[Objective] This study was conducted to investigate the effect of laundry wastewater on the quality of river water and the dilution purification effect of river water on laundry wastewater. [Method] The effects of lau...[Objective] This study was conducted to investigate the effect of laundry wastewater on the quality of river water and the dilution purification effect of river water on laundry wastewater. [Method] The effects of laundry wastewater on the contents of total nitrogen(TN), total phosphorus(TP), suspended solids(SS), chemical oxygen demand(COD) and linear alkylbenzene sulfonic acid(LAS) were studied in 7 rivers of Shaoxing City. [Result](1) The contents of TN, TP, SS, COD and LAS increased by 92%, 99%, 340%, 351% and 923%, respectively, at the discharging moment of laundry wastewater; and(2) the five pollutional indexes significantly decreased over time, and especially 2 h after the discharge of laundry wastewater, compared with former the discharge of laundry wastewater, the contents of TN, TP, COD and LAS increased by 6%, 11%, 9% and13%, respectively,while the contents of SS still increased by 76%, i.e., SS required a longer time to achieve self-purification. [Conclusion] Laundry wastewater has some influence on thequality of river water, and the self-purification function of river water could effectively remove pollutants.展开更多
Benthic biofilms,the aggregates of multi-trophic microorganisms,play an important role in nitrogen cycling in aquatic ecosystems and are significantly influenced by flow velocity.Nevertheless,the roles of multi-trophi...Benthic biofilms,the aggregates of multi-trophic microorganisms,play an important role in nitrogen cycling in aquatic ecosystems and are significantly influenced by flow velocity.Nevertheless,the roles of multi-trophic microbial communities in nitrogen cycling of benthic biofilms remain unclear,especially under flow velocity conditions.In this study,we investigated how low trophic level microbial communities(bacteria,fungi,and algae),primary predator(protozoa)and secondary predator(metazoan)mediate the nitrogen cycling in benthic biofilms under low(0.05 m/s)moderate(0.1 m/s)and high(0.15 m/s)flow velocity conditions.The results showed that the activities of ammonia monooxygenase,nitrate reductase and nitrite reductase in benthic biofilms under high flow velocity increased 26.32%,18.66%,and 10.46%,respectively,compared with those under low flow velocity.Metagenomic sequencing analysis indicated that high flow velocity enhanced the relative abundances of functional genes involved in nitrification(amoABC)and denitrification(narG,nirK,and nirS).Compared with other trophic level microorganisms,the bacterial richness had the highest explanation(42.36%)for the variation in ammonia monooxygenase,and the variations in activities of nitrate reductase and nitrite reductase were explained 33.29%and 36.68%by protozoan richness,respectively.High richness index might promote nitrification and denitrification process via upregulating amino acid transport and metabolism,and signal transduction mechanisms.The negative cross trophic associations(potential predation activity)enhanced nitrification and denitrification by promoting microbial activity further enhancing ATPase activity and potential electron donor production.This study provides a new understanding of how multi-trophic microorganisms regulate the nitrogen cycling in benthic biofilms under increased flow velocity,which will benefit river management.展开更多
Compared to well-established 1,5-HAT of N-centered radicals,the synthetic applications of 1,2-HAT process were scarce due to the high barrier and constrained three-membered transition state.Here,we have developed a no...Compared to well-established 1,5-HAT of N-centered radicals,the synthetic applications of 1,2-HAT process were scarce due to the high barrier and constrained three-membered transition state.Here,we have developed a novel C(sp')-H gem-difluoroallylation via a base assisted formal 1,2-HAT of amidyl radicals with the reductive quenching cycle of photocatalyst.This transformation enables the efficient formation ofα-aminoalkyl radicals via 1,2-HAT and showcases good functional group tolerance.Our preliminary mechanistic experiments,along withDensity Functional Theory(DFT)calculations demonstrate thefeasibility of 1,2-HAT of amidyl radicals,especially when assisted by a base.Furthermore,our method also succeeds in the Giese addition of electron-deficient alkenes as well as styrene.展开更多
基金Supported by Natural Science Foundation of China(31500321)Scientific Research Foundation of Shaoxing University(20145024)
文摘[Objective] This study was conducted to investigate the effect of laundry wastewater on the quality of river water and the dilution purification effect of river water on laundry wastewater. [Method] The effects of laundry wastewater on the contents of total nitrogen(TN), total phosphorus(TP), suspended solids(SS), chemical oxygen demand(COD) and linear alkylbenzene sulfonic acid(LAS) were studied in 7 rivers of Shaoxing City. [Result](1) The contents of TN, TP, SS, COD and LAS increased by 92%, 99%, 340%, 351% and 923%, respectively, at the discharging moment of laundry wastewater; and(2) the five pollutional indexes significantly decreased over time, and especially 2 h after the discharge of laundry wastewater, compared with former the discharge of laundry wastewater, the contents of TN, TP, COD and LAS increased by 6%, 11%, 9% and13%, respectively,while the contents of SS still increased by 76%, i.e., SS required a longer time to achieve self-purification. [Conclusion] Laundry wastewater has some influence on thequality of river water, and the self-purification function of river water could effectively remove pollutants.
基金supported by the National Natural Science Foundation of China(Nos.52425902,52279061,and U2443217)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(No.KYCX24_0905).
文摘Benthic biofilms,the aggregates of multi-trophic microorganisms,play an important role in nitrogen cycling in aquatic ecosystems and are significantly influenced by flow velocity.Nevertheless,the roles of multi-trophic microbial communities in nitrogen cycling of benthic biofilms remain unclear,especially under flow velocity conditions.In this study,we investigated how low trophic level microbial communities(bacteria,fungi,and algae),primary predator(protozoa)and secondary predator(metazoan)mediate the nitrogen cycling in benthic biofilms under low(0.05 m/s)moderate(0.1 m/s)and high(0.15 m/s)flow velocity conditions.The results showed that the activities of ammonia monooxygenase,nitrate reductase and nitrite reductase in benthic biofilms under high flow velocity increased 26.32%,18.66%,and 10.46%,respectively,compared with those under low flow velocity.Metagenomic sequencing analysis indicated that high flow velocity enhanced the relative abundances of functional genes involved in nitrification(amoABC)and denitrification(narG,nirK,and nirS).Compared with other trophic level microorganisms,the bacterial richness had the highest explanation(42.36%)for the variation in ammonia monooxygenase,and the variations in activities of nitrate reductase and nitrite reductase were explained 33.29%and 36.68%by protozoan richness,respectively.High richness index might promote nitrification and denitrification process via upregulating amino acid transport and metabolism,and signal transduction mechanisms.The negative cross trophic associations(potential predation activity)enhanced nitrification and denitrification by promoting microbial activity further enhancing ATPase activity and potential electron donor production.This study provides a new understanding of how multi-trophic microorganisms regulate the nitrogen cycling in benthic biofilms under increased flow velocity,which will benefit river management.
基金We thank the National Natural Science Foundation of China(22001233)Zhejiang Provincial Ten Thousand Talent Program(2020R52021)and Zhejiang Normal University for financial support.
文摘Compared to well-established 1,5-HAT of N-centered radicals,the synthetic applications of 1,2-HAT process were scarce due to the high barrier and constrained three-membered transition state.Here,we have developed a novel C(sp')-H gem-difluoroallylation via a base assisted formal 1,2-HAT of amidyl radicals with the reductive quenching cycle of photocatalyst.This transformation enables the efficient formation ofα-aminoalkyl radicals via 1,2-HAT and showcases good functional group tolerance.Our preliminary mechanistic experiments,along withDensity Functional Theory(DFT)calculations demonstrate thefeasibility of 1,2-HAT of amidyl radicals,especially when assisted by a base.Furthermore,our method also succeeds in the Giese addition of electron-deficient alkenes as well as styrene.
