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In this study, FeS 2 @SiO 2 microspheres were firstly employed as a heterogeneous catalyst to activate persulfate (PS) for the degradation of bisphenol A (BPA) from aqueous solutions. The most relevant findings revealed that UV irradiation induced a significant improvement in the degradation of BPA by the FeS 2 @SiO 2 microspheres/PS system. Nearly 100% of BPA degradation by the FeS 2 @SiO 2 microspheres/PS/UV system was achieved within 120 min at reaction conditions of 1 mM PS, 0.066 mM BPA, 1.0 g/L FeS 2 @SiO 2 microspheres and pH 3.0. A high performance on the degradation of BPA might be attributable to a synergistic effect between the PS/UV and the FeS 2 @SiO 2 microspheres/PS catalytic processes. It was found that the BPA degradation could be inhibited by the coexisting anions like Cl − , HCO 3 − and PO 4 3− to different extents at much higher concentrations, whereas NO 3 − had a negligible effect. Organic acids such as ethylene diamine tetra-acetic acid (EDTA) and oxalic acid (OA) would lead to an enhancement with a lower dosage, whereas a significantly negative effect was observed at much higher dosages. Radical scavenging tests revealed that the SO 4 − radicals prevailed over HO . A total of seven intermediates during the degradation of BPA were identified by GC/MS, and a possible reaction pathway and mechanism of BPA degradation by the FeS 2 @SiO 2 microspheres/PS/UV system was proposed. This study demonstrated a simple water treatment method involving the use of low cost natural iron minerals for organic pollutants removal. [ABSTRACT FROM AUTHOR]

Nowadays, environmental problems caused by residual antibiotics are getting increasing attention. In the present work, peroxymonosulfate (PMS) was firstly employed for the enhanced degradation of norfloxacin (NOF) by a calcium-based Ag 3 PO 4 composite (Ca-Ag 3 PO 4) under visible light irradiation. Experiment results show that NOF removal in Ca-Ag 3 PO 4 /PMS/visible light process was higher than the sum of that in Ca-Ag 3 PO 4 /visible light and Ca-Ag 3 PO 4 /PMS processes. This significant enhancement of NOF removal was mainly due to a synergistic effect between photocatalysis of Ca-Ag 3 PO 4 /visible light process and Fenton reaction of Ca-Ag 3 PO 4 /PMS process. The inhibitory effects of water quality components on NOF removal followed: Humic acid (HA) > PO 4 3-> HCO 3 −> NO 3 −> Cl−. NOF and co-existing heavy metals (ie., Cr(VI) and Ni(II)) or organic compounds like tetracycline (TC) could be simultaneously removed. Both PMS and H 2 O 2 exhibit positive effects on the removal of NOF, but PMS could more effectively improve NOF removal compared with H 2 O 2. An excellent PMS decomposition had been achieved in Ca-Ag 3 PO 4 /PMS/visible light process. HO•, SO 4 •− and 1O 2 all took part in NOF degradation by Ca-Ag 3 PO 4 /PMS/visible light process, but both HO• and SO 4 •− might be primary species for NOF degradation. A plausible degradation pathway of NOF in Ca-Ag 3 PO 4 /PMS/visible light process was thereby proposed to proceed through ring-opening cracking hydroxylation and elimination reactions reactions. The enhanced reaction mechanism for the degradation of NOF in Ca-Ag 3 PO 4 /PMS/visible light process was also proposed. [Display omitted] • An efficient NOF removal was obtained in Ca-Ag 3 PO 4 /PMS/visible light process. • PMS could more effectively improve NOF removal compared with H 2 O 2. • Both HO.• and SO 4 •− might be primary species responsible for NOF degradation. • NOF degradation was achieved via hydroxylation and elimination reactions. • The enhanced reaction mechanism of NOF degradation was proposed. [ABSTRACT FROM AUTHOR]

• A synergistic effect between BC/PMS and nZVI/PMS processes has been achieved. • ATZ removal of BC-nZVI/PMS was higher than that of BC-nZVI/H 2 O 2 or BC-nZVI/PS. • SO 4 − was the predominant radical species responsible for ATZ degradation. • ATZ was degraded through de-alkylation, dechlorination and hydroxylation processes. • A reaction mechanism of PMS activation by BC-nZVI for ATZ degradation was proposed. Over the past decade, herbicides contaminated soil poses a serious threat to humans and environment. In this study, a novel biochar supported zero valent iron (BC-nZVI) was used as a heterogeneous catalyst activating peroxymonosulfate (PMS) for the removal of herbicide atrazine (ATZ) from soil. The results revealed that the removal of ATZ by BC-nZVI/PMS process was superior to that of BC/PMS or nZVI/PMS process. A synergistic effect between BC/PMS and nZVI/PMS processes has been successfully achieved in BC-nZVI/PMS process, and nearly 96% of ATZ removal was obtained at optimum reaction conditions. BC-nZVI/PMS process exhibited an excellent performace on ATZ removal compared with BC-nZVI/H 2 O 2 or BC-nZVI/persulfate (PS) process. PMS decomposition by BC-nZVI/PMS process was higher than the sum of BC/PMS and nZVI/PMS processes. A low Cu concentration accelerated ATZ removal, and Cu was also effectively immobilized. SO 4 − was the predominant reactive oxygen species responsible for ATZ degradation, and OH and 1O 2 also took part in reaction. Four kinds of ATZ degradation products were identified, and ATZ degradation could be achieved through de-alkylation, dechlorination and hydroxylation processes. A reaction mechanism of PMS activation by BC-nZVI was proposed based on the synergistic effect of BC and nZVI. In addition to ATZ, coexisting pollutants such as 2,4-dichlorophenol (2,4-DCP), Cu and Cd were also simultaneously removed from soil. [ABSTRACT FROM AUTHOR]

In this study, bentonite-supported nZVI (B-nZVI) was used as a catalyst to activate H 2 O 2 for atrazine (ATZ) degradation in the presence of FeS 2. Results indicated that ATZ degradation by B-nZVI/H 2 O 2 process was significantly enhanced when FeS 2 was introduced, and nearly 98% of ATZ was degraded by B-nZVI/FeS 2 /H 2 O 2 process within 60 min under the optimum conditions. ATZ degradation of B-nZVI/FeS 2 /H 2 O 2 process was much higher than the sum of B-nZVI and FeS 2 /H 2 O 2 processes. The presence of HCO 3 −, PO 4 3− and F− exhibited significant negative effects on the ATZ degradation, whereas both Cu2+ and Ni2+ exhibited positive effects on that. Both citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) with lower concentration enhanced ATZ degradation rate, but significant suppression effects on that with higher concentration. The degradation of ATZ and 2,4-Dichlorophenol (2,4-DCP) could be simultaneously achieved in B-nZVI/FeS 2 /H 2 O 2 process under certain conditions. High soluble Fe2+ induced an excellent decomposition of H 2 O 2 by B-nZVI and FeS 2. OH was dominant radical, and contributed to nearly 86% of the overall ATZ removal. A total of five intermediate products of ATZ were identified, and ATZ degradation was achieved via de-alkylation and hydroxylation processes. An enhanced reaction mechanism for ATZ degradation by B-nZVI/FeS 2 /H 2 O 2 process was proposed, and B-nZVI/FeS 2 /H 2 O 2 process exhibited an excellect catalytic performance within four successive runs. Unlabelled Image • ATZ degradation by B-nZVI/H 2 O 2 process was enhanced in the presence of FeS 2. • High Fe2+ was favorable to H 2 O 2 decomposition by B-nZVI/FeS 2 /H 2 O 2 process. • OH was dominant radical, and contributed to 86.1% of the overall ATZ removal. • Possible pathways of ATZ degradation were proposed based on intermediate products. • Enhanced mechanism for ATZ degradation by B-nZVI/FeS 2 /H 2 O 2 process was proposed. [ABSTRACT FROM AUTHOR]

• A synergistic effect between sonochemistry and catalytic chemistry was achieved. • PS decomposition of BC/PS/US process was superior to BC/PS or US/PS process. • SO 4 ― was predominant radical responsible for the degradation of BPA. • A possible mechanism of BPA degradation by BC/PS/US process was proposed. • The BC catalyst exhibited a relatively stability after five successive runs. Recently, clean-up of resistant organic compounds has attracted growing attention. In this study, a novel heterogeneous ultrasound-enhanced sludge biochar catalyst/persulfate (BC/PS/US) process was firstly developed for the degradation of bisphenol A (BPA) in water. The results revealed that BC/PS/US process could successfully achieve a positively synergistic effect between sonochemistry and catalytic chemistry on the degradation of BPA compared to its corresponding comparative process. Nearly 98% of BPA could be degraded within 80 min at optimum reaction conditions. The coexisting substances including Cl−, SO 4 2- and NO 3 − had no obvious inhibition on the BPA degradation, whereas HCO 3 − and humic acid (HA) had significant inhibition effects on that. PS decomposition of BC/PS/US process was superior to that of BC/PS or US/PS process. Both SO 4 ― and HO participated in the degradation of BPA, but SO 4 ― was predominant radical in the BC/PS/US process. A possible pathway of BPA degradation was proposed, and the BPA molecule was attacked by SO 4 ― and degraded into five kinds of intermediate products through hydroxylation and demethylation processes. This study helps to comprehend the application of sludge biochar catalyst as a persulfate activator for the degradation of organic compounds under ultrasound irradiation, and provides a new strategy in wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxalic acid (OA) maintain a high dissolved Fe2+ in the PC-ZVI/PMS process. • Peroxymonosulfate (PMS) greatly improve atrazine (AE) removal. • The contribution order of reactive species followed as HO• > SO 4 •- greater than1O 2 > O 2 •−. • The possible degradation pathways of AE by PC-ZVI/PMS/OA process proposed. • Enhanced mechanism of Cr6+ and AE removal by PC-ZVI/PMS/OA process was proposed. Nowadays, clean-up of heavy metals and pesticides from environment has received great attention. A green biochar iron composite (PC-ZVI) was successfully synthesized using pomelo peel residues and FeCl 3 solution. Peroxymonosulfate (PMS) was introduced into the PC-ZVI system for Cr(VI) and atrazine (AE) removal, and results showed that PMS greatly promoted Cr(VI) and AE removal. The presence of oxalic acid (OA) could maintain a relatively high dissolved Fe2+ species for Cr(VI) reduction and AE oxidation in the PC-ZVI/PMS process. The contribution order of reactive oxygen species followed as HO• > SO 4 •- greater than1O 2 > O 2 •− in both Cr(VI) and AE removal by PC-ZVI/PMS/OA process. A total of six intermediates products of AE degradation were detected, and AE molecular was effectively degraded into CO 2 , H 2 O, inorganic N and Cl through hydroxylation, substitution and de-alkylation processes. The underlying mechanism of Cr(VI) and AE removal by PC-ZVI/PMS/OA process was also proposed. Most Cr(VI) species were transformed into Cr 2 O 3 and Cr(OH) 3 through reduction and precipitation processes. PC-ZVI has a relatively high recyclability toward both Cr(VI) and AE removal from solutions. The potential toxicity of PC-ZVI solution was small at three PC-ZVI dosages levels, and the corresponding toxicity of AE reaction solution by PC-ZVI/PMS/OA process decreased as reaction time increased. The order of both Cr(VI) and AE removal in different water systems was tap water > river water > lake water > wastewater, and this PC-ZVI/PMS/OA process exhibited the better adaptability in application for several actual water environments. [ABSTRACT FROM AUTHOR]

In this study, a green zero-valent iron-loaded carbon composite (ZVI-SCG) was synthesized using coffee grounds and FeCl3 solution through two-steps method, and the synthesized ZVI-SCG was used in the activation of peroxydisulfate (PDS) to degrade Levofloxacin (LEX). Results revealed that ZVI-SCG exhibited a great potential for LEX removal by adsorption and catalytic degradation in the ZVI-SCG/PDS system, and 99% of LEX was removed in the ZVI-SCG/PDS system within 60 min. ZVI-SCG/PDS system showed a high reactivity toward LEX degradation under realistic environmental conditions. Also, the ZVI-SCG/PDS system could effectively degrade several quinolone antibiotics including gatifloxacin, ciprofloxacin and LEX in single and simultaneous removal modes. A potential reaction mechanism of LEX degradation by ZVI-SCG/PDS system was proposed, SO 4 •−, HO•, O 2 •- and 1O 2 involved in radical and non-radical pathways took part in catalytic degradation of LEX by ZVI-SCG/PDS system, but HO• might be the main reactive species for LEX degradation. The possible degradation pathway of LEX was also proposed based on the identified ten intermediate products, LEX degradation was successfully achieved through decarboxylation, opening ring and hydroxylation processes. The potential toxicity of LEX and its oxidation products decreased significantly after treatment. This study provides a promising strategy of water treatment for the antibiotics-containing wastewater. [Display omitted] • A green zero-valent iron-loaded carbon composite (ZVI-SCG) was synthesized. • ZVI-SCG/PDS system reveals high adsorption and catalytic degradation capacity for LEX. • The radical (SO 4 •−, HO• and O 2 •−) and the non-radical (1O 2) were involved in LEX degradation. • The degradation mechanism of LEX in the ZVI-SCG/PDS system was proposed. • Toxicity of LEX reaction solution decreased significantly after treatment. [ABSTRACT FROM AUTHOR]