Investigating the activation of the persulfate process through heterogeneous carbonaceous catalysts to expedite the reduction of uranyl ions(U(Ⅵ))is imperative.The primary hurdle involves understanding the transfer a...Investigating the activation of the persulfate process through heterogeneous carbonaceous catalysts to expedite the reduction of uranyl ions(U(Ⅵ))is imperative.The primary hurdle involves understanding the transfer and distribution of photogenerated carriers during the reduction process in this intricate system and deciphering the role of activated groups in promoting reduction efficiency.In this study,we strategically regulate the structure of polymeric carbon nitride to promote the N-doped state,thereby facilitating delocalization electron enrichment.The resulting active sites effectively activate peroxyl disulfate(PDS),generating radicals that expedite the selective reduction of U(VI).This strategic approach mitigates the inherent disadvantage of the short half-life of free radicals in persulfate-based advanced oxidation processes.As a consequence of our endeavors and with the simultaneous presence of PDS and hydrogen peroxide,we achieve an exceptional photoreduction efficiency of 100%within a remarkably short period of 20 min.This breakthrough presents a high-efficiency application with significant potential for addressing the pollution associated with uranylcontaining wastewater.Our findings not only contribute to the fundamental understanding of AOPs but also offer a practical solution with implications for environmental remediation.展开更多
Stable isotope probing （SIP） was used to identify microbes stimulated by ethanol addition in microcosms containing two sediments collected from the bioremediation test zone at the US Department of Energy Oak Ridge s...Stable isotope probing （SIP） was used to identify microbes stimulated by ethanol addition in microcosms containing two sediments collected from the bioremediation test zone at the US Department of Energy Oak Ridge site, TN, USA. One sample was highly bioreduced with ethanol while another was less reduced. Microcosms with the respective sediments were amended with ^13C labeled ethanol and incubated for 7 days for SIP. Ethanol was rapidly converted to acetate within 24h accompanied with the reduction of nitrate and sulfate. The accumulation of acetate persisted beyond the 7 d period. Aqueous U did not decline in the microcosm with the reduced sediment due to desorption of U but continuously declined in the less reduced sample. Microbial growth and concomitant 13C-DNA production was detected when ethanol was exhausted and abundant acetate had accumulated in both microcosms. This coincided with U（VI） reduction in the less reduced sample. I3C originating from ethanol was ultimately utilized for growth, either directly or indirectly, by the dominant microbial community members within 7 days of incubation. The microbial community was comprised predominantly of known denitrifiers, sulfate-reducing bacteria and iron （Ⅲ） reducing bacteria including Desulfovibrio, Sphingomonas, Ferribacterium, Rhodanobacter, Geothrix, Thiobacillus and others, including the known U（VI）-redueing bacteria Acidovorax, Anaeromyxobacter, Desulfovibrio, Geobac- ter and Desulfosporosinus. The findings suggest that ethanol biostimulates the U（VI）-reducing microbial com- munity by first serving as an electron donor for nitrate, sulfate, iron （IH） and U（VI） reduction, and acetate which then functions as electron donor for U（VI） reduction and carbon source for microbial growth.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:22162009,32360236。
文摘Investigating the activation of the persulfate process through heterogeneous carbonaceous catalysts to expedite the reduction of uranyl ions(U(Ⅵ))is imperative.The primary hurdle involves understanding the transfer and distribution of photogenerated carriers during the reduction process in this intricate system and deciphering the role of activated groups in promoting reduction efficiency.In this study,we strategically regulate the structure of polymeric carbon nitride to promote the N-doped state,thereby facilitating delocalization electron enrichment.The resulting active sites effectively activate peroxyl disulfate(PDS),generating radicals that expedite the selective reduction of U(VI).This strategic approach mitigates the inherent disadvantage of the short half-life of free radicals in persulfate-based advanced oxidation processes.As a consequence of our endeavors and with the simultaneous presence of PDS and hydrogen peroxide,we achieve an exceptional photoreduction efficiency of 100%within a remarkably short period of 20 min.This breakthrough presents a high-efficiency application with significant potential for addressing the pollution associated with uranylcontaining wastewater.Our findings not only contribute to the fundamental understanding of AOPs but also offer a practical solution with implications for environmental remediation.
基金The authors thank Benli Chai for bioinformatic support and Anthony Gaca and Ami Smith for technical assistance in the laboratory. This study was funded by the US DOE Office of Science under grants DE-FG02-97ER62469, DE-FG02-97ER64398, AC05-00OR22725, and DE-SC0006783. Mary Beth Leigh was supported by a US National Science Foundation postdoctoral fellowship in Microbial Biology.
文摘Stable isotope probing （SIP） was used to identify microbes stimulated by ethanol addition in microcosms containing two sediments collected from the bioremediation test zone at the US Department of Energy Oak Ridge site, TN, USA. One sample was highly bioreduced with ethanol while another was less reduced. Microcosms with the respective sediments were amended with ^13C labeled ethanol and incubated for 7 days for SIP. Ethanol was rapidly converted to acetate within 24h accompanied with the reduction of nitrate and sulfate. The accumulation of acetate persisted beyond the 7 d period. Aqueous U did not decline in the microcosm with the reduced sediment due to desorption of U but continuously declined in the less reduced sample. Microbial growth and concomitant 13C-DNA production was detected when ethanol was exhausted and abundant acetate had accumulated in both microcosms. This coincided with U（VI） reduction in the less reduced sample. I3C originating from ethanol was ultimately utilized for growth, either directly or indirectly, by the dominant microbial community members within 7 days of incubation. The microbial community was comprised predominantly of known denitrifiers, sulfate-reducing bacteria and iron （Ⅲ） reducing bacteria including Desulfovibrio, Sphingomonas, Ferribacterium, Rhodanobacter, Geothrix, Thiobacillus and others, including the known U（VI）-redueing bacteria Acidovorax, Anaeromyxobacter, Desulfovibrio, Geobac- ter and Desulfosporosinus. The findings suggest that ethanol biostimulates the U（VI）-reducing microbial com- munity by first serving as an electron donor for nitrate, sulfate, iron （IH） and U（VI） reduction, and acetate which then functions as electron donor for U（VI） reduction and carbon source for microbial growth.
