Nanoscale Fe0 was synthesized through a reductive method in this paper. The experiments were per-formed to investigate the reduction of 2,4-dichlorophenol (2,4-DCP) by nanoscale Fe0 under different conditions. The pat...Nanoscale Fe0 was synthesized through a reductive method in this paper. The experiments were per-formed to investigate the reduction of 2,4-dichlorophenol (2,4-DCP) by nanoscale Fe0 under different conditions. The pathways for the reduction of 2,4-DCP by nanoscale Fe0 were discussed. Batch studies demonstrated that the mechanism includes adsorption, dechlorination and cleavage of the benzene ring. Dechlorination, which occurs after 2,4-DCP molecule is adsorbed on the interface of Fe particle, is an interfacial reaction. One or two chlorine atom can be removed from 2,4-DCP to form 2-chlorophenol, 4-chlorophenol or phenol. As the concentration of 2,4-DCP increased, the relative dechlorination ratio decreased. However, the reduced quantities of 2,4-DCP increased. Temperature can influence dechlo-rination rate and pathway. Dechlorination is prior to cleavage of the benzene ring at a higher tempera-ture, but at a lower temperature, adsorption may be the main pathway, and cleavage of the benzene ring may be prior to dechlorination.展开更多
In this study a new water treatment system that couples （photo-） electrochemical catalysis （PEC or EC） in a microbial fuel cell （MFC） was configured using a stainless-steel （SS） cathode coated w th Fe / TiO2....In this study a new water treatment system that couples （photo-） electrochemical catalysis （PEC or EC） in a microbial fuel cell （MFC） was configured using a stainless-steel （SS） cathode coated w th Fe / TiO2. We examined the destruction of methylene blue （MB） and tetracycline. Fe^0/TiO2 was prepared using a chemical reduction-deposition method and coated onto an SS wire mesh （500 mesh） using a sol technique. The anode generates electricity using microbes （bio-anode）. Connected via wire and ohmic resistance, the system requires a short reaction time and operates at a low cost by effectively remowng 94% MB （initial concentration 20 mg·L^-1） and 83% TOC/TOCo under visible light illumination （50 W; 1.99 mW·cm^-2 for 120 rain, MFC-PEC）. The removal was similar even without light irradiation （MFC-EC）. The EEo of the MFC-PEC system was approximately 0.675 kWh·m^-3. order-l whereas that of the MFC-EC system was zero. The system was able to remove 70% COD in tetracycline solution （initial tetracycline concentration 100 mg·L^-1） after 120 min of visible light illumination; without light, the removal was 15% lower. The destruction of MB and tetracycline in both traditional photocatalysis and photoelectrocatalysis systems was notably low. The electron spinresonance spectroscopy （ESR） study demonstrated that. OH was formed under visible light, and. 02 was formed without light. The bio-electricity-activated O2 and ROS （reactive oxidizing species） generation by Fe^0/TiO2 effectively degraded the pollutants. This cathodic degradation improved the electricity generation by accepting and consuming more electrons from the bio-anode.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 50325824, 50678089) the Excellent Young Teacher Program of MOE
文摘Nanoscale Fe0 was synthesized through a reductive method in this paper. The experiments were per-formed to investigate the reduction of 2,4-dichlorophenol (2,4-DCP) by nanoscale Fe0 under different conditions. The pathways for the reduction of 2,4-DCP by nanoscale Fe0 were discussed. Batch studies demonstrated that the mechanism includes adsorption, dechlorination and cleavage of the benzene ring. Dechlorination, which occurs after 2,4-DCP molecule is adsorbed on the interface of Fe particle, is an interfacial reaction. One or two chlorine atom can be removed from 2,4-DCP to form 2-chlorophenol, 4-chlorophenol or phenol. As the concentration of 2,4-DCP increased, the relative dechlorination ratio decreased. However, the reduced quantities of 2,4-DCP increased. Temperature can influence dechlo-rination rate and pathway. Dechlorination is prior to cleavage of the benzene ring at a higher tempera-ture, but at a lower temperature, adsorption may be the main pathway, and cleavage of the benzene ring may be prior to dechlorination.
文摘In this study a new water treatment system that couples （photo-） electrochemical catalysis （PEC or EC） in a microbial fuel cell （MFC） was configured using a stainless-steel （SS） cathode coated w th Fe / TiO2. We examined the destruction of methylene blue （MB） and tetracycline. Fe^0/TiO2 was prepared using a chemical reduction-deposition method and coated onto an SS wire mesh （500 mesh） using a sol technique. The anode generates electricity using microbes （bio-anode）. Connected via wire and ohmic resistance, the system requires a short reaction time and operates at a low cost by effectively remowng 94% MB （initial concentration 20 mg·L^-1） and 83% TOC/TOCo under visible light illumination （50 W; 1.99 mW·cm^-2 for 120 rain, MFC-PEC）. The removal was similar even without light irradiation （MFC-EC）. The EEo of the MFC-PEC system was approximately 0.675 kWh·m^-3. order-l whereas that of the MFC-EC system was zero. The system was able to remove 70% COD in tetracycline solution （initial tetracycline concentration 100 mg·L^-1） after 120 min of visible light illumination; without light, the removal was 15% lower. The destruction of MB and tetracycline in both traditional photocatalysis and photoelectrocatalysis systems was notably low. The electron spinresonance spectroscopy （ESR） study demonstrated that. OH was formed under visible light, and. 02 was formed without light. The bio-electricity-activated O2 and ROS （reactive oxidizing species） generation by Fe^0/TiO2 effectively degraded the pollutants. This cathodic degradation improved the electricity generation by accepting and consuming more electrons from the bio-anode.
