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As reported, the persistent toxic and harmful pollutant bisphenol A (BPA) from industrial emissions has been consistently found in aquatic environments inhabited by humans. Periodate (PI)-based advanced oxidation processes (AOPs) have been employed to degrade BPA, although activating PI proves more challenging compared to other oxidants. A novel nano iron metal catalyst, sulfided nanoscale iron-nickel bimetallic nanoparticle supported on biocarbon (S-(nFe0-Ni)/BC) was synthesized and utilized to activate PI for the removal of BPA. The morphology, structure, and composition of S-(nFe0-Ni)/BC were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy dispersive spectrometer (SEM–EDS), and fourier-transform infrared spectrum (FTIR). The catalyst demonstrates an excellent ability to activate PI, achieving a BPA removal efficacy of 86.4%, accompanied by a 33% reduction in total organic carbon (TOC) in the {S-(nFe0-Ni)/BC}/PI system. BPA degradation exhibited a significant change at the 5-min mark. In the first stage (0–5 min), nonlinear dynamic fitting research, combined with scavenging experiments, unveiled the competitive degradation of pollutants primarily driven by iodate radical ( IO 3 · ), singlet oxygen 1 O 2 , and hydroxyl radical ( · OH ). The competitive dynamics aligned with the ExpAssoc model. The contribution rates of different active species during the second stage (5–120 min) were calculated. The contributions of main species to BPA removal follow the order of IO 3 · > 1 O 2 > · OH throughout the entire process. The influence of various parameters, such as the dosage of S-(nFe0-Ni)/BC, initial PI concentration, BPA concentration, pH, temperature, and the presence of coexisting anions, was also examined. Finally, a plausible reaction mechanism in the system is proposed, suggesting that the {S-(nFe0-Ni)/BC}/PI system involves a heterogeneous synergistic reaction occurring primarily on the surface of S-(nFe0-Ni)/BC. Therefore, this study proposes a promising approach for PI-based AOPs to degrade organic pollutants, aiming to mitigate the irreversible harm caused by such pollutants to organisms and the environment. [ABSTRACT FROM AUTHOR]

Owing to the easy over‐oxidation, it is a promising yet challenging task to explore renewable carbon resources to control the sunlight‐driven selective catalytic oxidation of biomass‐derived 5‐hydroxymethylfurfural (HMF), producing important chemical feedstocks, namely, less‐oxidized 2,5‐diformylfuran (DFF) and 5‐hydroxymethyl‐2‐furancarboxylic acid (HMFCA). Herein, we have developed a photocatalyst by anchoring a Ru complex on CdS quantum dots, which achieves selective oxidation of HMF toward DFF or HMFCA with high conversion (>81 %) and selectivity (>90 %), based on the controllable generation of two oxygen radicals under different atmospheres. Such selective conversion can also work well outside the laboratory by using natural sunlight. In particular, the selective production of HMFCA through photocatalytic HMF oxidation is achieved for the first time. More importantly, our photocatalyst is applicable for the selective oxidation of other compounds with hydroxyl and aldehyde groups. [ABSTRACT FROM AUTHOR]

This study presents a catalytic membrane based on cobalt-loaded carbon nanotubes and graphene oxide (Co@CNT-GO). Cobalt, serving as the active center, efficiently activates peroxymonosulfate for the degradation of organic compounds in transmembrane water. The uniform dispersion and firm loading of Co on CNT prevent the aggregation and leakage issues typically associated with conventional catalysts. The two-dimensional channels formed by the vacuum-assisted self-assembly of CNT and GO enhance the probability of contact between organic compounds and Co and prolong the contact duration thereby ensuring catalytic efficiency while maintaining a low water permeability resistance. The water flux of the catalytic membrane is 90 L/m2/h, and the atrazine removal efficiency is more than 92%, maintaining high stability even after continuous operation for 72 h. The generated active free radicals, including sulfate radicals, hydroxyl radicals, and singlet oxygen, synergistically facilitate the mineralization of organic compounds. Furthermore, the presence of oxygen vacancies on CNT accelerates the redox cycle of ≡ Co(II)/≡Co(III), sustaining the catalytically active center. Compared to the precursor catalytic membrane, Co@CNT-GO catalytic membrane possesses the characteristics of high removal efficiency and high flux, holding promise as a platform technology for the rapid and precise treatment of organic pollutants in contaminated water. [Display omitted] • Membranes are prepared via vacuum-assisted self-assembly of Co@CNT-GO. • Catalytic oxidation process occurs in 2D nanochannels filled with 1D nanotubes. • Co@CNT-GO membrane achieves almost 100% removal of ATZ within 175 ms. • Oxygen vacancies accelerate the redox cycle of ≡ Co(II)/≡Co(III). [ABSTRACT FROM AUTHOR]

In this study, the synergistic and antagonistic effects of Fe species and coexisting natural organic matter (NOM) on the efficacy of solar light disinfection of water are investigated. Different initial iron species (Fe2+/Fe3+) and naturalorganic matter types (Suwannee River-SRNOM, Nordic Reservoir NOM-NDNOM, SR Humic Acid-SRHA, and SR Fulvic Acid-SRFA) were selected. The bactericidal actions of Fe and NOM, alone or in conjunction, were evaluated at various initial iron dosing concentrations, NOM concentrations, irradiation intensities, and pH values. We show that when an appropriate iron (1 ppm Fe2+ or 0.25 ppm Fe3+) and NOM concentration (2 ppm SRNOM or 5 ppm NDNOM) coexisted, synergistic inactivation was observed in the pH range 5.0–8.0. A plausible explanation is that the presence of Fe+NOM significantly promoted the generation of hydroxyl radicals (•OH) and singlet oxygen (1O 2), which led to enhanced disinfection rates. These results elucidate the previously understudied effects of ubiquitous elements in natural waters and their impact on solar-mediated bacterial inactivation. [Display omitted] ● We analyzed the synergistic disinfection effects between Fe and NOM in sunlit waters. ● Various types of Fe and NOM reveal different synergistic capacity under varied pH. ● The coexistence of Fe and NOM in water enhances the Fe2+/Fe3+ cycling and PPRI production. ● 1O 2 is a key mediator of the bacterial inactivation under solar exposure. [ABSTRACT FROM AUTHOR]

Rapid self-decomposition and low reactivity to natural organic compounds with more unsaturated functional groups in alkaline water were the two critical parameters that restricted the practical application of Ferrate (VI). Herein, we reported a novel approach to reactivate the stabilized Fe (VI) for highly efficient membrane cleaning. The Fe (VI) stabilized by bicarbonate/carbonate (HCO 3 −/CO 3 2−) buffer was reactivated by calcium ions (Ca2+) to facilitate releasement of O 2 and generate high-valent iron species with subsequent hydroxyl radicals (•OH). The process was rationally utilized for removal of the membrane foulants, humic acid (HA) coupled with Ca2+, which exhibited excellent cleaning performance with membrane flux recovered from 67% to 98%. The outstanding removal performance of membrane foulants could be mainly attributed to the high-valent iron species and •OH, with their contribution rate ratio being about 7:3. Significantly, the proposed FeO 4 2− + HCO 3 −/CO 3 2− buffer + Ca2+ strategies paved a novel way for upgrading the Fe(VI) utilization pattern compared with Fe(VI) direct oxidation, which was expected to provide an effective option for Fe(VI)-based membrane cleaning in alkaline water. [Display omitted] • A novel cleaning strategy in alkaline condition using Fe (VI) was proposed. • The stabilized Fe (VI) was reactivated by Ca2+ to facilitate releasement of O 2. • Ca2+ could activate stabilized ferrate (VI) for effective membrane cleaning. • High-valent iron species and.•OH radicals were the reactive species for cleaning process. [ABSTRACT FROM AUTHOR]

Studying the ecological risks of antibiotics and their degradation products is of great importance to water environment security and advanced oxidation processes (AOPs) development. This work studied the changes and internal influencing mechanisms of ecotoxicity and the capacity for inducing antibiotic resistance genes (ARGs) shown by the tetracycline (TC) degradation products generated in AOPs with differential free radicals. Under the action of superoxide radicals and singlet oxygen in the ozone system, and sulfate and hydroxyl radicals in the thermally activated potassium persulfate system, TC exhibited differential degradation pathways and resulted in the differential growth inhibition trends on the determined strains. Microcosm experiments combined with metagenomics were also performed to analyze the remarkable changes in the TC resistance genes tetA (60), tetT , and otr (B) induced by the degradation products and ARG hosts in the natural water environment. Microcosm experiments exhibited that the microbial community in actual water have changed significantly with the addition of TC and degradation intermediates. Furthermore, the richness of genes related to oxidative stress was investigated to discuss the effect on reactive oxygen species production and SOS response caused by TC and its intermediates. • ARGs induction testing and hosts analysis usingmicrocosm experiment combined with metagenomic methods. • Tetracycline was degraded by active oxidizing species domination. • The ecological risks of tetracycline intermediates changed with the different degradation mechanisms. [ABSTRACT FROM AUTHOR]

Natural organic matter humic acid (HA) coupled with the inorganic metal oxides FeO x + MnO x will cause severe irreversible membrane fouling. Chemical cleaning is indispensable for the removal of irreversible membrane foulants and sustainable membrane filtration, while conventional cleaning methods have limitations with low cleaning efficiency, high reagents consumption and potential membrane damage. For the first time, calcium peroxide (CaO 2), a solid alternative for liquid hydrogen peroxide (H 2 O 2), is proposed for the membrane cleaning. For membranes fouled by HA, it is noteworthy that 40 mg/32.15 cm2 CaO 2 tablet without any other catalyst can restore the terminal membrane flux dramatically from 51% to 82% in only 5 min, which is far more than 3 wt% H 2 O 2 alone (only from 51% to 59%). Moreover, Fenton-like reaction induced by in-situ membrane foulants FeO x + MnO x further enhances the membrane flux from 53% to 97%. Based on HA oxidation tests and reactive species identification in CaO 2 tablets cleaning process for the case of HA-fouled membranes and HA + FeO x + MnO x -fouled membranes, singlet oxygen ( O 2 1) in CaO 2 system dominated the strong oxidation of electron-rich compounds HA, which plays a key role in membrane flux recovery. With involvement of FeO x + MnO x , signal intensities of free radicals such as hydroxyl radicals (O H •) are enhanced greatly, which further achieves more outstanding membrane cleaning performance. These results underline that the novel CaO 2 system provides a promising candidate for more portable and cost-effective membrane cleaning method in a nonradical pathway. [Display omitted] • A novel non-radical cleaning strategy using CaO 2 was proposed. • CaO 2 system achieves outstanding flux recovery from irreversible foulants. • Singlet oxygen was identified as the dominated reactive species for cleaning process. • Membrane foulants, FeO x and MnO x , could further increase permeate flux recovery. [ABSTRACT FROM AUTHOR]

Developing high-efficiency catalysts for peroxymonosulfate (PMS)-based advanced oxidation processes is important for eliminating pollutants in water. Herein, α-MnO 2 with major exposed {110} and {100} facets prepared via a hydrothermal method were used as catalysts to activate PMS for the degradation of Orange Ⅰ (OⅠ). α-MnO 2 -100, with more abundant surface hydroxyl groups and greater reductive ability, performed remarkably better than α-MnO 2 -110 for degrading OⅠ. OⅠ removal of 86.20% was obtained in the α-MnO 2 -100/PMS system. The apparent rate constant of OⅠ removal over α-MnO 2 -100 was 2.11 times higher than that of α-MnO 2 -110. The effects of PMS concentration, catalyst dosage, OⅠ concentration, initial pH, anions and humic acid (HA) on OⅠ degradation in the α-MnO 2 -100/PMS system were systematically investigated. Quenching experiments and electron paramagnetic resonance (EPR) demonstrated that SO 4 •−, •OH, O 2 •− and 1O 2 were the reactive oxygen species (ROS) in the α-MnO 2 -100/PMS system. Moreover, the possible degradation pathway of OⅠ in the α-MnO 2 -100/PMS system was proposed. This work provides an ideal metal oxide catalyst for sewage remediation. • α-MnO 2 with major exposed {110} and {100} facets were prepared, respectively. • α-MnO 2 -100 exhibited excellent activity to activate PMS to remove Orange Ⅰ. • Surface hydroxyl groups played an important role in the α-MnO 2 /PMS system. [ABSTRACT FROM AUTHOR]

[Display omitted] • NaOH showed dramatical enhancement for ACE elimination in heat/PMS system. • 1O 2 and •OH were the primary reactive oxygen species responsible for ACE degradation. • 1O 2 and •OH separately came from base-activated PMS and thermolysis of peroxide bond. • Chloride ion significantly accelerated ACE removal in NaOH-enhanced heat/PMS system. • Heat/PMS system had better performance than heat/PDS system under alkaline conditions. Owing to the high peroxide bond dissociation energy (377 kJ mol−1), peroxymonosulfate (PMS) is rather difficult to be activated by heat for degrading organic pollutants. This work is the first to add sodium hydroxide (NaOH) to enhance the elimination of acetaminophen in heat/PMS system. Heat/PMS system even possessed a better Performance than heat/peroxydisulfate (PDS) system with the addition of NaOH. Quenching experiments and electron paramagnetic resonance tests demonstrated that singlet oxygen and hydroxyl radical were the primary reactive oxygen species responsible for acetaminophen elimination in NaOH-enhanced heat/PMS system. Singlet oxygen mainly came from the alkaline activation of PMS, while hydroxyl radical was generated from the thermolysis of peroxide bond. Increasing PMS concentration and reaction temperature favored the production of reactive oxygen species and the elimination of acetaminophen. Nine degradation intermediates of acetaminophen were identified by LC/TOF/MS and the corresponding degradation pathways were proposed. Chloride ion significantly accelerated the elimination of acetaminophen, while humic acid and carbonate ion slightly retarded acetaminophen removal. NaOH-enhanced heat/PMS system was highly efficient in eliminating many organic pollutants and more prone to degrading electron-rich organics. This study developed a simple and efficient approach to strengthening the oxidation capacity of heat-activated PMS and highlighted the superiority of PMS to PDS in thermolysis under alkaline conditions. [ABSTRACT FROM AUTHOR]

• AgFe 1− x Ni x O 2 with rich oxygen vacancy enhance PMS decomposition and BPA removal. • O 2 − and 1O 2 work as the main ROSs, rather than traditional SO 4 − or OH. • The adsorbed PMS molecules preferentially dissociate into O 2. • Superior surface oxygen mobility and electronic conductivity raise O 2 − and 1O 2 yield. • A synergy among Mn+/M(n+1)+, V O · · / O O × and O2−/O 2 ensures continuous ROSs generation. Oxygen vacancies (OVs) modulation has emerged as a prevalent strategy to optimize the performance of Fenton-like catalysts. Nevertheless, the OVs-induced evolution of reactive oxygen species (ROSs) and associated mechanisms in the Fenton-like process remain insufficient. Herein, a series of oxygen-defective AgFe 1− x Ni x O 2 were synthesized to enhance peroxymonosulfate (PMS) decomposition and efficient degradation of bisphenol A (BPA) in water. The total amounts of OVs were regulated by varying the ratio of Ni dopant. Compared with original AgFeO 2 , the AgFe 1− x Ni x O 2 with rich OVs exhibited a better redox potential for PMS interaction and a lower reaction energy barrier of PMS decomposition. Superoxide radical (O 2 −) and singlet oxygen (1O 2) worked as the dominant ROSs during the oxidation, rather than traditional sulfate radical (SO 4 −) or hydroxyl radical (OH). Notably, in situ electron spin resonance witnessed the evolution of growing O 2 − and 1O 2 , as well as lessened SO 4 − and OH with increasing OVs content. It was mainly attributed to the preferential dissociation of PMS into O 2 on the OVs, additionally, OVs facilitated the superior surface oxygen mobility and electrical conductivity, which also gave rise to a significant enhancement in O 2 − and 1O 2 generation. Consequently, an OVs-dependent PMS activation mechanism was proposed. [ABSTRACT FROM AUTHOR]