Due to the toxicity of bioaccumulative organohalides to human beings and ecosystems,a variety of biotic and abiotic remediation methods have been developed to remove organohalides from contaminated environments.Biorem...Due to the toxicity of bioaccumulative organohalides to human beings and ecosystems,a variety of biotic and abiotic remediation methods have been developed to remove organohalides from contaminated environments.Bioremediation employing organohalide-respiring bacteria(OHRB)-mediated microbial reductive dehalogenation(Bio-RD)represents a cost-effective and environmentally friendly approach to attenuate highly-halogenated organohalides,specifically organohalides in soil,sediment and other anoxic environments.Nonetheless,many factors severely restrict the implications of OHRB-based bioremediation,including incomplete dehalogenation,low abundance of OHRB and consequent low dechlorination activity.Recently,the development of in situ chemical oxidation(ISCO)based on sulfate radicals(SO_(4)^(·−))via the persulfate activation and oxidation(PAO)process has attracted tremendous research interest for the remediation of lowly-halogenated organohalides due to its following advantages,e.g.,complete attenuation,high reactivity and no selectivity to organohalides.Therefore,integration of OHRB-mediated Bio-RD and subsequent PAO(Bio-RD-PAO)may provide a promising solution to the remediation of organohalides.In this review,we first provide an overview of current progress in Bio-RD and PAO and compare their limitations and advantages.We then critically discuss the integration of Bio-RD and PAO(Bio-RD-PAO)for complete attenuation of organohalides and its prospects for future remediation applications.Overall,Bio-RD-PAO opens up opportunities for complete attenuation and consequent effective in situ remediation of persistent organohalide pollution.展开更多
A straightforward protocol using readily available aromatic amines,N,N,N',N'-tetramethyl-p-phenylenediamine or N,N,N',N'-tetramethylbenzidine,as photocatalysts was developed for theefficient hydrodehal...A straightforward protocol using readily available aromatic amines,N,N,N',N'-tetramethyl-p-phenylenediamine or N,N,N',N'-tetramethylbenzidine,as photocatalysts was developed for theefficient hydrodehalogenation of organic halides,such as 4'-bromoacetophenone,polyfluoroarenes,cholorobenzene,and 2,2',4,4'-tetrabromodiphenyl ether(a resistant and persistent organic pollu-tant).The strongly reducing singlet excited states of the amines enabled diffusion-controlled disso-ciative electron transfer to effectively cleave carbon-halogen bonds,followed by radical hydrogena-tion.Diisopropylethylamine served as the terminal electron/proton donor and regenerated theamine sensitizers.展开更多
Biodegradation of lower chlorinated benzenes(tri-, di-and monochlorobenzene) was assessed at a coastal aquifer contaminated with multiple chlorinated aromatic hydrocarbons. Field-derived microcosms, established with g...Biodegradation of lower chlorinated benzenes(tri-, di-and monochlorobenzene) was assessed at a coastal aquifer contaminated with multiple chlorinated aromatic hydrocarbons. Field-derived microcosms, established with groundwater from the source zone and amended with a mixture of lower chlorinated benzenes, evidenced biodegradation of monochlorobenzene(MCB) and 1,4-dichlorobenzene(1,4-DCB) in aerobic microcosms,whereas the addition of lactate in anaerobic microcosms did not enhance anaerobic reductive dechlorination. Aerobic microcosms established with groundwater from the plume consumed several doses of MCB and concomitantly degraded the three isomers of dichlorobenzene with no observable inhibitory effect. In the light of these results, we assessed the applicability of compound stable isotope analysis to monitor a potential aerobic remediation treatment of MCB and 1,4-DCB in this site. The carbon isotopic fractionation factors(ε) obtained from field-derived microcosms were-0.7‰ ± 0.1 ‰ and-1.0‰ ± 0.2 ‰ for MCB and1,4-DCB, respectively. For 1,4-DCB, the carbon isotope fractionation during aerobic biodegradation was reported for the first time. The weak carbon isotope fractionation values for the aerobic pathway would only allow tracing of in situ degradation in aquifer parts with high extent of biodegradation. However, based on the carbon isotope effects measured in this and previous studies, relatively high carbon isotope shifts(i.e., Δδ13C > 4.0 ‰) of MCB or 1,4-DCB in contaminated groundwater would suggest that their biodegradation is controlled by anaerobic reductive dechlorination.展开更多
基金This study was supported by the National Natural Science Foundation of China(Grant Nos.41922049 and 41877111)the Fundamental Research Funds for the Central Universities(No.19lgzd30)the Guangzhou Science and Technology Program general project(No.201804010141).
文摘Due to the toxicity of bioaccumulative organohalides to human beings and ecosystems,a variety of biotic and abiotic remediation methods have been developed to remove organohalides from contaminated environments.Bioremediation employing organohalide-respiring bacteria(OHRB)-mediated microbial reductive dehalogenation(Bio-RD)represents a cost-effective and environmentally friendly approach to attenuate highly-halogenated organohalides,specifically organohalides in soil,sediment and other anoxic environments.Nonetheless,many factors severely restrict the implications of OHRB-based bioremediation,including incomplete dehalogenation,low abundance of OHRB and consequent low dechlorination activity.Recently,the development of in situ chemical oxidation(ISCO)based on sulfate radicals(SO_(4)^(·−))via the persulfate activation and oxidation(PAO)process has attracted tremendous research interest for the remediation of lowly-halogenated organohalides due to its following advantages,e.g.,complete attenuation,high reactivity and no selectivity to organohalides.Therefore,integration of OHRB-mediated Bio-RD and subsequent PAO(Bio-RD-PAO)may provide a promising solution to the remediation of organohalides.In this review,we first provide an overview of current progress in Bio-RD and PAO and compare their limitations and advantages.We then critically discuss the integration of Bio-RD and PAO(Bio-RD-PAO)for complete attenuation of organohalides and its prospects for future remediation applications.Overall,Bio-RD-PAO opens up opportunities for complete attenuation and consequent effective in situ remediation of persistent organohalide pollution.
文摘A straightforward protocol using readily available aromatic amines,N,N,N',N'-tetramethyl-p-phenylenediamine or N,N,N',N'-tetramethylbenzidine,as photocatalysts was developed for theefficient hydrodehalogenation of organic halides,such as 4'-bromoacetophenone,polyfluoroarenes,cholorobenzene,and 2,2',4,4'-tetrabromodiphenyl ether(a resistant and persistent organic pollu-tant).The strongly reducing singlet excited states of the amines enabled diffusion-controlled disso-ciative electron transfer to effectively cleave carbon-halogen bonds,followed by radical hydrogena-tion.Diisopropylethylamine served as the terminal electron/proton donor and regenerated theamine sensitizers.
基金supported by the Catalan Water Agency (No. CTN1900901)supported by the projects CGL2017–82331-R (Spanish Ministry of Economy and Competitiveness)2017SGR 1733 (Catalan Government)。
文摘Biodegradation of lower chlorinated benzenes(tri-, di-and monochlorobenzene) was assessed at a coastal aquifer contaminated with multiple chlorinated aromatic hydrocarbons. Field-derived microcosms, established with groundwater from the source zone and amended with a mixture of lower chlorinated benzenes, evidenced biodegradation of monochlorobenzene(MCB) and 1,4-dichlorobenzene(1,4-DCB) in aerobic microcosms,whereas the addition of lactate in anaerobic microcosms did not enhance anaerobic reductive dechlorination. Aerobic microcosms established with groundwater from the plume consumed several doses of MCB and concomitantly degraded the three isomers of dichlorobenzene with no observable inhibitory effect. In the light of these results, we assessed the applicability of compound stable isotope analysis to monitor a potential aerobic remediation treatment of MCB and 1,4-DCB in this site. The carbon isotopic fractionation factors(ε) obtained from field-derived microcosms were-0.7‰ ± 0.1 ‰ and-1.0‰ ± 0.2 ‰ for MCB and1,4-DCB, respectively. For 1,4-DCB, the carbon isotope fractionation during aerobic biodegradation was reported for the first time. The weak carbon isotope fractionation values for the aerobic pathway would only allow tracing of in situ degradation in aquifer parts with high extent of biodegradation. However, based on the carbon isotope effects measured in this and previous studies, relatively high carbon isotope shifts(i.e., Δδ13C > 4.0 ‰) of MCB or 1,4-DCB in contaminated groundwater would suggest that their biodegradation is controlled by anaerobic reductive dechlorination.
