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The ability of persulfate (PS) and peroxymonosulfate (PMS) activated by micron or nanoscale zero-valent copper (ZVC or nZVC) to degrade 2,4-dichlorophenol (2,4-DCP) was quantified under various conditions. Mechanism investigation revealed that PS and PMS accelerated the corrosion of ZVC or nZVC to release Cu + under acidic conditions. The in-situ generated Cu + further decomposed PS or PMS to produce SO 4 − and OH, which then dramatically degraded 2,4-DCP. The k obs for 2,4-DCP removal followed pseudo-first-order kinetics, k obs of ZVC/PMS and nZVC/PMS systems were 10 ∼ 30 times greater than these in ZVC/PS and nZVC/PS systems. The nZVC/PMS system was most effective to remove 2,4-DCP which even did better than the nZVI/PMS system, with rate constant values ranging from 0.041 to 1.855 min −1 . At higher pH ZVC is ineffective, but nZVC can activate PS and PMS to significantly degrade 2,4-DCP at pH up to 7.3. The 2,4-DCP degradation pathway was found to involve dechloridation, dehydrogenation, hydroxylation, ring open and mineralization. 56.7% and 45.3% of TOC removals were respectively obtained in the ZVC/PMS and nZVC/PMS systems within 120 min. This study helps to comprehend the application of zero-valent metals in reactive radicals-based oxidation processes and the reactivity of Cu + as an activator of PS and PMS. [ABSTRACT FROM AUTHOR]

In order to accelerate the photo-Fenton reaction process of Fe(III) under visible light irradiation, BiOI was introduced into the Fe(III)/peroxydisulfate (PDS) system. The catalytic oxidation performance of vis-light/BiOI/Fe(III)/PDS system was evaluated using bisphenol AF (BPAF) as a representative organic contaminant. Within 30 min, nearly 100% of BPAF was degraded, proving that the system had an excellent ability to degrade organic pollutants in water. Free radical quenching experiments, electron spin resonance (ESR), and molecular probing experiments determined that the main reactive species in the system were hydroxyl radicals (•OH) and sulfate radicals (SO 4 •−). The comparative experiments showed that the degradation rates were closely related to the PDS consumption, while the Fe(II) absorbed on the surface of BiOI was responsible for the PDS consumption. The production pathway of Fe(II) was analyzed by XRD, FTIR and XPS characterization, the Fe(III) on the surface of BiOI was reduced by photogenerated electrons to generate Fe(II). The result confirmed that the reduction of Fe(III) by photogenerated electrons could effectively inhibit the recombination of electron-hole pairs, and accelerate the reduction progress of Fe(III)/Fe(II) cycle that was the rate-limiting step in PDS activation. Afterwards, a reliable mechanism for degradation of BPAF in visible light/BiOI/Fe(III)/PDS system was proposed. Finally, the influence of reactant dosages, visible light intensity, initial pH, humic acid (HA) and anions in the solution on the degradation of BPAF were discussed. [Display omitted] • The vis-light/BiOI/Fe(Ⅲ)/PDS system showed an excellent oxidation capability. • The Fe(Ⅱ) generated was responsible for peroxydisulfate activation. • The Fe(Ⅲ) was reduced by photogenerated electrons from BiOI to realize the Fe(Ⅲ)/Fe(Ⅱ) redox cycle. [ABSTRACT FROM AUTHOR]

Abstract: The efficient conversion of Cr(VI) to Cr(III) has attracted an increasing concern in recent years owing to its threat to the environment. In the present paper, the catalytic role of biogenetic schwertmannite in the reduction of Cr(VI) by sulfide and its mechanism were investigated under different conditions through batch experiments. The results demonstrated that schwertmannite markedly accelerated the removal of Cr(VI) by sulfide, and the rates of the reaction were enhanced by 11, 8 and 6 times, respectively at pH 7.5, 8.0 and 8.8 as compared with control (no schwertmannite). In addition, the conversion of Cr(VI) into Cr(III) increased with schwertmannite loading and temperature. However, the facilitating role of schwertmannite in the reduction of Cr(VI) by sulfide was markedly suppressed by an introduction of F−, a complex agent for Fe(III). It is concluded that the catalysis of schwertmannite results from the activated Fe(III) on the surface of schwertmannite, serving as a “bridge” in the transportation of electrons between sulfide and Cr(VI), and leading to the improving reduction of Cr(VI) by sulfide. [Copyright &y& Elsevier]

In this study, Fenton-like chain reaction is constructed by coupling nanoscale tungsten powders (nW0) and peroxydisulfate (PDS). The nanoscale tungsten powders/peroxydisulfate (nW0/PDS) system exhibits a high oxidation efficiency toward diverse pollutants and expands the effective pH range up to 9.8. Results reveal •OH and sulfate radical (SO 4 •−) were confirmed to be responsible for 4,4′-ethylidenebisphenol (EBP) degradation, especially •OH. The corrosion process of nW0 results in the in-situ production of H 2 O 2 and the transient-state tungsten species (W (x, x < VI)), initiating the reaction of H 2 O 2 and tungsten species to generate •OH. PDS can accelerate nW0 corrosion to enhance the Fenton-like reaction, and can be activated by tungsten species (nW0 and W (x, x < VI)) to produce •OH and SO 4 •−. Integrated the analysis results of LC-QTOF-MS/MS, EBP degradation pathways were proposed. This study reveals the high oxidation efficiency over a wide pH range in the nW0/PDS system and provides new insight into the tungsten species induced Fenton-like reaction. [Display omitted] • The nW0/PDS system exhibits high oxidation efficiency over a wide pH range. • The stepwise oxidation between nW0 and dissoved oxygen in-situ produces H 2 O 2. • •OH and SO 4 •− are generated by the tungsten species induced Fenton-like reaction. • PDS accelerates the corrosion of nW0 and the Fenton-like reaction. • Degradation process of EBP was proposed based on LC-QTOF-MS/MS results. [ABSTRACT FROM AUTHOR]

• Coffee grounds as a carbon source, it's environmentally sustainable. • High tetracycline removal rate is due to 1O 2 and electron transfer. • Point defects and carbonyl groups were critical for 1O 2 and electron transfer. • N/S-codoped carbons may provide an advanced strategy for green wastewater treatment. Nitrogen and sulfur-codoped porous carbons (SNCs) with porous structures and high surface areas were successfully synthesized employing coffee grounds, sodium bicarbonate and L-cysteine monohydrochloride as precursors. The SNCs were highly efficient for adsorption and exhibited outstanding catalytic performance for the oxidative degradation of tetracycline hydrochloride (TeC) solutions, especially at a calcined temperature of 700 °C (SNCs-700). The radical quenching, advanced in situ electron paramagnetic resonance (EPR) technology, PS decomposition rates and Linear Sweep Voltammetry (LSV) indicated that the excellent oxidative effectiveness of the PS/SNCs-700 system originated from the nonradical pathways (singlet oxygen (1O 2) and electron transfer). It's supposed that N and S doping can effectively create point defects, which could generate 1O 2 , while carbonyl groups were determined to be the main active sites contributing to the electron transfer. TeC degradation intermediates were also identified, three degradation pathways, revealing that the pre-adsorption significantly accelerated the nonradical oxidation pathways. This approach provides an innovative method for the large-scale production and application of high-quality catalysts in water treatment. [ABSTRACT FROM AUTHOR]

• Cd(II)-tolerant electrochemically active bacteria (EAB) favor H 2 or acetate production. • EAB release extracellular polymeric substances (EPS) to increase products production. • Products distribution correlates with intracellular physiological activities. • EPS released exhibits catalytic activity toward the reduction of Cd(II) to Cd(0). • Circuital current and Cd(II) stress induce EAB to release higher EPS amounts. The simultaneous production of acetate from bicarbonate (from CO 2 sequestration) and hydrogen gas, with concomitant removal of Cd(II) heavy metal in water is demonstrated in multifunctional metallurgical microbial electrosynthesis systems (MES) incorporating Cd(II) tolerant electrochemically active bacteria (EAB) (Ochrobactrum sp. X1, Pseudomonas sp. X3, Pseudomonas delhiensis X5, and Ochrobactrum anthropi X7). Strain X5 favored the production of acetate, while X7 preferred the production of hydrogen. The rate of Cd(II) removal by all EAB (1.20–1.32 mg/L/h), and the rates of acetate production by X5 (29.4 mg/L/d) and hydrogen evolution by X7 (0.0187 m3/m3/d) increased in the presence of a circuital current. The production of acetate and hydrogen was regulated by the release of extracellular polymeric substances (EPS), which also exhibited invariable catalytic activity toward the reduction of Cd(II) to Cd(0). The intracellular activities of glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and dehydrogenase were altered by the circuital current and Cd(II) concentration, and these regulated the products distribution. Such understanding enables the targeted manipulation of the MES operational conditions that favor the production of acetate from CO 2 sequestration with simultaneous hydrogen production and removal/recovery of Cd(II) from metal-contaminated and organics-barren waters. [ABSTRACT FROM AUTHOR]

Mg-K homeostasis is essential for plant response to abiotic stress, but its regulation remains largely unknown. MsWRKY44 cloned from alfalfa was highly expressed in leaves and petioles. Overexpression of it inhibited alfalfa growth, and promoted leaf senescence and alfalfa sensitivities to acid and Al stresses. The leaf tips, margins and interveins of old leaves occurred yellow spots in MsWRKY44 -OE plants under pH4.5 and pH4.5 +Al conditions. Meanwhile, Mg-K homeostasis was substantially changed with reduction of K accumulation and increases of Mg as well as Al accumulation in shoots of MsWRKY44-OE plants. Further, MsWRKY44 was found to directly bind to the promoters of MsMGT7 and MsCIPK23 , and positively activated their expression. Transiently overexpressed MsMGT7 and MsCIPK23 in tobacco leaves increased the Mg and Al accumulations but decreased K accumulation. These results revealed a novel regulatory module MsWRKY44- MsMGT7 / MsCIPK23 , which affects the transport and accumulation of Mg and K in shoots, and promotes alfalfa sensitivities to acid and Al stresses. [Display omitted] • MsWRKY44 is induced by H+ and Al3+, and increased alfalfa sensitivities to acid and Al stresses. • MsWRKY44 directly targeted to MsMGT7 and MsCIPK23 promoters. • MsWRKY44-MsMGT7/MsCIPK23 module regulated Mg and K homeostasis in alfalfa shoots under acid and Al stresses. [ABSTRACT FROM AUTHOR]

Solution pH is one of the primary factors affecting the efficiency of water decontamination. Although the influence of pH on oxidants activation, catalyst activity, and reactive oxygen species have been widely explored, there is still a scarcity of systemic studies on the changes in the oxidation behavior of organic pollutants at different pH levels. Herein, we report the influence laws of pH on the forms, reactivities, active sites, degradation pathways, and products toxicities of organic pollutants. Changes in pH cause the protonation or deprotonation of organic pollutants and further affect their forms and chemistry (e.g., electrostatic force, hydrophobicity, and oxidation potential). The oxidation potential of organic pollutants follows the order: protonated form > pristine form > deprotonated form. Moreover, protonation or deprotonation can modify the active sites and degradation pathways of organic pollutants, wherein deprotonation renders them more susceptible to electrophilic attack, while protonation reduces their activity against electrophilic and nucleophilic attacks. Additionally, pH adjustments can modify the degradation pathway and the toxicity of transformation products. Overall, pH changes can affect the oxidation fate of organic pollutants by altering their structure, which distinguishes it from the effect of pH on oxidants or oxidant activation processes. [Display omitted] • Solution pH alters the oxidation behavior of organic pollutants. • Deprotonation augments the reactivity of organic pollutants while protonation diminishes it. • Protonation and deprotonation modify the active sites and degradation pathways. • The toxicity of the transformation products can be controlled by adjusting the solution pH [ABSTRACT FROM AUTHOR]

In this study, the porous carbon material (FeN-BC) with ultra-high catalytic activity was obtained from waste biomass through Fe-N co-doping. The prominent degradation rate (> 96.8%) of naproxen (NAP) was achieved over a wide pH range (pH 3.0–9.0) in FeN-BC/PAA system. Unlike previously reported iron-based peracetic acid (PAA) systems with •OH or RO• as the dominated reactive species, the degradation of contaminants was attributed to singlet oxygen (1O 2) produced by organic radicals (RO•) decomposition, which was proved to be thermodynamically feasible and favorable by theoretical calculations. Combining the theoretical calculations, characteristic and experimental analysis, the synergistic effects of Fe and N were proposed and summarized as follows: i) promoted the formation of extensive defects and Fe0 species that facilitated electron transfer between FeN-BC and PAA and continuous Fe(II) generation; ii) modified the specific surface area (SSA) and the isoelectric point of FeN-BC in favor of PAA adsorption on the catalyst surface. This study provides a strategy for waste biomass reuse to construct a heterogeneous catalyst/PAA system for efficient water purification and reveals the synergistic effects of typical metal-heteroatom for PAA activation. [Display omitted] • FeN-BC/PAA system exhibits excellent degradation of NAP over a wide pH range. • NAP degradation is proved as 1O 2 -dominated non-radical processes. • The formed Fe0 provides the active site and enhances electron transfer. • Synergistic effect between Fe and N species is successfully revealed for enhanced PAA activation. • Application potential of the proposed FeN-BC/PAA system is comprehensively evaluated. [ABSTRACT FROM AUTHOR]

A novel "ferrate/percarbonate (Fe(VI)/SPC) co-oxidation process" was used to treat ciprofloxacin (CIP) and various micropollutants (MPs), which owned better performance than mixture of Fe(VI), Na 2 CO 3 and H 2 O 2. The mechanism investigation found that the low-concentration H 2 O 2 (1–2 µM) released by SPC can promote the high-valent iron intermediates (Fe(IV)/Fe(V)) of Fe(VI) to the MP oxidation, and Fe(VI) products can also activate SPC to produce hydroxyl radical (·OH). The interactive activation of Fe(VI) and SPC was realized, which retained the high selectivity of Fe(VI) to electron-rich pollutants, and also made up the oxidation of electron-deficient pollutants through •OH, improving the degradation effect of various MPs by 20–30%, and the rate constant was increased by 1 to 3 times. Moreover, non-purgeable organic carbon (NPOC) determination confirmed that •OH participation reduced the NPOC value of CIP from 5.43 mg/L to 4.37 mg/L. The transformation pathway of CIP showed that Fe(VI)/SPC resulted in more hydroxylation intermediates of CIP than Fe(VI) alone. Acute toxicity assays found that the photoinhibition rate of CIP treated with Fe(VI) alone was 14.5%, while the sample treated with Fe(VI)/SPC showed no significant photoinhibition effect, which proved that the new process had good detoxification properties for CIP. [Display omitted] • The interaction between SPC and Fe(VI) formed both·OH and Fe(IV)/Fe(V). • Low-concentration H 2 O 2 released by SPC improved the electron utilization of Fe(VI). • The·OH enables CIP to generate hydroxylation products possessing reduced toxicity. • SPC/Fe(VI) process is suitable for oxidation of electron rich and electron deficient pollutants. [ABSTRACT FROM AUTHOR]

As one of the most promising advanced oxidation processes, the activation of S(IV) by iron-based materials to produce SO 4 •− has become a hot technology for the degradation of organic pollutants. However, the mechanism of radical chain reactions has not been clearly explored. Herein, we established a novel AOP system based on the combination of zero-valent iron (ZVI) and potassium pyrosulfite (PPS). Combined with the degradation trends of CBZ and the change of DO concentration, the system was proposed to be divided into a slow initiation stage in 5 min and a rapid degradation stage in 5 − 10 min. Through a series of quenching experiments, electron paramagnetic resonance tests and several probe experiments, the mechanisms of two radical chain reactions were proposed between ZVI and PPS: the first one produced O 2 •− and HO•, and the other produced SO 3 •−, SO 5 •−, SO 4 •− and HO•. The two-stage reaction and two radical production paths of the ZVI/PPS system were proposed for the first time, which provided theoretical guidance for the practical application of the ZVI/PPS system. The ZVI/PPS system has been found to have excellent environmental adaptability in the treatment of industrial wastewater. [Display omitted] • Two radical generation paths and mechanisms are analyzed. • O 2 plays a crucial role in two radical production pathways. • CBZ degradation is divided into slow initiation stage and rapid degradation stage. [ABSTRACT FROM AUTHOR]

The sluggish oxidation kinetics of ferrate (Fe(VI)) at neutral and slightly alkaline pH impedes its rapid abatement of micropollutants in practical application. This work discovers that graphite (GP), a metal-free carbonaceous material, can be a promising material to improve the reactivity of Fe(VI) in the pH range of 7.0 − 9.0. The performance of the GP/Fe(VI) process for sulfamethoxazole (SMX) removal was further evaluated via altering the dosages of Fe(VI), GP, and SMX. Probe analysis and quenching experiments identified Fe(IV) and Fe(V) as the primary active species responsible for the removal of organic compounds in the GP/Fe(VI) system. The detailed activation mechanism of GP is discussed via analyzing the surface chemical changes of GP exposed to Fe(VI). It is found that the carbonyl groups on GP surface execute a critical role in Fe(VI) activation. The GP/Fe(VI) system shows powerful anti-interference ability to environmental background substances. Therefore, the new oxidation process proposed in this work holds a great application prospect for contamination remediation. Finally, we discuss the underlying degradation pathways of SMX by the GP/Fe(VI) system. This study not only develops a promising system for the removal of micropollutants but also provides an in-depth insight into the activation mechanism of metal-free carbonaceous material in Fe(VI) oxidation process. [Display omitted] • GP can improve the oxidation activity of Fe(VI) to eliminate various micropollutants. • Fe(IV) and Fe(V) are the main active oxidants in the GP/Fe(VI) system. • The carbonyl group on GP surface plays a vital role in activating Fe(VI). • The GP/Fe(VI) system shows an excellent environmental adaptability. [ABSTRACT FROM AUTHOR]

Our previous study revealed that 1-nitropyrene (1-NP) exposure evoked pulmonary fibrosis in mice. However, the exact mechanism remained elusive. We found that 1-NP induced telomere damage and cellular senescence in mice lungs, and two alveolar epithelial cells lines. 1-NP downregulated telomere repeat binding factor 2 (TRF2), and upregulated FBXW7. Mechanistically, 1-NP-caused TRF2 ubiquitination and proteasomal degradation depended on E3 ubiquitin ligase activity of FBXW7. Moreover, 1-NP upregulated FBXW7 m6A modification via an ALKBH5-YTHDF1-dependent manner. Further analysis suggested 1-NP promoted ALKBH5 SUMOylation and subsequent proteasomal degradation. Additionally, 1-NP evoked mitochondrial reactive oxygen species (mtROS) overproduction. Mito-TEMPO, a mitochondrial-targeted antioxidant, mitigated 1-NP-caused mtROS overproduction, ALKBH5 SUMOylation, FBXW7 m6A modification, TRF2 degradation, cellular senescence, and pulmonary fibrosis. Taken together, mtROS-initiated ALKBH5 SUMOylation and subsequent FBXW7 m6A modification is indispensable for TRF2 degradation and cellular senescence in alveolar epithelial cells during 1-NP-induced pulmonary fibrosis. Our study provides target intervention measures towards 1-NP-evoked pulmonary fibrosis. [Display omitted] • 1-NP induces telomere damage and cellular senescence in mice lungs and AEC2 cells. • 1-NP-caused TRF2 ubiquitination and proteasomal degradation depends on E3 ubiquitin ligase activity of FBXW7. • 1-NP upregulates FBXW7 m6A modification via an ALKBH5-YTHDF1-dependent manner. • 1-NP promotes ALKBH5 SUMOylation and subsequent proteasomal degradation via an mtROS-dependent manner. • Mito-TEMPO mitigates 1-NP-caused mtROS overproduction, cellular senescence and pulmonary fibrosis. [ABSTRACT FROM AUTHOR]

Recently, the enhancing role of hydrogen peroxide (H 2 O 2), a self-decay product of ferrate (Fe(VI)), on Fe(VI) reactivity has received increasing attention. In this study, we found that calcium peroxide (CaO 2) as a slow-releasing reagent of H 2 O 2 could also enhance the Fe(VI) performance for removing sulfamethoxazole (SMX). Compared with sole Fe(VI), sole CaO 2 and Fe(VI)-H 2 O 2 systems, the Fe(VI)-CaO 2 system showed higher reactivity to remove SMX. The radical scavenger and chemical probe test results indicated that the better oxidation performance of Fe(VI)-CaO 2 system than Fe(VI) alone was ascribed to the generation of Fe(Ⅳ) and Fe(Ⅴ) rather than •OH. In addition, the performance of Fe(VI)-CaO 2 system for degradation of contaminants was also superior to Fe(VI)-Na 2 SO 3 , Fe(VI)-NaHSO 3 and Fe(VI)-Na 2 S 2 O 3 systems under the same experimental conditions. Moreover, the effects of critical operating parameters, inorganic anions, inorganic cations, and humic acid on the degradation of SMX by Fe(VI)-CaO 2 system were revealed. The Fe(VI)-CaO 2 system exhibited good applicability in authentic water. Finally, the underlying degradation intermediates of SMX by Fe(VI)-CaO 2 system and their toxicity were confirmed. In conclusion, this study provides a new strategy for enhancing the oxidation capacity of Fe(VI) and comprehensively reveals the oxidation mechanism. [Display omitted] • The Fe(VI)-CaO 2 system was developed for efficiently removing organic pollutants. • The negligible contribution of •OH was presented in Fe(VI)-CaO 2 system. • The mechanism of CaO 2 activating Fe(VI) was systematically investigated. • The key parameters of Fe(VI)-CaO 2 system were investigated thoroughly. • The degradation pathway of SMX in Fe(VI)-CaO 2 system was proposed. [ABSTRACT FROM AUTHOR]

In this study, the effects of ferric ion (Fe3+) on the degradation of atrazine (ATZ) in Bi 2 MoO 6 /peroxymonosulfate (PMS) system under visible light irradiation was investigated. With the addition of Fe3+, ATZ in the visible light/Bi 2 MoO 6 /PMS system degraded rapidly after 20 min treatment (removal rate > 99%). The enhancement of ATZ removal can be attributed to the role of Fe3+. As an electron transfer mediator, Fe3+ not only inhibits the recombination of photo-charges and prolongs the life of photogenerated carriers, but also promotes the activation of PMS by accelerating the electron transfer from Bi 2 MoO 6 to PMS. The generation of •OH and SO 4 •− in the system was determined via electron paramagnetic resonance (EPR) technology and quenching experiments. Furthermore, the characterization of Bi 2 MoO 6 before and after reaction, influence of the reaction parameters (i.e., catalyst and PMS dosages, Fe3+ and ATZ concentration, initial pH), influence of inorganic anions and humic acid, and the recyclability of catalyst in the vis/Bi 2 MoO 6 /PMS/Fe3+ system was also investigated. Additionally, the existence of Fe3+ also exhibits a wide selectivity for the degradation of different pollutants and high treatment efficiency. In general, the vis/Bi 2 MoO 6 /PMS/Fe3+ system demonstrated the potential as an efficient, economical, and environment-friendly water treatment process. [Display omitted] • Fe3+addition not only inhibits the recombination of the photo-charges, but also promotes PMS activation. • Fe3+ can activate PMS and capture photo-electron to enhance the photo-synergy for ATZ degradation. • •OH and SO 4 •− were the dominant species in the degradation of atrazine. • Bi 2 MoO 6 nanosheet showed excellent reusability and wide degradation selectivity in vis/Bi 2 MoO 6 /PMS/Fe3+ system. [ABSTRACT FROM AUTHOR]

Among all homogeneous catalysts, cobalt ions show the highest catalytic performance for the activation of peroxymonosulfate (PMS). Herein, we report a Co2+/PMS/H 3 BO 3 system that can effectively generate reactive oxygen species (ROS) with ultra–low Co2+ dosage (5 μg/L). Co2+/PMS/H 3 BO 3 system showed ultrafast reactivity and wide applicability for various pollutants. Sulfamethoxazole (SMX, 2 mg/L) could be completely removed within 5 min, and the corresponding k obs reached up to 1.1239 min−1. The introduction of H 3 BO 3 significantly promoted the generation of ROS. The turnover frequency (TOF) calculated through dividing k obs by the cobalt ions concentration is as high as 224.78 min−1, which is much higher than most of the current research. Through a series of theoretical and experimental analyses, the complex of H 2 BO 3 −–MS (HSO 5 B(OH) 3 –) was inferred to be the key substance that led to the excellent performance of the system. This work provides new insights into the Co2+/PMS system in the presence of borate buffer. [Display omitted] • Trace cobalt(II) (5 μg/L) can efficiently activate PMS in the presence of boric acid. • The corresponding k obs value reached up to 1.1239 min−1 in Co2+/PMS/H 3 BO 3 system. • H 2 BO 3 −-PMS was the key substance that caused the excellent performance of the system. • Co2+/PMS/H 3 BO 3 system showed wide applicability for various pollutants. • This study provides novel insights into the Co2+/PMS system in borate buffer. [ABSTRACT FROM AUTHOR]

Currently, many catalysts are inconvenient to separate from water, and the solvents used in the preparation process are not environmentally friendly, resulting in low recovery efficiency and secondary pollution. In this study, the magnetic and porous regenerated cellulose/carbon nanotubes/Fe 3 O 4 nanoparticles (RC/CNTs/Fe 3 O 4 NPs) composites were synthesized for activation of peroxydisulfate (PDS) in a green alkaline-urea system. The RC/CNTs/Fe 3 O 4 NPs-PDS system achieved 100% removal of bisphenol A compared with CNTs (~64.6%), RC (~0%) or Fe 3 O 4 NPs (~0%), which was closely related to the introduction of defects and functional groups, nitrogen doping and conductive networks. Interestingly, the strong interaction between CNTs and the sheath-like protective layer formed by urea on the cellulose surface promotes the introduction of nitrogen into the composites at the preparation temperature of 70 °C. Moreover, the mechanism of the system was found to be a typical non-radical pathway. Fortunately, there is no leaching of iron ions in the system, and the effects of the actual waterbody, initial pH, and different anions are negligible. The recycling and separation experiments revealed the practicality and superiority of the composite. This work provides a feasible and sustainable strategy for the application of natural cellulose-supported catalysts. [Display omitted] • Porous RC/CNTs/Fe 3 O 4 NPs were prepared using natural cellulose as a support. • The catalyst exhibited excellent performance for activating PDS. • The enhanced activity stems from the synergistic effect of cellulose and CNTs. • A way of doping nitrogen with a temperature of 70 °C was discovered. • The non-radical mechanism of RC/CNTs/Fe 3 O 4 NPs-PDS system was proposed. [ABSTRACT FROM AUTHOR]

Iron-based PAA activation process is a promising advanced oxidation process for water decontamination which depends on Fe(II) as the main reactive site for PAA activation, resulting in various reactive oxidative species (ROSs) generation. For practical application, the impact of water matrix chloride ion (Cl−) on ROSs production and contaminants removal should be carefully considered. In this study, it's found that the introduction of Cl− (0.1–10 mM) could significantly enhance the reaction rate of the rapid stage (k obs1) up to 2.15 times at the initial pH of 4.25 in the Fe(II)/PAA system. Further studies demonstrated that the improved removal capacity of NAP resulted from Cl− induced R-O• generation as indicated by the exposure dose of R-O• increasing from 7.74 × 10−11 M•s to 1.44 × 10−10 M•s, rather than chlorine-containing radicals' generation. DFT calculation results suggested that the formed Fe(II)-Cl− complexes could easily activate PAA to generate more ROSs for NAP removal. Moreover, Fe(II)/PAA treatment can alleviate the biological toxicity of pollutants via both the Escherichia coli test and toxicity assessment. The obtained new knowledge manifested that Cl− can boost ROSs generation and conversion in iron-based PAA systems, providing guidance for the efficient decontamination of chlorine-containing sewage with PAA-based AOPs. [Display omitted] • The presence of Cl− promotes NAP removal in the Fe(II)/PAA system at pH 3.0–9.0. • Cl− accelerates PAA depletion due to the formation of complex ([FeCl(H 2 O) 5 ]+ or [FeCl(OH)(H 2 O) 4 ]). • Cl− induced R-O• generation to become the dominant ROS in Fe(II)/PAA system. • Fe(II)/PAA/Cl− treatment can reduce the biological toxicity of wastewater. [ABSTRACT FROM AUTHOR]

The acceleration of Fe(III)/Fe(II) conversion in Fenton systems is the critical route to achieve the long-lasting generation of reactive oxygen species towards the oxidation of refractory contaminants. Here, we found that waste leather derived porous carbon materials (LPC), as a simple and readily available metal-free biochar material, can promote the Fe(III)/H 2 O 2 system to generate hydroxyl radicals (•OH) for oxidizing a broad spectrum of contaminants. Results of characterizations, theoretical calculations, and electrochemical tests show that the surface carbonyl groups of LPC can provide electron for direct Fe(III) reduction. More importantly, the graphitic-N on surface of LPC can enhance the reactivity of Fe(III) for accelerating H 2 O 2 induced Fe(III) reduction. The presence of LPC accelerates the Fe(III)/Fe(II) redox cycle in the Fe(III)/H 2 O 2 system, sustainable Fenton chain reactions is thus initiated for long-lasting generation of hydroxyl radicals without adding Fe(II). The continuous flow mode that couples in-situ Fenton-like oxidation and LPC with excellent adsorption catalytic properties, anti-coexisting substances interference and reusability performance enables efficient, green and sustainable degradation of trace organic pollutants. Therefore, the application of metal-free carbon materials in Fenton-like system can solve its rate-limiting problem, reduce the production of iron sludge, achieve green Fenton chemistry, and facilitate the actual engineering application of economic and ecological methods to efficiently remove trace organic contaminants from actual water sources. [Display omitted] • Waste leather-derived porous carbon can effectively boost Fenton oxidation. • H 2 O 2 can act as an electron donor for green and sustainable Fenton oxidation. • Surface nitrogen of LPC can elevate the reactivity of Fe(III) species. • Sustainable removal of trace refractory organic pollutants was achieved. • Hydroxyl radical induced oxidation pathway of DEP was proposed. [ABSTRACT FROM AUTHOR]

Ferrate (Fe(VI)) has aroused great research interest in recent years due to its environmental benignancy and lower potential in disinfection by-product generation. However, the inevitable self-decomposition and lower reactivity under alkaline conditions severely restrict the utilization and decontamination efficiency of Fe(VI). Here, we discovered that Ru(III), a representative transition metal, could effectively activate Fe(VI) to degrade organic micropollutants, and its performance on Fe(VI) activation exceeded that of previously reported metal activators. The high-valent metal species (i.e., Fe(IV)/Fe(V) and high-valent Ru species) made a major contribution to SMX removal by Fe(VI)−Ru(III). Density functional theory calculations indicated the function of Ru(III) as a two-electron reductant, leading to the production of Ru(V) and Fe(IV) as the predominant active species. The characterization analyses proved that Ru species was deposited on ferric (hydr)oxides as Ru(III), indicating the possibility of Ru(III) as an electron shuttle with the rapid valence circulation between Ru(V) and Ru(III). This study not only develops an efficient way to activate Fe(VI) but also offers a thorough understanding of Fe(VI) activation induced by transition metals. [Display omitted] • Ru(III) can significantly promote Fe(VI) to degrade SMX. • Enhanced SMX removal was attributed to the generation of high-valent metal species. • Two-electron transfer between Fe(VI) and Ru(III) led to the formation of Fe(IV) and Ru(V) as major reactive species. • Multiple roles of Ru(III) as the Fe(VI) activator, the precursor of reactive species, and the electron shuttle were proposed. [ABSTRACT FROM AUTHOR]

Periodate (PI) has recently been studied as an excellent oxidant in advanced oxidation processes, and its reported mechanism is mainly the formation of reactive oxygen species (ROS). This work presents an efficient approach using N-doped iron-based porous carbon (Fe@N-C) to activate periodate for the degradation of sulfisoxazole (SIZ). Characterization results indicated the catalyst has high catalytic activity, stable structure, and high electron transfer activity. In terms of degradation mechanism, it is pointed out that the non-radical pathway is the dominant mechanism. In order to prove this mechanism, we have carried out scavenging experiments, electron paramagnetic resonance (EPR) analysis, salt bridge experiments and electrochemical experiments, which demonstrate the occurrence of mediated electron transfer mechanism. Fe@N-C could mediate the electron transfer from organic contaminant molecules to PI, thus improving the efficiency of PI utilization, rather than simply inducing the activation of PI through Fe@N-C. The overall results of this study provided a new understanding into the application of Fe@N-C activated PI in wastewater treatment. [Display omitted] • The activation of PI was successfully promoted with Fe@N-C. • The reaction mechanism of Fe@N-C/PI system is electron transfer mechanism. • The degradation pathway of pollutants in Fe@N-C/PI system was proposed. • No iodate and other harmful byproducts were produced during the reaction. [ABSTRACT FROM AUTHOR]

The biological slow filtration reactor (BSFR) process has been found to be moderately effective for the removal of refractory dissolved organic matter (DOM) in the treatment of reused water. In this study, bench scale experiments were conducted using a mixture of landscape water and concentrated landfill leachate as feed water, to compare a novel iron oxide (Fe x O)/FeNC modified activated carbon (Fe x O@AC) packed BSFR, with a conventional activated carbon packed BSFR (AC-BSFR), operated in parallel. The results showed that the Fe x O@AC packed BSFR had a refractory DOM removal rate of 90%, operated at a hydraulic retention time (HRT) of 10 h at room temperature for 30 weeks, while under the same conditions the removal by the AC-BSFR was only 70%. As a consequence, the treatment by the Fe x O@AC packed BSFR substantially reduced the formation potential of trihalomethanes, and to a less extent, haloacetic acids. The modification of Fe x O/FeNC media raised the conductivity and the oxygen reduction reaction (ORR) efficiency of the AC media to accelerate the anaerobic digestion by consuming the electrons that are generated by anaerobic digestion itself, which lead to the marked improvement in refractory DOM removal. [Display omitted] • Fe x O@AC-BSFR removed 90% DOM by HRT of 10 h for 30 weeks to AC packed BSFR (70%). • Fe x O@AC-BSFR can effectively reduce the formation potential of trihalomethanes (THMs). • Fe x O/FeNC raised ORR efficiency and accelerate the anaerobic digestion for DOM removal. [ABSTRACT FROM AUTHOR]

Zerovalent iron (ZVI)-based Fenton-like processes have been widely applied in degrading organic contaminants. However, the surface oxyhydroxide passivation layer produced during the preparation and oxidation of ZVI hinders its dissolution and Fe(III)/Fe(II) cycling, and restricts the generation of reactive oxygen species (ROS). In this study, copper sulfide (CuS) was found to effectively enhance the degradation of diverse organic pollutants in the ZVI/H 2 O 2 system. Moreover, the degradation performance for the actual industrial wastewater (i.e., dinitrodiazophenol wastewater) in the ZVI/H 2 O 2 system was impressively improved by 41% with CuS addition, and the COD removal efficiency could reach 97% after 2 h of treatment. Mechanism investigation revealed that the introduction of CuS accelerated the sustainable supply of Fe(II) in the ZVI/H 2 O 2 system. Specifically, Cu(I) and reductive sulfur species (i.e., S2–, S 2 2–, S n 2– and H 2 S (aq)) from CuS directly induced efficient Fe(III)/Fe(II) cycling. The iron-copper synergistic effect between Cu(II) from CuS and ZVI expedited Fe(II) generation from ZVI dissolution and Fe(III) reduction by formed Cu(I). This study not only elucidates the promotion effects of CuS on ZVI dissolution and Fe(III)/Fe(II) cycling in ZVI-based Fenton-like processes, but also provides a sustainable and high-efficiency iron-based oxidation system for removal of organic contaminants. [Display omitted] • CuS as an excellent catalyst was used to enhance Fenton-like chemistry of ZVI. • CuS maintained a sustainable supply of Fe(II) to boost oxidation reaction. • Cu(I) and reductive sulfur species impressively induced Fe(II) regeneration. • Contribution of Cu(I) to enhancing the catalytic activity of CuS was assessed. • Cu(II) interacting with ZVI produced synergistic effect to boost Fe(II) production. [ABSTRACT FROM AUTHOR]

In this study, vanadium powder (V) was employed as a cocatalyst to enhance the Fenton-like system. The V-Fe(III)/H 2 O 2 system can rapidly produce hydroxyl radicals and completely oxidize chloramphenicol with exceptionally high stability for long-term operation. The low-valent vanadium sites on the surface during the stepwise oxidation of vanadium from V0 to V(IV) can donate electrons for direct H 2 O 2 activation and indirect Fenton reaction by reducing Fe(III) to produce hydroxyl radicals. Meanwhile, density functional theory (DFT) calculation unveils that low-valent vanadium sites of vanadium can lengthen Fe-O bonds of FeOH2+ to elevate the oxidation potential of Fe(III) and promote Fe(III) reduction induced by H 2 O 2. The self-cleaning effect of vanadium under acidic conditions can maintain reactive sites for sustainable electron donation and long-lasting enhanced Fenton oxidation. This study provides a novel enhanced Fenton oxidation for water remediation and the first mechanistic insights into the origins of V-based advanced oxidation technologies, it may also be beneficial to treat vanadium-contained wastewater. [Display omitted] • Vanadium strongly boosts the Fe(III)/H 2 O 2 system to generate hydroxyl radicals. • Vanadium outperforms most reported co-catalysts for boosting the Fe(III)/H 2 O 2 system. • Vanadium donates electrons stepwise for direct and indirect Fenton-like activation of H 2 O 2. • Vanadium elevates the oxidation potential of Fe(III) to accelerate H 2 O 2 induced Fe(III) reduction. • Self-cleaning effect of vanadium guarantees a reactive surface for sustainable operation. [ABSTRACT FROM AUTHOR]

Sodium bismuthate dihydrate (NaBiO 3.2 H 2 O, NBH) nanosheets were successfully prepared in this study using the persulfate oil bath oxidation method. Benefited from the unique layered structure of NBH, the Fe(III) as a variable valence metal ion was explored for enhancing NBH activation of peroxymonosulfate (PMS) to degrade levofloxacin (LVF) in the visible-light catalytic system. Based on results of the reactive oxygen species (ROS) quenching experiments and electron paramagnetic resonance (EPR) analysis, singlet oxygen (1O 2) and superoxide radical (O 2 ·-) were identified as the main ROS. The morphology, chemical structure, and optical properties of NBH were analyzed using various characterization methods. It was confirmed that Fe(III) embedded in the NBH via the ion exchange with Na, resulting in lattice oxygen vacancies on the surface of the NBH, after the formation of oxygen defect sites, reacts with PMS in the solution to produce active oxygen species with oxidizing efficiency. This study expands the technological application of NBH in the catalytic oxidation of variable valence metals, which are essential for the removal of fluoroquinolone antibiotics. [Display omitted] • The vis-light/NBH/Fe(Ⅲ)/PMS system shows excellent oxidation capability to degrade LVF. • Fe(III) embedded in the NBH via the exchange with Na to lead the lattice oxygen missing. • Oxygen defects of NBH can react with PMS produce reactive oxygen species. • Singlet oxygen and superoxide radical are the primary reactive oxygen species. [ABSTRACT FROM AUTHOR]

It is of great interest to explore physiological metabolism of electrochemically active bacteria (EAB) for combined organics and heavy metals in single-chamber microbial electrolysis cells (MECs). Four pure culture EAB varying degrees responded to the combined acetate (1.0–5.0 g/L) and Cd(II) (20–150 mg/L) at different initial concentrations in the single-chamber MECs, shown as significant relevance of Cd(II) removal (2.57–7.35 mg/L/h) and H 2 production (0–0.0011 m3/m3/h) instead of acetate removal (73–130 mg/L/h), to these EAB species at initial Cd(II) below 120 mg/L and initial acetate below 3.0 g/L. A high initial acetate (5.0 g/L) compensated the Cd(II) inhibition and broadened the removal of Cd(II) to 150 mg/L. These EAB physiologically released variable amounts of extracellular polymeric substances with a compositional diversity in response to the changes of initial Cd(II) and circuital current whereas the activities of typical intracellular enzymes were more apparently altered by the initial Cd(II) than the circuital current. These results provide experimental validation of the presence, the metabolic plasticity and the physiological response of these EAB directed by the changes of initial Cd(II) and acetate concentrations in the single-chamber MECs, deepening our understanding of EAB physiological coping strategies in metallurgical microbial electro-ecological cycles. [Display omitted] • Initial Cd(II) and acetate direct EAB physiological metabolism in MECs. • Cd(II) removal and H 2 evolution instead of acetate removal correlate with EAB strain. • Initial Cd(II) and circuital current correlate with amount of EPS and composite. • Initial Cd(II) alters more intracellular enzymatic activities than circuital current. • Acetate (5.0 g/L) alleviates Cd(II) stress for directing more CH 4 than H 2 evolution. [ABSTRACT FROM AUTHOR]

Highlights: [•] TBBPA was detected in fine solid wastes and dust samples from PCB production at considerable levels. [•] The highest TBBPA emission to the environment was exhibited by the fine solid waste. [•] Elevated TBBPA concentrations were found in dust and PM10 from workshops of PCB production. [•] TBBPA contamination occurred mainly in the form of dust rather than suspended particulate matter in PCB production. [•] TBBPA via dust exposures were more critical than PM10 in most production processes. [Copyright &y& Elsevier]

• The performance of ZVI/peroxymonosulfate could be enhanced with the Cu2+. • Radicals and non-radical species both contributed to the degradation. • The generation of singlet oxygen was investigated in the bimetallic AOPs systems. • Nine main byproducts and degradation pathways were identified. • Accurate toxicity of the byproducts was calculated. Advanced oxidation processes (AOPs) based on the bimetallic system has been demonstrated as a promising way to enhance the degradation of pollutants in the water. In this study, the degradation of Rhodamine B (RhB) in a zero-valent iron (ZVI)/ peroxymonosulfate system with Cu2+ was thoroughly investigated. RhB could be efficiently removed (99.3 %) in the optimal ZVI/PMS/Cu2+ system, while only 58.2 % of RhB could be degraded in the ZVI/PMS system. The influence of reaction parameters on the degradation of RhB was further investigated. Quenching experiments and electron paramagnetic resonance (EPR) tests revealed that various reactive oxygen species could be generated in the ternary system, of which, 1O 2 and O 2 − were identified for the first time. The effect of various anions, NOM and different water matrix were also considered at different concentrations. A variety of byproducts and degradation pathways were identified using HPLC/MS/MS. Finally, the Quantitative Structure Activity Relationship (QSAR) method of Toxicity Estimation Software Tool (TEST) was applied to estimate the toxicity of the byproducts and the results indicated that the overall toxicity of the target was relatively reduced. This study demonstrated the potential for the removal of environmental reluctant pollutants in water via the combined radical and non-radical pathways. [ABSTRACT FROM AUTHOR]