Halogenated benzoquinones(HBQs)could cause bladder cancer,but there were few related studies on the generation and control.In this study,the impact of different precursors,pH,bromide concentration,and algae-derived or...Halogenated benzoquinones(HBQs)could cause bladder cancer,but there were few related studies on the generation and control.In this study,the impact of different precursors,pH,bromide concentration,and algae-derived organic matters on the formation of HBQs and the removal efficiency by activated carbon were investigated.It was found that the chlorination of bisphenol A produced the most 2,6-dichloro-1,4-benzoquinone(2,6-DCBQ),reaching 14.86μg/L at 1 hr,followed by tyrosine,2-chlorophenol,P-hydroxybenzoic acid,trichlorophenol,and N-methylaniline.The production of 2,6-DCBQ increased first and then decreased from 0 to 36 hr(chlorination doses 0-20 mg/L),indicating that HBQs were unstable in water.Trihalomethanes(THMs)were detected during chlorination,and the concentration increased with prolongation of reaction time.2,6-DCBQ production decreased and 2,6-dibromo-1,4-benzoquinone(2,6-DBBQ)production increased with increment bromide concentration and the bromide promoted the formation of tribromomethane.The production of 2,6-DCBQ decreased with increase of pH,and the maximum production was 141.38μg/L at pH of 5.Microcystis aeruginosa,Chlorella algae cells,and intracellular organic matters(IOM)could be chlorinated as potential precursors for HBQs.The most amount of 2,6-DCBQ was generated from algae cells of Microcystis aeruginosa,followed by Chlorella algae cells,Microcystis aeruginosa IOM,and Chlorella IOM.This study compared the removal efficiency of HBQs by granular activated carbon(GAC)and columnar activated carbon(CAC)under different carbon doses and initial concentrations of HBQs.It was found that the removal efficiency by GAC(80.1%)was higher than that by CAC(51.8%),indicating that GAC has better control for HBQs.展开更多
Metal organic frameworks(MOFs)with their large surface area and numerous active sites have attracted significant research attention.Recently,the application of MOFs for the catalytic degradation of organic pollutants ...Metal organic frameworks(MOFs)with their large surface area and numerous active sites have attracted significant research attention.Recently,the application of MOFs for the catalytic degradation of organic pollutants has provided effective solutions to address diverse environmental problems.In this review,the latest progress in MOF-based removal and degradation of organic pollutants is summarized according to the different roles of MOFs in the removal reaction systems,such as physical adsorbents,enzyme-immobilization carriers,nanozymes,catalysts for photocatalysis,photo-Fenton and sulfate radical based advanced oxidation processes(SR-AOPs).Finally,the opportunities and challenges of developing advanced MOFs for the removal of organic pollutants are discussed and anticipated.展开更多
Network is dynamic and requires update in the operation. However, many confusions and problems can be caused by careless schedule in the update process. Although the problem has been investigated for many years in tra...Network is dynamic and requires update in the operation. However, many confusions and problems can be caused by careless schedule in the update process. Although the problem has been investigated for many years in tradi- tional networks where the control plane is distributed, soft- ware defined networking （SDN） brings new opportunities and solutions to this problem by the separation of control and data plane, as well as the centralized control. This paper makes a survey on the problems caused by network update, includ- ing forwarding loop, forwarding black hole, link congestion, network policy violation, etc., as well as the state-of-the-art SDN solutions to these problems. Furthermore, we summa- rize the network configuration strength and discuss the open issues of network update in the SDN paradigm.展开更多
基金supported by the National Natural Science Foundation of China (Nos.51608011 and 42007350)the National Key Research and Development program of China (Nos.2019YFC1906303,2019YFC1906000-4,and 2019YFD1100304)the Natural Science Foundation of Beijing Municipal (No.8202010)。
文摘Halogenated benzoquinones(HBQs)could cause bladder cancer,but there were few related studies on the generation and control.In this study,the impact of different precursors,pH,bromide concentration,and algae-derived organic matters on the formation of HBQs and the removal efficiency by activated carbon were investigated.It was found that the chlorination of bisphenol A produced the most 2,6-dichloro-1,4-benzoquinone(2,6-DCBQ),reaching 14.86μg/L at 1 hr,followed by tyrosine,2-chlorophenol,P-hydroxybenzoic acid,trichlorophenol,and N-methylaniline.The production of 2,6-DCBQ increased first and then decreased from 0 to 36 hr(chlorination doses 0-20 mg/L),indicating that HBQs were unstable in water.Trihalomethanes(THMs)were detected during chlorination,and the concentration increased with prolongation of reaction time.2,6-DCBQ production decreased and 2,6-dibromo-1,4-benzoquinone(2,6-DBBQ)production increased with increment bromide concentration and the bromide promoted the formation of tribromomethane.The production of 2,6-DCBQ decreased with increase of pH,and the maximum production was 141.38μg/L at pH of 5.Microcystis aeruginosa,Chlorella algae cells,and intracellular organic matters(IOM)could be chlorinated as potential precursors for HBQs.The most amount of 2,6-DCBQ was generated from algae cells of Microcystis aeruginosa,followed by Chlorella algae cells,Microcystis aeruginosa IOM,and Chlorella IOM.This study compared the removal efficiency of HBQs by granular activated carbon(GAC)and columnar activated carbon(CAC)under different carbon doses and initial concentrations of HBQs.It was found that the removal efficiency by GAC(80.1%)was higher than that by CAC(51.8%),indicating that GAC has better control for HBQs.
基金supported by the National Key Research and Development Program of China(No.2020YFC1606801).
文摘Metal organic frameworks(MOFs)with their large surface area and numerous active sites have attracted significant research attention.Recently,the application of MOFs for the catalytic degradation of organic pollutants has provided effective solutions to address diverse environmental problems.In this review,the latest progress in MOF-based removal and degradation of organic pollutants is summarized according to the different roles of MOFs in the removal reaction systems,such as physical adsorbents,enzyme-immobilization carriers,nanozymes,catalysts for photocatalysis,photo-Fenton and sulfate radical based advanced oxidation processes(SR-AOPs).Finally,the opportunities and challenges of developing advanced MOFs for the removal of organic pollutants are discussed and anticipated.
基金The work was supported by the National Key Basic Research Program of China （973 program） （2014CB347800）, the National Natural Science Foundation of China （Grant Nos. 61522205, 61432002, 61133006, and 61502045）, the National High-tech R＆D Program of China （863 program） （2013AA013303, 2015AA01AT05, and 2015AA016102）, EU FP7 Made Curie Actions project Grant Agreement （the Cleansky project） （607584）, ZTE corporation and Tsinghua University Initiative Sci- entific Research Program.
文摘Network is dynamic and requires update in the operation. However, many confusions and problems can be caused by careless schedule in the update process. Although the problem has been investigated for many years in tradi- tional networks where the control plane is distributed, soft- ware defined networking （SDN） brings new opportunities and solutions to this problem by the separation of control and data plane, as well as the centralized control. This paper makes a survey on the problems caused by network update, includ- ing forwarding loop, forwarding black hole, link congestion, network policy violation, etc., as well as the state-of-the-art SDN solutions to these problems. Furthermore, we summa- rize the network configuration strength and discuss the open issues of network update in the SDN paradigm.
