ECs might be eliminated by biological or physical treatment techniques when used in conjunction with modern oxidation techniques. According to this research, hybrid methods are the best approach for removing antibiotics and ECs from hospital wastewater. The document outlines the many features of effective hospital waste management and might be helpful during and after the coronavirus disease 2019 outbreak, when waste creation on all hospitals throughout the globe has considerably increased. [ABSTRACT FROM AUTHOR]

Over the past few decades, peroxymonosulfate (PMS)-driven advanced oxidation processes (AOPs) have garnered substantial interest in the field of organic decontamination. The copper (Cu)/PMS system is intriguing due to its diverse activation pathways and has been extensively employed for the clearance of refractory organic pollutants in water. This article is designed to offer a comprehensive overview of the latest trends in Cu-based catalysts such as single-metal and mixed-metal catalysts aimed at treating recalcitrant pollutants, highlighting PMS activation. Subsequently, investigative methodologies for assessing PMS activation with copper-based catalysts are reviewed and summarized. Then, the implications of pH, PMS and catalytic agent concentrations, anions, and natural organic matter are also addressed. The combination of Cu-based catalyst/PMS systems with other advanced oxidation technologies is also discussed. Following that, the degradation mechanisms in the Cu-based catalyst-activated PMS system are considered and synopsized. Lastly, potential future research avenues are proposed to enhance the technology and offer support for developing of economically viable materials based on copper for activating PMS. [ABSTRACT FROM AUTHOR]

Heterogeneous catalysts promoting efficient production of reactive species and dynamically stabilized electron transfer mechanisms for peroxomonosulfates (PMS) still lack systematic investigation. Herein, a more stable magnetic layered double oxides (CFLDO/N‐C), was designed using self‐polymerization and high temperature carbonization of dopamine. The CFLDO/N‐C/PMS system effectively activated PMS to remove 99% (k = 0.737 min−1) of tetracycline (TC) within 10 min. The CFLDO/N‐C/PMS system exhibited favorable resistance to inorganic anions and natural organics, as well as satisfactory suitability for multiple pollutants. The magnetic properties of the catalyst facilitated the separation of catalysts from the liquid phase, resulting in excellent reproducibility and effectively reducing the leaching of metal ions. An electronic bridge was constructed between cobalt (the active platform of the catalyst) and PMS, inducing PMS to break the O–O bond to generate the active species. The combination of static analysis and dynamic evolution confirmed the effective adsorption of PMS on the catalyst surface as well as the strong radical‐assisted electron transfer process. Eventually, we further identified the sites where the reactive species attacked the TC and evaluated the toxicity of the intermediates. These findings offer innovative insights into the rapid degradation of pollutants achieved by transition metals in SR‐AOPs and its mechanistic elaboration. [ABSTRACT FROM AUTHOR]

The worldwide pesticide marketplace was approximate 85 billion dollars in 2019, growing at a geometric progression rate of 4.2% from 2015, and by 2023 it is projected to grow at a rate of 11.5% to approximately 130.7 billion dollars. Pesticides' uniqueness is defined by the distinctiveness of their chemistry and their relationship with the environment. Pesticide mobility and bioavailability in water bodies are determined by their desorption and absorption processes from soil particles. Waterbodies are severely affected with the build-up of these poisonous impurities with its imbalance in pH and accumulation of heavy metals, which adversely distress the aquatic ecology in the waterbodies. Pesticides are not only damaging to the ecology of the waterbodies; it is also consequentially harmful to humans. It causes gastrointestinal disorders, cardiac and respiratory issues, and even affects the biotic molecules and organs subsequently leading to acute and/or chronic illnesses. This article reviews 200 scientific literatures for existence of pesticides in drinking water and the various remediation technologies available for the treatment to render the water potable. Upon review of more than 20 technologies, suggestions have been made for the best probable technologies for water with presence of pesticide. [ABSTRACT FROM AUTHOR]

Wastewater treatment in the paper industries is of paramount importance in terms of the concentration and type of pollutants as well as the quantity of water used in the production process. In this study, wastewater from a company in Tehran province was treated through two consecutive processes: electrocoagulation and electro-Fenton, in which the effluent of the electrocoagulation unit entered the electro-Fenton unit. After performing initial tests and setting the appropriate range of parameters affecting both processes, experiments were designed using Box Behnken Design. The objective was to reduce Total Suspended Solids and Chemical Oxygen Demand and optimize the variables influencing the performance of both processes. The impact of different factors, such as time, current, hydrogen peroxide concentration, and pH was investigated. Chemical Oxygen Demand and Total Suspended Solids removal of 55% and 96% were, respectively, achieved using EC conducted at pH 8.5, current of 1.049 A, and retention time of 32.4 min. The Chemical Oxygen Demand abatement efficiency of the electro-Fenton process was found as 66.2% within 46.2 min, hydrogen peroxide concentration of 1077 mg/L and current of 0.036 A. The initial Chemical Oxygen Demand of the untreated wastewater was 1080 mg/L, and after treatment, using the hybrid process it reached 175 mg/L. The result showed that the hybrid processes used less energy than single electrocoagulation or electro-Fenton. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substance (PFAS) contamination has emerged as a significant environmental concern, necessitating the development of effective degradation technologies. Among these technologies, ultrasonication has gained increasing attention. However, there is still limited knowledge of its scale-up or on-site applications due to the complexity of real-world conditions and its high energy consumption. Herein, we provide an overview of recent advancements in the ultrasonic degradation of PFAS toward hybrid technologies. This review contains information regarding the physical and chemical properties of PFAS, followed by an exploration of degradation challenges, the mechanisms of ultrasonication, and recent experimental findings in this field. The key factor affecting ultrasonication is cavitation intensity, which depends on ultrasonic frequency, power density, and PFAS structure. Its main advantages include the generation of reactive species without chemicals and the compatibility with other degradation technologies, while its main disadvantages are high energy consumption and limited applications to liquid-based media. We also highlight the integration of ultrasonication with other advanced oxidation processes (AOPs) to create hybrid systems for enhanced degradation of PFAS in order to significantly improve PFAS degradation efficiency, with enhancement factors ranging between 2 and 12. Finally, we discuss prospects for scaling up the ultrasonic degradation of PFAS and address the associated limitations. This review aims to deepen the understanding of ultrasonication technology in addressing PFAS contamination and to guide future research and development efforts. [ABSTRACT FROM AUTHOR]

There is a pressing demand for the introduction of environmentally safe technologies for the industries that supply the basic needs of industrialized societies. Advanced Oxidation Processes may become one of the answers to these uprising pollution management problems in the near future. The present investigation aimed to reduce the refractory organics present in the biologically treated (Activated Sludge Process) tannery effluent using Photocatalysis. The optimum time, pH, dosage of H2O2, and mass of NPAC required for the effective treatment using photocatalysis were found to be 60 mins, 8, 0.2 mg.L-1, and 1g. 100 mL-1, respectively. Although the efficiency of homogeneous photocatalysis was found to be higher than that of heterogeneous photocatalysis, the biodegradability was higher in the latter, with a value of 0.26. The experimental results have proved that photocatalysis could be a promising technology to reduce the refractory organics present in the tannery effluent. [ABSTRACT FROM AUTHOR]

The growing pharmaceutical industry has increased the production of wastewater containing pollutants that are resistant to conventional treatment. This study aimed to evaluate the effectiveness of an integrated Advanced Oxidation Process (AOP) combining ozonation and Fenton oxidation for treating pharmaceutical wastewater. The objective was to determine whether this combined approach could achieve higher removal efficiencies for key pollutants, including turbidity, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Total Organic Carbon (TOC), compared to individual processes. The research involved applying ozonation and Fenton oxidation, both separately and in combination, to wastewater samples. The study identified the optimal conditions for the integrated treatment by adjusting the concentrations of Fenton reagents and the duration of ozone exposure. The effectiveness of the treatment was assessed based on the removal efficiencies of turbidity, BOD, COD, and TOC. The results demonstrated that the combined ozone-Fenton process was highly effective, achieving removal efficiencies of 98.74% for turbidity, 96% for BOD, 99.56% for COD, and 96.63% for TOC. These findings highlight the potential of this combined AOP as a promising approach for improving the degradation of pollutants in pharmaceutical wastewater. However, the study's limitations include the need for further research to optimize the process for different wastewater types and to evaluate its long-term environmental impact and cost-effectiveness. The study's practical value lies in its potential industrial application, providing a more effective alternative to conventional treatment methods. The originality of the research is in systematically exploring the synergistic effects of combining ozonation and Fenton oxidation, contributing to advanced wastewater treatment development.

Abstract Rapid industrial growth in Bangladesh, especially in the textile industry, has led to water pollution from toxic azo dyes like orange-II, which are harmful to ecosystems and enter the food chain via irrigation. This study examined the use of chemical coagulation (using $${\text{C}}_{6} {\text{H}}_{11} {\text{NO}}_{4} {\text{X}}_{2}$$ C 6 H 11 NO 4 X 2 and $${\text{FeCl}}_{3} \cdot 6{\text{H}}_{2} {\text{O}}$$ FeCl 3 · 6 H 2 O ) and advanced oxidation process (using $${\text{NaOCl}}$$ NaOCl ) to treat orange-II dye for irrigation. However, $${\text{C}}_{6} {\text{H}}_{11} {\text{NO}}_{4} {\text{X}}_{2}$$ C 6 H 11 NO 4 X 2 and $${\text{FeCl}}_{3} \cdot 6{\text{H}}_{2} {\text{O}}$$ FeCl 3 · 6 H 2 O showed limited effectiveness in removing orange-II dye across various pH (3, 6, 9, and 12) levels. In contrast, $${\text{NaOCl}}$$ NaOCl achieved significant dye removal rates of over 90–99%. The study focused on high color removal, limited $${\text{ClO}}_{2}$$ ClO 2 and neutral pH after the test. Variables included $${\text{NaOCl}}$$ NaOCl doses (0.5 ml, 2.5 ml, and 5 ml), orange II dye doses (50 mg, 100 mg, and 150 mg) under different pH (3, 6, 8, 9 and 12) conditions. The manuscript is the first to assess orange-II dye using higher doses (2.5 ml and 5 ml) of $${\text{NaOCl}}$$ NaOCl compared to other studies, as an alkaline chemical to neutralize pH levels post-test. The highest dye removal occurred at pH 9 with similar results at other pH levels except pH 12. However, despite effective color removal, the pH remained alkaline at pH 8, 9, and 12 after the test. Hence, optimal experimental conditions of operational parameters were pH = 3 or 6, 2.5 ml $${\text{NaOCl}}$$ NaOCl dose with 100 mg/L or 150 mg/L dye doses. Further research is recommended on the degradation process, toxicological analysis of the final product, and cost-effectiveness for safe irrigation water.

It is necessary to treat textile effluents before discharging them into natural water bodies as they harm the environment. Compared to conventional treatment methods, catalytic ozonation has gained attention due to its effectiveness in removing refractory organic pollutants. In this study, the coprecipitation method was used to synthesize a composite metal oxide of silver and cerium oxide, and the synthesized catalyst was used to eliminate the Reactive Black 5 (RB5) dye. X-ray diffraction, scanning electron microscopic, and Brunauer–Emmett–Teller surface area analyses were performed to characterize the synthesized catalyst. Afterwards, relevant experimental parameters, such as pH, ozone and catalyst dosages, and initial dye concentration, were investigated. The experiments revealed that the optimal experimental conditions were a pH value of 10, a catalyst dosage of 0.7 g/L, and an ozone dosage of 60 L/h. In these optimized conditions, the RB5 dye was entirely removed, and a chemical oxygen demand removal efficiency of 88% was achieved within a reaction time of 80 min. Furthermore, the recycling potential of the catalyst was tested for three cycles, and no deterioration in its activity was observed. Additionally, studies were conducted using a hydroxyl radical scavenger in order to understand the reaction pathway of the system. As a result, the indirect pathway was more dominant than the direct pathway in the system.

Low-cost stainless-steel electrodes can activate hydrogen peroxide (H2O2) by converting it into a hydroxyl radical (•OH) and other reactive oxidants. At an applied potential of +0.020 V, the stainless-steel electrode produced •OH with a yield that was over an order of magnitude higher than that reported for other systems that employ iron oxides as catalysts under circumneutral pH conditions. Decreasing the applied potential at pH 8 and 9 enhanced the rate of H2O2 loss by shifting the process to a reaction mechanism that resulted in the formation of an Fe(IV) species. Significant metal leaching was only observed under acidic pH conditions (i.e., at pH

With the rapid development of industry, agriculture, and urbanization, various organic pollutants have accumulated in natural water, posing a potential threat to both the ecological environment and human beings, and removing organic pollutants from water is an urgent priority. Piezoelectric techniques, with the advantages of green, simple operation, and high efficiency, are highly sought after in the degradation of environmental organic pollutants. Moreover, combining piezoelectric techniques with advanced oxidation processes (AOPs), photocatalysis, or electrocatalysis can further effectively promote the efficient degradation of target pollutants. Therefore, a perspective is presented on the recent progress of piezoelectric techniques for the degradation of various organic pollutants from aqueous solutions. The classification of various piezoelectric materials, as well as modification strategies for improving piezocatalysis, are first systematically summarized. Furthermore, the latest research on piezocatalysis and its combination with other technologies, such as AOPs, photocatalysis, and electrocatalysis, in the degradation of environmental pollutants is discussed. The potential mechanisms of piezocatalysis are also analyzed in depth. Finally, the urgent challenges and future opportunities for piezoelectric techniques in the degradation of organic pollutants are provided.

[Display omitted] • A novel catalytic behavior was revealed in defective nanozymes. • Defects and self-supplied vacancies greatly boosted the generation of reactive oxygen species. • The catalytic behavior was confirmed for the degradation of tetracycline. • Defective nanozymes exhibited an ultrafast degradation rate (26.0 min−1 g−1 L). • Breaking the limitation of pH and expanding its scope of action (pH>5.0). Although nanozymes have shown significant potential in wastewater treatment, enhancing their degradation performance remains challenging. Herein, a novel catalytic behavior was revealed for defective nanozymes with catalase-mimicking characteristics that efficiently degraded tetracycline (TC) in wastewater. Hydroxyl groups adsorbed on defect sites facilitated the in-situ formation of vacancies during catalysis, thereby replenishing active sites. Additionally, electron transfer considerably enhanced the catalytic reaction. Consequently, numerous reactive oxygen species (ROS) were generated through these processes and subsequent radical reactions. The defective nanozymes, with their unique catalytic behavior, proved effective for the catalytic degradation of TC. Experimental results demonstrate that •OH, •O 2 −, 1O 2 and e− were the primary contributors to the degradation process. In real wastewater samples, the normalized degradation rate constant for defective nanozymes reached 26.0 min−1 g−1 L, exceeding those of other catalysts. This study reveals the new catalytic behavior of defective nanozymes and provides an effective advanced oxidation process for the degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

• An updated review on ROS implicated in AOPs for pharmaceutical waste is presented. • Potential ROS are implicated in the pharmaceutical waste degradation. • Mechanistic insights regarding ROS-mediated reaction pathways are discussed. • The main detected transformation products of ACT using specific ROS are reported. Innately designed to induce physiological changes, pharmaceuticals are foreknowingly hazardous to the ecosystem. Advanced oxidation processes (AOPs) are recognized as a set of contemporary and highly efficient methods being used as a contrivance for the removal of pharmaceutical residues. Since reactive oxygen species (ROS) are formed in these processes to interact and contribute directly toward the oxidation of target contaminant(s), a profound insight regarding the mechanisms of ROS leading to the degradation of pharmaceuticals is fundamentally significant. The conceptualization of some specific reaction mechanisms allows the design of an effective and safe degradation process that can empirically reduce the environmental impact of the micropollutants. This review mainly deliberates the mechanistic reaction pathways for ROS-mediated degradation of pharmaceuticals often leading to complete mineralization, with a focus on acetaminophen as a drug waste model. [ABSTRACT FROM AUTHOR]

• The mechanisms involved in the Fenton process were comprehensively elaborated. • The factors determining the influence of pH were emphatically illustrated. • We differentiate several Fenton-like process through their promoting mechanisms. • Substantive proposals toward future were proposed in this review. Fenton and Fenton-like processes, which could produce highly reactive species to degrade organic contaminants, have been widely used in the field of wastewater treatment. Therein, the chemistry of Fenton process including the nature of active oxidants, the complicated reactions involved, and the behind reason for its strongly pH-dependent performance, is the basis for the application of Fenton and Fenton-like processes in wastewater treatment. Nevertheless, the conflicting views still exist about the mechanism of the Fenton process. For instance, reaching a unanimous consensus on the nature of active oxidants (hydroxyl radical or tetravalent iron) in this process remains challenging. This review comprehensively examined the mechanism of the Fenton process including the debate on the nature of active oxidants, reactions involved in the Fenton process, and the behind reason for the pH-dependent degradation of contaminants in the Fenton process. Then, we summarized several strategies that promote the Fe(II)/Fe(III) cycle, reduce the competitive consumption of active oxidants by side reactions, and replace the Fenton reagent, thus improving the performance of the Fenton process. Furthermore, advances for the future were proposed including the demand for the high-accuracy identification of active oxidants and taking advantages of the characteristic of target contaminants during the degradation of contaminants by the Fenton process. [ABSTRACT FROM AUTHOR]

Ozonation (O3) is a widely used advanced oxidation process (AOP) for the treatment of wastewater, while its drawbacks include high energy consumption and poor solubility must be reduced or eliminated. Hence, a combined catalytic ozonation process with H2O2 and S2O82- was employed to degrade mono ethylene glycol (MEG) and eliminate ecological risks during the treatment of gas refinery wastewater. In this study, the reduction of chemical oxygen demand (COD) and MEG from wastewater by O3, O3/H2O2, O3/Na2 S2O8, O3/GAC, O3/GAC/S2O82- and O3/GAC/H2O2 oxidation treatment systems were investigated. The optimal treatment conditions were obtained as O3 dosage of 0.81 g h−1, H2O2 (0.15 mol L−1), S2O82- (2 g L−1), GAC (7 g L−1), pH of 11 and 60 min reaction time. The results revealed that the highest rate of degradation of MEG, COD reduction and the minimum electrical energy per order from the wastewater were 87.6%, 78.1% and 1.01 kWh/m3 respectively for O3/GAC/S2O82- process and 91.0%, 82.5% and 0.877 kWh/m3 respectively for O3/GAC/H2O2 process. The MEG degradation rate constant by O3/GAC/H2O2 system about 6.2 times and O3/GAC/S2O82- system over 5.3 times were higher than O3. After calculation, the synergy factors in O3/GAC with H2O2/S2O82- systems are more than 4.7, demonstrating that both systems have a strong synergistic effect. The finding related to the OH° trapping agent illustrates that indirect oxidation by OH° plays a vital role in the degradation of MEG. The performance of GAC stability was checked and resulted in the GAC also showing good stable catalytic activity in five consecutive cycles of use. The degradation pathways of MEG in the O3/GAC with H2O2 or S2O82- system were proposed based on intermediate analysis. The main intermediates found in MEG oxidation include glycolaldehyde, glycolic acid, glyoxal, glyoxylic acid, oxalic acid and formic acid. Finally, modification of wastewater treatment suggested that the burping phenomenon and the glycol foaming tendency were not observed. [ABSTRACT FROM AUTHOR]

• Separable polymers are formed from organic contaminants in raw coking wastewater. • Simultaneous abatement and recovery of organics from coking wastewater is realized. • About 89% of PDS is saved compared to conventional degradation-based process. • Polymerization mechanism is probed by the molecular structure of organic-polymers. • More energy efficient compared to degradation-based processes. Industrial wastewater should be treated with caution due to its potential environmental risks. In this study, a polymerization-based cathode/Fe3+/peroxydisulfate (PDS) process was employed for the first time to treat a raw coking wastewater, which can achieve simultaneous organics abatement and recovery by converting organic contaminants into separable solid organic-polymers. The results confirm that several dominant organic contaminants in coking wastewater such as phenol, cresols, quinoline and indole can be induced to polymerize by self-coupling or cross-coupling. The total chemical oxygen demand (COD) abatement from coking wastewater is 46.8% and the separable organic-polymer formed from organic contaminants accounts for 62.8% of the abated COD. Dissolved organic carbon (DOC) abatement of 41.9% is achieved with about 89% less PDS consumption than conventional degradation-based process. Operating conditions such as PDS concentration, Fe3+ concentration and current density can affect the COD/DOC abatement and organic-polymer yield by regulating the generation of reactive radicals. ESI-MS result shows that some organic-polymers are substituted by inorganic ions such as Cl–, Br–, I–, NH 4 +, SCN– and CN–, suggesting that these inorganic ions may be involved in the polymerization. The specific consumption of this coking wastewater treatment is 27 kWh/kg COD and 95 kWh/kg DOC. The values are much lower than those of the degradation-based processes in treating the same coking wastewater, and also are lower than those of most processes previously reported for coking wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

The growing pharmaceutical industry has increased the production of wastewater containing pollutants that are resistant to conventional treatment. This study aimed to evaluate the effectiveness of an integrated advanced oxidation process (AOP) combining ozonation and Fenton oxidation for treating pharmaceutical wastewater. The objective was to determine whether this combined approach could achieve higher removal efficiencies for key pollutants, including turbidity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC), compared to individual processes. The research involved applying ozonation and Fenton oxidation, both separately and in combination, to wastewater samples. The study identified the optimal conditions for the integrated treatment by adjusting the concentrations of Fenton reagents and the duration of ozone exposure. The effectiveness of the treatment was assessed based on the removal efficiencies of turbidity, BOD, COD, and TOC. The results demonstrated that the combined ozone-Fenton process was highly effective, achieving removal efficiencies of 98.74% for turbidity, 96% for BOD, 99.56% for COD, and 96.63% for TOC. These findings highlight the potential of this combined AOP as a promising approach for improving the degradation of pollutants in pharmaceutical wastewater. However, the study's limitations include the need for further research to optimize the process for different wastewater types and to evaluate its long-term environmental impact and cost-effectiveness. The study's practical value lies in its potential industrial application, providing a more effective alternative to conventional treatment methods. The originality of the research is in systematically exploring the synergistic effects of combining ozonation and Fenton oxidation, contributing to advanced wastewater treatment development. [ABSTRACT FROM AUTHOR]

In recent years, studies on the degradation of emerging organic contaminants by sulfate radical (SO4−·) based advanced oxidation processes (SR-AOPs) have triggered increasing attention. Metal-loaded biochar (Me-BC) can effectively prevent the agglomeration and leaching of transition metals, and its good physicochemical properties and abundant active sites induce outstanding in activating persulfate (PS) for pollutant degradation, which is of great significance in the field of advanced oxidation. In this paper, we reviewed the preparation method and stability of Me-BC, the effect of metal loading on the physicochemical properties of biochar, the pathways of pollutant degradation by Me-BC-activated PS (including free radical pathways: SO4−·, hydroxyl radical (·OH), superoxide radicals (O2–·); non-free radical pathways: singlet oxygen (1O2), direct electron transfer), and discussed the activation of different active sites (including metal ions, persistent free radicals, oxygen-containing functional groups, defective structures, etc.) in the SR-AOPs system. Finally, the prospect was presented for the current research progress of Me-BC in SR-AOPs technology. HIGHLIGHTS The characteristics of the preparation methods for metal-loaded biochar are summarized.; The effects of metals on the physicochemical properties of biochar are discussed.; The free radical and non-radical pathways for activation of persulfate by metal-loaded biochar are discussed.; The potential mechanisms of metal-loaded biochar catalysts are discussed.; The future blueprint for metal-loaded is described.;

Abstract Municipal wastewater treatment systems use the chemical oxygen demand test (COD) to identify organic contaminants in industrial effluents that impede treatment due to their high concentration. This study reduced the COD levels in tannery wastewater using a multistage treatment process that included Fenton oxidation, chemical coagulation, and nanotechnology based on a synthetic soluble COD standard solution. At an acidic pH of 5, Fenton oxidation reduces the COD concentration by approximately 79%. It achieves this by combining 10 mL/L of H2O2 and 0.1 g/L of FeCl2. Furthermore, the author selected the FeCl3 coagulant for the coagulation process based on the best results of comparisons between different coagulants. At pH 8.5, the coagulation dose of 0.15 g/L achieved the maximum COD removal efficiency of approximately 56.7%. Finally, nano bimetallic Fe/Cu was used to complete the degradation and adsorption of the remaining organic pollutants. The XRD, SEM, and EDX analyses proved the formation of Fe/Cu nanoparticles. A dose of 0.09 g/L Fe/Cu NPs, 30 min of contact time, and a stirring rate of 200 rpm achieve a maximum removal efficiency of about 93% of COD at pH 7.5. The kinetics studies were analyzed using pseudo-first-order P.F.O., pseudo-second-order P.S.O., and intraparticle diffusion models. The P.S.O. showed the best fit among the kinetic models, with an R2 of 0.998. Finally, the authors recommended that technique for highly contaminated industrial effluents treatment for agriculture or industrial purposes.

In this study, a potassium ferrate (K2FeO4)-modified biochar (Fe–BC) was prepared and characterized. Afterwards, Fe–BC was applied to activated periodate (PI) to degrade tetracycline (TC), an antibiotic widely used in animal farming. The degradation effects of different systems on TC were compared and the influencing factors were investigated. In addition, several reactive oxygen species (ROS) generated by the Fe–BC/PI system were identified, and TC degradation pathways were analyzed. Moreover, the reuse performance of Fe–BC was evaluated. The results exhibited that the Fe–BC/PI system could remove almost 100% of TC under optimal conditions of [BC] = 1.09 g/L, initial [PI] = 3.29 g/L, and initial [TC] = 20.3 mg/L. Cl−, HCO3−, NO3−, and humic acid inhibited TC degradation to varying degrees in the Fe–BC/PI system due to their quenching effects on ROS. TC was degraded into intermediates and even water and carbon dioxide by the synergistic effect of ROS generated and Fe on the BC surface. Fe–BC was reused four times, and the removal rate of TC was still maintained above 80%, indicating the stable nature of Fe–BC. HIGHLIGHTS Fe–BC with excellent morphology and composition was successfully prepared.; Fe–BC could effectively activate periodate in degrading tetracycline (TC).; The response surface methodology was utilized to determine the optimum conditions.; The reactive oxygen species generated were responsible for TC degradation.;

Hydroxychloroquine (HCQ), a 4-amino quinoline derivative, has antimalarial and anti-inflammatory activity and was most recently proposed in the treatment of SARS-COVID-19. Its pharmacokinetics and toxic side effects necessitate the monitoring of its presence in the environment and its removal from wastewater. In this study, HCQ was removed from an aqueous solution with a removal efficiency of between 80% and 90% under electron beam (EB) irradiation. The degradation of HCQ was propagated by reactions involving both the hydroxyl radical and aqueous electron. The degradation was observed to follow a pseudo-first-order kinetic reaction. The applied radiation dose, pH, and initial HCQ concentration were influential in the degradation efficiency under EB irradiation. Acidic and alkaline pH favored the removal of HCQ under EB irradiation. Even though the initial HCQ was successfully degraded, it was not completely mineralized. The TOC and chemical oxygen demand (COD) remained at a relatively stable level following EB irradiation of the aqueous solutions. This is attributed to the formation of other organic compounds that were not degraded under the investigated experimental conditions.

Environmental release of wastewater that contains cytostatic drugs can cause genotoxic impact, since these drugs act directly on the genetic material of aquatic organisms. Thus, the aim of this study was to evaluate the removal of the cytostatic drugs cytarabine (CTR) and methotrexate (MTX) using different physico-chemical methods individually (i.e. US, O3, H2O2 and UV) and combined (i.e. O3/US, US/H2O2, O3/H2O2 and O3/US/H2O2) under different pH conditions (4, 7 and 10). In the degradation tests, the efficiency of the methods applied was found to be dependent on the pH of the solution, with the degradation of CTR being better at pH 4 and MTX at pH 7 and pH 10. The US, H2O2 and US + H2O2 methods were the least efficient in degrading CTR and MTX under the pH conditions tested. The highest MTX degradation rate after 16 min of treatment at pH 7 was achieved by the O3 + H2O2 method (97.05% – C/C0 = 0.0295). For CTR, the highest degradation rate after 16 min of treatment was achieved by the O3 process (99.70% – C/C0 = 0.0030) at pH 4. In conclusion, most of the treatment methods tested for the degradation of CTR and MTX are effective. Notably, ozonolysis is an efficient process applied alone. Also, in combination with other methods (US + O3, O3 + H2O2 and O3 + H2O2 + US) it increases the degradation performance, showing a rapid removal rate of 70–94% in less than 4 min of treatment. [ABSTRACT FROM AUTHOR]

Activation of peroxymonosulfate (PMS) by catalysts for water treatment is very important for the sulfate radicals-based advanced oxidation technology. Constructing affordable and recyclable transition metal catalysts with high efficiency is highly desirable, but still challenging. In this study, a novel CoAl2O4/Co2O3@γ-Al2O3 catalyst for the activation of PMS was prepared with an excessive impregnation method, and its performance on the catalytic degradation of phenol in water was investigated. The composition and structure of the catalyst were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and N2 adsorption-desorption experiments. It was found that the catalyst could greatly promote the phenol mineralization in water as the total organic carbon removal increased from 4.27% to 57.64% after 60 min of reaction. The presence of Cl− inhibited the catalytic degradation of phenol in water at low concentrations, but promoted the catalytic degradation at high concentrations. However, HCO3− and CO32− revealed inhibitory effects on the catalytic degradation because they could scavenge free radicals in the system. Based on the electron spin resonance technique and the quenching experiments, O12 and SO4−· were identified to be the primary reactive species for the catalytic degradation. The CoAl2O4/Co2O3@γ-Al2O3 could be easily recovered and reused. The toxicity evaluation verified that the toxicity of the treated water was greatly decreased after the catalytic degradation. Therefore, the CoAl2O4/Co2O3@γ-Al2O3 prepared in this study could be an effective catalyst for the catalytic degradation of phenol in water by activating PMS. [ABSTRACT FROM AUTHOR]

To explore advanced oxidation catalysts, peroxymonosulfate (PMS) activation by Co-Ni-Mo/carbon nanotube (CNT) composite catalysts was investigated. A compound of NiCo2S4, MoS2, and CNTs was successfully prepared using a simple one-pot hydrothermal method. The results revealed that the activation of PMS by Co-Ni-Mo/CNT yielded an exceptional Rhodamine B decolorization efficiency of 99% within 20 min for the Rhodamine B solution. The degradation rate of Co-Ni-Mo/CNT was 4.5 times higher than that of Ni-Mo/CNT or Co-Mo/CNT, and 1.9 times as much than that of Co-Ni/CNT. Additionally, radical quenching experiments revealed that the principal active groups were 1O2, surface-bound SO4•−, and •OH radicals. Furthermore, the catalyst exhibited low metal ion leaching and favorable stability. Mechanism studies revealed that Mo4+ on the surface of MoS2 participated in the oxidation of PMS and the transformation of Co3+/Co2+ and Ni3+/Ni2+. The synergism between MoS2 and NiCo2S4 reduces the charge transfer resistance between the catalyst and solution interface, thus accelerating the reaction rate. Interconnected structures composed of metal sulfides and CNTs can also enhance the electron transfer process and afford sufficient active reaction sites. Our work provides a further understanding of the design of multi-metal sulfides for wastewater treatment. [ABSTRACT FROM AUTHOR]

Dexamethasone (DEX) degradation was investigated using three UV-based advanced oxidation processes combined with sodium persulphate, hydrogen peroxide, and free chlorine in aqueous solutions in a bench-scale reactor. The goal was to determine which process would be the best option in terms of DEX degradation without the subsequent generation of toxic compounds. The process performance for DEX degradation followed the UV/S2O82−> UV/H2O2> UV/HOCl order under equal conditions. In the UV/S2O82− process, sulphate radicals led to a 70.4% DEX degradation. The experimental mineral inhibitory factors showed that nitrite and bicarbonate further decrease the efficiency of the UV/S2O82− process. In the optimal conditions, the UV/S2O8−2 process removed DEX by 100% and had a 74.1% mineralisation. Furthermore, the intermediates were detected using LC-MS/MS, and the cytotoxicity of the UV/S2O8−2 process effluent was evaluated using human embryonic kidney cultured cells. The treatment of DEX solution by the UV/S2O8−2 process significantly decreased the toxicity of the effluent. Therefore, it can be concluded that the UV/S2O8−2 process can be a reliable process for DEX degradation and detoxification in aqueous solutions. [ABSTRACT FROM AUTHOR]

In this study, the researchers evaluated the use of nano-zero-valent iron (nZVI) activated persulfate (PS) for the degradation of Rhodamine B (RhB). The effects of various operating parameters such as initial pH, and dosages of PS, nZVI and citric acid (CA) on the removal rate of RhB were investigated. The results demonstrated that at a PS dosage of 5 mmol·L-1, nZVI dosage of 0.3 g·L-1, 0.1 mmol·L-1 CA, and pH of 5, the degradation rate of RhB was 94.970%. The degradation and kinetic analysis of RhB using micron-scale zero-valent iron (mZVI) and nZVI revealed that nZVI exhibited higher activity with PS due to its smaller particle size. The activation of PS by nZVI is higher compared to mZVI, and the ineffective consumption is half that of the mZVI/PS system, the TOC removal rate increased by 18.65%. Kinetic analysis indicated that under the mentioned reaction conditions, the degradation process followed a pseudo-second-order reaction model, with the highest apparent reaction rate constant (kobs). The researchers also identified active radical species in the nZVI/PS system. Additionally, Gas Chromatography-Mass Spectrometry (GC-MS) analysis was used to detect reaction intermediates and propose a possible degradation pathway for RhB. [ABSTRACT FROM AUTHOR]

Piezocatalysis is attracting extensive attention in recent years because it can directly convert mechanical energy from the ambient environment (such as tiny vibrations and noise) into piezopotential for catalytic activities. Dyes are widely used in diverse industries, including paper, printing, and textiles, which cause serious environmental problems due to their persistence and toxicity. Unlike traditional catalysts that rely on chemical reactions to drive dye degradation, piezocatalysts offer a sustainable and cost‐effective alternative to breaking down complex molecules through creating highly reactive species, which have shown a significant promise in the treatment of organic pollutants in wastewater. In this review, the basic principles of piezocatalysis are first outlined, specifically describing two ubiquitous forms of driving force in nature. Following the catalytic mechanism, the current mainstream piezocatalytic materials are classified into two categories: organic and inorganic materials with detailed discussions. Moreover, after investigating and analyzing previous literature, effective strategies for improving piezocatalytic efficiency for dye degradation are systematically compared and summarized. In the end, current issues that need to be addressed in the future as well as potential research directions related to piezocatalysis are prospected. This work provides an insight into solving current issues to advance the piezocatalysts. [ABSTRACT FROM AUTHOR]

Ribavirin (RBV), which is extensively used to treat viral diseases such as COVID-19, is considered one of the major emerging contaminants due to its long-term existence and health risk in the aqueous environmental system. However, research on effective removal of RBV still remains insufficient. In this study, we investigated the RBV degradation kinetics and mechanism in UV/chlorine/Fe(II) process. The degradation rate constant kobs-RBV of RBV was 2.52 × 10−4 s−1 in UV/chlorine/Fe(II) process, which increased by 1.6 times and 1.3 times than that in chlorine alone and UV/chlorine process, respectively. Notably, trace amount Fe(II) promoted RBV degradation in UV/chlorine system through Fe2+/Fe3+ cycles, enhancing the yield of reactive species such as HO· and certain species reactive chlorine radicals (RCS). The contributions of HO· and RCS toward RBV degradation were 53.91% and 16.11%, respectively. Specifically, Cl·, ClO·, and Cl2·− were responsible for 8.59%, 2.69%, and 4.83% of RBV removal. The RBV degradation pathway indicated that the reactive species preferentially attacked the amide moiety of RBV, which cleaved the ether bond and the hydroxyl group. The toxicity evaluation of RBV degradation products elucidated that UV/chlorine/Fe(II) process was beneficial for RBV detoxification. [ABSTRACT FROM AUTHOR]

Municipal wastewater treatment systems use the chemical oxygen demand test (COD) to identify organic contaminants in industrial effluents that impede treatment due to their high concentration. This study reduced the COD levels in tannery wastewater using a multistage treatment process that included Fenton oxidation, chemical coagulation, and nanotechnology based on a synthetic soluble COD standard solution. At an acidic pH of 5, Fenton oxidation reduces the COD concentration by approximately 79%. It achieves this by combining 10 mL/L of H2O2 and 0.1 g/L of FeCl2. Furthermore, the author selected the FeCl3 coagulant for the coagulation process based on the best results of comparisons between different coagulants. At pH 8.5, the coagulation dose of 0.15 g/L achieved the maximum COD removal efficiency of approximately 56.7%. Finally, nano bimetallic Fe/Cu was used to complete the degradation and adsorption of the remaining organic pollutants. The XRD, SEM, and EDX analyses proved the formation of Fe/Cu nanoparticles. A dose of 0.09 g/L Fe/Cu NPs, 30 min of contact time, and a stirring rate of 200 rpm achieve a maximum removal efficiency of about 93% of COD at pH 7.5. The kinetics studies were analyzed using pseudo-first-order P.F.O., pseudo-second-order P.S.O., and intraparticle diffusion models. The P.S.O. showed the best fit among the kinetic models, with an R2 of 0.998. Finally, the authors recommended that technique for highly contaminated industrial effluents treatment for agriculture or industrial purposes. [ABSTRACT FROM AUTHOR]

Following the goals of the circular economy, this work demonstrates that an industrial by-product can be used in environmental remediation. Metallurgical slag and citric acid were used to form an Fe:Cit complex by simultaneously carrying out the lixiviation of the iron and the chelating stages with an 87% iron recovery. This complex was evaluated in the photo-Fenton process to produce HO• through salicylic acid dosimetry or salicylic acid hydroxylation, producing 0.13 ± 0.1 mM HO• after 30 min of operation; such a value is three orders of magnitude higher than the one reported for the metallurgical slag (as a heterogeneous catalyst, 22 μM) in the photo-Fenton-like process. The system was tested for its ability to degrade a mixture of drugs, including dexamethasone (DEX), naproxen (NAP), and ketorolac (KTR), which are often used to treat the symptoms of COVID-19. The drug degradation tests were performed in two stages. In the first stage, the Fe:Cit complex from the metallurgical slag was compared to the one formed by analytical-grade reactants; the drug degradation was faster for the former, with the major difference being observed at 5 cm and 500 W/m2. Here, 85–90% of the drugs was degraded in 5 min using Fe:Cit from slag, while at least 20 min was necessary to achieve such degradation with the analytical reagent, conceivably because of the trace compounds being lixiviated from the slag. Then, the effects of the liquid depth (5, 10, and 15 cm) and irradiance (250, 500, and 750 W/m2) were tested; the pseudo-first-order kinetic degradation constants for the three model pollutants were in the range of 0.009 > kD > 0.09 min−1, showing that degradation is more feasible for DEX than for NAP and KRT because the radical attack feasibility is related to the molecular structures. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Industry / Hemijska Industrija is the property of Association of Chemical Engineers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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The present work investigates the treatment of wastewater containing an antibiotic, ciprofloxacin (CIP), using acoustic cavitation (AC) coupled with other advanced oxidation processes (AOPs). For the laboratory scale degradation study, operating parameters like drug concentration, operating pH, and initial temperature were initially optimized and then used in hybrid approach of AC in combination with AOPs. At 15 m/L initial drug concentration, neutral pH of 7, and ambient temperature of 30°C, optimum CIP degradation of 13.66% was obtained within 120 min of operation. The intensification of the AC‐based approach was subsequently achieved using other oxidants like H2O2, potassium persulphate (KPS), and O3. The combination of AC with H2O2 and KPS resulted in 44.30% and 35.41% CIP degradation, respectively, while AC combined with ozone resulted in almost complete degradation of CIP within 90 min of treatment with a maximum cavitational yield of 4.761 × 10−6 mg/J. The cost estimation for the optimized treatment approaches revealed that AC combined with ozone is the best process for degradation with the least operational cost of 8.7 Rs/L (105 US $/m3). Complete degradation of CIP with AC + O3 based approach at much lower costs opens a window for implementation in the pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Copyright of Tikrit Journal of Engineering Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Humic acid (HA) is one of the by-products of disinfection that is produced in the water treatment process by chlorination and can produce toxic and carcinogenic substances. Therefore, this study was performed to assess the efficiency of electrically activated peroxymonosulfate (PMS) with iron electrodes in removing HA from aqueous media and optimizing experiments with a central composite design. This study was an experimental study that was performed on a laboratory scale in a batch system. The effect of effective parameters such as current density, reaction time, pH, PMS concentration, and initial HA concentration was investigated on HA removal efficiency. The results of experiments showed that based on central composite design (CCD), the quadratic model was suitable for the data (Pvalue > 0.0001) and the proposed model was confirmed with a high correlation coefficient ((R2 = 0.992) and (R2Adj = 0.995)). The optimal values for the studied parameters were pH of 5.8, PMS concentration of 1.12 mmol/L, the current density of 1.05 mA/cm2, HA concentration of 50 mg/L, and reaction time of 20 min. The maximum HA removal efficiency was predicted to be 91.75% under optimal conditions. According to the results of this study, the process of electro-peroxymonosulfate (EPMS) as an effective oxidation process in the removal of HA and other similar pollutants has relatively high efficiency, and this method can be used to treat wastewater containing such organic matter. [ABSTRACT FROM AUTHOR]

As the by-product of wastewater treatment, a large amount of sludge is generated annually. Turning this waste into a resource is a feasible and sustainable strategy to reduce potential environmental risks and recover energy. As a way to realize the international goal of carbon dioxide emission peak and carbon neutrality, producing biochar from sludge has gained worldwide attention. This review evaluates recent progress in synthesis techniques for biochar of sludge origin. Different preparation techniques and their key affecting factors are compared and described. The obtained sludge-derived biochar could be employed for eliminating aqueous pollution or purifying wastewater, mainly through adsorption and catalytic reactions. The removal of various pollutants by sludge-derived biochar and its related mechanisms are discussed and summarized in detail. This review will be conducive for a comprehensive understanding of recent progress in sludge-derived biochar study and for guiding the purposeful production of biochar, as well as for developing wastewater purification technology based on sludge-derived biochar. [ABSTRACT FROM AUTHOR]

This paper reviews the sources, emissions, transfer of microplastics and their major health risks, describes the research progress on microplastic removal by more widely used advanced oxidation processes, such as UV/H2O2, ozone/H2O2, UV-induced photocatalysis, solar/visible light-induced photocatalysis, and sulfate radical advanced oxidation, and gives a future research direction on the treatment of microplastics by advanced oxidation processes. [ABSTRACT FROM AUTHOR]

The inability of most photocatalysts to continue the catalytic process after the removal of light irradiation is one of their major drawbacks. In this work, a ternary nanocomposite of titanium oxide (TiO 2) supported with tungsten oxide (WO 3) and hybridized with graphene oxide (GO) (TiO 2 -WO 3 @GO) photocatalyst with electron energy storage properties was synthesized for oilfield-produced water (OPW) treatment under visible light and in dark conditions. WO 3 addition extended the light absorption range of TiO 2 into the visible light while also serving as an electron storage material for dark catalysis (memory catalysis). The GO serves as an efficient electron acceptor and transporter to prevent charge carrier recombination, thereby enhancing interfacial electron transfer within the photocatalyst system. 2.5 wt%, 5 wt%, and 10 wt% of WO 3 precursors were reacted with TiO 2 precursor and GO was further added to synthesize the nanocomposites via a modified sol-gel and solution-based approach for the first time. The properties of the nanocomposite were assessed using a wide range of characterization. The nanocomposite containing 5 wt% WO 3 showed the best photocatalytic activity with the total organic content (TOC) degradation of 27.7% within 4 h of photodegradation in visible light, which is better than 22 % in 5 h under UV light so far reported in the literature. The nanocomposite also exhibited electron energy storage properties for dark catalysis after pre-illumination, i.e., 16.6% TOC degradation in 3 h in dark conditions. This low % TOC degradation in the dark could be attributed to the complex nature of OPW. This work has further confirmed the possibility of the use of photocatalysts for dark catalysis. [ABSTRACT FROM AUTHOR]

The narrow pH application range and lower utilization of ferrous ions (Fe(II)) restrict the application of Fe(II)/persulfate (PS) technology. In this paper, simulated sunlight and citric acid (Cit) as a chelator were introduced in an Fe(II)/PS system to overcome the drawbacks and enhance the degradation of typical antibiotic sulfamethoxazole (SMX) in secondary wastewater. The degradation kinetics, mechanism, and influence factors of SMX in a sunlight/Fe(II)/Cit/PS system and a sunlight/Fe(II)/Cit system as a comparable system were investigated. The removal efficiency of SMX can reach 71.15% and 85.25% in the sunlight/Fe(II)/Cit system and sunlight/Fe(II)/Cit/PS system with 0.1 mM Fe(II), 0.6 mM Cit, and 1 mM PS. The increase of Fe(II) concentration in both systems proved that sunlight promoted the regeneration of Fe(II) from the ferric ion chelates. However, the Fe(II) concentration decreased after 30 min in the sunlight/Fe(II)/Cit/PS system because of the decomposition of Cit. Radical quencher experiments indicated that SO4·−, ·OH, and O2·− contributed 2.48%, 88.43%, and 6.91% to the removal of SMX, respectively. Electron paramagnetic resonance spectra also proved the formation of ·OH and O2·−. The degradation of SMX was proposed to proceed via isomerization, cleavage of S–N bond, and hydroxylation. Overall, the sunlight/Fe(II)/Cit/PS process can be used as an advanced treatment technology for antibiotics in municipal wastewater. [ABSTRACT FROM AUTHOR]

Insecticides are toxic compounds widely used to prevent, destroy, and control any insect pests. A larger food production with increasing agricultural activity has been ensured from their application to farmlands. Insecticides have been detected in waters and soils being dangerous for living beings. Due to their high biorecalcitrance and stability at ambient conditions, they cannot be destroyed in conventional wastewater treatment plants (WWTPs) and powerful advanced oxidation processes (AOPs) are being developed for their removal. This review presents a detailed and critical analysis over the application of sulfate radical‐based AOPs to the remediation of waters and soils polluted with insecticides. Persulfate (PS) and peroxymonosulfate (PMS) are used as parent oxidants but they need to be activated to produce strong effective oxidizing radicals such as sulfate radical (SO4●−) and hydroxyl radical (●OH). Alkaline, thermal, catalytic, UV, UV with Fe, photocatalytic, and other methods applied as activators of PS and/or PMS are separately analyzed in waters and soils. For each hybrid procedure, the fundamentals are briefly detailed and the best results reported in the literature are summarized and discussed. The effect of operating parameters on the oxidation power of treatments in pure water, real waters, WWTPs effluents, and contaminated soils are remarked to show the viability of sulfate radical‐based AOPs for insecticides removal from waters and soils. The effect of added common anions and natural organic matter, the detection of oxidizing radicals by selective scavengers and electron paramagnetic resonance, and the identification of the generated by‐products in waters are described. Comparisons with analogous treatments with H2O2 and Fenton are discussed as well. Further research efforts should consider a deeper study of PS‐ and/or PMS‐based processes of insecticides not only in actual agricultural and real wastewaters, but also in many soils to confirm their possible suitability at the industrial level. [ABSTRACT FROM AUTHOR]