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Abstract Great amounts of nutrients discharged into the urbanized coastal areas, which are continuously subject to violently anthropogenic metal contamination, will result in eutrophication and hypoxic episode. In order to study the effects of dissolved oxygen (DO), salinity, nitrogen and phosphorus on the release of six metals including Zn, Pb, Cd, Cu, As and Cr from coastal sediments, a series of 60-days microcosm experiments consisting of sediments and seawater were conducted. Severe hypoxia could result in the enhanced peak values of Pb, Cd, Cu and Cr concentrations in the overlying water. A higher level of water salinity could elevate the peak value of As concentration in water column, and a higher level of nitrogen could increase the peak value of Zn concentration in water. The exchange fluxes demonstrated that the diffusion from the sediments was a dominant process during the first 10 days, However, a relative equilibrium of adsorption and precipitation in the sediment-water interface reached during the later periods. In addition, the bioavailability of the studied metals in sediments was elevated under severe hypoxia, or a high level of water salinity, or high levels of nitrogen and phosphorus. The results of linear regression analysis suggested that higher metal bioavailability in sediments could facilitate the metal release, but the process could be restrained by the higher aqueous phosphorus due to the precipitation of metal phosphates. Graphical abstract Unlabelled Image Highlights • Elevated hypoxia, salinity or nitrogen enhanced the metal release from sediments. • Higher water phosphates restrained the metal release from sediments. • Dissolved oxygen was the dominated factor for the release of Pb, Cd, Cu and Cr. • Increased hypoxia, salinity or nutrients could elevate the metal bioavailability. [ABSTRACT FROM AUTHOR]

Abstract In this study, the feasibility of a novel Ca-Ag 3 PO 4 composite with visible light irradiation for the phenanthrene (PHE) degradation and algae inactivation in artificial seawater was firstly investigated. The experimental findings revealed that Ag 3 PO 4 phase was sucessfully formed on the Ca-based material, and the presence of Ca-based material could effectively keep Ag 3 PO 4 particles stable. An excellent performance on PHE degradation or algae inactivation was observed from Ca-Ag 3 PO 4 composite under visible light irradiation. The degradation of PHE or inactivation of algae not only could be efficiently achieved in the single mode, but also could be successfully achieved in the coexisting mode. Above 96% of PHE and algae were simultaneously removed within 12 h in the Ca-Ag 3 PO 4 /visible light system. It was further observed that the degradation of PHE and/or inactivation of algae increased with the increase of Ca-Ag 3 PO 4 dosage. HO was the primary radical responsible for PHE degradation, whereas HO and Ag+ released from Ca-Ag 3 PO 4 mainly contributed to the algae inactivation. A possible mechanism involving the catalytic removal of PHE and algae by Ca-Ag 3 PO 4 under visible light irradiation was proposed. This study provides helpful guide for the simultaneous removal of various pollutants in real seawater. Graphical abstract Image 1 Highlights • A novel Ca-Ag 3 PO 4 composite was prepared by a facile two-step method. • Removal of PHE and algae over Ca-Ag 3 PO 4 composite were efficiently achieved. • Removal of PHE and/or algae increased with the increase of Ca-Ag 3 PO 4 dosage. • HO was primary radical responsible for PHE degradation and algae inactivation. • A mechanism of the photocatalytic removal of PHE and algae was proposed. [ABSTRACT FROM AUTHOR]

Abstract Herein, the application of a novel acid mine drainage-based nanoscale zero valent iron (AMD-based nZVI) for the remediation of nitrate and norfloxacin (NOR) was studied. Experimental results indicated that the catalytic reactivity of AMD-based nZVI toward nitrate reduction was superior to that of iron salt-based nanoscale zero valent iron (Iron salt-based nZVI). The presence of ultrasound irradiation could significantly enhance the reactivity toward both the nitrate reduction and NOR oxidation processes. The optimal efficiencies of nitrate and NOR by AMD-based nZVI/US process could be kept 96 and 94% within 120 min, respectively. Ammonia was identified as a major product in nitrate reduction process, while three oxidation products were observed in NOR degradation process. Both reduction reaction of nitrate from AMD-based nZVI and oxidation reaction of NOR from US-assisted Fenton system might be involved in AMD-based nZVI/US process. The AMD-based nZVI/US process showed a better performance on the removal of NOR compared with that of nitrate. The findings of the present work could be as a guide and show that AMD-based nZVI/US process is feasible for the remediation of both nitrate and NOR in real wastewater. Graphical abstract Unlabelled Image Highlights • A novel zero valent iron was successfully synthesized using acid mine drainage. • A synergistic effect between nitrate reduction and NOR oxidation was achieved. • HO produced from US-assisted Fenton system was responsible for NOR oxidation. • A reaction mechanism for the nitrate reduction and NOR oxidation was proposed. • AMD-based nZVI has a better recyclability on the NOR removal than nitrate. [ABSTRACT FROM AUTHOR]

Abstract In-situ study on arsenic speciation and the release kinetics in marine sediments was scarce. In this study, the distributions of labile As and their speciation in coastal sediments of Daya Bay were obtained by separate diffusive gradients in thin films (DGT) probes. Results showed that the DGT-labile As(V) was the main speciation in surface sediments (from −20 to 0 mm) with a concentration range of 0.07–3.05 μg·L−1, while the labile As(III) was the main speciation in deep layers of sediments (from −100 to −20 mm). In coastal areas, mariculture farms was the most dominated contributor to As(V) contamination in surface sediments. Both the apparent diffusion flux estimation and the DGT induced flux in sediments (DIFS) simulation indicated that As(V) contamination in surface sediments of mariculture, harbor and petrochemical areas suffered the potential risk of As(V) release into the overlying water from sediments. DIFS modeling also found that the sediments of mariculture farms were the main sediment As pools. Linear regression analysis indicated that the mobility of As mainly attributed to the As(V) in sediments. Graphical abstract Unlabelled Image Highlights • Labile As(V) in coastal surface sediments increased due to human activities. • Labile As(III) was the dominated speciation in the deep layers of sediments. • Mariculture was the dominated source of As(V) contamination in surface sediments. • Sediments in mariculture farms were the largest As pool for supply to pore water. • As mobility in surface sediments mainly attributed to the As(V), not As(III). [ABSTRACT FROM AUTHOR]

Cr 6+ and Pb 2+ are both highly toxic pollutants and commonly co-exist in some industrial effluents and contaminated waters. In this study, simultaneous removal of Cr 6+ and Pb 2+ by a novel sewage sludge-derived biochar immobilized nanoscale zero-valent iron (SSB-nZVI) was systematically investigated. It was well demonstrated that a porous structure was successfully formed on the SSB-nZVI when the starch was used as an additive. A synergistic effect on the adsorption and reduction over the SSB-nZVI was achieved, resulting in nearly 90 and 82% of Cr 6+ and Pb 2+ removal within 30 min, respectively. Cr 6+ was reduced prior to Pb 2+ . A low pH could accelerate the corrosion of nZVI as well as phosphate leaching. When Malachite green was added as a coexisting organic pollutant, its effective removal was found due to the formation of a Fenton-like system. The SSB-nZVI could be run consecutively three times with a relatively satisfactory performance. Most of Cr 6+ was converted into Cr 2 O 3 and Cr(OH) 3 on the SSB-nZVI surface, whereas most of Pb 2+ species existed as Pb(OH) 2 (or PbO). A possible reaction mechanism on the SSB-nZVI involved the adsorption, reduction and precipitation of both Cr 6+ and Pb 2+ over the particles. Present study sheds light on the insight of the fate and transport of Cr 6+ and Pb 2+ in aquatic environment, as well provides helpful guide for the remediation of coexistence of pollutants in real applications. [ABSTRACT FROM AUTHOR]

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, clean-up of waters with coexisting heavy metal ions and organic pollutants is of great environmental importance. In this study, a novel sewage sludge-derived char-based catalyst was firstly synthesized, and coupled with hydrogen peroxide for the simultaneous removal of copper (II) and norfloxacin in aqueous solutions. The most relevant findings revealed that zero-valent iron and zero-valent aluminum particles were successfully formed on the catalyst surface when the leaching of the sludge-derived char was reduced by the green tea extract. Nearly 100% of both copper (II) and norfloxacin were simultaneously removed due to a synergistic effect between the reduction of copper (II) and the oxidation of norfloxacin over the catalyst. The gradual addition mode of hydrogen peroxide exhibited a better performance on the simultaneous removal of copper (II) and norfloxacin. The coexisting anions like nitrate and phosphate had significant negative effects on the copper (II) removal, whereas carbonate, fluoride and phosphate had significant negative effects on the norfloxacin removal. Different copper species like zero-valent copper, copper oxide and copper hydroxide were identified in copper (II) reduction process, whereas a total of eight oxidative products were identified in norfloxacin oxidation process. A possible reaction mechanism for the simultaneous removal of copper (II) and norfloxacin by the sewage sludge-derived char-based catalyst/hydrogen peroxide system was proposed. The adsorption of both copper (II) and norfloxacin over the catalyst were firstly occurred, and then the reduction of copper (II) over both zero-valent iron and zero-valent aluminum particles on the catalyst surface as well as the Fenton oxidation of norfloxacin were followed. [ABSTRACT FROM AUTHOR]

This study makes a comparison between the pyrite/H 2 O 2 and pyrite/persulfate (PS) Fenton systems to investigate the degradation of Rhodamine B (RhB). The most relevant findings revealed that a significantly negative effect of carbonate and a narrow pH range of 2–4 were found in the pyrite/H 2 O 2 system, whereas a relatively less negative effect of carbonate and a broad pH range of 2–11 were observed in the pyrite/PS system. It was demonstrated that the pyrite catalyst in the pyrite/PS system exhibited better structural stability and showed a relatively limited loss in performance upon reuse as compared to pyrite in the pyrite/H 2 O 2 system. Experiments with different scavengers indicated that HO radicals were the major reactive species responsible for RhB degradation by pyrite/H 2 O 2 . In this case the contribution of radical was in the order of HOHO >O 2 − , whereas the SO 4 − radicals prevailed over HO in the pyrite/PS system. The role of O 2 − in the recycling of Fe(III) to Fe(II) was very important. The possible mechanism for RhB degradation by pyrite/H 2 O 2 mainly involves the reaction of the dissolved Fe 2+ released by the surface of the pyrite with added H 2 O 2 , whereas the reaction of the dissolved Fe 2+ formed in the pyrite with PS triggers degradation in the pyrite/PS system. The degradation of RhB is initiated in both cases by N-de-ethylation, chromophore cleavage and ring opening processes, which leads to the production of a series of oxidation products with smaller molecular sizes. The pyrite/PS system is here proven to be a superior heterogeneous Fenton-like oxidant process for the removal of dyes from wastewater. [ABSTRACT FROM AUTHOR]

Coexistence of organic compounds and heavy metals in aquaculture waters is a widespread problem. In this study, a rapid reduction of Cr(VI) and oxidation of ciprofloxacin (CIP) in a simultaneous manner was firstly reported through the photocatalysis of TiO 2 /Fe 0 composite under aerobic conditions. The significantly enhanced removals of Cr(VI) and CIP by TiO 2 /Fe 0 composite due to a synergetic effect between oxidation and reduction processes. Within 60 min UV light irradiation, the simultaneous removals of Cr(VI) and CIP by TiO 2 /Fe 0 composite were 97.7 and 94.6%, respectively, whereas the corresponding values by TiO 2 were 57.9 and 68.7%. CIP oxidation process could be significantly accelerated under acidic and aerobic conditions. Intriguingly, a low Pb(II) concentration could induce an enhancement of CIP oxidation, whereas a negative effect on both Cr(VI) reduction and CIP oxidation was observed at a relatively high concentration. A low concentration of ethylene diamine tetra-acetic acid (EDTA) did positively affect both Cr(VI) reduction and CIP oxidation processes, whereas a negative effect on CIP oxidation was found at a relatively high concentration. A possible reaction pathway and mechanism between CIP oxidation and Cr(VI) reduction was proposed. CIP was attacked by HO produced from the decomposition of water and photo-excited holes through substitution and hydroxylation processes, leading to the production of a series of intermediates, whereas the Cr(VI) was converted into Cr(III) through the capture of photo-excited electrons and Fe 0 reduction. [ABSTRACT FROM AUTHOR]

In this study, the application of FeS 2 /SiO 2 microspheres as a catalyst to activate H 2 O 2 for the degradation of ciprofloxacin (CIP) was systematically investigated. Results demonstrated that the presence of SiO 2 microspheres on the surface of FeS 2 could effectively make the reaction of aqueous Fe 2+ and H 2 O 2 smoothly continuous by controlling the release of aqueous Fe 2+ from FeS 2 . Nearly 100% of CIP was degraded after 60 min under the optimum conditions. A superior performance on the CIP degradation and high reusability of the catalyst was obtained in FeS 2 /SiO 2 microspheres activated H 2 O 2 system. A low concentration of ethylene diamine tetraacetie acid (EDTA) did positively affect the degradation rate of CIP. A synergetic effect between adsorption and oxidation processes contributed to the significant enhancement of CIP degradation. Seven oxidation intermediates were identified during the CIP degradation process, and the direct HO oxidation proved to be a main CIP degradation pathway. For degradation pathway of CIP, oxidation of piperazine ring would be its first step, followed by cleavage of the heterocyclic ring. Subsequently, the substitution, hydroxylation and decarboxylation processes occurred. This is the first report on the feasibility of FeS 2 /SiO 2 microspheres activated H 2 O 2 system for the enhanced degradation of CIP. [ABSTRACT FROM AUTHOR]

In this study, bentonite-supported nanoscale zero-valent iron (B-nZVI) was used as a catalyst to activate persulfate (PS) for the simultaneous removal of Cr(VI) and phenol from aqueous solutions. Experimental results indicated that the presence of bentonite could decrease the aggregation of nZVI and increase its reactivity. The removal rates of Cr(VI) and phenol by B-nZVI system were 99.90% and 6.50%, respectively. Whereas the corresponding values by B-nZVI/PS system were 99.30% and 71.50%, respectively. The presence of persulfate could not significantly decline B-nZVI reactivity toward Cr(VI) reduction but remarkably promote phenol oxidation. The addition of Cr(VI) did positively affect the oxidation rate of phenol, a significant synergistic effect between Cr(VI) reduction and phenol oxidation was achieved in B-nZVI/PS system. A positive correlation between persulfate decomposition and dissolved Fe 2+ was found. Cr(III) species such as Cr 2 O 3 , Cr(OH) 3 were identified in Cr(VI) reduction process, whereas the oxidation products such as catechol, 1,4-benzoquinone, propionic acid and formic acid were identified in phenol oxidation process. The reusability experiments of B-nZVI demonstrated that the structure of B-nZVI was relatively stable after four cycles of reuse. This is the first report for the feasibility of B-nZVI as a catalyst to activate persulfate for the simultaneous removal of heavy metal and organic pollutant. [ABSTRACT FROM AUTHOR]

The applicability of bentonite-supported nanoscale zero-valent iron (B-nZVI) as a catalyst to activate persulfate (PS) for the simultaneous removal of Cr(VI) and phenol was systematically investigated in this study. Experimental results demonstrated that phenol degradation was significantly enhanced under acidic condition and with oxygen supply, whereas the Cr(VI) reduction was not obviously declined. The removal efficiencies of Cr(VI) and phenol in B-nZVI/PS combined system were 99.8 and 72.3%, respectively. Cr(VI) reduction and phenol oxidation was simultaneously achieved in B-nZVI/PS combined system, which provided a promising environmental treatment for industrial wastewater containing metal ions and organic compounds. An acidic condition was more favorable to the decomposition of persulfate for the production of sulfate radicals. Radical scavenging tests revealed that the predominant reactive oxygen species for phenol degradation was SO 4 − , neither HO nor O 2 − . A reaction mechanism, which involves the Cr(VI) removal mainly by the reduction of nZVI and the degradation of phenol mainly by the SO 4 − from the decomposition of persulfate, was proposed. These findings revealed that B-nZVI/PS combined system has a potential in the environmental remediation polluted jointly by organic compounds and/or heavy metals. [ABSTRACT FROM AUTHOR]

Coexistence of organic compounds and heavy metals in industrial wastewater effluent is a serious environmental problem. In this study, pyrite was successfully employed as a photocatalyst for the simultaneous removal of malachite green (MG) and Cr(VI). The removal efficiency of MG and Cr(VI) were 96.7% and 53.1%, respectively after 120 min. The presence of Cr(VI) significantly promoted MG degradation, and the reduction ratio of Cr(VI) was significantly accelerated in the presence of MG, demonstrating an obvious synergism between MG degradation and Cr(VI) reduction. The presence of Cr(VI) did not change the kinetic order of MG degradation. The presence of dissolved oxygen could enhance the degradation ratio of MG, but decrease the reduction ratio of Cr(VI) despite the fact that both Cr(VI) and O 2 are competitive electron acceptors. Photocatalytic efficiency of the coexistence system was superior to that of the single system when the catalyst was continuously used for 5 times. A synergistic mechanism involving reactive oxygen species produced from photo-Fenton-like process for the MG degradation, whereas the Cr(VI) reduction mainly by direct electrons of pyrite, not reaction of O 2 − with Cr(VI) was proposed. This is the first report on the application of pyrite particles as a photocatalyst for the simultaneous removal of organic compounds and heavy metals. [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]

[Display omitted] • Persulfate (PS) significantly enhanced AMX removal by TiO 2 @nZVI/UV process. • The decomposition rate of PS in TiO 2 @nZVI/PS/UV process was the highest. • Both HO• and SO 4 •− were the dominant radicals in TiO 2 @nZVI/PS/UV process. • AMX was effectively degraded through hydroxylation and deamination reactions. • A mechanism for the simultaneous removals of AMX and NOF was proposed. In recent years, a serious threat of antibiotic residues in aquatic environments to human health and ecological security has become increasingly widespread attention. In this study, this is the first report on an alternative strategy on enhanced degradation of amoxicillin (AMX) and norfloxacin (NOF) by TiO 2 @nZVI/persulfate (PS) process under UV irradiation. Results revealed that a signficantly synergistic effect on AMX degradation had been achieved in TiO 2 @nZVI/PS/UV process due to the photocatalysis and Fenton-like reactions. NO 3 –, HCO 3 –, PO 4 3- and humic acid exhibited inhibitory effects on AMX degradation, whereas Cl- was negligible on that. The degradation of AMX decreased as the addition of Cr(VI) concentrations increased, whereas the correspond values were enhanced when a low Cu(II) concentration was introduced. TiO 2 @nZVI/PS/UV process was the most efficient for activating PS decomposition. HO•, SO 4 •− and 1O 2 were all generated in TiO 2 @nZVI/PS/UV process, but HO• and SO 4 •− were the dominant radical species for AMX degradation. The AMX intermediates products identified by LC-MS system confirmed AMX was effectively degraded through hydroxylation and deamination reactions. A better performance on the simultaneous removals of AMX and NOF by TiO 2 @nZVI/PS/UV process could be achieved at lower concentration conditions, and the simultaneous reaction mechanism was thereby proposed base on expriment results. [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]

Nowadays, nanoscale zero valent iron (nZVI) has been extensively applied for the decontamination of various pollutants, but passivation of nZVI severely affects its reactivity in use. In this study, ultrasound (US)-assisted catalytic reduction of Cr(VI) by an acid mine drainage based nZVI (AMD-nZVI) coupling with FeS 2 system was systematically examined. Results show that the presence of FeS 2 and US induced a synergistic enhancement of Cr(VI) removal by AMD-nZVI. Nearly 98% of Cr(VI) removal was achieved by AMD-nZVI/FeS 2 /US process within 60 min under optimal reaction conditions. Several coexisting substances with lower concentration including Pb(II), Ni(II), bisphenol A (BPA) and 2,4-diclorophenol (2,4-DCP) could be effectively removed in simultaneous manner with Cr(VI) removal. The inhibitory order of water matrix species on Cr(VI) removal was NO 3 − > PO 4 3− > HCO 3 − > Ca2+ > Mg2+ > Cl−, and a serious suppression effect was induced by humic acid (HA). Addition of ethylene diamine tetra-acetic acid (EDTA) and citric acid (CA) could enhance Cr(VI) removal rate. An enhanced reaction mechanism was proposed, which involved the regeneration of more Fe2+ and H+ by AMD-nZVI/FeS 2 /US process, leading to the reduction of Cr(VI) by AMD-nZVI and FeS 2 into Cr(III) species inculding Cr 2 O 3 and Cr(OH) 3. This study well demonstrates that AMD-nZVI/FeS 2 /US process is considered as a potential candidate for the remediation of Cr(VI) in real wasterwater. Image 1 • FeS 2 induced an enhanced removal of Cr(VI) by AMD-nZVI/US process. • The formation of Fe2+ and acidic condition played a primary role in this process. • Removal of Pb(II), Ni(II), 2,4-DCP and BPA could be achieved with Cr(VI) removal. • Most of Cr(VI) species was sucessfully reduced into Cr 2 O 3 and Cr(OH) 3. • Enhanced mechanism of Cr(VI) removal by AMD-nZVI/FeS 2 /US process was proposed. [ABSTRACT FROM AUTHOR]

The applicability of sludge biochar catalyst (SBC) coupling with ultrasound (US) irradiation for the simultaneous removal of Pb(II) and phenol was firstly investigated in this study. Results indicate that Pb(II) removal of SBC/US process was superior to that of SBC without US. The inhibitory order of the coexisting anions on Pb(II) removal was PO 4 3− > HCO 3 − > NO 3 − > F− > SO 4 2− > Cl−. Also, several coexisting metals ions inculding Cr(VI), Ni(II) and Cu(II) could be removed in a simultaneous manner with Pb(II). A high removal performance of Pb(II) by SBC/US process and its synergism with phenol oxidation had been successfully achieved. The simultaneous removal efficiencies of Pb(II) and phenol were high up to 95% within 60 min at optimum reaction conditions. Four kinds of Pb species inculding Pb0, PbCO 3 , PbO and Pb(OH) 2 were formed during the reaction, whereas five kinds of transformation compounds of phenol such as 1,4-benzoquinone, acetic acid, formic acid, maleic acid and propionic acid were detected. Both HO and O 2 − contributed to the oxidation of phenol by SBC/US process, but HO was dominant radical. A reaction mechanism for the synergistic removal of Pb(II) and phenol by SBC/US process involving in four stages-namely adsorption, precipitation, reduction and Fenton-like oxidation processes was proposed. This study demonstrates that SBC/US process could be considered as a potential candidate for the remediation of real wastewaters containing Pb(II) and phenol. Image 1 • Pb(II) removal of SBC/US process was superior to that of SBC. • High removal performance of Pb(II) and phenol had achieved in SBC/US process. • HO was dominant radical responsible for the degradation of phenol. • Transformation products of Pb(II) and phenol after reaction were identified. • A mechanism for the simultaneous removal of Pb(II) and phenol was proposed. [ABSTRACT FROM AUTHOR]

• A high performance of Cr(VI) removal was obtained in AMD-nZVI/PDS process. • Transformation products of Cr(VI), Cd(II) and ATZ were identified. • SO 4 − contributed to nearly 84% of the overall ATZ degradation. • The possible pathways of ATZ degradation were proposed. • A reaction mechanism for the removals of Cr(VI), Cd(II) and ATZ was proposed. Nowadays, inorganic and organic pollutants always coexist in the environment, thus an economic and efficient treatment is urgently required. In this paper, a novel nanoscale zero valent iron (AMD-nZVI) produced from the reaction of acid mine drainage (AMD) with NaBH 4 was combined with peroxydisulfate (PDS) for the simultaneous removals of Cr(VI), Cd(II) and atrazine (ATZ) in water. Results demonstrate that the reactivity of AMD-nZVI/PDS process toward Cr(VI) removal was superior to that of AMD-nZVI/HCl or AMD-nZVI/H 2 O 2 process. The coexisting species inculding PO 4 3-, HCO 3 −, NO 3 and humic acid exhibited obvious suppression on the Cr(VI) removal. The simultaneous removal efficiencies of Cr(VI), Cd(II) and ATZ by AMD-nZVI/PDS process were high up to 90% within 40 min. Most of Cr(VI) species were converted to Cr 2 O 3 and Cr(OH) 3 , whereas both Cd(OH) 2 and CdO were main Cd(II) species. The radical quenching tests affirmed that SO 4 − was the primary radical species for ATZ degradation. A total of five intermediate products of ATZ were sucessfully identified, and the degradation of ATZ was achieved through dealkylation, dechlorinatione and hydroxylation processes. A possible reaction mechanism involving in Cr(VI) reduction, Cd(II) precipitation and ATZ Fenton-like oxidation by AMD-nZVI/PDS process therefore was proposed. [ABSTRACT FROM AUTHOR]

• A synergistic effect between sonolysis and Fenton-like reaction has been achieved. • Pyrite/PMS/US system was the most efficient for the PMS decomposition. • SO 4 − radicals prevailed over HO for 2,4-DCP reaction in pyrite/PMS/US system. • The possible degradation pathways of 2,4-DCP were proposed. • A mechanism of 2,4-DCP degradation by pyrite/PMS/US system was summarized. In this paper, the natural pyrite was firstly used as peroxymonosulphate (PMS) activator in conjunction with ultrasonic irradiation (US) for 2,4-dichlorophenol (2,4-DCP) degradation in water. The most relevant findings indicated that a superior degradation of 2,4-DCP has been successfully achieved in pyrite/PMS/US system compared with pyrite/PMS and/or pyrite/US systems, which involved a synergistic effect between sonolysis and Fenton-like reaction. Within 120 min, nearly 98% of 2,4-DCP could be degraded at optimum reaction conditions of pyrite 1.00 g L−1, 2,4-DCP 10 mg L−1, PMS 2.00 mM and pH 4.02. A significantly enhanced PMS decomposition was probably ascribed to the sonochemistry (PMS/US and pyrite/US systems) and catalytic chemistry (pyrite/PMS system) under acidic conditions. Both SO 4 − and HO took part in reaction process, while the SO 4 − was dominant for 2,4-DCP degradation. A total of six intermediate products including 3,5-dichlorocatechol, 2-chlorophenol, 4-chlorocatechol, hydroquinone, maleic acid and oxalic acid were identified using GC/MS analyses to clarify the possible degradation pathways, which involved hydroxylation and substitution reactions. Compared to other Fenton reaction systems, both maximum degradation and mineralization levels of 2,4-DCP have been obtained from pyrite/PMS/US system. This study provides an interesting insight for PMS activation by the natural mineral-based catalyst with US irradiation for in situ organic pollutants remediation. [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]

• PS could induce a significant improvement of 2,4-DCP degradation by B-nZVI. • SO 4 − was primary radical responsible for the degradation of 2,4-DCP. • A possible pathway of 2,4-DCP degradation by B-nZVI/PS process was proposed. • 2,4-DCP degradation and Cd(II) immobilization has been simultaneously achieved. • A mechanism for 2,4-DCP degradation and Cd(II) immobilization was proposed. Nowadays, the remediation of heavy metals and organic compounds contaminated soil has been greatly growing attentions. In this paper, the feasibility of a novel biochar-supported zero valent iron (B-nZVI) based system for the degradation of 2,4-Dichlorophenol (2,4-DCP) and immobilization of Cd(II) in contaminated soil was firstly investigated. The most relevant findings revealed that persulfate (PS) could obviously improve the degradation of 2,4-DCP by B-nZVI process. Within 240 min, nearly 91% of 2,4-DCP degradation could be reached at reaction conditions of 40 mg kg−1 2,4-DCP, 6 mM PS, 3.0 g L−1 B-nZVI and pH 4.51. A much higher performance on the 2,4-DCP degradation was observed at acidic and aerobic conditions. A lower concentration of ethylene diamine tetraacetic acid (EDTA) exhibited a slight improvement of 2,4-DCP degradation, whereas humic acids (HA) exhibited a significant inhibitory effect on that. Radical scavenging tests revealed that SO 4 − was primarily involved in degradation reaction of 2,4-DCP by B-nZVI/PS process. A total of five intermediate products including 2-chlorohydroquinone, 3,5-dichlorocatechol, phenol, fumaric acid and acetic acid were generated in 2,4-DCP degradation process, whereas two Cd species such as Cd(OH) 2 and CdO were identified in Cd(II) immobilization process. A possible mechanism for the 2,4-DCP degradation and Cd(II) immobilization by B-nZVI/PS process was proposed. [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]

[Display omitted] • A new biochar-based magnesium oxide composite (MTBC) was firstly prepared. • TDF adsorption was well described by pseudo-second-order and Langmuir models. • Chemical adsorption process was dominant in TDF adsorption over MTBC. • Simultaneous removals of TDF and DIN has been achieved by MTBC. • A reaction mechanism of TDF and DIN adsorption by MTBC was proposed. In recent years, the ecological security has been seriously threatened by the residues of pesticides in the environment. In this study, a new biochar-based magnesium oxide composite (MTBC) was successfully prepared using Traditional Chinese Medicine residues and MgCl 2 solution, and then applied for the removal of triadimefon (TDF) and/or dinotefuran (DIN) in water. Batch experiments results indicated that 86.42 and 87.86 % of TDF and DIN removals could be obtained by MTBC within 120 min, respectively. The TDF adsorption process was proved to be well fitted with the pseudo-second-order kinetic, Elovich, liquid film diffusion, Intra-particle diffusion and Langmuir isothermal models. The TDF adsorption by MTBC was a spontaneous endothermic reaction, and chemical adsorption process was dominant. The inhibitory of the coexisting anions on TDF removal followed the order of SO 4 2−＜Cl−＜HPO 4 3−＜HCO 3 –. Both TDF and DIN could be simultaneously removed by MTBC at the certain concentrations levels. The possible removal mechanism for the adsorption of TDF and DIN by MTBC was proposed, both TDF and DIN were rapidly distributed and adsorbed on MTBC surface, then diffused into the interior pores structure and were finally adsorbed on MTBC through various reaction processes. The TDF removal process might be involved with hydrogen bonding, π-π interaction, pore filling and electrostatic interaction, while DIN removal might be involved with hydrogen bonding, pore filling and electrostatic interaction. These findings suggested that biochar-based magnesium oxide composite was an effective adsorbent for the remediation of agricultural effluents containing TDF and DIN. [ABSTRACT FROM AUTHOR]

• Immobilization of metals by BC-nZVI process was superior to that of BC or nZVI. • Immobilization of Cd or Pb was inhibited with addition of 2,4-dichlorophenol. • Cd and Pb availability decreased, whereas soil pH and organic matter increased. • Stable metals speices such as CdCO 3 , Cd(OH) 2 , PbCO 3 and Pb(OH) 2 were formed. • Mechanism for the simultaneous immobilization of Cd and Pb in soil was proposed. Risk associated with heavy metals in soil has been received widespread attention. In this study, a porous biochar supported nanoscale zero-valent iron (BC-nZVI) was applied to immobilize cadmium (Cd) and lead (Pb) in clayey soil. Experiment results indicated that the immobilization of Cd or Pb by BC-nZVI process was better than that of BC or nZVI process, and about 80% of heavy metals immobilization was obtained in BC-nZVI process. Addition of BC-nZVI could increase soil pH and organic matter (SOM). Cd or Pb immobilization was inhibited with coexisting organic compound 2,4-dichlorophenol (2,4-DCP), but 2,4-DCP could be removed in a simultaneous manner with Cd or Pb immobilization at low concentration levels. Simultaneous immobilization of Cd and Pb was achieved in BC-nZVI process, and both Cd and Pb availability significantly decreased. Stable Cd species inculding Cd(OH) 2 , CdCO 3 and CdO were formed, whereas stable Pb species such as PbCO 3 , PbO and Pb(OH) 2 were produced with BC-nZVI treatment. Simultaneous immobilization mechanism of Cd and Pb in soil by BC-nZVI was thereby proposed. This study well demonstrates that BC-nZVI has been emerged as a potential technology for the remediation of multiple heavy metals in soil. [Display omitted] [ABSTRACT FROM AUTHOR]

Chickpea (Cicer arietinum L.) is of prime importance because of vital source of protein as major food legume. Globally, it is cultivated on large area to meet dietary requirements of humans. Climatic extremes (erratic rainfall, extreme high and low temperature) are key restrains for its production. Optimum sowing time is considered as an important factor to address climatic variations and to attain maximum yield. Foliar application of potassium (K) has also been reported to increase resistance against abiotic stresses. Similarly, exogenous application of plant based growth substances (bio-stimulants) like moringa leaf extract (MLE) are extensively used to enhance productivity of field crops. Therefore, current study was planned to evaluate the impact of foliar applied K and MLE on growth, physiology and productivity of kabuli chickpea grown under varying sowing dates. There were two sowing dates (normal sown; November 15 and late sown; December 15, 2020). Experiment was comprised of treatments i.e. control, water spray, foliar application of K at 1%, foliar application of MLE at 3% and combined application of K and MLE. Foliar applied K and MLE significantly improved physiological, biochemical and yield attributes of kabuli chickpea cultivated under normal and late sown conditions. Increase in growth and yield attributes like plant height, number of nodules per plant, nodules dry weight, branches and pods per plant, 100- grain weight, biological and grain yield were recorded in case of combined foliar application of K and MLE in normal and late sown chickpea. Maximum improvement in gas exchange attributes (stomatal conductance and transpiration rate), chlorophyll contents, antioxidants (catalase, superoxide dismutase and ascorbate peroxidase) and osmolytes (proline) were recorded with combined application of K and MLE in both sowing dates. Thus, combined applied K and MLE can be used to enhance productivity of kabuli chickpea. [ABSTRACT FROM AUTHOR]

[Display omitted] Nowadays, the harm of antibiotics residues in environments to human health and ecological safety has been causing more and more attention. In this paper, a biochar based iron material (MBC) was used to activate persulfate (PS) for the removal of sulfadiazine (SDZ) from aqueous solution. Experiment results indicate that the degradation and mineralization of SDZ by MBC/PS system reached 91.79% and 60% within 60 min under the optimal reaction conditions, respectively. MBC/PS system exhibited a better performance on SDZ removal compared with MBC/H 2 O 2 system. The addition of Cu2+ ion could enhance the degradation of SDZ by MBC/PS system. PO 4 3-, Cl- and SO 4 2- had a certain degree of inhibitory effect on the SDZ degradation. Both radicals and non-radical species such as SO 4 •-, •OH and 1O 2 participated in the degradation reaction of SDZ by MBC/PS system, but •OH was the main radical species responsible for SDZ degradation. The liquid chromatograph-mass spectrometer (LC-MS) technique was used to identify the intermediate products of SDZ, and it was proposed that the degradation of SDZ might be achieved through hydrolyzation, hydroxylation, deamination and amino-oxidization processes. A possible reaction mechanism involving a synergistic effect between PS homogeneous and heterogeneous activation processes as well as both radicals and non-radicals reactions was finally proposed. [ABSTRACT FROM AUTHOR]

A novel spent coffee grounds biomass carbon block (SCC) with heteroatoms (P and S) doped graphene structure was firstly successfully synthesized which showed high oxygen reduction reaction activity. It represented high degradation performance and cycle stability as electrocatalytic block electrode for degradation of Favipiravir,. [Display omitted] • Heteroatoms P and S doped biomass carbon block with graphene structure was firstly prepared. • The biomass carbon block acts as electrocatalytic electrode with oxygen reduction reaction activity. • The biomass carbon block electrode represents high performance and cycle stability for degradation of Favipiravir. • The biomass carbon electrocatalytic system has realized the recycle and utilization of biomass resources. In this study, a biomass-derived carbon block with heteroatoms (P and S) self-doped graphene structure was successfully synthesized by spent coffee grounds (SCG) directly sintered method. The spent coffee grounds biomass-derived carbon (SCC) block was used as electrocatalytic electrode to effectively degrade the antiviral drug of Favipiravir (FAV) in water, which represented excellent oxygen reduction reaction (ORR) activity with the H2O2 production. The doped heteroatoms in the graphene structure of SCC provided many active sites in the electrocatalytic electrode for ORR as well as more production of reactive OH･. Based on the structural characterization, radical species identification and intermediate products analysis, the reaction mechanism of FAV degradation by the SCC block electrode was proposed. This catalytic system also showed high ecological safety that the ecological toxicity for Vibrio fischeri was significantly reduced with the degradation process of FAV. The degradation of FAV in recycle test and in real sample of lake water, well water, tap water all demonstrated high stability of structure and catalytic activity of SCC. The electrocatalytic system based on SCC block electrode has realized the recycling and utilization of biomass resources and has promising application on the removal of environmental pollutants. [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]

In current years, the harm of pesticide residual pollution to environmental ecology and human health has obtained increasing attention. Hydroxylamine (HA) promoted activation of persulfate (PS) by the natural metallic sulfide mineral chalcopyrite (CuFeS 2) for the removal of pesticide chlorpyrifos (CPF) and imidacloprid (IMP) in water had been systematically investigated in this study. Experimental results showed that HA could greatly accelerate the regeneration of Cu2+ and Fe3+ in solutions for PS decomposition. Nearly 99% of CPF removal by CuFeS 2 /PS/HA process was achieved within 80 min under optimal conditions. The decomposition of PS in the CuFeS 2 /PS/HA process was higher than that in the CuFeS 2 /PS process. Several coexisting cations (ie., Ca2+, Mg2+ and Al3+) and anions (ie., HCO 3 − and HPO 4 2−) presented different levels of negative effects on CPF removal. Both HO• and SO 4 •− were generated in the CuFeS 2 /PS/HA process, and HO• might be the main reactive species responsible for the removal of CPF. The synchronized removal of CPF and IMP by CuFeS 2 /PS/HA process had been successfully achieved under certain conditions. The possible pathways of CPF degradation and enhanced mechanism for both CPF and IMP removal by CuFeS 2 /PS/HA process were thereby proposed. This study highlights the applications of CuFeS 2 /PS/HA process for the remediation of multiple pesticides-polluted wastewaters. [Display omitted] • HA accelerated the regeneration of Cu2+ and Fe3+ for PS decomposition. • HO.• might be the main reactive species responsible for the removal of CPF. • Two possible degradation pathways of CPF by CuFeS 2 /PS/HA process proposed. • About 90% of both CPF and IMP removal by CuFeS 2 /PS/HA process was achieved. • Enhanced mechanism of CPF and IMP removal by CuFeS 2 /PS/HA process was proposed. [ABSTRACT FROM AUTHOR]

Abstract Biodegradable plastics, as alternatives to conventional plastics, are increasingly used, but their interactions with organic pollutants are still unknown. In this study, the sorption and desorption behaviors on a type of biodegradable plastic−poly(butylene adipate co-terephtalate) (PBAT) were investigated, and at the same time two types of conventional plastics−polyethylene (PE c and PE v) and polystyrene (PS) were used for comparison. Phenanthrene (PHEN) was chosen as one of representative organic pollutants. Results indicated that the sorption and desorption capacities of PBAT were not only higher than those of the other types of microplastics, but also higher than those of carbonaceous geosorbents. The surface area normalized results illustrated that sorption and desorption of the microplastics were positively correlated with their abundance of rubbery subfraction. The sorption kinetic results showed that the sorption rates of PBAT and PE c were higher than PE v and PS. The effects of water chemistry factors including salinity, dissolved organic matter and Cu2+ ion on the sorption process displayed the same trend, but the degrees of influence on the four microplastics differed. The degrees of influence were mainly dependent on the abundance of rubbery subfraction for microplastics. These findings indicate that the biodegradable poly(butylene adipate co-terephtalate) microplastics are actually stronger vectors than the conventional microplastics, and crystallization characteristics of the microplastics have great influences on the vector effect. Graphical abstract Image 1 Highlights • Biodegradable microplastics sorbed/desorbed more PHEN than conventional ones. • Sorption/desorption capacities depended on the content of rubbery subfraction. • Plastic additives didn't alter the microplastics adsorption process. • High salinity and low DOM strengthen the sorption of PHEN onto microplastics. [ABSTRACT FROM AUTHOR]

Nowadays, the residual heavy metals and antibiotics in water and soil have a potential threat to human being health, thereby their purification is of great importance. In this study, the application of Cr6+ and chlortetracycline (CTC) removal using a new fruit peel based biochar composite (FPBC) had been explored. Batch experiments results showed that FPBC presented excellent removal performance on Cr6+ and CTC, and the simultaneous removal efficiencies of Cr6+ and CTC were 97% and 81% within 180 min, respectively. The adsorption kinetics and isotherms of Cr6+ by FPBC could be well described by the pseudo-second-order and Langmuir models, respectively, and its adsorption was a spontaneous endothermic process. The inhibitory of the coexisting anions on Cr6+ removal of followed the order of HPO 4 3-> HCO 3 -> SO 4 2->NO 3 -> Cl-. The simultaneous removal of Cr6+ and CTC by FPBC had been achieved at low CTC content levels. The presence of NaCl showed a significant inhibitory on Cr6+ removal but a positive effect on CTC removal at low content level. A potential reaction mechanism of both Cr6+ and CTC removal over FPBC was proposed on the basic of the comprehensive characterizations and adsorption performance. Both reduction and surface precipitation reactions might be dominant in Cr6+ removal process, whereas both complexation and hydrogen bond interaction might be mainly responsible for CTC removal. These findings suggested that this fruit peel based biochar composite might be a promising material for the remediation of Cr6+ and CTC-contaminated wastewater. [Display omitted] • A new fruit peel based biochar composite (FPBC) was firstly synthesized. • Cr6+ adsorption was well described by pseudo-second-order and Langmuir models. • NaCl showed an inhibitory on Cr6+ removal but a positive effect on CTC removal. • FPBC presented a high simultaneous removal of Cr6+ and CTC. • A potential mechanism for Cr6+ and CTC removal over FPBC was proposed. [ABSTRACT FROM AUTHOR]

The negative impacts of residual antibiotics in the environment on ecosystem and human health are big concerns. However, little information is available on the antibiotic bioaccumulation in aquaculture farms. In this study, the bioaccumulative potentials of 21 antibiotics in the plasma, bile, liver and muscle of cultured fish from a typical aquaculture area were systematically investigated. Results indicated that antibiotic distribution in the cultured fish was mainly influenced by species and specific substances. The mean values of log bioaccumulation factors (Log BAFs) for the detected antibiotics were in the range of 0.43-3.70, 0.36-4.75, −0.31-4.48, and 0.23-4.33 in the fish plasma, bile, liver and muscle tissues, respectively. For grass carp, both ciprofloxacin and enrofloxacin showed high transportability from the plasma to the muscle and liver. The correlations of various antibiotic concentrations between the plasma and the other three tissues indicated that the concentrations of ciprofloxacin and enrofloxacin in the fish tissues could be predicted by their concentrations in the plasma. Based on the calculated hazard quotients, human health risk evaluation of antibiotic exposure by fish consumption indicated that the consumption of these cultured fish posed low risks to human health. [ABSTRACT FROM AUTHOR]

Recently, a large number of agricultural wastes have been extensively converted into biochar based materials, these biochar materials have been popularly employed in the removal of various pollutants from environment. Herein, a novel pigeon waste based biochar composite (FeBC) was firstly synthesized and applied for hexavalent chromium (Cr(VI)) and p-nitrophenol (PNP) adsorption in water. The most relevant findings showed that FeBC exhibited a superior performance on Cr(VI) and PNP adsorption compared with pristine biochar. The Cr(VI) monolayer adsorption onto FeBC might be dominant, and Cr(VI) adsorption by FeBC was an endothermic process. Both Cr(VI) and PNP adsorption behavior were well fitted with the pseudo-second-order kinetic model, Elovich, intra-particle diffusion (IPD), liquid film diffusion kinetic (LFD) and chemical reaction models. Both the pathway of PNP degradation and mechanism for Cr(VI) and PNP adsorption over FeBC were proposed. Almost half of Cr(VI) was reduced into Cr 2 O 3 and Cr(OH) 3 , both reduction and precipitation reactions might be dominant in Cr(VI) adsorption. O 2 •−, 1 O 2 and •OH were involved in PNP removal reaction, but the contribution of •OH was small. The oxidation, π-π interaction and hydrogen bonds interactions might be involved in this PNP removal process, and PNP was oxidized to form several intermediates via hydroxylation and ring cleavage reactions. This study could provide a novel treatment strategy for the simultaneous decontamination of effluents combined with heavy metals and organic compounds in realistic remediation application. [Display omitted] • A novel pigeon waste based biochar composite (FeBC) was firstly synthesized. • Almost half of Cr(VI) species were reduced into Cr 2 O 3 and Cr(OH) 3. • O 2 •−, 1 O 2 and •OH were involved in p-nitrophenol removal reaction. • Both Cr(VI) and p-nitrophenol removal were successfully achieved by FeBC. • A mechanism for the removal of Cr(VI) and p-nitrophenol was proposed. [ABSTRACT FROM AUTHOR]

The pollution of heavy metals and organic compounds has received increased attention in recent years. In the current study, a novel biochar-based iron oxide composite (FeYBC) was successfully synthesized using pomelo peel and ferric chloride solution through one-step process at moderate temperature. Results clearly demonstrate that FeYBC exhibited more efficient removal of Cr(VI) and/or phenol compared with the pristine biochar, and the maximum adsorption amounts of Cr(VI) and phenol by FeYBC could reach 24.37 and 39.32 mg g−1, respectively. A series of characterization data suggests that several iron oxides such as Fe 2 O 3 , Fe0, FeOOH and Fe 3 O 4 were formed on the FeYBC surface as well as oxygen-containing groups. Thermodynamics study indicates that Cr(VI) and phenol adsorption by FeYBC were endothermic and exothermic processes, respectively. Langmuir adsorption isotherm and pseudo-second order models could better explain the Cr(VI) and phenol adsorption behaviors over FeYBC. The Cr(VI) adsorption might be primarily achieved through the ion exchange and surface complexation and reduction, whereas the π–π interaction and electron donor–acceptor complex mainly contributed to phenol adsorption. The findings indicate that the biochar-based iron oxide composites material was an efficient adsorbent for the remediation of industrial effluents containing Cr(VI) and phenol. [Display omitted] • A novel biochar-based iron oxide composite (FeYBC) was firstly synthesized. • FeYBC exhibited more efficient Cr(VI) and phenol removal than pristine biochar. • Langmuir and pseudo second order models well explain Cr(VI) and phenol adsorption. • Cr(VI) and phenol adsorption were endothermic and exothermic nature, respectively. • The possible removal mechanism of both Cr(VI) and phenol adsorption was proposed. [ABSTRACT FROM AUTHOR]