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This study explores the utilization of adsorption and advanced oxidation processes for the degradation of ofloxacin (OFL) and ciprofloxacin (CIP) using a green functionalized carbon nanotube (MWCNT-OH/COOH-E) as adsorbent and catalyst material. The stability and catalytic activity of the solid material were proved by FT-IR and TG/DTG, which also helped to elucidate the reaction mechanisms. In adsorption kinetic studies, both antibiotics showed similar behavior, with an equilibrium at 30 min and 60% removal. The adsorption kinetic data of both antibiotics were well described by the pseudo-first-order (PFO) model. Different advanced oxidation processes (AOPs) were used, and the photolytic degradation was not satisfactory, whereas heterogeneous photocatalysis showed high degradation (⁓ 70%), both processes with 30 min of reaction. Nevertheless, ozonation and catalytic ozonation have resulted in the highest efficiencies, 90%, and 70%, respectively, after 30-min reaction. For AOP data modeling, the first-order model better described CIP and OFL in photocatalytic and ozonation process. Intermediates were detected by MS–MS analysis, such as P313, P330, and P277 for ciprofloxacin and P391 and P332 for ofloxacin. The toxicity test demonstrated that a lower acute toxicity was observed for the photocatalysis method samples, with only 3.1 and 1.5 TU for CIP and OFL, respectively, thus being a promising method for its degradation, due to its lower risk of inducing the proliferation of bacterial resistance in an aquatic environment. Ultimately, the analysis of MWCNT reusability showed good performance for 2 cycles and regeneration of MWCNT with ozone confirmed its effectiveness up to 3 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] The structure of MnO 2 was modified by constructing the composites CeO 2 / MnO 2 via a facile hydrothermal method. The catalytic performance of optimal composite (Mn-Ce10) in peroxymonosulfate (PMS) activation for the degradation of bisphenol A (BPA) is approximately three times higher than that of MnO 2 alone. The average valence of manganese in CeO 2 /MnO 2 is lowered compared to MnO 2 , which induces the generation of more free radicals, such as OH and SO 4 •−. In addition, the composite exhibits a higher concentration of oxygen vacancies than MnO 2 , facilitating bonding with PMS to produce more singlet oxygen (1O 2). Moreover, the incorporation of CeO 2 activates the lattice oxygen of MnO 2 , improving its oxidative ability. Consequently, approximately 48% of BPA decomposition in 10min is attributed to direct oxidation in the Mn-Ce10/PMS system, whereas only 36% occurs in 30min for the MnO 2 /PMS system. Simulation results confirm weakened Mn-O covalency and elongated Mn-O bonds due to the activation of lattice oxygen in CeO 2 /MnO 2 , demonstrating that PMS tends to be adsorbed on the composite rather than on MnO 2. This work establishes a relationship between lattice oxygen and the degradation pathway, offering a novel approach for the targeted regulation of catalytic oxidation. [ABSTRACT FROM AUTHOR]

This study investigated the use of heat-activated persulfate (HAP) as a chemical oxidation technique for removing tinidazole (TNZ) antibiotic from aqueous solutions. The impact of various operating parameters, including TNZ initial concentration (20 μM), persulfate (PS) initial dose (0.2–2 mM), solution pH (3–11), solution temperature (20–60 °C), and reaction time (10–120 min), was examined. The results indicated that sulfate radicals were the primary species responsible for TNZ degradation. Higher temperatures and PS concentrations improved the process, while higher pH values and TNZ initial concentrations slowed it down. Additionally, chloride and bicarbonate ions reduced reaction rates, with chloride ions having a more significant effect. Under optimal conditions (including [TNZ]0 = 20 μM, pH = 7, [PS]0 = 1 mM, temperature = 60 °C, and reaction time = 120 min), the removal efficiency achieved was 91.15%, with a mineralization rate of 85.8%. These results suggest that the process is relatively safe. The degradation of TNZ was best described by the pseudo-first-order model compared to other models. Additionally, the process was found to be exothermic and spontaneous, with a negative Gibbs free energy change indicating that it is thermodynamically feasible. The study found HAP to be an effective and cost-efficient technique for removing TNZ antibiotic due to its ease of operation and the absence of the need for additional chemicals or waste handling. Based on these findings, HAP can be considered an advanced oxidation technique for treating antibiotic-contaminated water. [ABSTRACT FROM AUTHOR]

Recently, biochar has emerged as a promising option for environmentally friendly remediation due to its cost-effectiveness, extensive surface area, porosity, and exceptional electrical conductivity. Biochar-based advanced oxidation procedures (BC-AOPs) have gained popularity as an effective approach to breaking down organic pollutants in aqueous environments. It is commonly recognized that the main reactive locations within BC-AOPs consist of functional groups found on biochar, which encompass oxygen-containing groups (OCGs), imperfections, and persistent free radicals (PFRs). Additionally, the existence of metallic components supported on biochar and foreign atoms doped into it profoundly impacts the catalytic mechanism. These components not only modify the fundamental qualities of biochar but also serve as reactive sites. Consequently, this paper offers a comprehensive review of the raw materials, preparation techniques, modification approaches, and composite catalyst preparation within the biochar catalytic system. Special attention is given to explaining the modifications in biochar properties and their impacts on catalytic activity. This paper highlights degradation mechanisms, specifically pathways that include radical and non-radical processes. Additionally, it thoroughly examines the importance of active sites as catalysts and the basic catalytic mechanism of BC-AOPs. Finally, the potential and future directions of environmental remediation using biochar catalysts and advanced oxidation processes (AOPs) are discussed. Moreover, suggestions for future advancements in BC-AOPs are provided to facilitate further development. [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries 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.)

Oxidation by metal activated persulfate and peroxide produces sulfate radicals ( SO 4 • − ) and hydroxyl radicals ( ∙ O H), powerful oxidants that can be used for the destruction of a wide range of pollutants in water and wastewater. In this study, methylene blue dye was used as an indicator to determine the reaction kinetics and identify the radicals produced during oxidation by persulfate, which was added in the form of monopersulfate, and peroxide in the presence of ferrous ions. There was a positive correlation between the monopersulfate concentration and the degradation of methylene blue in the absence of ferrous ions at pH 3, 5, and 7. In the absence of ferrous ions, peroxide had little to no effect on the degradation of methylene blue. Fe2+/monopersulfate and Fe2+/peroxide systems at a ratio of 0.5:1 resulted in the rapid degradation (<20 min) of methylene blue. Humic acid, at a concentration as high as 20 mg/L, did not affect the degradation kinetics in both systems. Bicarbonate inhibited the Fe2+/peroxide reaction; however, in the Fe2+/monopersulfate system, the scavenging effect of bicarbonate was inhibited at higher concentrations, that is, <100mM. The dominant radical species in Fe2+/monopersulfate system was identified as the SO 4 • − using ethanol and tert-butyl alcohol as probes. This screening method was validated by using the same oxidation conditions for the degradation of microcystin-LR (MC-LR). Similar reaction kinetics were observed between MC-LR and monopersulfate. Fe2+/monopersulfate and Fe2+/peroxide reactions resulted in the rapid degradation of MC-LR. Humic acid and bicarbonate had a similar effect on the MC-LR degradation. SO 4 • − was again identified as the dominant radical species in degradation of MC-LR in the Fe2+/monopersulfate system. [ABSTRACT FROM AUTHOR]

Anaerobic digestion effluent from sewage treatment plants (STP) poses a challenge to the operator because of its high organic matter and inorganic nitrogen concentrations, which require an effective process for biological treatment. This study aimed to introduce a UV-VIS spectrum representative index by discrete Fourier transform (DFT) and apply UV-Vis spectrophotometric techniques for real-time organic compound monitoring in the AOP process using anaerobic digestion tank effluent wastewater. The effect of advanced oxidation on the organic compounds of effluent using ozonation was examined. In this research, after treating secondary treated water with the UV-AOP process and anaerobic digestion effluent with ozone microbubble systems, changes in organic substances were expressed by the UV-Vis spectrum and compared with conventional water quality parameters. The anaerobic digestion process effluent was treated through ozone oxidation, had a high curve, and fell gently from 230 to 667 nm. Discrete Fourier transform (DFT) was applied to obtain representative values from the obtained spectrum. From among the coefficients obtained by analyzing the UV-Vis spectrum through DFT, an expected value was selected, and the correlation between CODMn and a3 was the highest (correlation function = 0.694, RSQ = 0.482). Therefore, a linear regression analysis was performed to determine which water quality factor it was related to. [ABSTRACT FROM AUTHOR]

Whole tumor cells expressing a wide array of tumor antigens are considered as a highly promising source of antigens for cancer vaccines. However, simultaneously preserving the antigen diversity, improving immunogenicity, and eliminating the potential tumorigenic risk of whole tumor cells are highly challenging. Inspired by the recent progress in sulfate radical‐based environmental technology, herein, an advanced oxidation nanoprocessing (AONP) strategy is developed for boosting the immunogenicity of whole tumor cells. The AONP is based on the activation of peroxymonosulfate by ZIF‐67 nanocatalysts to produce SO4−∙ radicals continuously, leading to sustained oxidative damage to tumor cells and consequently extensive cell death. Importantly, AONP causes immunogenic apoptosis as evidenced by the release of a series of characteristic damage associated molecular patterns and at the same time maintains the integrity of cancer cells, which is critical to preserve the cellular components and thus maximize the diversity of antigens. Finally, the immunogenicity of AONP‐treated whole tumor cells is evaluated in a prophylactic vaccination model, demonstrating significantly delayed tumor growth and increased survival rate of live tumor‐cell‐challenged mice. It is expected that the developed AONP strategy would pave the way to develop effective personalized whole tumor cell vaccines in future. [ABSTRACT FROM AUTHOR]

High cellulase cost is a significant challenge to reducing the production cost of the lignocellulosic ethanol industry. Fenton reagents can oxidize and degrade organic matter through the advanced oxidation process. This study combined the Fenton reagent with cellulase to improve lignocellulose degradation efficiency and reduce the amount of enzyme dosage. Fenton reaction studies showed that the experimental group of 1000 mmol/L H 2 O 2 + 10 mmol/L FeSO 4 was the most suitable condition for coupled cellulase hydrolysis and excessive reagents might cause a decrease in the promotion effect. The solid loading analysis evidenced that the lignocellulose degradation can be facilitated by the Fenton reagent in the 15%–30% solids range. Treated with the Fenton reagent, the release of free water and the increase of specific surface area in the degradation process were enhanced. It's indicated that the amount of cellulase decreased by 76.2% under the combination of advanced oxidation and enzymatic hydrolysis. The techno-economic analysis of 300,000 t/a lignocellulosic ethanol showed that the combination reduced 26.96% annual costs. These results confirmed that the method of combining advanced oxidation with enzymatic hydrolysis is an effective way to improve the economics of industrial ethanol. [Display omitted] • Advanced oxidant facilitated lignocellulose degradation in 15%–30% high solids. • Advanced oxidant increased mass transfer and lignocellulose specific surface area. • Advanced oxidation coupled enzymatic hydrolysis reduced 76.2% cellulase dosage. • The annual cost was reduced by 26.96% in the techno-economic analysis. [ABSTRACT FROM AUTHOR]

Ultraviolet advanced oxidation processes (UV-AOPs) were compared using sodium perborate (UV/NaBO3 AOP) or hydrogen peroxide (UV/H2O2 AOP) for 1,4-dioxane removal from tertiary wastewater effluent. Both UV-AOPs were also tested with the addition of acetic acid. Results revealed that sodium perborate performed similarly to hydrogen peroxide. The UV/NaBO3 AOP with 6 milligrams per liter (mg/L) as H2O2 resulted in 43.9 percent 1,4-dioxane removal, while an equivalent UV/H2O2 AOP showed 42.8 percent removal. Despite their similar performance, NaBO3 is approximately 3.3 times more expensive than H2O2. However, the solid form of NaBO3 can provide a major benefit to remote and mobile operations. Unlike H2O2 solution, which degrades over time and requires repeated costly shipments, NaBO3 is a convenient source of H2O2, and a long-term supply can be shipped at once and mixed into solution as needed. The addition of acetic acid to a UV/H2O2 AOP was found to enhance 1,4-dioxane removal, increasing treatment effectiveness by 5.7%. [ABSTRACT FROM AUTHOR]

2,4-Dinitrophenol (2,4-DNP) is a toxic compound that is widely used in many industrial and agricultural processes. This compound has low biodegradability in the environment due to its aromatic structure, and it is unsuccessfully eliminated by other chemical methods. Therefore, in this study, an integrated oxidation and reduction method was used to remove 2,4-DNP from the aqueous medium, in order to simultaneously use the benefits of oxidizing and reducing radicals in 2,4-DNP degradation. 2,4-DNP degradation was modeled by response surface methodology (RSM) and central composite design (CCD). According to the results obtained from RSM, the optimal values for the studied parameters were obtained at pH = 8.9, time = 25 min, ZnO dose = 0.78 g/L, SO3 = 1.89 mmolL−1 and 2,4-DNP concentration = 5 mg/L. Also, the removal efficiency with the integrated process was 3 to 4 times higher than the advanced oxidation or advanced reduction processes alone. Analysis of the data showed that at the time of the study, 2,4-DNP had been converted to linear hydrocarbons, and increased periods of time were required for complete mineralization. A decrease in the first-order model rate constant (kobs) and an increase in 2,4-DNP degradation rate (robs) were observed at higher DNP concentrations. [ABSTRACT FROM AUTHOR]

This Special Issue includes manuscripts on mechanistic understanding, development, and implementation of advanced oxidation processes (AOPs) for the removal of contaminants of emerging concern in water and wastewater treatment. The main goal was successfully achieved under the joint effort of authors, anonymous reviewers, and editorial managers. Totally, one review and 15 research papers are included in the Special Issue. These are mainly focused on catalyst synthesis, reactor design, treatment performance, kinetic modeling, reaction mechanisms, and by-product formation during electrochemical, photocatalytic, plasma, persulfate, chlorine, ozone-based, and Fenton-related AOPs at different scales. This Special Issue received attention from researchers from different parts of the world such as Argentina, Brazil, Canada, China, Germany, India, Mexico, and the USA. The guest editors are happy to see that all papers presented are innovative and meaningful, and hope that this Special Issue can promote mechanistic understanding and engineering applications of AOPs for the removal of contaminants of emerging concern in water. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes (AOPs) during wastewater treatment oxidise Cl − to active inorganic chlorine species (AICS). AICS can react with organic compounds in wastewater to form toxic and hazardous chlorinated organic compounds, most of which are carcinogenic, teratogenic, and mutagenic. In this study, the abilities of three AOPs, i.e., electrochemical, ozone, and Fenton, to convert Cl − to AICS were compared. The results showed that at an initial Cl − concentration of 710 mg-Cl/L and a reaction time of 120 min, the conversion efficiencies of electrochemical, ozone, and Fenton processes were 74.1%, 21.0%, and 4.1%, respectively. The respective concentrations were 436.44 mg-Cl/L, 2.23 mg-Cl/L, and below detection limit for free chlorine; and 82.29 mg-Cl/L, 65.11 mg-Cl/L, and 6.30 mg-Cl/L for ClO 3 −. The abilities of the three AOPs to convert Cl − to AICS were in the order, electrochemical ≫ ozone ≫ Fenton. In the present study, the potential reasons for the significant differences in the Cl − oxidising ability of the AOPs were discussed. The effects of temperature and initial pH on the formation of free chlorine in the ozone and electrochemical processes were also investigated. These results are of great significance for the selection of AOPs for treating wastewater containing Cl − in practical applications. [Display omitted] [ABSTRACT FROM AUTHOR]

• Degradation of eight sulfonamides in the Fe 3 O 4 /PDS oxidation system was investigated. • Ten new oxidation products from sulfameter were identified. • The degradation pathways of sulfameter were proposed. Sulfonamides (SAs) are one of the most widely used antibiotics and their residuals in the environment could cause some negative environmental issues. Advanced oxidation such as Fenton-like reaction has been widely applied in the treatment of SAs polluted water. Degradation rates of 95%-99.7% were achieved in this work for the tested 8 SAs, including sulfisomidine, sulfameter (SME), phthalylsulfathiazole, sulfamethoxypyridazine, sulfamonomethoxine, sulfisoxazole, sulfachloropyridazine, and sulfadimethoxine, in the Fe 3 O 4 /peroxodisulfate (PDS) oxidation system after the optimization of PDS concentration and pH. Meanwhile, it was found that a lot of unknown oxidation products were formed, which brought up the uncertainty of health risks to the environment, and the identification of these unknown products was critical. Therefore, SME was selected as the model compound, from which the oxidation products were never elucidated, to identify these intermediates/products. With liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS), 10 new products were identified, in which 2-amino-5-methoxypyrimidine (AMP) was confirmed by its standard. The investigation of the oxidation process of SME indicated that most of the products were not stable and the degradation pathways were very complicated as multiple reactions, such as oxidation of the amino group, SO 2 extrusion, and potential cross-reaction occurred simultaneously. Though most of the products were not verified due to the lack of standards, our results could be helpful in the evaluation of the treatment performance of SAs containing wastewater. Graphical Abstract [Display omitted] [ABSTRACT FROM AUTHOR]

The toxic pollutants present in water should be treated by advanced oxidation processes (AOP). This investigation deals with study of sonocatalytic degradation of the prepared zinc oxide nanorods (ZnONR) under ultrasonic (US) irradiation for the degradation of Direct blue (DB71) dye molecule. ZnONR has been prepared by sol-gel method using zinc acetate and ammonia. The prepared ZnONR have been characterized using FT-IR, XRD, FE-SEM, HR-TEM, EDAX, AFM and BET techniques and found that the prepared catalyst is highly crystalline with hexagonal structured nano rods with Wurtzite crystal phase. In-situ generation of the OH. radicals has been analyzed by EPR technique. Preliminary experiments are conducted such as effects of pH, catalyst loading, dye concentration and effect of energy input to optimize suitable experimental conditions. Kinetics of sonocatalytic degradation of dye molecules have also been carried out and the reaction followed pseudo first-order kinetics. The interference of electrolytes on the degradation of dye molecules has also been carried out. Degradation of the dye molecules are examined by UV-Visible absorption, COD and TOC measurements. The by-products formation of the degraded samples has been analyzed by ESI-MS+ technique. The reusability of the catalyst for its efficiency and the degradation of real dye house effluents have also been tested [ABSTRACT FROM AUTHOR]

Degradation and mineralization of antidiabetic metformin (MTF) and opioid tramadol (TMD) in water were studied in UV photolytic oxidation and pulsed corona discharge (PCD) combined with extrinsic persulfate (PS) as UV/PS and PCD/PS systems. The effect of PS dose variation on the oxidation rate and efficiency was assessed. The UV/PS combination showed considerable effect in MTF and TMD removal, enhancing the removal of TOC up to 60–65% at maximum applied PS dose, thus providing the highest cost efficiency. As for the PCD/PS oxidation, the synergy was noticed for MTF, moderately increasing the oxidation rate and mineralization at somewhat increased expense. The PS addition to PCD treatment, however, demonstrated no effect on TMD oxidation. The highest energy efficiency in MTF and TMD degradation was thus showed by non-assisted PCD treatment with an energy yield at 90% conversion of the target compound of 5.6 and 13 g kW-1 h-1, respectively, confirming its practical applicability. The effective mineralization of the target compounds in persulfate photolysis makes it promising for use in advanced water purification. To assess the environmental safety of the studied oxidation processes, the acute toxicity of the treated MTF and TMD solutions to luminous bacteria (Vibrio fischeri) was examined. [Display omitted] [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are salts with exceptional properties, such as high thermal stability and low melting point, making them potential substitutes for conventional organic solvents. However, because of their relatively high solubility in water, ILs can enter aquatic systems as pollutants via wastewater discharge. The presence of ILs in the environment is concerning because many ILs have low biodegradability, which can be associated with high ecotoxicity. Crucially, the degradability of ILs is dependent on the nature of their anion and cation components, and many ILs are not readily degraded in conventional wastewater treatment plants and, thus, accumulate in the environment. Therefore, cost-effective solutions to treat these pollutants are required. Advanced oxidation processes (AOPs) are a group of technologies that can remove a wide range of recalcitrant pollutants. In this work, we review the literature concerning IL degradation by AOPs, including Fenton-based systems and photo- and electrochemical treatments, as well as their combinations. The operating conditions, kinetic aspects, and degradation pathways are reviewed. [ABSTRACT FROM AUTHOR]

In this work, Fe–Mn based ternary catalysts (Fe–Mn-X, X = Ce, Co and Cu) were evaluated in the plasma-catalytic oxidation of ethylene oxide (EO) using a cylindrical dielectric barrier discharge (DBD) reactor. The addition of transition metal dopants to the Fe–Mn catalyst significantly improved the performance of plasma-catalyzed EO oxidation compared to the reaction using plasma only and the Fe–Mn catalyst. The highest EO conversion (91.9%) and CO 2 selectivity (78.9%) were obtained over the Fe–Mn–Co catalyst at a specific energy input (SEI) of 730.2 J l−1. Moreover, the presence of water vapor improved EO conversion and CO 2 selectivity in the relative humidity (RH) range of 0–60%, while further increasing the RH to 80% reduced EO conversion. The interactions between Fe, Mn and dopants increased the specific surface area and pore volume of the Fe–Mn-X catalyst, while maintaining the crystalline structure of the catalysts. The presence of the dopants enhanced the reducibility of the Fe–Mn-X catalysts and produced more surface adsorbed oxygen (O ads) on the catalyst surfaces. Moreover, the interactive effects among the Fe, Mn and dopants facilitated the plasma-catalytic oxidation reactions via enhanced surface reactions. The coupling of plasma with the Fe–Mn–Co catalyst reduced the formation of organic by-products in the plasma-catalyzed oxidation of EO. • Plasma-catalytic oxidation of ethylene oxide over Fe–Mn-X catalysts was carried out. • The doping of Ce, Co and Cu enhanced the reducibility of the Fe–Mn-X catalysts. • The Fe–Mn–Co catalyst showed the highest conversion and CO 2 selectivity. • There was an optimal relative humidity to maximize the plasma-catalytic performance. • The plasma-catalyst coupling reduced the formation of by-products. [ABSTRACT FROM AUTHOR]

Bench‐scale testing was conducted to evaluate the application of an Ultraviolet‐hydrogen peroxide (UV‐H2O2) advanced oxidation process (AOP) for the destruction of 1,4‐Dioxane (47 μg/L) and varying concentrations of three volatile organic chemicals (VOCs), including trichloroethylene (TCE), tetrachloroethylene (PCE), and 1,1‐dichloroethylene (1,1‐DCE), from three samples of groundwater containing high alkalinity (281 mg/L as CaCO3). The UV doses applied ranged from zero to 5500 mJ/cm2 while the H2O2 concentrations ranged from 0 to 16 mg/L. The results showed that the bicarbonate and carbonate alkalinity greatly dominated the hydroxyl radical consumption and thus the 1,4‐Dioxane destruction rate. The removal of perchlorate, chlorate, and nitrate prior to UV‐H2O2 treatment had no discernable effect on 1,4‐Dioxane destruction, while the removal of TOC increased the rate of 1,4‐Dioxane destruction by approximately 25%. Depending on the combination of H2O2 concentration and UV dose, 1,4‐Dioxane destruction ranged from negligible to greater than 99%. [ABSTRACT FROM AUTHOR]

Cl- activated peroxymonosulfate (PMS) oxidation technology can effectively degrade pollutants, but the generation of chlorinated disinfection byproducts (DBPs) limits the application of this technology in water treatment. In this study, a method of nanobubbles (NBs) synergistic Cl-/PMS system was designed to try to improve this technology. The results showed the synergistic effects of NBs/Cl-/PMS were significant and universal while its upgrade rate was from 12.89% to 34.97%. Moreover, the synergistic effects can be further improved by increasing the concentration and Zeta potential of NBs. The main synergistic effects of NBs/Cl-/PMS system were due to the electrostatic attraction of negatively charged NBs to Na+ from NaCl, K+ from PMS, and H+ from phenol, which acted as a "bridge" between Cl- and HSO 5 - as well as phenol and Cl-/HSO 5 -, increasing active substance concentration. In addition, the addition of NBs completely changed the oxidation system of Cl-/PMS from one that increases environmental toxicity to one that reduces it. The reason was that the electrostatic attraction of NBs changed the active sites and degradation pathway of phenol, greatly reducing the production of highly toxic DBPs. This study developed a novel environmentally friendly oxidation technology, which provides an effective strategy to reduce the generation of DBPs in the Cl-/PMS system. [Display omitted] • There was a synergistic effect between NBs and the Cl-/PMS system. • NBs reduced the dosage of PMS and the risk of SO 4 2- pollution. • NBs could alter the degradation pathway and degree of pollutants in the Cl-/PMS system. • NBs reduced the production of disinfection byproducts from the Cl-/PMS system. • A low concentration of Cl- can drive the NB&PMS system. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of Technology 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.)

Pollution from industrial effluents is more diverse and complex than municipal wastewater due to the use of thousands of new chemical compounds in industry every year. Subsequent introduction of small quantities of these compounds into water streams through industrial effluents has complicated water pollution problems and posed many challenges in removing contaminants from water. The purpose of the present study was to remove phenol contaminants from the effluent of petrochemical wastewater treatment plants using advanced photochemical oxidation method (ultraviolet/hydrogen peroxide/ozone) in a laboratory scale. The experiments were performed using UVC light, 30 % H2O2 as oxidizer and phenol (100 mg/L). The effective parameters studied in phenol removal included pH, H2O2 concentration, solution temperature and UVC irradiation time. The experimental results showed an increase in phenol removal efficiency with increasing H2O2 concentration up to 400 mg/L while decreasing with increasing oxidizer concentration to 500 mg/L, thus suggesting a concentration of 400 mg/L as the optimal value. Using a flow rate of 200 mg/L of ozone for 80 min, by optimizing other conditions, increased the phenol removal efficiency by 98 %. The phenol removal efficiency was much higher at acidic conditions than at alkaline and neutral ones. The phenol content decreased significantly with increasing contact time. In other words, prolonged contact time increased the phenol removal efficiency in the tested sample. The highest phenol removal efficiency (75.7 %) occurred at the pH value of 4 and the phenol removal efficiency in the sample decreased with increasing pH value. Prolonged contact time caused more phenol concentration to be removed from the test sample, so that 69.8 % of the phenol concentration in the sample was reduced. The results of this study showed that advanced oxidation reduced the phenol content in the analyzed sample. To conclude, the advanced oxidation methods can be useful in the process of treating petrochemical wastewater and effluent of units containing toxic aromatic compounds such as phenol. [ABSTRACT FROM AUTHOR]

The objective was to analyze the treatment of leachates by Advanced Oxidation Processes (AOPs), based on the Fenton method. To search for information, the keywords "Advanced Oxidation", "Sanitary Landfill", "Leached", "Fenton", "Leachate" and "Landfill" were used in the Scopus, Dialnet, Scielo and Redalyc databases. We worked with the Prisma method for systematic reviews, whose search showed 2751 articles, of which 199 were taken from Scopus, 14 from Dialnet, 12 from Scielo, and 2526 from Redalyc, of which 2718 articles were excluded because they were not related. with the objective of the investigation. Of the 33 selected scientific publications, nine presented direct applications of the Fenton method, and with combined applications of the Fenton method there were 24. The results obtained are characterized and analyzed in relation to their efficiencies based on COD (Chemical Oxygen Demand). that the Fenton method with direct application can reach efficiencies between 42 to 85% of the COD, while the combined method reaches a range of 65 to 99.88% for the COD. [ABSTRACT FROM AUTHOR]

Bisphenol-A (BPA), a precursor for many polymers, is a harmful compound for living organisms if present beyond permissible limits in aqueous streams. The combinations of oxidation processes like Hydrodynamic Cavitation (HC), hydrogen peroxide (H2O2), and Fenton's reagent (H2O2 + FeSO4) were examined for the degradation of BPA in the present study. The effects of operating parameters like inlet pressure, initial concentration of BPA, orifice geometry were investigated on BPA degradation. The degradation rates of BPA increased with inlet pressure up to 0.5 MPa and then showed a decreasing trend beyond 0.5 MPa. The initial concentration of BPA had an inverse relation with the degradation percentage. The multiple hole orifice plate showed better degradation of BPA compared to the single hole orifice plate. In the intensification studies, the addition of hydrogen peroxide to BPA in the cavitation reactor favored BPA degradation. A combination of HC + Fenton's reagent (0.1 M H2O2 + 0.01 M FeSO4) significantly degraded BPA present in the aqueous streams. [ABSTRACT FROM AUTHOR]

Reactive electrochemical membrane (REM) emerges as an attractive strategy for the elimination of refractory organic pollutants that exist in wastewater. However, the limited reaction sites in traditional REMs greatly hinder its practical application. Herein, a feed-through coating methodology was developed to realize the uniform loading of SnO 2 -Sb catalysts on the interior surface of a REM. The uniformly coated REM (Unif-REM) exhibited 2.4 times higher reaction kinetics (0.29 min–1) than that of surface coated REM (Surf-REM) for the degradation of 2 mM 4-chlorophenol (4-CP), rendering an energy consumption as low as 0.016 kWh g TOC –1. The fast degradation of various emerging contaminants, e.g., sulfamethoxazole (SMX), ofloxacin (OFLX), and tetracycline (TC), also confirms its superior oxidation capability. Besides, the Unif-REM exhibited good performance in generating hydroxyl radicals (•OH) and a relatively long service lifetime. The simulation of spatial current distribution demonstrates that the interior reaction region in the Unif-REM channels can be drastically extended, thereby maximizing the surface coupling of mass diffusion and electron transfer. This study offers an in-depth look at the spatially confined reactions in REM and provides a reference for the design of electrochemical systems with economically efficient water purification. [Display omitted] • The Unif-REM can degrade 257 mg L–1 4-CP with a kinetic rate of 0.29 min–1. • An energy consumption as low as 0.016 kWh g TOC –1 was achieved. • The extended interior reaction region increases the generation of •OH. • A theoretical lifetime of 2.15 years could be achieved for the Unif-REM. • Electrolyte concentration strongly impacts the electro-active area of REMs. [ABSTRACT FROM AUTHOR]

• pH governs the types and formation of reactive species in the Fe(VI)/S(IV) process. • Alkalinine conditions favors the formation of SO 4 •−. • The generation of Fe(V/IV) was more significant at low pH. • The efficiency and mechanisms of the degradation of SMX and IBU were compared. • Fe(V/IV) involved in destroying SMX and IBU primarily at low pH. Studies on the Fe(VI)/S(IV) process have focused on improving the efficiency of emerging contaminants (ECs) degradation under alkaline conditions. However, the performance and mechanisms under varying pH levels remain insufficiently investigated. This tudy delved into the efficiency and mechanism of Fe(VI)/S(IV) process using sulfamethoxazole (SMX) and ibuprofen (IBU) as model contaminants. We found that pH was crucial in governing the generation of reactive species, and both Fe(V/IV) and SO 4 •− were identified in the reaction system. Specifically, an increase in pH favored the formation of SO 4 •−, while the formation of Fe(VI) to Fe(V/IV) became more significant at lower pH. At pH 3.2, Fe(III) resulting from the Fe(VI) self-decay reactedwith HSO 3 −to produce SO 4 •−and •OH. Under near-neutral conditions, the coexistance of Fe(V/IV) and SO 4 •− in abundance contributed to the optimal oxidation of both pollutants in the Fe(VI)/S(IV) process, with the removal exceeding 74% in 5 min. Competitive quenching experiments showed that the contributions of Fe(V/IV) to SMX and IBU destruction dimished, while the contributions of radicals increased with an increase in pH. However, this evolution was slower during SMX degradation compared to IBU degradation. A comprehensive understnding of pH as the key factor is essential for the optimization of the sulfite-activated Fe(VI) oxidation process in water treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Treatment of wastewater generated in carpet manufacturing is a problematic issue, mainly because of the toxic impact of chemicals used in different processes. Fenton oxidation may be a suitable approach for reducing toxicity but the cost of chemicals may be prohibitive to adopt this process as the main treatment phase. In this context, this study explored the feasibility of implementing either Fenton or Fenton-like oxidation process as a pretreatment stage before the biological treatment of carpet manufacturing effluents. It also included optimization of operation parameters using response surface methodology. Optimization was mainly focused on molar ratios of H2O2/COD and H2O2/Fe along with the reaction time for Fenton and Fenton-like advanced oxidation. For the Fenton process, the optimum H2O2/COD and H2O2/Fe2+ molar ratios were determined as 0.06 and 0.60 mol/mol, respectively. Different optimum values of 0.29 and 4 mol/mol, respectively, were applied to the same molar ratios for the Fenton-like oxidation. The Fenton process yielded 81% and 68% for COD removal and toxicity reduction, respectively. Similarly, removal yields of 62% for COD and 76% for toxicity were achieved by means of the Fenton-like oxidation. This process proved to be suitable as a pre-treatment step, where adequate toxicity reduction was achieved to allow effective COD removal in the following biological treatment phase. [ABSTRACT FROM AUTHOR]

This study has been carried out with the aim of evaluating the treatability of polycyclic aromatic hydrocarbon compounds of PAHs available in urban and industrial sewage sludge utilizing advanced chemical oxidation methods contingent on free sulfate radicals using hydrogen peroxide and heat activation methods. For this purpose, various parameters including (3, 5, 7, 9, and 10), persulfate's concentration (2, 10, 5, 15, and 20 mmol), the ratio of peroxide to persulfate (1, 0.5, 0.3, 0.2, and 0.1), sludge temperature (25°C, 35°C, 45°C, and 55°C) and the primary concentration of PAHs were considered at the 20 d reaction periods. Through making use of gas chromatography- mass spectrometry (GC-MS), after 40-min period, the quality and quantity of the compounds available in the samples were determined using a mass detector and the drawn standards curve. After examining the effectiveness of eliminating PAH compounds in various conditions, the chemical oxygen demand test was carried out for the samples related to optimal removal of PAH compounds to determine the real efficiency of the process in eliminating intermediate compounds originated from PAHs oxidation. The results demonstrate that the advanced chemical oxidation method (persulfate-peroxide) can effectively result in the elimination of PAH compounds from the sludge. [ABSTRACT FROM AUTHOR]

Industrial effluents, particularly from dye industry, is one of the major causes of serious concern as it contaminates the environmental water resources and affect human health. Treatment of such contaminants is a challenging area of interest to researchers. In this context, here, we have explored degradation and mineralization of Direct Blue (DB71) dye in aqueous solution by means of ultrasound irradiation at a frequency of 25 kHz and its combination with a novel homogenous sonocatalyst is investigated. The following experiments have been conducted to achieve complete degradation of the dye molecule. In-situ generation of the radicals under ultrasonic irradiation is measured by EPR technique. The effects of various operational parameters such as the effects of pH, dye concentration, catalyst dosage, electrolytes, energy input and kinetics of oxidation processes on the degradation efficiency are studied. COD measurements are also carried out in order to evaluate the mineralization efficiency of DB71. The effect of electrolytes on dye degradation is studied with different inorganic electrolytes. The rate constant decreases with increasing dye concentration. The degradation increases with increasing catalyst concentration and decreases with increasing dye concentration. Sonocatalytic degradation of the dye molecules are observed by UV-visible absorption and TOC measurements. The by-products formation of the sonocalytically degraded dye samples are analyzed by ESI-MS+ analysis. The catalyst is also tested for its efficiency in the degradation of real dye house effluents. [ABSTRACT FROM AUTHOR]

The removal of cyanotoxins, microcystin-LR (MLR), anatoxin-a (ANA), and cylindrospermopsin (CYN) in Detroit River water (DRW) was investigated by ozone and advanced oxidation process (AOP). Enhanced removal of all cyanotoxins was observed with increasing applied ozone dose. The reactivity of cyanotoxins with ozone followed the order of MLR>CYN>ANA in DRW at its natural pH of 7.6, as indicated by the calculated pseudo first-order oxidation coefficients (kd) of 17.5, 7.41, and 2.03 L/mg, respectively. The most efficient oxidations of MLR, CYN, and ANA with ozone in DRW were obtained at pH 5, 7.6, and 10, respectively, with kd values of 29.5, 7.41, and 4.65 L/mg. Ozone-based AOP with hydrogen peroxide did not make a significant difference in the removal of cyanotoxins compared to the application of ozone alone. [ABSTRACT FROM AUTHOR]

Metal-persulfate is currently used for SO4∙- generation and oxidation to remove organic contaminants. However, homogeneous metal-persulfate requires acidic pH conditions and metal ions cannot be separated from the bulk after the reaction. To address these issues, a heterogeneous nanoscale zero-valent metal catalyst was used to activate peroxymonosulphate for advanced oxidation of hydroxypropyl guar gum (HPG) and other polymers in oilfield wastewater. It was found that the nanoscale Cu(0) performed high catalytic activity in a wide pH range of 7.0-11.0. The viscosity of HPG can be reduced effectively from 24 to 2.5 with the 10.0% Na2S2O8 (mass ratio to HPG) and 10.0% Cu(0) (mass ratio to Na2S2O8), and the chemical oxygen demand of HPG solution can be decreased from 7,602 to 1,070 mg L-1 in presence of the nanoscale Cu(0). Furtherly, the morphology and pore structure of catalysts were characterized in detail by scanning electron microscopy, X-ray diffraction and Brunauer-Emmett-Teller. [ABSTRACT FROM AUTHOR]

A system consisting of hydrogen peroxide/persulfate (H2O2/S2O82−) catalyzed by siderite was attempted to oxidize nine representative petroleum hydrocarbon compounds [benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene, 1,2,4-trimethylbenzene, methyl-tert-butyl ether, and naphthalene] that tend to persist in the environment. Oxidation under different siderite dosages, H2O2:S2O82− ratios, and pH conditions were investigated. Results indicated that oxidation rates increased from 1.21–4.62 to 1.77–8.94 d−1 as siderite increased from 0.16 to 0.48 g/40 mL (H2O2:Na2S2O8 = 5:1, initial pH = 3.0), except for naphthalene (decreased from 0.58 to 0.45 d−1 with increased siderite dosage). When the H2O2:S2O82− ratio was increased from 1:1 to 5:1 (siderite = 0.16 g, initial pH = 3.0), the oxidation rates increased from 0.02–0.73 to 0.33–2.19 d−1. However, as pH increased to > 5.5 (siderite = 0.16 g, H2O2:Na2S2O8 = 2.5:1), the oxidation rates of petroleum hydrocarbons decreased to 0.003–0.09 d−1, which was approximately 90% less than that at pH = 3.0. The partial correlations and principal component analysis of the experimental data were conducted. Overall, both siderite dosage and H2O2:S2O82− ratio correlated positively with oxidation efficiency. The oxidation potential by H2O2/S2O82− mixtures towards the target petroleum hydrocarbon compounds seemed to be more sensitive to pH conditions than to siderite dosages or H2O2:S2O82− ratios. [ABSTRACT FROM AUTHOR]

Recently, the European Food Safety Authority (EFSA) has banned the use of iprodione (IPR), a common hydantoin fungicide and nematicide that was frequently used for the protective treatment of crops and vegetables. In the present study, the treatment of 2 mg/L (6.06 μM) aqueous IPR solution through ultraviolet-C (UV-C)-activated persulfate (PS) advanced oxidation process (UV-C/PS) was investigated. Baseline experiments conducted in distilled water (DW) indicated that complete IPR removal was achieved in 20 min with UV-C/PS treatment at an initial PS concentration of 0.03 mM at pH = 6.2. IPR degradation was accompanied with rapid dechlorination (followed as Cl− release) and PS consumption. UV-C/PS treatment was also effective in IPR mineralization; 78% dissolved organic carbon (DOC) was removed after 120-min UV-C/PS treatment (PS = 0.30 mM) compared with UV-C at 0.5 W/L photolysis where no DOC removal occurred. LC analysis confirmed the formation of dichloroaniline, hydroquinone, and acetic and formic acids as the major aromatic and aliphatic degradation products of IPR during UV-C/PS treatment whereas only dichloroaniline was observed for UV-C photolysis under the same reaction conditions. IPR was also subjected to UV-C/PS treatment in simulated tertiary treated urban wastewater (SWW) to examine its oxidation performance and ecotoxicological behavior in a more complex aquatic environment. In SWW, IPR and DOC removal rates were inhibited and PS consumption rates decreased. The originally low acute toxicity (9% relative inhibition towards the photobacterium Vibrio fischeri) decreased to practically non-detectable levels (4%) during UV-C/PS treatment of IPR in SWW. [ABSTRACT FROM AUTHOR]

When treating drinking water using UV/H2O2 advanced oxidation, the H2O2 residual is usually quenched to allow for downstream chlorine stability. In some utilities, monochloramine (NH2Cl) is used for secondary disinfection, and H2O2 may not need to be quenched because NH2Cl and H2O2 can coexist for some time. However, when ammonia and chlorine are applied to form NH2Cl in the H2O2 -containing water, H2O2 will compete with ammonia to react with the applied chlorine, compromising the NH2Cl formation efficiency. This research combined theory and experiments to evaluate NH2Cl formation efficiency in the presence of H2O2 in Lake Ontario water and, after NH2Cl formation, its subsequent decay at different temperatures and pH. The results demonstrated that at many typical temperatures and pH, the presence of H2O2 does not significantly impair the formation of NH2Cl. Furthermore, while H2O2 accelerates NH2Cl decay, the results suggest that under specific conditions, such as short to medium residence times (e.g., less than 48 h), it may be possible for NH2Cl to coexist with as much as 5 mg/L H2O2 without compromising secondary disinfection. [ABSTRACT FROM AUTHOR]

In this study, the performance of electro-peroxymonosulfate and electro-peroxydisulfate methods in biologically stabilized leachate nanofiltration concentrate treatment was investigated. To increase treatability and biodegradability of the concentrated leachate was aimed. Central composite design was applied for the optimization of process parameters and development of mathematical model. Variance analyses were performed to attain the interaction among the responses and process variables and to analyze the data. Second-order regression models were developed by Statgraphics Centurion XVI.I software program in order to estimate the removal efficiencies. Model's correlation coefficients for COD removal through electro-peroxymonosulfate and electro-peroxydisulfate processes were determined to be 0.8769 and 0.8910, respectively, expressing conformity of the experimental data to the model. COD removal rates obtained through electro-peroxymonosulfate and electro-peroxydisulfate processes under optimum conditions (HSO5−/COD ratio: 2.5, current: 1.8 A, pH: 6.4 and reaction time: 35.9 min for electro-peroxymonosulfate process and S2O8−2/COD ratio: 1.9, current: 2.1 A, pH: 5.1 and reaction time: 32.3 min for electro-peroxydisulfate process) were determined as 84.2% and 79.6%, respectively. Before advanced treatment processes, the biodegradable COD fraction of leachate nanofiltration concentrate was 12.7% and the soluble COD fraction was 78.3%. After electro-peroxymonosulfate process, biodegradable COD fraction increased to the value of 44.6% and the soluble COD fraction increased to the value of 90.5%, whereas after electro-peroxydisulfate process, biodegradable COD fraction increased to the value of 37.5% and the soluble COD fraction increased to the value of 87.4%. The results of the study showed that electro-peroxymonosulfate and electro-peroxydisulfate oxidation processes were effective treatment methods for leachate concentrates with low biodegradability. [ABSTRACT FROM AUTHOR]

Coagulation and advanced oxidation process (AOP) are the two most significant conditioning methods in sludge dewatering. However, previous studies mainly focus on their differences and overlook their similarities in dewatering mechanisms. In this study, PAC and Fe3+ were selected as typical coagulants, and Fenton and Fenton-like reactions as typical AOP. By regulating the reagent dosage to achieve basically the CST-based filterability (CST = 22.9 ± 1.5 s), AOP had superior dewatering efficiency (59.54–63.04 wt%) compared to coagulation (68.84–69.16 wt%). Obviously, the filterability of sludge could not accurately reflect its dewatering performance. The mechanism revealed that AOP had both "extracellular oxidation" and "intracellular oxidation", whereas coagulation mainly affected the properties of extracellular organic matter. Both processes improved the sludge's relative hydrophobicity and reduced its interfacial free energy. AOP was superior to coagulation in improving sludge fluidity, hydrophobicity, permeability, cell disintegration and reducing bound water content. While coagulation had a better effect on electric neutralization, floc particle size growth and colloidal structure strength. Moreover, this study emphasized the significance of considering the vector-based relationship between sludge dewatering performance and various influencing factors for analyzing the dewatering mechanism. These findings are expected to deepen our understanding of the similarities and disparities in dewatering efficacy and the related mechanisms between the these two pretreatments. [Display omitted] • The filterability of sludge can not accurately reflect its dewatering performance. • Advanced oxidation process has extracellular oxidation and intracellular oxidation. • Coagulation has only extracellular oxidation and little intracellular oxidation. • Vector-based relationship between dewatering ability and impact factors is critical. [ABSTRACT FROM AUTHOR]

As a technology for industrial wastewater advanced treatment, there is a lack of relevant information the impacts of the treated effluents by advanced oxidation processes (AOPs) on ecological environment. Therefore, this study mainly compared the differences of the formation types and concentrations of chlorinated organic products（COPs）and active inorganic chlorine species (AICS) and toxicity changes in the oxidation of CH 3 COOH by three commonly used AOPs technologies as Fenton, ozone and electrochemical advanced oxidation process (EAOP) with the addition of Cl −. The results illustrate that in the EAOP process, trichloromethane (TCM) and Chloroacetic acids (CAAs) were the main COPs in the oxidation of CH 3 COOH by EAOP at 120 min. CCl 4 was major COPs for the Fenton and ozone oxidation of CH 3 COOH, respectively. Through the algae growth inhibition experiment and the toxicity evaluation by using ECOTOX toxicity database, the toxicity of EAOP oxidation of CH 3 COOH to algae and fish were much higher than those from Fenton and ozone oxidation as the highest formation concentrations of inorganic by-products. Considering the toxic effects on the environment, when choosing the AOPs for the further treatment of wastewater containing Cl − , try to avoid the use of EAOP technology, and it is better to choose Fenton and ozone oxidation. • The oxidation of Cl − in three commonly used AOPs technologies to generate AICS reacted with CH 3 COOH leading to the formation of COPs. • The toxicity values for algae and fish from AICS during EAOP oxidation were much higher than those from Fenton and ozone oxidation. • When choosing the AOPs for the further treatment of wastewater containing Cl − , it is better to choose Fenton and ozone oxidation. [ABSTRACT FROM AUTHOR]

The aim of the work was the removal of diclofenac (DCF) and amoxicillin (AMX) Pharmaceuticals by integrated methods of advanced oxidation and membrane filtration. The advanced oxidation process was carried out using UV/H2O2. Two polymer membranes, HL and NF270, were applied for the separation procedure. The effectiveness of the UV/H2O2 treatment, nanofiltration and the integrated processes was comparatively evaluated by monitoring the concentration of DCF/AMX and the removal of chemical oxygen demand (COD) and total organic carbon (TOC). It was found that despite the complete disappearance of the tested compounds during advanced oxidation process the slight reduction of COD and TOC was observed. Moreover, the solution after UV/H2O2 treatment exhibited higher toxicity towards Vibrio fischeri than the initial solution, proving that the transformation by-products of DCF and AMX are more toxic than the parent compound. The nanofiltration process led to an almost complete removal of DCF and AMX from the solution. The integration of the two methods enabled both the chemical modification of tested compounds and the removal of their toxic oxidation products from the solution. [ABSTRACT FROM AUTHOR]

The photolysis of chlorine by UV light leads to the formation of the hydroxyl radicals (OH) as well as reactive chlorine species (RCS) that can be effective as advanced oxidation processes (AOPs) for water treatment. Much of the research to date has been done at laboratory- or bench-scale. This study reports results from a model that demonstrates that the relative effectiveness of the UV/Cl 2 AOP compared to the more traditional UV/H 2 O 2 AOP is a function of optical path length. As such, the relative effectiveness of the two treatment options evaluated at small scale may not reflect the relative performance at full-scale, making results previously obtained at small-scale potentially less scalable. This study therefore compares the performance of UV/Cl 2 to UV/H 2 O 2 at a full-scale water treatment plant, using sucralose and caffeine as spiked surrogates for contaminants that are reactive solely to OH radicals, and to both OH and RCS, respectively. pH was varied between 6.5 and 8.0. The results demonstrated that when using a medium pressure UV lamp, UV/Cl 2 might lead to approximately twice the production of OH radicals as UV/H 2 O 2 at pH 6.5 when using the same molar oxidant concentration, but adding chlorine to the UV reactor at pH 8.0 had a negligible impact on OH radical concentration in comparison to UV alone. The study also confirmed previous small-scale results that RCS can be a major contributor to UV/Cl 2 treatment for compounds such as caffeine that are susceptible to RCS, with UV/Cl 2 effective at both pH 6.5 and 8.0 for such compounds. Disinfection byproducts were monitored, with adsorbable organohalide (AOX) formation increasing by approximately 10 μg-Cl/L due to chlorine photolysis, but only at pH 6.5 and not at pH 8.0. This implies that UV/Cl 2 might increase AOX mostly due to reaction between OH and organic precursors to make them more reactive with chlorine, and not due to RCS. The formation of specific DBPs of current or emerging regulatory interest was minimal under all conditions, except for chlorate. Chlorate yields were in the order of 6–18% of the photolysed chlorine. Image 1 • The relative effectiveness of MP UV/H 2 O 2 versus UV/Cl 2 is light path length dependent. • UV/Cl 2 produced twice as much OH radical as UV/H 2 O 2 at pH 6.5. • The reactive chlorine species generated in UV/Cl 2 at pH 8.0 did not contribute to AOX formation. • Chlorate yields were in the order of 6–18% of the photolysed chlorine in UV/Cl 2. [ABSTRACT FROM AUTHOR]

Highlights • A novel removal process of Hg0 using enhanced Fenton was proposed. • Products and mechanism of Hg0 removal were studied. • Hg0 was removed by four pathways. • Hg0 removal by OH oxidation is the leading pathway. Abstract A novel removal process of elemental mercury (Hg0) from gas using Cu2+-enhanced Fenton system in a bubble column reactor was developed. Experiments were conducted to explore the influence of several factors (concentrations of H 2 O 2 , Fe2+ and Cu2+, reagent pH, reaction temperature, concentrations of Hg0, NO and SO 2) on Hg0 removal. Mechanism and routes of Hg0 removal using Cu2+-enhanced Fenton system were also proposed. The results revealed that adding Cu2+ obviously strengthened removal process of Hg0 in Fenton system. The contrast results of free radical yield found that the enhancement effect was originated from generation of more hydroxyl radicals that were produced from the synergistic role between Cu2+ and Fe2+ in Fenton system. Hg0 removal efficiency was raised by increasing concentrations of Cu2+ and Fe2+, and was reduced via increasing reaction temperature. Increasing concentration of H 2 O 2 and reagent pH exhibited double impact on Hg0 removal. Hg0 was removed by four pathways: (1) Hg0 was oxidized by · OH that was produced from the synergistic role between Cu2+ and Fe2+ in Fenton system; (2) Hg0 was oxidized by OH that was produced from Fe2+/H 2 O 2 system; (3) Hg0 was oxidized by OH that was produced from Cu2+/H 2 O 2 system; (4) Hg0 was oxidized by H 2 O 2. The pathways (1) and (2) were the main routes of Hg0 removal. [ABSTRACT FROM AUTHOR]

• MOFs and their hybrid materials enhance depollution performance. • MOFs as visible photocatalysts promote dyes degradation. • MOFs catalyze Fenton and sulfate radical-based oxidations for depollution. • Iron-based MOFs as sustainable heterogeneous materials efficiently degrade. organics. This paper presents a review on the environmental applications of metal-organic frameworks (MOFs), which are inorganic-organic hybrid highly porous crystalline materials, prepared from metal ion/clusters and multidentate organic ligands. The emphases are made on the enhancement of the performance of advanced oxidation processes (AOPs) (photocatalysis, Fenton reaction methods, and sulfate radical (SO 4 −)-mediated oxidations) using MOFs materials. MOFs act as adsorption and light absorbers, leading to superior performance of photocatalytic processes. More recent examples of photocatalytic degradation of dyes are presented. Additionally, it is commonly shown that Fe-based MOFs exhibited excellent catalytic performance on the Fenton-based and SO 4 •−-mediated oxidations of organic pollutants (e.g., dyes, phenol and pharmaceuticals). The significantly enhanced generation of reactive species such as OH and/or SO 4 − by both homogeneous and heterogeneous catalysis was proposed as the possible mechanism for water depollution. Based on the existing literature, the challenge and future perspectives in MOF-based AOPs are addressed. [ABSTRACT FROM AUTHOR]

Highlights • Removal of gaseous H 2 S using enhanced Fenton-like system is studied. • Free radicals, products and mechanism of H 2 S removal are studied. • More OH are produced from synergistic effect between Fe3+ and Ce3+/Mn2+. • Oxidation of OH plays a leading role for H 2 S removal. • Sulphuric acid and elemental sulfur are the main oxidation products. Abstract A novel separation process of hydrogen sulfide from gas phase using Ce3+/Mn2+-enhanced Fe3+/H 2 O 2 oxidation systems (i.e., Ce3+/Mn2+-enhanced Fenton-like oxidation systems) in a bubbling stirred reactor was developed. Experiments were conducted to study the effects of several influencing factors (Fe3+ and H 2 O 2 concentrations, concentrations of Ce3+/Mn2+, solution temperature, H 2 S inlet concentration, gas flow rate, stirring rate and initial solution pH) on H 2 S removal. Ion chromatography, high performance liquid chromatography, flue gas analyzer and electron spin resonance capture technology were used to measure the reaction products and free radicals in H 2 S removal process. Mechanism and routes of H 2 S removal were also proposed preliminarily. The results reveal that addition of Ce3+/Mn2+ effectively enhances H 2 S removal in Fenton-like oxidation system. The enhancement effects are caused by production of more OH that are produced from synergistic effect between Fe3+ and Ce3+/Mn2+ in the Fenton-like oxidation systems. H 2 S removal efficiency was increased by increasing Fe3+ concentration and concentrations of Ce3+/Mn2+, and decreased by increasing H 2 S inlet concentration and gas flow rate. Increasing H 2 O 2 concentration, solution temperature, stirring rate and initial solution pH show double impact on H 2 S removal. H 2 S is mainly removed by oxidation of OH (it is the main reaction route of H 2 S removal). The new removal technology can provide new an option for removal of gaseous hydrogen sulfide. [ABSTRACT FROM AUTHOR]

BACKGROUND: Iron (Fe)–copper (Cu) bimetallic catalysts such as CuFe2O4, CuFeO2 and CuO/Fe3O4 have been widely applied in persulfate oxidization process. Among these catalysts, CuFe2O4 has shown excellent performance in catalyzing peroxymonosulfate. However, because the catalytic effect of CuFe2O4 on persulfate (PS) is not obvious, the application of CuFe2O4 to activate persulfate has been investigated only rarely. Hence, structural modification has been applied in order to improve the catalytic activity of CuFe2O4 on persulfate. RESULT: In this study, Oxygen (O)‐deficient CuFe2O4 was synthesized via the hydrogen reduction method and first used to activate PS for degrading acetaminophen (APAP) in aqueous solution with low catalyst concentration of 0.3 g L−1. Results reveal that high‐concentration APAP (100 mg L−1) could be efficiently removed by O‐deficient CuFe2O4‐activated PS, and 91% removal rate could be reached in 60 min using 0.8 g L−1 PS and 0.3 g L−1 catalyst under unadjusted pH. Dissolved O2 and Cl−showed inhibitory effects on the degradation process. Radical scavenger experiments, in which methanol, tert‐butyl alcohol (TBA) and nitrobenzene (NB) were used as radical trappers, indicated that SO4− and OH were the active radicals in the reaction, but the main radical was SO4−. Oxygen‐deficient CuFe2O4 showed strong reduction ability and could activate PS efficiently, and the electron transfer capability was remarkably enhanced after this structural modification. CONCLUSIONS: Results indicated that compared to the pristine crystal, the catalytic activity of CuFe2O4 could be improved through structural modification. Additionally, the structurally modified catalyst showed high potential to treat wastewater with high antibiotic content under mild conditions. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Many technologies have been proposed to oxidize chromium, such as roasting-water leaching technology and hydrometallurgical methods such as pressure oxidative leaching coupled with oxygen, ozone, permanganate and ferrate, but the problems associated with the high temperature, low overall resource utilization efficiency, high energy consumption, and the environmental pollution, still remain unsolved. This paper focuses on the oxidation process of chromium (III) with hydrogen peroxide (H2O2) in an alkaline medium. The effect of parameters including dosage of H2O2, dosage of NaOH, reaction time, reaction temperature and stirring rate on the oxidation efficiency of chromium were investigated. The oxidation efficiency was significantly affected by the dosage of H2O2 and NaOH, reaction time and reaction temperature took second place; last was the stirring rate. Oxidation efficiency was nearly 100% under the optimal conditions: volume ratio of H2O2 to mass of Cr2(SO4)3 of 2.4 mL/g, mass ratio of NaOH to Cr2(SO4)3 0.6 g/g, reaction time of 90min, reaction temperature of 90 °C and stirring rate of 500 rpm. [ABSTRACT FROM AUTHOR]

Highlights • La 0.4 Sr 0.6 MnO 3-δ exhibited boosting catalytic property and stability to activate PMS for organic oxidation. • 1O 2 -based activation mechanism was raised in La 0.4 Sr 0.6 MnO 3-δ /PMS system. • The negative effects of diverse water characteristics were demonstrated in La 0.4 Sr 0.6 MnO 3-δ /PMS system. Abstract ABO 3 -type perovskite oxides, characterized by high structural flexibility, have found potential applications in many redox processes, including as catalysts for advanced oxidation in wastewater remediation. Here, we demonstrated that by doping the generally believed catalytically inert A-site of LaMnO 3 (LMO) perovskite with strontium, the catalytic performance for advanced oxidation is surprisingly boosted. Specifically, La 0.4 Sr 0.6 MnO 3-δ (LSMO46) was designed which exhibited a high specific activity (0.0608 min−1 m−2) for peroxymonosulfate (PMS) activation, ∼6 times that of LMO and ∼41 times that of reported nanosized MnFe 2 O 4 and Fe/Fe 3 C. The superior activity was also embodied by low activation energy (44.3 kJ mol−1). Moreover, LSMO46 displayed a lower metal leaching and a better reusability than LMO and Fe/Fe 3 C and easy catalyst recovery for its magnetic behavior. Such enhanced catalytic activity was attributed to the positively-charged surface (8.3 mV) that favored the adsorption of negatively-charged organics and the presence of a large amount of surface anion defects (oxygen vacancies), created by the doping, that induced the generation of considerable amount of singlet oxygen (1O 2) which was demonstrated as the dominant reactive species by selective radical scavenging and EPR trapping. A coupled activation mechanism involving major singlet oxygen and minor free radicals was further proposed for the effective decomposition of organics in LSMO46/PMS system. The findings in this study thus provide us a new strategy for the development of efficient catalysts for advanced oxidation in environmental treatment. [ABSTRACT FROM AUTHOR]

Photocatalysis has received ever‐growing attention as a promising alternative to traditional water treatment technologies for waterborne biohazard inactivation. Due to unique optical, electronic, physicochemical properties and feasibility of functional architecture assembly, two‐dimensional (2D) nanomaterials have become important in developing novel photocatalysts. This review summarizes the recent progress in configuring nanostructures with 2D materials as building blocks for photocatalytic water disinfection. In this review, five categories of 2D nanomaterials, that is, graphene, graphitic carbon nitride, 2D metal oxides and metallates, metal oxyhalides and transition metal dichalcogenides, for photocatalytic pathogen inactivation are introduced. First, the synthesis process, nanostructure engineering and disinfection performance of 2D‐based photocatalysts are reviewed in categories. In the following section, the bacteria destruction mechanism based on the generation and roles of reactive species (RSs) is presented. Moreover, the effects of the chemical characteristics of the water matrix on photocatalytic bactericidal performance are discussed. Finally, the challenges regarding the development and application of 2D‐based photocatalysts for highly efficient water sterilization are highlighted. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]