In situ capping is an attractive and cost-effective method for remediation of contaminated sediments,but few studies on enhancing contaminant degradation in sediment caps have been reported,especially for chlorinated ...In situ capping is an attractive and cost-effective method for remediation of contaminated sediments,but few studies on enhancing contaminant degradation in sediment caps have been reported,especially for chlorinated benzenes.Electrically enhanced bioactive barrier is a new process for in situ remediation for reducible compounds in soil or sediments.The primary objective of this study is to determine if electrodes in sediment could create a redox gradient and provide electron acceptor/donor to stimulate degradation of chlorinated contaminant.The results demonstrate that graphite electrodes lead to sustainable evolution of hydrogen,displaying zero-order kinetics in the initial stages with different voltages.The constant rates of hydrogen evolution at 3,4,and 5 V are1.05,2.54,and 4.3 nmol·L 1·d 1,respectively.Even higher voltage can produce more hydrogen,but it could not keep long time because the over potentials on electrode surfaces prevent its function.The study shows that 4 V is more appropriate for hydrogen evolution.The measured and evaluated concentration of 1,2,3,5-tetrachlorobenzene in pore water of sediment and concentration of sulfate show that dechlorination is inhibited at higher concentration of sulfate.展开更多
As a major source of air pollution in urban areas, the motor vehicle exhaust has attracted more and more attention due to its growing amount and serious harm to human health. It is of benefit to the pollutant control ...As a major source of air pollution in urban areas, the motor vehicle exhaust has attracted more and more attention due to its growing amount and serious harm to human health. It is of benefit to the pollutant control to make clear the transportation characteristics of vehicle exhausts. In this paper, the transportation characteristics of vehicle exhaust pollutants are investigated by means of the on-site measurement based on a typical Beijing expressway-Badaling expressway （G6 state expressway）. The concentrations of CO, NOx, S02 and particles near the expressway were obtained, by which the variations of the particle num- ber and mass concentrations, as well as the gas pollutant volume concentrations in the vicinity of the roadways with the dis- tance from the expressway were fitted. The results show that the gas pollutant concentrations and particle concentrations de- crease almost exponentially with the distance from the expressway, which is helpful for the air pollutant database establish- ment and future pollution control in big cities.展开更多
基金Supported by the National Natural Science Foundation of China（51108317） the Municipal Natural Science Foundation of Tianjin（12JCQNJC05400）
文摘In situ capping is an attractive and cost-effective method for remediation of contaminated sediments,but few studies on enhancing contaminant degradation in sediment caps have been reported,especially for chlorinated benzenes.Electrically enhanced bioactive barrier is a new process for in situ remediation for reducible compounds in soil or sediments.The primary objective of this study is to determine if electrodes in sediment could create a redox gradient and provide electron acceptor/donor to stimulate degradation of chlorinated contaminant.The results demonstrate that graphite electrodes lead to sustainable evolution of hydrogen,displaying zero-order kinetics in the initial stages with different voltages.The constant rates of hydrogen evolution at 3,4,and 5 V are1.05,2.54,and 4.3 nmol·L 1·d 1,respectively.Even higher voltage can produce more hydrogen,but it could not keep long time because the over potentials on electrode surfaces prevent its function.The study shows that 4 V is more appropriate for hydrogen evolution.The measured and evaluated concentration of 1,2,3,5-tetrachlorobenzene in pore water of sediment and concentration of sulfate show that dechlorination is inhibited at higher concentration of sulfate.
基金supported by the National Natural Science Foundation of China(Grant No.51476055)National Basic Research Program of China("973"Project)(Grant No.2015CB251503)
文摘As a major source of air pollution in urban areas, the motor vehicle exhaust has attracted more and more attention due to its growing amount and serious harm to human health. It is of benefit to the pollutant control to make clear the transportation characteristics of vehicle exhausts. In this paper, the transportation characteristics of vehicle exhaust pollutants are investigated by means of the on-site measurement based on a typical Beijing expressway-Badaling expressway （G6 state expressway）. The concentrations of CO, NOx, S02 and particles near the expressway were obtained, by which the variations of the particle num- ber and mass concentrations, as well as the gas pollutant volume concentrations in the vicinity of the roadways with the dis- tance from the expressway were fitted. The results show that the gas pollutant concentrations and particle concentrations de- crease almost exponentially with the distance from the expressway, which is helpful for the air pollutant database establish- ment and future pollution control in big cities.
