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In this study, cobalt molybdate (CoMoO 4) activated peracetic acid (PAA) was developed for water purification. CoMoO 4 /PAA system could remove 95% SMX with pseudo-first-order reaction rate constant of 0.15410 min−1, which was much higher than CoFe 2 O 4 /PAA, FeMoO 4 /PAA, and CoMoO 4 /persulfate systems. CoMoO 4 /PAA system follows a non-radical species pathway dominated by the high-valent cobalt (Co(IV)), and CH 3 C(O)OO• shows a minor contribution to decontamination. Density functional theory (DFT) calculation indicates that the generation of Co(IV) is thermodynamically more favorable than CH 3 C(O)OO• generation. The abundant Co(IV) generation was attributed to the special structure of CoMoO 4 and effect of molybdenum on redox cycle of Co(II)/Co(III). DFT calculation showed that the atoms of SMX with higher ƒ0 and ƒ- values are the main attack sites, which are in accordance with the results of degradation byproducts. CoMoO 4 /PAA system can effectively reduce biological toxicity after the reaction. Benefiting from the selective of Co(IV) and CH 3 C(O)OO•, the established CoMoO 4 /PAA system exhibits excellent anti-interference capacity and satisfactory decontamination performance under actual water conditions. Furthermore, the system was capable of good potential practical application for efficient removal of various organics and favorable reuse. Overall, this study provides a new strategy by CoMoO 4 activated PAA for decontamination with high efficiency, high selectivity and favorable anti-interference. [Display omitted] • Synergic effect of Co and Mo in cobalt molybdate enhances PAA activation. • High-valent cobalt was identified as the main active species for decontamination. • Special structure and Mo for Co redox cycle cause abundant Co(IV) generation. • Degradation pathways were proposed and biological toxicity was reduced. • Excellent anti-interference and various pollutant removal efficiency were exhibited. [ABSTRACT FROM AUTHOR]

In this study, we demonstrate that Fe(III)-doped g-C 3 N 4 can efficiently activate peracetic acid (PAA) to degrade electron-rich pollutants (e.g., sulfamethoxazole, SMX) over a wide pH range (3−7). Almost ∼100% high-valent iron-oxo species (Fe(V)) was generated and acted as the dominant reactive species responsible for the micropollutants oxidation based on the analysis result of quenching experiments, 18O isotope-labeling examination and methyl phenyl sulfoxide (PMSO) probe method. Electrochemical testing (e.g., amperometric i−t and linear sweep voltammetry (LSV)) and density functional theory (DFT) calculations illustrated that the main active site Fe atom and PAA underwent electron transfer to form Fe(V) for attacking SMX. Linear free energy relationship (LFER) between the pseudo-first-order rates of different substituted phenols (SPs) and the Hammett constant σ+ depicted the electrophilic oxidation properties. The selective oxidation of Fe(V) endows the established system remarkable anti-interference capacity against water matrices, while the Fe(V) lead to the formation of iodinated disinfection by-products (I-DBPs) in the presence of I−. Fe(III)-doped g-C 3 N 4 /PAA system showed excellent degradation efficiency of aquaculture antibiotics. This study enriches the knowledge and research of high-valent iron-oxo species and provides a novel perspective for the activation of PAA via heterogeneous iron-based catalysts and practical environmental applications. [Display omitted] • Nearly 100% Fe(V) was generated in Fe(III)-doped g-C 3 N 4 /PAA process. • A favorable SMX removal was observed over a wide pH range (3−7). • An outstanding anti-interference was exhibited in Fe(III)-doped g-C 3 N 4 /PAA process. • Iodinated disinfection byproducts (I-DBPs) was formed during Fe(III)-doped g-C 3 N 4 /PAA/I− process. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The new multifunctional UF membrane with ultrahigh MOF loading of 67% was prepared. • The new membrane showed much better efficiency for MB removal comparatively. • Acceptable ultrafiltration and permeability performance of the new membrane was kept. • The relationship and contribution of adsorption & catalytic oxidation were clarified. • The mechanism of decontamination, ultrafiltration and permeability was proposed. Abstract Multifunctional ultrafiltration membranes need to be further developed with ultrafiltration performance and high multifunctional decontamination efficiency. Here, the MIL-PVDF multifunctional ultrafiltration membrane with ultrahigh MIL loading was demonstrated by a new blending method of predispersion in acetone and thermally induced phase separation. Due to the improved dispersity and restriction of pore size, the MIL-53(Fe) mass loading was as high as approximately 61%. The new membrane showed high performance for methylene blue (MB) removal and maintained high permeability and ultrafiltration efficiency. The characteristics of the membranes were analyzed to explain the above advantages. Meanwhile, compared to the traditional blend ultrafiltration membrane, the 67-MIL-PVDF membrane showed an 9-fold increase in effective treatment volume for more than 75% MB removal. The contribution and efficiency of adsorption and catalytic oxidation were analyzed and explained. The relationship between them was confirmed as being independent, and the reasons for this independence were proposed. Additionally, the mechanism of multifunctional decontamination and permeability by MIL-PVDF membranes was proposed. Moreover, the 67-MIL-PVDF membrane was also suitable for long-term run and real wastewaters treatment. In conclusion, this study sheds new light on the preparation strategy for multifunctional blend ultrafiltration membranes with ultrahigh particles loading displaying high decontamination and permeability performance. [ABSTRACT FROM AUTHOR]

Annular iron sheet (AIS), playing a dual role of anode electrode and source of activator, was combined with electrolysis technology for the activation of persulfate to improve the degradation of 2, 4-dinitrophenol (DNP) in aqueous solution. In this study, effects of current density (0–10.0 mA/cm 2 ), persulfate (PS) dosage (0–8.0 mM), initial pH (3.0–11.0), reaction temperature (25–60 °C) and reaction time (0–30 min) on COD removal of DNP in aqueous solution were investigated, respectively. COD removal reached its maximal value (63.4%) after 15 min treatment due to the synergistic effect in electro/AIS/PS system under the optimal conditions. Furthermore, comparative studies of 7 different experimental processes were setup. In addition, the reasonable DNP degradation pathway was proposed based on intermediates detected by HPLC. According to characterization analysis of SEM-EDS, XRD and XPS of the generated flocculation in electro/AIS/PS system, the possible reaction mechanism was proposed in detail. In a word, the electrolysis process coupled with annular iron sheet as anode activating persulfate technology shows a significant synergetic effect in enhancing degradation of DNP in aqueous solution. [ABSTRACT FROM AUTHOR]

To decompose or transform the toxic and refractory reverse osmosis (RO) concentrate and improve the biodegradability, 1stFe/Cu/air-Fenton-2ndFe/Cu/air were developed to treat RO concentrate obtained from an amino acid production plant in northern China. First, their operating conditions were optimized thoroughly. Furthermore, 5 control experiments were setup to confirm the superiority of 1stFe/Cu/air-Fenton-2ndFe/Cu/air and synergistic reaction between Fe/Cu/air and Fenton. The results suggest that the developed method could obtain high COD removal (65.1%) and BOD 5 /COD ratio (0.26) due to the synergistic reaction between Fe/Cu/air and Fenton. Under the optimal conditions, the influent and effluent of 1stFe/Cu/air-Fenton-2ndFe/Cu/air and 5 control experiments were analyzed by using UV, FTIR, EEM and LC, which confirm the superiority of 1stFe/Cu/air-Fenton-2ndFe/Cu/air. Therefore, the developed method in this study is a promising process for treatment of RO concentrate. [ABSTRACT FROM AUTHOR]

• A dual-layer membrane was used for performance enhancement of Fenton-like oxidation. • Sequential decontamination was achieved by a UF layer above a catalysis layer. • BPS and macromolecular substances removal were enhanced in multicomponent wastewater. • The enhancement mechanisms by sequential interception-oxidation were proposed. Fenton-like oxidation for multicomponent wastewater treatment suffers from a low efficiency due to non-selective nature of produced reactive species. In this study, a multifunctional dual-layer ultrafiltration membrane (Seq-ICM) was synthesized for multiple pollutants decontamination. Characterizations of the membranes indicate that Seq-ICM comprises a skin layer for ultrafiltration, and a porous support layer loaded with ∼50% MIL-53(Fe) for catalysis. With bovine serum albumin coexisting, Seq-ICM can remove 75.7% bisphenol S (BPS), which is much higher than that of a simultaneous interception-catalysis membrane (44.2 %). For multicomponent wastewater treatment, Seq-ICM system can save ∼59%-67% oxidant dosage as well compared with catalysis alone membrane system to achieve 50% BPS removal. Furthermore, the decontamination mechanisms were investigated to explain the advantages of Seq-ICM. Sequential interception and oxidation process by Seq-ICM leads to the interception of macromolecular substances first, following by catalytic oxidation of low-molecular-weight organics. This process prevents macromolecular substances from competing for active species with low-molecular-weight organics, thereby enhancing selectivity and oxidation efficiency. Meanwhile, Seq-ICM shows satisfactory BPS removal efficiency for treatment of 2865 L/m2 synthetic solution, as well as in real wastewater matrix. We believe the proposed technology based on a composite membrane is promising for the removal of multicomponent substances from wastewater. [ABSTRACT FROM AUTHOR]

Both adsorption and oxidation occur and contribute to organics removal in carbonaceous materials based advanced oxidation processes, while the correction of adsorption and oxidation, and the role of adsorption in the veritable removal of organic are not clear. Herein, we investigated the performance of carbamazepine (CBZ) removal by peroxymonosulfate (PMS) activated by magnetic Fe-doped biochar through two models of pre-adsorption oxidation and synchronous adsorption oxidation processes. The adsorption process was better fitted by pseudo-second-order kinetic model and the adsorption mechanism was obtained by comprehensive analysis of equilibrium adsorption capacities, surface functional groups, specific surface area, pore volume, and I D /I G value. It is noted that pre-adsorption highly inhibited the further oxidation of CBZ in 0.5Fe@LSBC700/PMS system due to the occupied catalytic active sites. Total CBZ removal in pre-adsorption oxidation (45 %) was inferior to synchronous adsorption oxidation (∼100 %), as well as the veritable CBZ oxidation removal of 27 % for pre-adsorption oxidation vs ∼100 % in synchronous adsorption oxidation at 30 min. Oxidation degradation of CBZ based on radical oxidation was identified by quenching experiments and electron paramagnetic resonance measurements. This work is conducive to identifying the role of adsorption during the removal of organics in the adsorption-oxidation process, as well as veritable adsorption and oxidation removal of organics. [Display omitted] • Adsorption behavior of CBZ on xFe@LSBCy materials was a chemical adsorption process. • Pre-adsorption process inhibited the performance of further catalytic oxidation processes. • CBZ removal in pre-adsorption oxidation was inferior to synchronous adsorption oxidation. • Radicals dominated both pre-adsorption oxidation and synchronous adsorption oxidation processes. [ABSTRACT FROM AUTHOR]

• A novel designed PVA/Cu-iMOFs/PVDF UF membrane is prepared successfully. • Cu-iMOFs particles immobilized on PVDF membrane surface is reinforced by amido bonds. • Membrane exhibits outstanding selectivity and reusability toward ClO 4 − trapping. • Membrane shows excellent permeability and stability in cross-flow filtration. • The mechanism is specific exchange between R-SO 3 group and tetrahedral oxo-anion. We design a novel cationic metal-organic framework hybrid ultrafiltration polyvinylidene fluoride membrane (PVA/Cu-iMOFs/PVDF-0.05) and report its unique capture of aqueous perchlorate (ClO 4 −) at ppm-level. This membrane outperformed traditional adsorption materials and exhibited a specific affinity toward ClO 4 − in the presence of various competing anions at greater levels (up to a concentration ratio of 20). In the batch experiment, the ClO 4 − removal ratio reached 99.6% over a wide pH range (3˜10). Membrane filtration by using a 12.56 cm2 PVA/Cu-iMOFs/PVDF-0.05 membrane could effectively treat 4.71 L of ClO 4 −-contaminated water before breakthrough occurred, while maintaining a satisfactory permeability (˜627.32 L/(m2 h bar)) and antifouling property. The exhausted membrane could easily be regenerated in aminoethanesulfonic acid solution for repeated use with a negligible decrease in capacity. Moreover, the membrane showed excellent long-term stability in a cross-flow filtration process due to the amido bond between the Cu-iMOFs and membrane surface as well as the "protection" of polyvinyl alcohol. Selective and reversible ion-exchange between the sulfonic acid (R-SO 3) ligands of Cu-iMOFs and tetrahedral oxo-anionic species was verified to be the pathway for ClO 4 − trapping. Thus, other problematic elements that also occur in tetrahedral form in water can be removed by this method. [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]

Effective treatment of industrial wastewater containing complex pollutants, such as nitrate (NO 3 --N) and organic pollutants, remains a significant challenge to date. Here, a strain Nocardioides sp. ZS2 with denitrification and degradation of p -nitrophenol (PNP) was isolated and its culture conditions were optimized by kinetic analysis. Hydrophilic sponge carriers were prepared using polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), and chitosan (CS) to construct bioreactors. Furthermore, to further enhance the PNP degradation and denitrification performance of bioreactors, Pseudomonas stutzeri GF2 with denitrification capability was introduced. The results revealed that the removal efficiencies of PNP and NO 3 --N reached 97.9 % and 91.9 %, respectively, when hydraulic retention time (HRT) of 6 h, C/N of 2.0, and pH of 6.5. The bioreactor exhibited stable denitrification performance even with fluctuations in the influent PNP concentration. The potential functional prediction results revealed that the abundance of amino acids, fatty acids, and carbohydrates increased as the influent C/N decreased, reflecting a tendency of the microbial community to adjust carbon source utilization to maintain cell growth, metabolic balance, and resist adverse C/N environments. This research provides new insights into the effective removal of organic pollutants and NO 3 --N in wastewater treatment. [Display omitted] • A novel Nocardioides sp. ZS2 with the ability to remove PNP and NO 3 --N was isolated. • PNP degradation by-products alleviate NO 2 --N accumulation in denitrification process. • A novel hydrophilic sponge biocarrier was prepared by hydroxyaldol reaction. • Dual bacterial collaboration enhanced the removal efficiencies of NO 3 --N and PNP. • The increase in PNP concentration promoted substance transport and metabolism. [ABSTRACT FROM AUTHOR]

In this work, a g-C 3 N 4 supported NiCx nanoclusters catalyst (NiCx-CN) was developed, and its performance in activating peroxymonosulfate (PMS) was evaluated. Mechanism investigation stated that although singlet oxygen (1O 2) was formed in the catalytic process, its contribution to BPA elimination was weeny. Interestingly, through the experiment with dimethyl sulfoxide as the probe, it was considered that the high-valent nickel-oxo species (Ni&+=O), generated after the interaction of NiCx-CN and PMS, was the dominating reactive oxygen species (ROS). Theoretical calculations (DFT) implied that NiCx-CN might lose electrons to generate high-valent Ni, which was consistent with the detection of Ni3+ on the surface of the used NiCx-CN. Besides, the prepared NiCx-CN showed advantages in resisting the interference of inorganic anions. Meanwhile, three BPA degradation routes had been proposed based on the transformation intermediates. This study will establish a new protocol for PMS activation using heterogeneous Ni-based catalysts to efficiently degrade organic pollutants via a nonradical mechanism. [Display omitted] • A g-C3N4 supported NiCx nanocluster catalyst was prepared by one-step pyrolysis. • The PMSO probe method was extended to the exploration of high-valent Ni&+ =O. • High-valent Ni&+ =O and 1O2 are the main ROS in the NiCx-CN/PMS system. • The formation mechanism of high-valent Ni&+ =O was obtained by DFT calculations. • A reasonable PMS activation mechanism was put forward. [ABSTRACT FROM AUTHOR]