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[Display omitted] • It was firstly demonstrated that the synergistic activation of PMS by MoS 2 @PANI and Cu(II). • High removal rate of sulfathiazole (≥85 %) achieved within a wide range of pH (3–10) in Cu(II)/MoS 2 @PANI/PMS. • H O ∙ , Cu(Ⅲ) and 1 O 2 were generated in Cu(II)/MoS 2 @PANI/PMS, while SO 4 ∙ - was negligible. • Compared with Fe(II), Cu(II) improved reusability and applicability of MoS 2 @PANI in activation of PMS. • The absorption of Cu(II) on MoS 2 @PANI improved the stability of MoS 2 @PANI. This paper synergistically combined MoS 2 @PANI (coating MoS 2 on polyaniline (PANI)) with Cu(II) to obtain effective activation of PMS in a wide range of pH (3–10). The removal rate of sulfathiazole (ST) in Cu(II)/MoS 2 @PANI/PMS (98 %) in 60 min was higher than in Cu(II)/PMS (50 %) and MoS 2 @PANI/PMS (70 %). Besides, the PMS consumption rate was 100 % within 30 min in Cu(II)/MoS 2 @PANI/PMS. Different concentrations of Cl - and HCO 3 - promoted the degradation of ST in varying degrees. And NO 3 - slightly inhibited the degradation of ST (removal rate more than 84 %). Notably, Cu(II)/MoS 2 @PANI/PMS could remove more than 80 % ST in different water bodies. The special structure of MoS 2 @PANI increased many activity sites of Mo(IV) to promote the cycle of Cu(II)/Cu(I) for activating PMS which generated H O ∙ , Cu(III) and 1 O 2. Twenty-seven degradation intermediates were identified and four possible degradation paths of ST were proposed. Moreover, Cu(II)/MoS 2 @PANI/PMS possessed a good non-selectivity for various organic pollutants. After three consecutive cycles, the removal rate still retained more than 90 % in Cu(II)/MoS 2 @PANI/PMS system. Compared with Fe(II), MoS 2 @PANI was more stable in Cu(II)/MoS 2 @PANI/PMS. The synergy of Cu and Mo broke the limitation of PMS activation under environmental aquatic conditions. Given that Cu(II) widely existed in wastewater, the new research strategy increased the application scope for homogeneous PMS activation with inherently Cu(II) in wastewater in environmental remediation. [ABSTRACT FROM AUTHOR]

This work successfully synthesized magnetic FeWO 4 /Cu 2 S through a facile method with efficient peroxymonosulfate (PMS) activation to eliminate sulfachloropyridazine (SCP) in water, in which 97.56% of SCP was removed in 30 min with activating only 0.2 mM PMS. Factors such as calcination temperature, the addition amount of WS 2 in FeWO 4 /Cu 2 S, molar ratio of Cu/Fe in FeWO 4 /Cu 2 S, catalyst dosage, solution pH, inorganic anions and natural organic matters（NOM）were investigated. It was found that in FeWO 4 /Cu 2 S at 1:2 possessed the best catalytic performance for PMS. FeWO 4 /Cu 2 S performed well in a wide pH range (3–9) and the effect was better under acidic conditions. A high catalyst dosage could supply more catalytic active sites for PMS activation and encourage the production of reactive oxygen species. Anions (HCO 3 −and HPO 4 2−) and NOM significantly inhibited SCP degradation, whereas Cl− had only a tiny inhibitory impact. In addition, H 2 PO 4 − and NO 3 − demonstrated duality in the degradation of SCP. The oxidation process was dominated by non free radical oxidation by 1O 2 rather than free radicals oxidation by HO⋅ and SO 4 •−. Three SCP degradation pathways—SO 2 extrusion, S-N bond cleavage and hydroxylation were proposed according to intermediate products analysis. The mechanism was found that the introduction of W improved the dual metals cycles of Fe3+/Fe2+ and Cu+/Cu2+ which could efficiently promote PMS activation. In addition, the magnetic FeWO 4 /Cu 2 S was easy to separate after reaction, which had great application potential in the water treatment. [Display omitted] • PMS could be activated at a rapid rate in the FeWO 4 /Cu 2 S-3/PMS system. • The involvement of Fe2+-Fe3+ and Cu2+-Cu+ redox cycles during PMS activation process. • Radical and non-radical pathways were participated in SCP degradation. • SCP could be removed almost completely with activating only 0.2 mM PMS in 30 min. [ABSTRACT FROM AUTHOR]

UV/persulfate (UV/PS) has been as an efficient method to remove many organic contaminants in water. However, little is known about the impact of UV/PS pretrement on the formation of disinfection byproducts (DBPs) during chlorination of 2,4-Di-tert-butylphenol (2,4-D). This research evaluated that UV/PS preoxidation of 2,4-D greatly decreased the DBPs generation during following chlorination. In the 2,4-D solution without any treatment system (O system), trichloromethane (TCM) as the only detected DBP increased with the increase of chlorine dosage. While the formation of TCM declined with the increase of PS dosage in the PS and UV/PS preoxidation systems and decreased the estimated toxicity accordingly. And it was found the residual PS in system could combine free chlorine to further oxidize 2,4-D. And intermediate products were analysed by high-performance liquid chromatography combined with triple quadrupole mass spectroscopy analysis. In the presence of bromine, the bromodichloromethane augmented first and then slowly decreased while dibromochloromethane and tribromethane increased both in O and UV/PS systems with the increase of [Br − ]. Bromine substitution was decreased by preoxidation of UV/PS. UV/PS could decrease the total-DBPs formation when used in the real water matrix contained 100 μg/L 2,4-D. [ABSTRACT FROM AUTHOR]

Al 2 O 3 -based CoFe 2 O 4 (CoFe 2 O 4 /Al 2 O 3 ) as a catalyst was prepared to activate peroxymonosulfate (PMS) for degradation of sulfachloropyridazine (SCP). In general, the catalytic performance of CoFe 2 O 4 /Al 2 O 3 in activation PMS was demonstrated more effective than CoFe 2 O 4 . Several influence factors were inspected, including scavengers, PMS concentration, pH, anions, nature organic matter (NOM) and temperature. The oxidation of SCP fitted a pseudo-first-order kinetics model and was efficient with the pH from 5.00 to 8.00. The influence of scavengers demonstrated that SO 4 - · played a more significant role than HO · in the oxidation process. The removal was strongly inhibited by adding NOM or HCO 3 - , and almost unaffected by adding NO 3 - , while chloride could enhance the degradation in the system. The increasing temperature greatly promoted the degradation of SCP. After four recycles, CoFe 2 O 4 /Al 2 O 3 still showed preferable catalytic performance with 97.6% removal rate of SCP. Furthermore, the degradation mechanism was explored based on the XPS results. In the composit of CoFe 2 O 4 /Al 2 O 3 , Al 2 O 3 had no additional catalytic performance but just as a matrix base. [ABSTRACT FROM AUTHOR]

[Display omitted] • The MoS 2 @PANI/PMS with trace Fe(II) system degraded nearly 100 % of TAP in 15 min. • The cycle of Fe(III)/Fe(II) was greatly accelerated by MoS 2 @PANI. • The degradation of TAP was effective in a wide pH range of 3 to 9. • SO 4 · - , H O · , O 2 · - and 1O 2 were identified in the Fe(II)/MoS 2 @PANI/PMS system. • Possible degradation pathways and product toxicity of TAP were proposed. Fe(II) displayed a great potential in peroxymonosulfate (PMS) activation to remove pollutants but was limited by the cycle of Fe(III)/Fe(II) in the process. To solve this problem, different percentages of flower-like MoS 2 nanosheets were successfully coated on the surface of polyaniline (PANI) nanotubes named as MoS 2 @PANI-X(1, 2, 3) activating PMS efficiently with trace Fe(II) to remove thiamphenicol (TAP), in which MoS 2 @PANI-2 with 92.6% of MoS 2 was the best by removing 99% TAP within 15 min. Notably, the used trace Fe(II) concentration (2 μM) was environmentally friendly because it was far lower than the allowable limit (0.3 mg/L) in standard for drinking water by WHO. With the increase of PMS concentration (0.1–2.0 mM), k PMS increased from 0.083 to 0.118 min−1 and then decreased to 0.098 min−1.When MoS 2 @PANI-2 dosage increased from 10 to 50 mg/L, k M o S 2 @ P A N I - 2 increased from 0.068 to 0.558 min−1. However, N O 3 - , C l - , H P O 4 2 - , H C O 3 - , H 2 P O 4 - and natural organic matter inhibited the degradation of TAP in varying degrees. The special structure of MoS 2 @PANI increased many activity sites of Mo(IV) to promote the cycle of Fe(III)/Fe(II) for sustainable and effective activating PMS which generated SO 4 · - , H O · , O 2 · - and 1O 2 to achieve high removal rate of TAP in a wide range of pH (3–9) (>93%). Twenty-two degradation intermediates were identified and three possible degradation paths of TAP were proposed. Overall, this study provided a novel strategy to remove antibiotics by overcoming the limiting cycle of Fe(III)/Fe(II) in the peroxymonosulfate activation process, which had a great application in water treatment. [ABSTRACT FROM AUTHOR]

In this study, the degradation performance of 2,4-Di-tert-butylphenol (2,4-D) by the ultraviolet/persulfate (UV/PS) process was evaluated for the first time. To better understand the possible degradation mechanism in the UV/PS advance oxidation process system, a kinetic model involved hydroxyl and sulfate radicals was developed for predicting pseudo-first order rate constants (k o ) and radical contributions. The results showed that the degradation of 2,4-D was promoted by increasing dosages of PS. H 2 PO 4 - almost had no significant impact on the degradation of 2,4-D, whereas the removal of 2,4-D was suppressed when NO 3 - dosage was added up to 50 mM. HCO 3 - , HPO 4 2 - and natural organic matter significantly inhibited the degradation of 2,4-D. The reaction rate constants between SO 4 - and 2,4-D were not affected by pH. However, the degradation was suppressed with the increasing pH due to the increasing HPO 4 2 - from the phosphate buffer in alkaline. The degradation of 2,4-D was promoted by adding Cl − . The proposed degradation pathways were elucidated on the basis of results obtained by high-performance liquid chromatography combined with triple quadrupole mass spectroscopy analysis. [ABSTRACT FROM AUTHOR]

• MgO wrapped CoO nanoparticles in bimetallic oxides and limited cobalt ion leaching. • Optimal Co/Mg molar ratio was found in bimetallic oxides for degradation of BPA. • Activation mechanism of PMS and degradation pathways of BPA were proposed. Cobalt oxide (CoO) could activate peroxymonosulfate (PMS) to remove pollutants but the catalytic performance was restricted by limited active sites and it was with risk of harmful cobalt ion leaching. In order to solve these problems, bimetallic oxides with package structure were researched by dispersing CoO nanoparticles on a stable support (magnesium oxide, MgO) via simple one-step coprecipitation method. Co-Mg bimetallic oxides with minute quantities of CoO and highly dispersed structure could efficiently activate PMS for degradation of bisphenol A (BPA). The catalytic properties of catalysts with different molar ratios of Co and Mg were evaluated. The optimal molar ratio (0.075:15) of Co and Mg was found in the Co-Mg bimetallic oxides, which could maximize its catalytic performance for PMS in a wide pH range. Influences of different systems, catalyst dosages, PMS concentrations, temperatures, initial pH values and mineralization rates were researched for BPA degradation. And the oxidation capacities to remove BPA in the different aqueous matrices were evaluated for the catalyst/PMS system. The addition of anions and nature organic matter (NOM) showed that there existed positive ( C l - and H 2 P O 4 -) and negative ( N O 3 - , H C O 3 - , H P O 4 2 - and NOM) effects for BPA degradation. Additionally, main reactive radicals were certified by quenching experiments. Four successive experiments and evaluation of concentration of cobalt ion leaching illustrated good stability of the catalyst, which was related with its package structure. Finally, activation mechanism of PMS, proposed degradation pathways of BPA and acute toxicity of degradation intermediates of BPA were analyzed. [ABSTRACT FROM AUTHOR]

In this work, the degradation performance of Fe2+/PAA/H2O2 on three typical pollutants (reactive black 5, ANL, and PVA) in textile wastewater was investigated in comparison with Fe2+/H2O2. Therein, Fe2+/PAA/H2O2 had a high removal on RB5 (99%) mainly owing to the contribution of peroxyl radicals and/or Fe(IV). Fe2+/H2O2 showed a relatively high removal on PVA (28%) mainly resulting from ·OH. Fe2+/PAA/H2O2 and Fe2+/H2O2 showed comparative removals on ANL. Additionally, Fe2+/PAA/H2O2 was more sensitive to pH than Fe2+/H2O2. The coexisting anions (20–2000 mg/L) showed inhibition on their removals and followed an order of HCO3− > SO42− > Cl−. Humic acid (5 and 10 mg C/L) posed notable inhibition on their removals following an order of reactive black 5 (RB5) > ANL > PVA. In practical wastewater effluent, PVA removal was dramatically inhibited by 88%. Bioluminescent bacteria test results suggested that the toxicity of Fe2+/PAA/H2O2 treated systems was lower than that of Fe2+/H2O2. RB5 degradation had three possible pathways with the proposed mechanisms of hydroxylation, dehydrogenation, and demethylation. The results may favor the performance evaluation of Fe2+/PAA/H2O2 in the advanced treatment of textile wastewater. [ABSTRACT FROM AUTHOR]

• The DBPs formation by chlorination of alachlor was measured for the first time. • The ZVI/PS preoxidation was considered in DBPs formation for the first time. • The formation of DBPs was compared after different preoxidations. • The toxicity of formed DBPs was estimated. The occurrence of alachlor in natural drinking water sources raises concerns due to adverse health effects. Advanced oxidation with zero valent iron activating persulfate (ZVI/PS) can degrade alachlor with great potential. But no information was reported about effect of ZVI/PS preoxidation on the generation of disinfection byproducts (DBPs) during the downstream chlorination of alachlor. The objective was to investigate DBP formation through chlorination of alachlor preoxidized by ZVI/PS. The results found that ZVI/PS preoxidation enhanced the DBP formation, compared with original system without any treatment. The longer the preoxidation time of ZVI/PS during the experiment, the more DBPs that were generated. During 48.0 h chlorination time, the produced DBPs increased to a stable value. Nitrate posed almost no impact on the DBP formation in the ZVI/PS system, while chloride significantly decreased DBP formation, which was attributed to the reduction of trichloromethane. During the chlorination process, alachlor could be further oxidized by remaining PS and free chlorine collectively. ZVI/PS had little effect on the DBP formation in the real water matrix. However, it could reduce carbonaceous DBP formation and increase nitrogenous DBP formation when the real water matrix contained 100 μg/L alachlor. The acute toxicity of alachlor solution could be reduced by the ZVI/PS system, while after chlorination the acute toxicity was largely increased due to the formation of DBPs. With increase of PS concentration, the DBP formation decreased in the ZVI/PS preoxidation system and increased in the system with PS alone. In conclusion, application of ZVI/PS in actual water containing alachlor declined DBP generation by augmenting PS concentration which should consider standard limited value of sulfate. Further investigation is needed for high bromide water. [ABSTRACT FROM AUTHOR]

In this study, the perchlorate sorption behaviors of three various representative anion resins were systematically investigated with respect to sorption kinetics, equilibrium capacity, perchlorate selectivity, thermodynamics and isotherms. Results showed that the equilibrium capacity of the three investigated resins followed the order of Purolite A530E≈magnetic ion exchange resin > Purolite A532E due to the effect of structure type, while magnetic ion exchange resin (MIEX) reached the equilibrium much faster than Purolite A530E and Purolite A532E, which can be attributed to its smaller particle size and larger surface area. Furthermore, the two Purolite resins showed superior perchlorate selectivity than MIEX resin because of matrix and functional groups. The adsorption kinetics for each of three selected resins fitted best with the pseudo-second-order model, indicating the adsorption process was controlled by chemical sorption. While the fitting of intra-particle model implied that intra-particle diffusion was not the only rate-limiting step of the whole process. The isotherm data can be best described by the Freundlich isotherm and the value of intensity of adsorption was larger than 1, suggesting the process was heterogenous and favorable adsorption. The negative Δ G ° manifested that the adsorption of perchlorate by each of the three resins was a spontaneous process, and the positive indicated it was also an endothermic and entropy driven process. Besides, the effects of independent variables on the perchlorate sorption of the three resins were also evaluated completely. Results suggested that the removal of perchlorate increased with the increase of resin dosage and temperature for each of the three resins, and the sorption process was nearly independent of solution pH in a wide range of 4–10 for each of the resins. [ABSTRACT FROM AUTHOR]

[Display omitted] • The catalyst with Co/Mg molar ratio of 1/200 rapidly activated PMS to remove CQP. • CoO nanoparticles were wrapped by MgO in catalyst, limiting cobalt ion leaching. • MgO accelerated the formation of Co-OH complex and redox cycle of Co2+- Co3+- Co2+. • Activation mechanism of PMS by the catalyst was analyzed in depth. Cobalt oxide could be used to activate peroxymonosulfate (PMS) for removal of contaminants, while its use was restricted due to low catalytic activity by limited active sites and the risk of cobalt ion leaching. This study investigated chloroquine phosphate (CQP) degradation by Co-Mg mixed metal oxides with highly dispersed minute quantities of CoO nanoparticles to activate PMS. It was demonstrated that the Co/Mg optimal molar ratio of catalyst was 1/200, and by characterization of catalysts and their effects on degradation of CQP, CoO nanoparticles could be widely dispersed and wrapped by MgO support. In the catalyst/PMS system, degradation of CQP could accelerate with the increase of catalyst dosage, PMS concentration and temperature and the addition of C l - , H P O 4 2 - and H 2 P O 4 - , but decrease with the addition of Mg2+, N O 3 - , H C O 3 - and nature organic matter (NOM). By quenching experiments of active radicals, it was illustrated that S O 4 · - and O 2 · - made more significant contributions than H O · in this system for CQP degradation. The activation mechanism of PMS by the catalyst with good repeatability and stability was explained that MgO could effectively adsorb hydroxy groups, promoting the formation of Co-OH complex and accelerating the redox cycle of Co2+- Co3+- Co2+ in the catalyst. The strong interaction between CoO and MgO prevented cobalt ion leaching and enhanced catalyst activity over the wide pH range (5–10). And proposed intermediates and degradation pathways of CQP were analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The catalyst with optimized Cu/Mg molar ratio rapidly activated PMS to remove TAP. • MgO wrapped CuO nanoparticles in the catalyst and limited copper ion leaching. • MgO promoted the formation of Cu-OH complex and redox cycle of Cu+-Cu2+-Cu+. • Activation mechanism of PMS and degradation pathways of TAP were proposed. Copper-base catalysts with high load content of CuO were commonly utilized to activate peroxymonosulfate (PMS) for removal of contaminants but limited catalytic efficiency and increased risk of copper ion leaching restricted their use. In this paper, Cu-Mg mixed metal oxides with highly dispersed minute quantities of CuO were successfully prepared by one-pot synthesis for efficiently activating PMS to remove thiamphenicol (TAP), which was economical and environmentally friendly. The catalytic activities of catalysts with different molar ratios of Cu and Mg for PMS and their characteristics were evaluated, illustrating the optimal molar ratio of Cu and Mg (1:15, named CuMg-MMO) in the catalyst. For the CuMg-MMO catalyst, MgO widely dispersed and wrapped CuO nanoparticles, minimized the copper ion leaching and promoted the generation of Cu-OH complex and non-radical species. In the CuMg-MMO/PMS system, the influence factors for TAP degradation were analyzed, including different systems, catalyst dosages, PMS concentrations, temperatures, initial pH values, TAP concentrations, anions (N O 3 - , H C O 3 - , C l - , H P O 4 2 - and H 2 P O 4 -) and natural organic matter (NOM) concentrations. Under the optimal conditions (i.e., [catalyst]: 75 mg/L, [PMS]: 0.3 mM, temperature: 30 °C and initial pH: 6.5), TAP removal efficiency obtained by this system was 99.9%. S O 4 · - , · O 2 - and 1O 2 played more important roles than H O · in TAP degradation. Four successive repeated experiments indicated that CuMg-MMO possessed good reusability and stability. PMS decomposition, mineralization of TAP, the activation mechanism of PMS and possible degradation pathways of TAP were analyzed. [ABSTRACT FROM AUTHOR]

Traditional thermal hydrolysis pretreatment (THP) for sludge deep dewatering is energy-intensive and poses the risk of generating bio-toxic substances that affect downstream wastewater treatment processes. To address these challenges, this study introduces the novel application of polyoxometalates (POMs) in THP to achieve sludge deep dewatering at lower temperatures. Specifically, under the optimal conditions with a POMs dosage of 1.0 mM/g VSS and a THP temperature of 140 °C, a reduction of 30.36%, 88.31%, and 55.04% in W C , SRF, and CST, respectively, was achieved compared to 20-RS-THP. Further analysis revealed that both the acidity and the biological effect of POMs played the dominant role in enhancing sludge dewatering. Spectroscopic techniques and molecular simulations revealed changes in protein structure during THP induced the POMs-proteins interaction. Results revealed that at lower THP temperatures (<80 °C), POMs induced protonation of functional groups in amino acid residues, strengthening electrostatic interactions. As temperatures increased (80–140 °C), more binding sites in hydrophilic amino acid residues became available for hydrogen bonding with POMs. This interaction led to structural changes in proteins, facilitating water liberation and the formation of sludge colloidal aggregates with improved drainage channels. However, at higher temperatures (140–180 °C), the exposure of hydrophobic sites, the loss of hydrophilic amino acids, and the occurrence of the Maillard reaction in proteins partially offset POMs' binding effects. Moreover, the development of magnetized POMs-based materials may offer sustainability and economic benefits for POMs-based sludge treatment and disposal technologies. [Display omitted] • Polyoxometalates-thermal hydrolysis pretreatment achieved sludge deep dewatering. • Effective thermal hydrolysis pretreatment temperature reduced to 140 °C or even lower. • The acidity and biological effect of POMs played dominant roles in sludge dewatering. • The POMs-proteins interaction was affected by temperature variations. • Hydrogen bonding between POMs and proteins was intensified in solubilization stage. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Perchlorate reduction rate was greatly increased in the presence of humic acids or AQDS. • The proposed redox reactions in the "bacteria-quinone-ClO 4 −" system were confirmed. • Quinone alleviated the inhibition of long oxygen exposure and high levels of NO 3 − on ClO 4 − reduction. • Perchlorate reduction rate was further increased with the combination of quinone and Fe (III) oxide. • Thaeura was predominant in perchlorate-acclimated inocula regardless of the presence of quinones. Abstract Humic acids (HA) and anthraquinone-2,6-Disulfonate (AQDS) are conceived as quinone-based redox mediators (QRM) in contaminant transformation processes, however, their effects on perchlorate (ClO 4 −) reduction remain unclear. This study explored the efficacy of quinone-mediated perchlorate reduction and the redox reactions occurred in QRM-amended systems. Relative to the average perchlorate reduction rate (k) in the control system, k was increased by 1.8, 1.9, and 2.3-fold in the presence of 100 mg/L commercial HA, extracted HA, and AQDS, respectively. Moreover, in AQDS-amended systems, k was further increased by 66.3% and 158.6%, respectively, with the addition of 0.003 g and 0.032 g hematite to the 200 mL culture. The critical redox reactions implying the electron transferring mechanism were explored and proven to be enzymatically driven. The presence of AQDS shortened the nitrate-induced lag of perchlorate reduction by stimulating nitrate exhaustion rate (2.83 mM NO 3 − h−1 compared to 1.26 mM NO 3 − h−1 in the control). Also, the inhibition of the 5-h aeration was alleviated (36.6% compared to 52.5% in the control) due to the higher redox-buffer capacity in AQDS-amended systems. Thaeura was predominant in all perchlorate-acclimated inocula, while the presence of QRM contributed to the enrichment of Desulfuromonas and Geobacter. [ABSTRACT FROM AUTHOR]

The priority pollutant antimony (Sb) exists primarily as Sb(V) and Sb(III) in natural waters, and Sb(III) is generally with greater mobility and toxicity than Sb(V). The bio-reduction of Sb(V) would not become a meaningful Sb-removal process unless the accumulation of produced dissolved Sb(III) could be controlled. Here, we examined the dissimilatory antimonate bio-reduction with or without the coexistence of sulfate using Sb-acclimated biomass. Results demonstrated that 0.8 mM Sb(V) was almost completely bio-reduced within 20 h along with 48.6% Sb(III) recovery. Kinetic parameters q max and K s calculated were 0.54 mg-Sb mg-DW −1 h −1 and 41.96 mg L −1 , respectively. When the concentrations of coexisting sulfate were 0.8 mM, 1.6 mM, and 4 mM, the reduction of 0.8 mM Sb(V) was accomplished within 17, 9, and 5 h, respectively, along with no final Sb(III) recovery. Also, the bio-reduction of sulfate occurred synchronously. The precipitated Sb 2 O 3 and Sb 2 S 3 were characterized by scanning electron microscopy coupled with energy dispersive spectrometer, X-ray diffraction, and X-ray photoelectron spectroscopy. Compared with bacterial compositions of the seed sludge obtained from anaerobic digestion tank in a wastewater treatment plant, new genera of Pseudomonas and Geobacter emerged with large proportions in both Sb-fed and Sb-sulfate-fed sludge, and a small portion of sulfate reduction bacteria emerged only in Sb-sulfate-fed culture. [ABSTRACT FROM AUTHOR]

The haloacetamides (HAcAms), an emerging class of nitrogen-containing disinfection byproducts (N-DBPs), are highly cytotoxic and genotoxic, and typically occur in treated drinking waters at low μg/L concentrations. Since many drinking distribution and storage systems contain unlined cast iron and copper pipes, reactions of HAcAms with zero-valent iron (ZVI) and metallic copper (Cu) may play a role in determining their fate. Moreover, ZVI and/or Cu are potentially effective HAcAm treatment technologies in drinking water supply and storage systems. This study reports that ZVI alone reduces trichloroacetamide (TCAcAm) to sequentially form dichloroacetamide (DCAcAm) and then monochloroacetamide (MCAcAm), whereas Cu alone does not impact HAcAm concentrations. The addition of Cu to ZVI significantly improved the removal of HAcAms, relative to ZVI alone. TCAcAm and their reduction products (DCAcAm and MCAcAm) were all decreased to below detection limits at a molar ratio of ZVI/Cu of 1:1 after 24 h reaction (ZVI/TCAcAm = 0.18 M/5.30 μM). TCAcAm reduction increased with the decreasing pH from 8.0 to 5.0, but values from an integrated toxic risk assessment were minimised at pH 7.0, due to limited removal MCAcAm under weak acid conditions (pH = 5.0 and 6.0). Higher temperatures (40 °C) promoted the reductive dehalogenation of HAcAms. Bromine was preferentially removed over chlorine, thus brominated HAcAms were more easily reduced than chlorinated HAcAms by ZVI/Cu. Although tribromoacetamide was more easily reduced than TCAcAm during ZVI/Cu reduction, treatment of tribromoacetamide resulted in a higher integrated toxicity risk than TCAcAm, due to the formation of monobromoacetamide (MBAcAm). [ABSTRACT FROM AUTHOR]

This study demonstrates the use of MIEX resin as an efficient adsorbent for the removal of clofibric acid (CA) and diclofenac (DCF). The adsorption performance of CA and DCF are investigated by a batch mode in single-component or bi-component adsorption system. Various factors influencing the adsorption of CA and DCF, including initial concentration, contact time, adsorbent dosage, initial solution pH, agitation speed, natural organic matter and coexistent anions are studied. The Langmuir model can well describe CA adsorption in single-component system, while the Freundlich model gives better fitting in bi-component system. The DCF adsorption can be well fitted by the Freundlich model in both systems. Thermodynamic analyses show that the adsorption of CA and DCF is an endothermic (ΔH o > 0), entropy driven (ΔS o > 0) process and more randomness exists in the DCF adsorption process. The values of Gibbs free energy (ΔG o < 0) indicate the adsorption of DCF is spontaneous but nonspontaneous (ΔG o > 0) for CA adsorption. The kinetic data suggest the adsorption of CA and DCF follow the pseudo-first-order model in both systems and the intra-particle is not the unique rate-limiting step. The adsorption process is controlled simultaneously by external mass transfer and surface diffusion according to the surface diffusion modified Biot number (Bi s ) ranging from 1.06 to 26.15. Moreover, the possible removal mechanism for CA and DCF is respectively proposed based on the ion exchange stoichiometry. [ABSTRACT FROM AUTHOR]

[Display omitted] • The combination of UV irradiation and chlorine significantly facilitated VEN degradation. • Kinecus software could simulated the VEN degradation well. • HO· was the dominant radical species responsible for the loss of VEN at acidic pH. • Transformation of VEN in UV/chlorine process can occur via four dominant reactions. • The toxicity of the products are generally lower than that of VEN. The presence of serotonin-norepinephrine reuptake inhibitors (SNRIs) such as venlafaxine (VEN) in surface waters has caused some concerns due to their harmful impacts on the human health and environment security. In the study, ultraviolet (UV) coupled with chlorine was developed for degrading VEN. Among the experiments, the UV/chlorine process demonstrated the highest performance in eliminating VEN. UV irradiation alone played a negligible role in VEN degradation. 39.56% of VEN was degraded by dark chlorination in 30 min, while 76.02% of VEN was decayed by UV/chlorine treatment within 30 min. Adding chlorine dosage and raising solution pH both facilitated the VEN removal. HCO 3 −, Cl− and HA inhibited VEN degradation during UV/chlorine treatment in accordance with predicted data. Furthermore, Kintecus software was applied to simulate the process of VEN degradation. Under UV/chlorine co-exposure, hydroxyl radical (HO·), chlorine and reactive chlorine species (RCS) were all proved to provide significant contribution to VEN oxidation. Note that both experimental and predicted contributions of HO· decreased as solution pH increased from 5.0 to 8.0. Four transformation pathways of VEN during UV/chlorine process were elucidated on basis of the DFT calculation and LC/MS analysis. Moreover, ECOSAR model program showed that UV/chlorine process reduced ecological toxicity of VEN obviously. Considering the influence of various factors, the most economical experimental conditions consist of chlorine (2.0–4.0 mg L−1) and pH (7.0–8.0). [ABSTRACT FROM AUTHOR]

• AA can remarkably improved DEET removal by Fe(III)/PS process. • ·SO 4 − and ·OH played a major role in DEET removal. • The existence of Fe(IV) in Fe(III)/PS/AA system was successfully identified. • Introducing AA into Fe(III)/PS system performed better than other reducing agents. • The reduction and chelation ability of AA both played crucial roles. The introduction of ascorbic acid (AA) into Fe(III)/PS system exhibited extremely high activity on the removal of N,N-diethyl- meta -toluamide (DEET) and other pollutants. The removal efficiency of DEET within 30 min reached 90.13%, its dynamic curve obeyed second-order kinetic model and the k obs was calculated to be 0.150 L·mg−1·min−1. Compared with other reducing agents, AA was tested to be the most suitable. The optimal dosages of Fe(III), PS and AA were tested to be 0.1, 1.0 and 0.5 mM, respectively. Furthermore, the introduction of AA extended the working pH to 2.5–9.3. Common anions posed different degrees of inhibition on DEET degradation at relatively high concentration, while a small dosage of HCO 3 − (<1 mM) abnormally exerted a positive role. In terms of reaction mechanism, scavenger experiment and EPR observation illustrated that ·OH and ·SO 4 − dominated DEET degradation, yet slight Fe(Ⅳ) was also found during the reaction, which indicated that Fe(Ⅳ) may also contribute to DEET removal. Different from the rapid consumption of Fe(II) in Fe(II)/PS system, Fe(II) in Fe(III)/PS/AA system entered a dynamic equilibrium state in the later stage of the reaction, which can decompose PS to form ·SO 4 − continuously. Furthermore, the reduction and chelation ability of AA both functioned a key role. According to the degradation intermediates identified by LC-MS analysis, the degradation pathways of DEET could be divided into two directions, which covered opening benzene ring and removing side chain. [ABSTRACT FROM AUTHOR]

In this paper, a compact repetitive nanosecond pulsed power generator based on transmission line transformer (TLT) is developed for non-thermal plasma generation. The high voltage capacitor, the spark gap switch and the input side of the TLT are built into a compact structure to obtain a fast high-power pulse. The properly designed magnetic cores placed around the coaxial cables of the TLT have been chosen to obtain a higher voltage gain. The layout of TLT is optimized to make the generator more compact. Experiment test shows that voltage pulses of 30 kV with rise time of about 25 ns, pulse duration of about 100 ns, pulse repetition rate of 500 pps have been achieved. [ABSTRACT FROM AUTHOR]