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Pharmaceutical effluents generated during drugs production and application are often times released into the water systems with little or no treatment, which could pose potential danger to the ecosystem. Advanced oxidation processes for organic pollutants treatment have gained wide consideration due to their effectiveness. In this work, hydrogen peroxide (H2O2) and hydrogen peroxide-supported nano zerovalent iron (H2O2@nZVIs) were deployed to study pharmaceutical effluents (PE) degradation via batch experiments, under various reaction time, (H2O2) and (H2O2@nZVIs) concentrations, pH, PE concentration, and temperature. The nZVIs was prepared from the green synthesis of Vernonia amygdalina leaf extract and characterized using different analytical tools such as Fourier Transform-Infrared Spectroscopy (FT-IR), Gas Chromatography Mass Spectroscopy (GC-MS), Scanning Electron Microscopy (SEM), and X-Ray Diffraction Spectroscopy (XRD). The FT-IR results showed the presence of -C = O, -NH, -OH, -C = C and, -C-O functional groups, SEM report showed that the morphology of the nZVIs is round in shape, while GC-MS revealed the presence of several phytochemicals. When the concentration of the effluent was increased from 10 to 30 ml, the percentage decolourization decreased from 74.74 to 51.96% and from 80.36 to 54.38% for H2O2 and H2O2@nZVI respectively, whereas when the contact time was increased from 10 to 60 min, the percentage decolourization rose from 70.39 to 83.49% for H2O2 and from 85.19 to 89.73% when H2O2@nZVI was used. When the effect of pH was assessed, it was observed that on increasing the pH from 2 to 10, the percentage decolourization rose from 74.5 to 80.25% for H2O2, however, with H2O2@nZVI, the percentage decolourization decreased from 81.50 to 68%. Maximum percentage decolourization of 57.10% and 94.56% for H2O2 and H2O2@nZVI was achieved at catalyst volume of 25 ml. For all the parameters tested, the H2O2@nZVIs performed much better indicating that the nZVIs enhanced the decolourization ability of the H2O2. The kinetic results showed that the decolorization of pharmaceutical effluent by both catalysts fitted very well with the second-order model, while thermodynamic properties of enthalpy change were found to be 10.025 and 27.005 kJ/mol/K for H2O2 and H2O2@nZVIs respectively suggesting that the oxidation process is endothermic in nature. This technique employed in using hydrogen peroxide-supported zero valent iron, proved to be highly efficient not only for pharmaceutical effluent degradation but also in the elimination of lead from the effluent. [ABSTRACT FROM AUTHOR]

Many existing research focuses on the differences or performance comparisons between single‐atom or small‐sized nanocluster catalysts, but there is a lack of comprehensive research on the coupling relationship between the structure and activity and the mechanism of synergy. This study investigates the combined catalytic potential of cobalt single atoms (SAs) and nanoclusters (NCs) for enhanced peroxymonosulfate (PMS) activation to degrade norfloxacin (NFX). A novel CoSAs‐NCs/CN/TiO2 catalyst is synthesized, featuring cobalt SAs and NCs uniformly dispersed on the carbon film wrapping TiO2, and the degradation efficiency of the NFX solution is almost completely degraded, with a mineralization rate of 76.35%. Density functional theory (DFT) calculations indicate that the synergistic interaction between cobalt SAs and NCs promotes more efficient PMS adsorption and activation and significantly reduces the activation energy barrier, which enhances electron transfer and increases reactive oxygen species (ROS) generation. This research highlights the robust and versatile nature of this novel catalyst system in addressing various contaminants. This study elucidates the activation mechanism of catalysts, providing new ideas for advanced oxidation processes (AOPs) in environmental remediation, linking the structure and performance of catalysts, and emphasizes the practicality and importance of the CoSAs‐NCs/CN/TiO2 catalyst in effectively and long‐term remediation of water pollutants. [ABSTRACT FROM AUTHOR]

To overcome the shortcomings of Fe(Ⅱ)/peroxydisulfate (PDS) system including the limited working pH range and large iron sludge production, a Fe-doped alginate (Fe-Alg) catalyst was prepared and combined with hydroxylamine (HA) to continuously activate PDS for the removal of organic pollutants in neutral condition. Due to the strong reductive capability of HA, it could significantly enhance the catalytic capability of Fe-Alg for PDS. The results of characterization suggested that Fe(Ⅲ)/Fe(Ⅱ) was evenly distributed in Alg through its complexation with carboxyl groups, and the reduction of Fe(Ⅲ) to Fe(Ⅱ) initiated by HA enabled Orange G (OG) to be continuously degraded in the Fe-Alg/HA/PDS system. The results of quenching experiments suggested that ${\rm S}{\rm O}_4^{ \bullet -}$ S O 4 ∙ − and HO• played a dominant role for OG removal in the Fe-Alg/HA/PDS process. The effect of influence factors (e.g. initial pH, HA concentration, Fe-Alg dose and PDS concentration) and water matrix components (i.e. ${\rm S}{\rm O}_4^{2-}$ S O 4 2 − , ${\rm N}{\rm O}_3^-$ N O 3 − , Cl–, ${\rm HC}{\rm O}_3^-$ HC O 3 − and dissolved organic matters (DOM)) on the performance of Fe-Alg/HA/PDS system was systematically investigated. Other refractory organic contaminants, including diclofenac (DCF), sulfamethoxazole (SMX), oxytetracycline (OTC) and bisphenol AF (BPAF) were also efficiently eliminated in Fe-Alg/HA/PDS system, suggesting the feasibility of this system for the treatment of organic pollutants. This work provides a method to optimize Fe(Ⅱ)/PDS system and a novel process applied to degrade refractory pollutants. [ABSTRACT FROM AUTHOR]

The release of synthetic dyes into water bodies poses many environmental issues, and their removal is a necessity. Advanced oxidation processes (AOPs) can be employed for removal, in many of which a catalyst is used. graphene oxide (GO) is a viable catalyst due to its distinctive structural properties; however, it is reportedly incapable of effectively activating persulfate. Thus, this study delves for the first time into the influence of doping silica on enhancing GO's catalytic performance to activate persulfate for decolorizing Acid Blue 25 (AB25). Based on the results, an equal weight proportion of GO to silica was selected as the most efficient ratio. In addition, pH had no significant effect on removal efficiency, while temperature had the highest impact. Within 150 min with 0.075 gr/L of GO-SiO2 as the catalyst and 1 gr/L of Na2S2O8 as the oxidant, the investigated process removed Acid Blue 25 up to 82%, which was 9% higher than when GO alone was used as the catalyst. As for COD removal, the contribution of doping silica was more significant and led to 37% COD removal, which was 17% higher than when GO alone was used. [ABSTRACT FROM AUTHOR]

In this study, type-II heterojunction WO 3 /BaTiO 3 and Z-scheme WO 3 /SrTiO 3 or WO 3 /Ba 0.5 Sr 0.5 TiO 3 nanocomposite photocatalysts were constructed for photodegradation of organic pollutants in wastewater under visible light. The photocatalytic performance of three WO 3 /titanate systems were estimated. Some influencing factors such as molar ratio of WO 3 and titanates, light irradiation time, catalyst dose, and initial concentration of organic pollutants on the photocatalytic activity were investigated. The stability and reusability of three WO 3 /titanates systems were examined. Moreover, the production of some radicals in the three WO 3 /titanates photocatalytic systems was demonstrated, and the three WO 3 /titanates photocatalytic reaction mechanisms were compared. The results reveal that the configurations of WO 3 /titanates photocatalytic systems are transformed from type-II heterojunction WO 3 /BaTiO 3 with lower activity to Z-scheme WO 3 /SrTiO 3 and WO 3 /Ba 0.5 Sr 0.5 TiO 3 with higher activity via the change of titanates. The WO 3 /titanate nanocomposites show higher photocatalytic activity at 3.0:1.0 M ratio of WO 3 and titanates, and WO 3 /Ba 0.5 Sr 0.5 TiO 3 nanoparticles have superior photocatalytic activity. The order of photocatalytic activity is as follows: WO 3 /Ba 0.5 Sr 0.5 TiO 3 > WO 3 /SrTiO 3 > WO 3 /BaTiO 3. Several organic pollutants, such as rhodamine B, methyl parathion, direct brilliant yellow-4R, and methylene blue, can be efficiently degraded using WO 3 /Ba 0.5 Sr 0.5 TiO 3 under visible light, and the RhB has higher degradation rate. After four cycles, WO 3 /titanate nanocomposites still have relatively high stability and reusability. •OH plays a major role in three WO 3 /titanates photocatalytic degradation. It is expected that the Z-scheme WO 3 /Ba 0.5 Sr 0.5 TiO 3 photocatalytic technology creates a good foreground for disposing of dyes and pesticides in water and wastewater. [ABSTRACT FROM AUTHOR]

Plastic wastes, widely distributed in the environment, can be transformed into microplastics, posing a huge threat to ecosystems and human health due to their stability and adsorbability to other toxic pollutants (e.g., heavy metals and antibiotics). Recently, microbial degradation of (micro)plastics has gained widespread attention because of its green and sustainable properties. Microbial degradation of (micro)plastics is based on the cascade effects of various enzymes secreted by microorganisms, which can convert (micro)plastics into oligomers and monomers, or even mineralize them into CO2 and H2O. The microbial degradation of (micro)plastics is affected by multiple factors, such as microbial species, plastic properties, and environmental conditions. Currently, limited efficient plastic-degrading microorganisms have been discovered, and their degradation mechanisms are still unclear. Furthermore, the efficiency of microbial degradation needs to be improved for future application. Therefore, this review systematically summarizes the sources and properties of existing plastics, identifies pure cultures and mixed cultures for plastic degradation, and examines their influencing factors. In particular, the microbial degradation behaviors of (micro)plastics, including relevant enzymes, degradation efficiency, and degradation mechanisms, were thoroughly discussed. Additionally, the augmentation technologies coupling with microbial degradation, such as advanced oxidation, electrochemical, and genetic engineering technologies, were introduced and highlighted for their potential prospects. This review provides a reference for future research and development of (micro)plastic biodegradation technology. [ABSTRACT FROM AUTHOR]

Abstract Pharmaceutical effluents generated during drugs production and application are often times released into the water systems with little or no treatment, which could pose potential danger to the ecosystem. Advanced oxidation processes for organic pollutants treatment have gained wide consideration due to their effectiveness. In this work, hydrogen peroxide (H2O2) and hydrogen peroxide-supported nano zerovalent iron (H2O2@nZVIs) were deployed to study pharmaceutical effluents (PE) degradation via batch experiments, under various reaction time, (H2O2) and (H2O2@nZVIs) concentrations, pH, PE concentration, and temperature. The nZVIs was prepared from the green synthesis of Vernonia amygdalina leaf extract and characterized using different analytical tools such as Fourier Transform-Infrared Spectroscopy (FT-IR), Gas Chromatography Mass Spectroscopy (GC-MS), Scanning Electron Microscopy (SEM), and X-Ray Diffraction Spectroscopy (XRD). The FT-IR results showed the presence of -C = O, -NH, -OH, -C = C and, -C-O functional groups, SEM report showed that the morphology of the nZVIs is round in shape, while GC-MS revealed the presence of several phytochemicals. When the concentration of the effluent was increased from 10 to 30 ml, the percentage decolourization decreased from 74.74 to 51.96% and from 80.36 to 54.38% for H2O2 and H2O2@nZVI respectively, whereas when the contact time was increased from 10 to 60 min, the percentage decolourization rose from 70.39 to 83.49% for H2O2 and from 85.19 to 89.73% when H2O2@nZVI was used. When the effect of pH was assessed, it was observed that on increasing the pH from 2 to 10, the percentage decolourization rose from 74.5 to 80.25% for H2O2, however, with H2O2@nZVI, the percentage decolourization decreased from 81.50 to 68%. Maximum percentage decolourization of 57.10% and 94.56% for H2O2 and H2O2@nZVI was achieved at catalyst volume of 25 ml. For all the parameters tested, the H2O2@nZVIs performed much better indicating that the nZVIs enhanced the decolourization ability of the H2O2. The kinetic results showed that the decolorization of pharmaceutical effluent by both catalysts fitted very well with the second-order model, while thermodynamic properties of enthalpy change were found to be 10.025 and 27.005 kJ/mol/K for H2O2 and H2O2@nZVIs respectively suggesting that the oxidation process is endothermic in nature. This technique employed in using hydrogen peroxide-supported zero valent iron, proved to be highly efficient not only for pharmaceutical effluent degradation but also in the elimination of lead from the effluent.

This study synthesized a ferric oxide–nanographite (NG) nanocomposite (Fe2O3@NG) from waste toner powder through carbonization. Subsequently, a TiO2/Fe2O3@NG nanohybrid was fabricated using the sol–gel technique to improve the photocatalytic degradation of dyes. TiO2/Fe2O3@NG nanocomposites were prepared at TiO2:Fe2O3@NG ratios of 2:1 (Ti:T-21), 1:1 (Ti:T-11), and 1:2 (Ti:T-12). The porosity, morphology, surface chemistry, and chemical interactions between TiO2, Fe2O3, and graphite in the prepared TiO2/Fe2O3@NG nanocomposites were characterized using the Brunauer–Emmett–Teller (BET) method and microscopic and spectroscopic analyses. The TiO2/Fe2O3@NG nanohybrid exhibited a reduced bandgap (2.4–2.9 eV) and enhanced charge carrier separation through charge transfer at the junction of the hetero-structured TiO2/Fe2O3@NG nanohybrid. Preliminary experiments revealed that Ti:T-21 was the most effective photocatalyst for degrading acid blue-25 (AB-25) compared to Ti:T-11, Ti:T-12, sole TiO2, and Fe2O3@NG. This study also investigated the impacts of catalyst dose and initial dye concentration on the AB-25 photocatalytic degradation. Notably, 97% of 5-mg/L AB-25 was removed using 1.25-g/L Ti:T-21 at an unmodified pH of 6.4 within 120 min. Furthermore, Ti:T-21 exhibited remarkable recyclability in its immobilized form, achieving degradation ratios of 74.7%–71.8% over five consecutive runs, compared to removal efficiencies of 85.0%–62.3% in the suspended mode. Trapping experiments identified hydroxyl radicals, holes, and superoxide as the principal reactive radicals. The TiO2/Fe2O3@NG/light system was effective in disintegrating and mineralizing other synthetic dyes such as Congo red, methylene blue, and methyl red, indicating its potential for industrial-scale degradation of authentic dye wastewater. The utilization of waste toner for water treatment is highlighted as a strategy to promote environmental sustainability, foster a circular economy, and contribute to pollution remediation.

Advanced oxidation process is an efficient and innovative method for the complete removal of organic pollutants, which works by using active species, especially hydroxyl radicals. In this process, different oxidation mechanisms are used. Direct electrical discharge on the surface and inside the liquid is a more complex and effective process than electrical discharge on gases. In this process, the electronic current is transferred by surface and water ions and produces plasma, which leads to chemical and physical effects such as the production of radicals and ultraviolet light. In this study, wastewater from textile industries was selected as the target wastewater. The removal of methylene blue as one of the important and toxic dyes in this type of wastewater was investigated under the influence of atmospheric pressure plasma. The electrodes used to generate plasma were made of 316 stainless steel. The experiment was carried out for a duration of 2.5 to 60 minutes. In the conducted analyses, optimal pH, suitable injected gas into the reactor, chemical oxygen demand, effective voltage (V), and distance between electrodes (d) were also studied. The results showed that corona pulse plasma had a high efficiency in dye removal, with over 99% color removal achieved in less than 10 minutes using injected oxygen gas into the system at a pH of 8 and an effective voltage of 130 kV. Additionally, the highest reduction in COD value in the corona pulse method for real textile wastewater reached from 1760 to 200 mg/L, and complete color removal was achieved, reducing its color from 2500 Pt/CO to 75 Pt/CO, indicating the extraordinary impact of this method.

Polyacrylamide (PAM) in environmental water has become a major problem in water pollution management due to its high molecular mass, high viscosity and non-absorption by soil. CoFe2O4 with strong magnetic properties was prepared by solvent-thermal synthesis method and used as the catalyst for the removal on PAM in heterogeneous Electro-Fenton (EF) system. It showed that the removal efficiency of PAM by the heterogeneous EF system using CoFe2O4 catalyst was 92.01% at pH 3 after 120 min. Further studies indicated that ·OH was the most significant active species for the removal of PAM, and the contribution of ·O2− and SO4·− for the removal of PAM was less than 15%. The reusability test and XRD, XPS, FTIR analyses proved that the catalyst had good stability. After a repeated use for five times, the catalyst still had a high PAM removal rate and stable structure. The valence distribution and functional groups of the phase components of the catalyst did not change significantly before and after the reaction. The possible mechanism of catalyst activation of H2O2 was deduced by mechanism investigation. The CoFe2O4 is an efficient and promising catalyst for the removal of PAM wastewater. HIGHLIGHTS A Co–Fe bimetallic oxide catalyst was prepared by hydrothermal method and used to treat polymer-containing wastewater.; The prepared catalyst has strong magnetic properties, is easy to recover and can be reused (resource reuse).; In the CoFe2O4 heterogeneous system, the higher contaminant removal rate can be achieved with less catalyst dosage.;

A three-dimensional electrode electro-Fenton system was constructed using titanium coated ruthenium iridium electrode(RuO2-IrO2/Ti) as the anode, graphite as the cathode, and activated carbon as the particle electrode. The influencing factors of three-dimensional electrode electro-Fenton treatment of azithromycin pharmaceutical wastewater were studied, and the effects of activated carbon particle electrode type and dosage on treatment efficiency were systematically investigated. The optimal reaction conditions were determined by changing factors such as electrode spacing, pH, aeration intensity, electrolysis voltage, and reaction time. The results showed that the optimal process conditions were pH=3, electrolysis voltage of 15 V, aeration intensity of 1.0 L/min, electrode spacing of 7 cm, and the reaction time of 2 hours as the particle electrode was 3 mm column carbon, with mass concentration of 100 g/L. Under these conditions, the average COD removal rate of wastewater was 72.28%, and the B/C increased from the initial 0.086 to 0.312, which resulted in the optimal treatment effect. In addition, the influence of each factor on the treatment of azithromycin pharmaceutical wastewater by three-dimensional electrode electro-Fenton was pH>aeration intensity>electrolysis voltage>reaction time>electrode spacing.

Bisphenol A (BPA) is an environmental endocrine-disrupting compound that is resistant to conventional biological treatment, making it crucial to develop an oxidation process. This study introduces a novel hydrodynamic cavitation (HC) coupled with a Fenton + periodate (PI) oxidation system for the efficient degradation of BPA. By systematically examining the key parameters such as inlet pressure, Fe (II), H2O2, and PI concentration, it was found that HC performed optimally at a pressure of 0.5 MPa. A conversion of 98.14% was achieved within 60 min when the molar ratio of BPA, Fe (II), H2O2, and PI was approximately 1:1:5:1. Further analysis revealed that the gray correlation between H2O2 and PI concentrations on the degradation efficiency was 0.833 and 0.843, respectively, indicating that both of them had significant effects on the degradation process. The free radical quenching assay confirmed the hydroxyl radical (•OH) as the main active substance. Additionally, the toxicity of the degradation intermediates was evaluated using the Toxicity Estimation Software Tool (TEST). An artificial neural network (ANN)-based model was constructed to predict the BPA-degradation process, facilitating precise reagent dosing and providing robust support for the intelligent application of water-treatment technologies. [ABSTRACT FROM AUTHOR]

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The article describes the photocatalytic degradation of Evan's blue in aqueous solution using graphitic carbon nitride. The experiment records the absorbance of Evan's blue and its rate of constant reaction and it observed the effect of pH on photocatalytic degradation, effect of dye concentration on the rate of reaction, effect of amount of photocatalyst on the rate of photocatalytic degradation, and effect of light intensity on the rate of Evan's blue.

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board 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.)

Nanotechnology, a rapidly growing field, holds tremendous promise as it harnesses the unique properties and applications of nanoparticulate materials on a nanoscale. In parallel, the pressing global environmental concerns call for the development of sustainable chemical processes and the creation of new materials through eco-friendly synthesis methods. In this work, zero-valent iron nanoparticles (nZVI) were synthesized using an innovative and environmentally friendly approach as an alternative to conventional methods. This method leverages the antioxidant capacity of natural plant extracts to effectively reduce dissolved metals and produce nZVI. The chosen extract of green tea plays a pivotal role in this process. With the extract in focus, this study delves into the remarkable capability of nZVI in degrading two dyes commonly used in medicine, chrysoidine G and methylene blue, in aqueous solutions. Additionally, Fenton-type oxidation processes are explored by incorporating hydrogen peroxide into the nanoparticle mixture. By applying the statistical design of experiments and Response Surface Methodology, the influence of four key parameters—initial concentrations of Fe2+, Fe3+, H2O2, and polyphenols—on dye elimination efficiency in aqueous solutions is thoroughly analyzed. The obtained results demonstrate that advanced oxidation technologies, such as Fenton-type reactions in conjunction with nanoparticles, achieve an excellent efficiency of nearly 100% in eliminating the dyes. Moreover, this study reveals the synergistic effect achieved by simultaneously employing nZVI and the Fenton process, showcasing the potential for further advancements in the field. [ABSTRACT FROM AUTHOR]

Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & 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.)

Electrooxidation is commonly used in wastewater treatment but faces challenges with recalcitrant pollutants like tetrabromobisphenol A (TBBPA). Understanding the role of direct electron transfer (DET) and secondary free radicals in forming intermediate products can not only reveal halogenated phenols' electrooxidation mechanism but also aid in electrode design. Coupling triple quadrupole mass spectrometer and quadrupole time-of-flight mass spectrometer, the transformation products (TPs) and their dynamics were investigated during electrooxidation treatments of TBBPA. Furthermore, electrophilic addition and ring-opening mechanisms were simulated by density functional theory (DFT), and toxic changes of TPs were assessed by quantitative structural-activity relationship. The results demonstrate that the steady-state concentration of hydroxyl radicals (•OH) significantly influences the oxidation kinetics before reaching the mass transfer limit. In addition, DET occurs at low potentials (Ep ≈ +0.35 to +0.45 V vs SHE), accompanied with the process of film formation. Six novel intermediates of TBBPA were discovered in electrooxidation process, revealing the ring-opening mechanisms of TBBPA regulated by the steady-state density of hydroxyl radicals. The toxicity of intermediates towards fish and daphnia decreased significantly than that of TBBPA. Our findings offer valuable insights into the electrooxidation process of brominated phenols including their transformation and toxicity changes. [ABSTRACT FROM AUTHOR]

The resource scarcity and pollution leakage risk caused by discarding the spent power lithium‐ion batteries has aroused growing concern. Recovering and regenerating the cathode material from spent power lithium‐ion batteries in an easy and environmentally friendly manner remains a significant challenge and an area of focus in battery research. Hence, a green and convenient method to recover FePO4 from spent LiFePO4 cathode powder by using Na2S2O8 as an oxidizer and as cathode materials for lithium/sodium‐ion batteries (LIBs/SIBs) is reported. Benefiting from the remarkable graphene oxide (GO) and vanadium oxide (V2O5) coating, the regenerated FePO4–V2O5–graphene oxide (FePO4–V2O5–GO) is suitable for Li/Na storage (153 mAh g−1 at 0.2C/118 mAh g−1 at 0.5C). The high capacity retention, that stable for 300 cycles in LIBs and 300 cycles for SIBs, is also realized due to the stable structure. This work provides a green strategy for regenerating the cathode of spent lithium‐ion batteries and designing cathodes of alkali metal ion batteries. [ABSTRACT FROM AUTHOR]

CuFeO2 nanoparticles were decorated on biochar by one-step hydrothermal method to form the CuFeO2 /BC catalyst for persulfate (PS) activation and application of CuFeO2/BC in sulfadiazine (SDZ) contaminated soil was explored in this study. The influence of some key factors such as catalyst doses, PS concentration, initial pH and different soil types on degradation of SDZ were investigated. The results showed that CuFeO2/BC system has better catalytic performance and PS utilization efficiency compared with the pure CuFeO2. Under the condition of CuFeO2/BC dosage of 8 g/kg and PS addition of 3 g/kg, 91.72% SDZ (initial concentration of 20 mg/kg) could be removed from the soil within 120 minutes. Furthermore, the mechanism of the CuFeO2/BC/PS system was revealed by quenching experiments and electron paramagnetic resonance (EPR) tests. It demonstrated that active species (SO4•-, HO•, O2•-) were involved in SDZ degradation, the weak EPR signal confirmed the existence of 1O2 but not participated in the degradation of SDZ. The steady-state concentrations of HO• and SO4•- were calculated by using free radical probes. Afterwards, the contribution rates of SO4•-, HO•, O2•- to the degradation of SDZ were obtained to be 43.89%, 32.87%, and 23.24%, respectively. Combined X-ray photoelectron spectroscopy revealed that the high catalytic efficiency was attributed to the synergistic effect of Cu+/Cu2+ and Fe2+/Fe3+ redox cycles. These findings help to achieve more comprehensive understanding of the heterogeneous activation process of PS by CuFeO2 /BC to degrade SDZ in actual contaminated sites. [ABSTRACT FROM AUTHOR]

Understanding the degradation kinetics and mechanisms of trace organic contaminants (TrOCs) by UV-based advanced oxidation processes (UV-AOPs) are pivotal in realizing their efficient application in water treatment. However, the relevant knowledge in practical flow-through reactors remains a void, compared with that of commonly used batch reactors. To fill the knowledge gaps, the current work investigated the degradation of atrazine (ATZ) in flow-through UV-AOP systems with different light sources and chlorine additions. The results showed that UV/Cl2 in the reactors (with a diameter of 50 mm) was not very efficient in ATZ degradation while the pseudo-first order degradation rate constant was elevated by over 2.7 times with vacuum UV (VUV)/UV. In contrast to observations in the batch reactors, the addition of chlorine to the flow-through VUV/UV system unexpectedly decreased the rate constant by about 39%. The analysis of the relative contributions of different degradation pathways revealed that the inhibitory effect of the chlorine addition arose from the transformation of HO• to reactive chlorine species (e.g., ClO•) which had low reaction rate constants with ATZ. The baffle implementation promoted the ATZ degradation by 12–58%, mainly due to an enhanced mixing that facilitated the radical oxidation. The energy costs of the UV-AOPs in ATZ removal ranged within 0.40–1.11 kWh m−3 order−1. The findings of this work are helpful in guiding efficient VUV/UV and VUV/UV/Cl2 processes in drinking water treatment. [ABSTRACT FROM AUTHOR]

Water pollution caused by antibiotics is one of the major challenges in the world today. The current research aims to investigate the effect of the Photo-Fenton process in removing indomethacin antibiotics from aqueous solutions. This experiment-based study was conducted on a laboratory scale and discontinuous manner. The influential variables affecting the removal efficiency of indomethacin include initial antibiotic concentration, pH, time, hydrogen peroxide concentration, and iron ion. The study was conducted base on standard methods (APHA, AWWA, CFWP, 2005). The Design Expert software was used to analyze the effect of independent variables on the removal efficiency of indomethacin antibiotics in the Photo-Fenton process (UV/H2O2/Fe2+) using response surface methodology (RSM) and central composite design (CCD). To ensure the repeatability of the results, each experiment was repeated three times and the reported the average. The results showed that the optimal removal conditions for indomethacin antibiotics were pH = 4, H2O2 oxidant concentration = 50 ppm, Fe2+catalyst concentration = 50 ppm, time = 75 minutes, and initial antibiotic concentration = 20 ppm, with a removal efficiency of 91.03%. The variables of initial antibiotic concentration, H2O2 concentration, and pH had the greatest impact on the removal efficiency of indomethacin. The results of this study indicate that under optimal conditions, more than 90% of indomethacin antibiotics can be removed from aqueous solutions using the Photo-Fenton process, which is a significant result for removing this pharmaceutical pollutant from aquatic environments. [ABSTRACT FROM AUTHOR]

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Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute 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.)

Water pollution has become a major environmental menace due to municipal and industrial effluents discharged into water bodies. Several processes have been devised for the treatment and disposal of wastewater and sludge. Yet, most of the conventional technologies do not meet the requirements of sustainability as they impose a higher load on the environment in terms of resource depletion and toxic waste generation. Recently, sustainable innovative technologies, like hydrodynamic cavitation (HC), have emerged as energy-efficient methods, which can enhance the conventional wastewater treatment processes. HC is a very effective technique for the intensification of processes, like aeration, activated sludge treatment, and anaerobic digestion processes in conventional wastewater treatment plants, particularly for the enhanced degradation of persistent pollutants. On the other hand, advanced oxidation is a proven enhancement method for wastewater treatment. This review provides a comprehensive overview of recently published literature on the application of HC for the treatment of persistent organic pollutants. The potential synergistic impact of HC coupled with advanced oxidation and alternative pre-treatment methods was also reviewed in this study. Moreover, an overview of the present state of model-based research work for HC reactors and a feasibility analysis of various advanced oxidation process is also covered. Options for the pilot-to-large scale implementation of HC and advanced oxidation technologies to ensure the better sustainability of wastewater treatment plants are recommended. [ABSTRACT FROM AUTHOR]

This study investigates the environmental impacts caused by the scaling up of the photocatalytic purification of drinking water using ultraviolet light-emitting diode technology. The life cycle assessment methodology was utilised to estimate the environmental impacts of two different reactor setups commonly used in lab-scale studies: an immobilised and a suspended TiO2 catalytic system. The functional unit adopted was the treatment of 1 L of water with an initial 7.8 mg/L concentration of natural organic matter, achieving a final 1 mg/L concentration. The use of a suspended photocatalyst was found to have an environmental footprint that was 87% lower than that of the immobilised one. From the sensitivity analysis, the environmental hotspots of the treatment process were the electricity usage and immobilised catalyst production. Therefore, alternative scenarios investigating the use of a renewable electricity mix and recyclable materials were explored to enhance the environmental performance of the photocatalytic treatment process. Using a renewable electricity mix, a decrease of 55% and 15% for the suspended and immobilised catalyst, respectively, was observed. Additionally, the process of recycling the glass used to support the immobilised catalyst achieved a maximum reduction of 22% in the environmental impact from the original scenario, with 100 glass reuses appearing to provide diminishing returns on the environmental impact savings. [ABSTRACT FROM AUTHOR]

This article is oriented to the degradation of nickel in an ionic state at laboratory level from synthetic water made with nickel sulfate, using the electrocoagulation process with aluminum cathodes and modifying this process by the addition of the Fenton reagent, which results from the combination of hydrogen peroxide (H2O2) and ferrous sulfate (FeSO4) being this reagent a catalyst and oxo-coagulant agent, The efficiency of this reagent will be compared with the typical treatment with aluminum sulfate, which is a typical process based on ion exchange/ coagulation at the same percentage concentrations as the Fenton reagent. For this purpose, the optimum conditions of the advanced electrocoagulation process were determined, which consisted of determining the concentrations of Fenton's reagent at concentrations of 150 ppm, 300 ppm, and 450 ppm, in addition to the operating variables such as pH of 8 and 10, voltage of 17.5 V and 19 V and their reaction time, which were compared with aluminum sulfate at 300 ppm, 600 ppm, and 900 ppm. The results obtained with respect to the typical treatment were 0% nickel degradation. However, with the advanced oxidation treatment, an average reduction of 97.5% was found at the conditions of 19 V, pH 10, and Fenton 150 ppm in a time of 30 min. [ABSTRACT FROM AUTHOR]

The number of published literature on the effect of ultrasonic cavitation and advanced oxidation pretreatment on the dewatering performance of anaerobically digested sludge is very limited. This study aims at determining the optimum operating conditions of large-scale filtering centrifuges in wastewater treatment plants. The optimum dose of hydrogen peroxide, ultrasonic power, ultrasonic duration, ultrasonic pulse and particle size distribution for improved dewatering performance were determined in this study. In addition, shear stress–shear rate and viscosity–shear rate rheograms were developed to show the rheological flow properties for varying ultrasonic power and treatment duration. Optimum sonication power, time, pulse and amplitude were determined to be 14 W, 1 min, 55/5 and 20%, respectively. At a pH of 6.8, the optimum concentration of hydrogen peroxide was found to be 43.5 g/L. The optimum hydrogen peroxide dose in the combined conditioning experiments was determined to be 500 mg/L at a pH of 3. Under these optimum conditions, capillary suction time was reduced significantly by 71.1%. This study helps to reduce polymer consumption and provides the optimum pretreatment and dewatering operating conditions, and better monitoring and control in the dewatering unit has significant impact in the overall economy of wastewater treatment plants. HIGHLIGHTS Digested sludge dewatering is a cost-intensive operation in wastewater treatment plants.; The proposed ultrasonic and advanced oxidation pretreatment significantly improves the dewatering performance.; Rheological flow characteristics of digested sludge also improved after ultrasonic pretreatment.; Sonication and advanced oxidation can be used along with conventional dewatering polymers for better performance.;

Regeneration of adsorption saturated activated carbon by traditional electrochemical technology has the advantages of high regeneration efficiency and no mass loss of activated carbon, but it has defects such as low mineralization efficiency, generation of toxic by-products, and high energy consumption. Electrochemical advanced oxidation(E-AOP) regeneration technology can effectively overcome the problems of traditional electrochemical regeneration. In this paper, the regeneration efficiency and mechanism of activated carbon by traditional electrochemical are briefly described, and the effects of operating parameters (current, electrolyte type and concentration, regeneration location,anode material, etc.) on the desorption-adsorption balance and the mineralization efficiency of pollutants are analyzed. The mechanism and application of three types of E-AOP regeneration technologies(electro-Fenton regeneration, electro-peroxone regeneration, and electro-persulfate regeneration) in the process of activated carbon regeneration are summarized. The electric-Fenton regeneration technology has better regeneration effect, and the problem of metal ion pollution in the system can be effectively overcome by new regeneration. The electro-peroxone regeneration technology does not require the addition of any chemicals and catalysts, which is conducive to the control of reaction conditions and automation of the regeneration process. The electro-persulfate regeneration technology is convenient in operation with low energy consumption and wide applicability. Finally, the problems and development prospects of E-AOP regeneration technology are proposed. This review provides theoretical basis for the development of new efficient and environmentally friendly activated carbon regeneration technologies.

Abstract Toluene, a prominent member of volatile organic compounds (VOCs), exerts a substantial adverse influence on both human life and the environment. In the context of advanced oxidation processes, the ·OH radical emerges as a highly efficient oxidant, pivotal in the elimination of VOCs. This study employs computational quantum chemistry methods (G4MP2//B3LYP/6-311++G(d,p)) to systematically investigate the degradation of toluene by ·OH radicals in an implicit solvent model, and validates the rationale of choosing a single-reference method using T1 diagnostics. Our results suggest three possible reaction mechanisms for the oxidation of toluene by ·OH: firstly, the phenyl ring undergoes a hydrogen abstraction reaction followed by direct combination with ·OH to form cresol; secondly, ·OH directly adds to the phenyl ring, leading to ring opening; thirdly, oxidation of sidechain to benzoic acid followed by further addition and ring opening. The last two oxidation pathways involve the ring opening of toluene via the addition of ·OH, significantly facilitating the process. Therefore, both pathways are considered feasible for the degradation of toluene. Subsequently, the UV-H2O2 system was designed to induce the formation of ·OH for toluene degradation and to identify the optimal reaction conditions. It was demonstrated that ·OH and 1O2 are the primary active species for degrading toluene, with their contribution ranking as ·OH > 1O2. The intermediates in the mixture solution after reactions were characterized using GC–MS, demonstrating the validity of theoretical predictions. A comparative study of the toluene consumption rate revealed an experimental comprehensive activation energy of 10.33 kJ/mol, which is consistent with the preliminary activation energies obtained via theoretical analysis of these three mechanisms (0.56 kJ/mol to 13.66 kJ/mol), indicating that this theoretical method can provide a theoretical basis for experimental studies on the oxidation of toluene by ·OH.

Abstract 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.

In this study, we investigate visible-light-driven photocatalytic and photo-Fenton degradation of tetracycline (TC) using bismuth-impregnated lanthanum orthoferrite (BixLa1–xFeO3 (x = 0, 0.01, 0.05, 0.07)) nanostructures. Bi doping significantly improves the removal of TC, with Bi0.05La0.95FeO3 (LFO-Bi5) exhibiting optimal degradation. In both photocatalysis (PC) and photo-Fenton catalysis (PFC), the reaction follows pseudo-first-order kinetics, with LFO-Bi5 showing rate constants of 0.0065/min for PC and 0.02716/min for PFC, surpassing LaFeO3 by 2.76 and 3.43 times, respectively. The long-term presence of photoexcited carriers in LFO-Bi5 is confirmed through transient PL, TRPL, and EIS studies. The superior degradation capabilities are attributed to radicals in photocatalysis and OH• radicals in photo-Fenton catalysis. The PFC exhibited faster kinetics due to the rapid production of OH• radicals via the Fe-redox cycle and direct dissociation of H2O2 at oxygen vacancies. LFO-Bi5 demonstrates excellent photostability and reusability for up to six consecutive cycles. The degradation pathway and toxicological properties of the intermediates are analyzed, highlighting the potential of LFO-Bi5 catalysts in antibiotic-contaminated water treatment. [ABSTRACT FROM AUTHOR]

Microplastics are an emerging class of recalcitrant organic pollutants that are of general scientific and public interest nowadays. It would be ideal to remove microplastics from the environment through biodegradation, as biodegradation is a highly ecological and economically acceptable approach. Unfortunately, the efficiency of biodegradation of conventional plastic polymers is low. The application of a suitable pretreatment could increase the efficiency of biodegradation. In this study, the applicability of UV-C/H2O2 and UV-C/S2O82− advanced oxidation processes as pretreatments for the biodegradation of polystyrene and poly(vinyl chloride) microplastics by the yeast Candida parapsilosis was investigated. For the investigated range (pH 4–10, peroxide concentration up to 20 mM and treatment duration up to 90 min), the UV-C/H2O2 process proved to be more effective in degrading polystyrene microplastics, while the UV-C/S2O82− process was more efficient at degrading poly(vinyl chloride) microplastics. Samples pretreated under optimal conditions (90 min treatment time at a pH of 5.7 and H2O2 concentration of 20.0 mM for polystyrene samples; 90 min treatment time at a pH of 8.6 and S2O82− concentration of 11.1 mM for poly(vinyl chloride) samples) were subjected to biodegradation by Candida parapsilosis. The biodegradation conditions included an agitation speed of 156 rpm and an initial pH of 5.7 for the experiments with the polystyrene samples, while an agitation speed of 136 rpm and an initial pH of 4.9 were used for the poly(vinyl chloride) experiments. The initial value of the optical density of the yeast suspension was 1.0 in both cases. The experiments showed a positive effect of the pretreatment on the number of yeast cells on the surface of the microplastics. [ABSTRACT FROM AUTHOR]

There is more and more research focusing on the removal of dioxane by advanced oxidation technology at this stage, and this study investigated the efficacy of an advanced oxidation system with UV-activated persulfate (UV/PDS). This method had the advantages of fast reaction rate, simple equipment and convenient operation. Free radical quenching test and electron paramagnetic resonance (EPR) analysis showed that the main active radicals in the reaction system were SO 4 − and ·OH. This study also investigated that the optimal parameters were the initial PDS dosage of 3 mM, the UV intensity of 0.190 mM/cm2, the pH between 5 and 7 and the initial dioxane concentration of 50 mg/L. Additionally, after a reaction time of 150 min, the total organic carbon (TOC) content still remained at 83.53%, which revealed that the mineralization degree of organic matter was not fully achieved through UV/PDS treatment. The concentration of SO 4 2 − in the reaction system was 74.69 mg·L−1, which complied with the standard concentration specified. Furthermore, the cytotoxicity of the system exhibited an initial increase followed by a subsequent decrease, under the influence of the intermediates. It showed that the technology could efficiently degrade organic pollutants. [ABSTRACT FROM AUTHOR]

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Removal of recalcitrant dyes from agroindustrial wastewater produced in flower processes represents a significant environmental challenge for flower industries worldwide. Advanced oxidation processes (AOPs) emerge as a clean and effective costly alternative for removing dye contaminants in wastewater. This study used an electro-Fenton technique as an alternative for the treatment of colored wastewater from flower-producing crops in Colombia. Initially, the physicochemical characterization of the wastewater was carried out by Chemical Oxygen Demand (COD), color, pH, conductivity, temperature, and oxidation-reduction potential. Subsequently, an electrochemical process was carried out through a power source and six iron electrodes. Variables, such as hydrogen peroxide concentration (500 and 700 mg/l H2O2), amperage (1 and 2 A), and treatment time (60 and 90 minutes), were controlled. Based on a desirability function for multiple response analysis, the electro-Fenton process allowed a maximum COD removal of 80.9% and 88.5% for color (desirability criterion of 86%). Residence time in the reactor, voltage, current density, and concentration of hydrogen peroxide were the most significant variables. Finally, the role of other physicochemical variables involved during the dye degradation process was explained. [ABSTRACT FROM AUTHOR]

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]

This manuscript proposes a method for effective discharging method of pulsed energy in industrial effluents. The proposed approach is based on the dielectric barrier discharge (DBD) and Electro hydraulic Plasma Discharge (EHPD). The objective function of the proposed approach is minimizing the concentration of the ethylene blue (MB) dye in the industrial waste water. Using DBD and EHPD technique, treating such industrial effluents before mixing to the running water can effectively prevent polluting the water bodies and human health. It is one of the tertiary waste water treatments, which can also degrade biological substances. DBD technique is one of the advanced oxidation technique to de-color MB dye and the EHPD reactor is a strong and extremely efficient method for the degradation of MB. By then, the proposed model is implemented in the MATLAB platform and the implementation is calculated with the present procedure. The study concludes that the DBD and EHPD method outperforms other methods in terms of degradation efficiency. De-colorization of methylene blue (MB) took just 15 s using a 3 KV, 50μs pulse. • Hybrid method using optimal power quality enhancement. • Honey Badger Algorithm (HBA). • Golden Jackal optimization (GJO). • Electro hydraulic Plasma Discharge (EHPD). [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]

In this paper, a low-content Ce-doped trimetallic sulfide catalyst (Ce–NiFe2S4) was prepared by the hydrothermal method. The prepared catalyst can improve the oxidant potential of peroxymonosulfate (PMS) to degrade rhodamine B (RhB) dye efficiently in a low dosage. In addition, Ce–NiFe2S4 possessed a magnetic property due to the contained nickel-iron elements. Therefore, the catalyst material has good separation and reusability characteristics. The factors influencing the degradation efficiency of rhodamine by a Ce–NiFe2S4-facilitated PMS oxidation system, such as initial solution pH, PMS dosage, catalyst dosage, and temperature were investigated. The results revealed that RhB can be degraded by 95 % in 30 min at the optimal conditions (100 mg/L catalyst, 200 mg/L PMS). The reaction rate would be further increased when the initial solution pH was 3 with the reaction temperature at 50°C. Furthermore, the quenching experiments verified that 1O2 made an important contribution to the degradation of pollutants as a main active species. SO4•– and •OH, to some extent, participated in the chemical degradation reaction. S2– promoted cycling of redox reactions between metal ions and PMS to ensure catalyst stability and reusability. [ABSTRACT FROM AUTHOR]

As an azo dye, OG has toxic and harmful effects on ecosystems. Therefore, there is an urgent need to develop a green, environmentally friendly, and efficient catalyst to activate peroxymonosulfate (PMS) for the degradation of OG. In this study, the catalysts MIL-101(Fe) and NH2-MIL-101(Fe) were prepared using a solvothermal method to carry out degradation experiments. They were characterized by means of XRD, SEM, XPS, and FT-IR, and the results showed that the catalysts were successfully prepared. Then, a catalyst/PMS system was constructed, and the effects of different reaction systems, initial pH, temperature, catalyst dosing, PMS concentration, and the anion effect on the degradation of OG were investigated. Under specific conditions (100 mL OG solution with a concentration of 50 mg/L, pH = 7.3, temperature = 25 °C, 1 mL PMS solution with a concentration of 100 mmol/L, and a catalyst dosage of 0.02 g), the degradation of OG with MIL-101(Fe) was only 36.6% within 60 min; as a comparison, NH2-MIL-101(Fe) could reach up to 97.9%, with a reaction constant k value of 0.07245 min−1. The NH2-MIL-101 (Fe)/PMS reaction system was able to achieve efficient degradation of OG at different pH values (pH = 3~9). The degradation mechanism was analyzed using free-radical quenching tests. The free-radical quenching tests showed that SO4•−, •OH, and 1O2 were the main active species during the degradation of OG. [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]

Peroxymonosulfate (PMS) advanced oxidation is gaining recognition as a promising method for tackling persistent soil pollutants. However, developing an efficient PMS activator remains a formidable task. This study harnessed Shewanella oneidensis MR-1, a model dissimilatory metal-reducing bacterium (DMRB), to synthesize Mn2O3 nanoparticles by oxidizing Mn(II). These nanoparticles were employed to activate PMS for phenanthrene degradation in soil. Remarkably, biogenic Mn2O3 outperformed chemically synthesized Mn2O3, removing 77.4% of phenanthrene compared to 55.7%. This superior performance is attributed to biogenic Mn2O3's faster electron transfer rate and higher Mn(III) ratio, facilitating electron donation to PMS. Additionally, we assessed the feasibility of PMS advanced oxidation for soil remediation by examining microbial community diversity. Given manganese's prevalence in natural soil and groundwater, in-situ biogenic Mn2O3 synthesis emerges as an innovative soil remediation strategy. [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]

Refractory organic pollutants pose a great threat to public health in water bodies due to their toxicity and low biodegradability. Developing a method of activating persulfate efficiently and in an environmentally friendly way has become a popular topic of research in current advanced oxidation water treatment technologies. Fe(III)-g-C3N4 was prepared by the calcination method. Fe(III) was anchored on the framework of g-C3N4. The characterization analysis indicated that Fe(III) was successfully loaded on g-C3N4. The best effect for MB degradation was Fe(III)-g-C3N4 (0.1 g/L) dosed with 30 µmol/L KMnO4 for synergistic catalyzed PMS (0.1 g/L), where the degradation rate could reach 95.4%. The optimum temperature for MB degradation was determined to be 10 °C. The optimum pH range of Fe(III)-g-C3N4/Mn(VII) synergistic catalyzed PMS for MB degradation was pH 4.4–6.6 under acidic conditions, and the optimum pH range for MB degradation was pH 8–10 under alkaline conditions. The Fe(III)-g-C3N4/Mn(VII) synergistic catalyzed PMS system was also tested for the degradation of methyl orange and rhodamine b, and good degradation results were obtained with the degradation rates of 87.37% and 84%, respectively. It facilitates the reduction in pollutant emissions, improves water quality and will have a positive impact on the sustainability of the environment. [ABSTRACT FROM AUTHOR]