Preparation Of Pd/Ag Modified Foam-Ni Electrode And Its Electro-Catalytic Dechlorination Properties

With the rapid development of the economy and the social industry,the seriousness of water pollution problems highlighted gradually.Poisonous and harmful,refractory wastewater has seriously hindered the sustainable development of the society.Chlorophenols are typical representative of toxic organic compounds which are difficult to be degraded in wastewater treatment.This kind of compounds not only has carcinogenic,teratogenic and mutagenic effect,but also is not easy to be broken down or biodegraded.Moreover,they could be enriched in the human body through food chain and significantly threaten the global environment and peoples' health.In this paper,palladium/silver/foam nickel electrode was fabricated as an electro-reduction cathode.Pentachlorophenol was chosen as the targeted pollutant to study the influence factors in the reductive dechlorination of pentachlorophenol.(1)In this paper,the constant current deposition method was used to prepare the electrode.The deposition temperature,deposition time,deposition current and the concentration of deposition liquid was investigated in order to obtain the optimum preparation conditions of palladium/foam nickel electrode.The results showed that the temperature has little effect on the electrode properties of dechlorination;with the extension of deposition time,the dechlorination effect increased.Deposition of electrode current has more effect on dechlorination performance.Considering the dechlorination,energy consumption and cost,the best conditions for preparing palladium/foam nickel electrode were deposition temperature of 20 ?,deposition current of 48 mA,concentration of palladium chloride of 1.0 mM and deposition time of 60 min.Pentachlorophenol was chosen as the targeted pollutant to investigate the operating conditions,such as initial concentration,pH,working current.Considering the target pollutant's removal efficiency and current efficiency,it is concluded that the best conditions of dechlorination were pentachlorophenol initial concentration of 15 mg/L,pH value of 1,the working current of 10 mA.After 180 min of electrochemical reductive dechlorination,the pentachlorophenol removal rate could reach 79.6%.(2)The constant current deposition method was used to prepare the electrode.The deposition temperature,deposition time,deposition current and the concentration of deposition liquid was investigated in order to obtain the optimum preparation conditions of silver/foam nickel electrode.Considering the dechlorination property of electrodes,energy consumption and cost,the best conditions for preparing silver/foam nickel electrode were deposition temperature of 20 ?,deposition current of 20 mA,concentration of silver nitrate solution was 0.5 mM and deposition time of 30 min.Pentachlorophenol was chosen as the targeted pollutant to investigate the operating conditions,such as initial concentration,pH,working current.Considering the target pollutant's removal efficiency and current efficiency,it is concluded that the best conditions of dechlorination were pentachlorophenol initial concentration of 10 mg/L,the pH value of 2,the working current of 8 mA.After 180 min of electrochemical reductive dechlorination,the pentachlorophenol removal rate could reach 68.4%.(3)The constant current deposition method was used to prepare the electrode.The deposition temperature,deposition time,deposition current and the concentration of deposition liquid was investigated in order to obtain the optimum preparation conditions of silver/foam nickel electrode.Considering the dechlorination property of electrodes,energy consumption and cost,the best conditions for preparing palladium/silver/nickel foam electrode were 0.5 mM silver nitrate,deposition time of 60 min,deposition temperature of 20 ?,deposition current of 20 mA for silver deposition;palladium chloride 1 mM,deposition time of 60 min,deposition temperature of 20 ?,deposition current of 48 mA for palladium deposition.Pentachlorophenol was chosen as the targeted pollutant to investigate the operating conditions,such as initial concentration,pH,working current.Considering the target pollutant's removal efficiency and current efficiency,it is concluded that the best conditions of dechlorination were pentachlorophenol initial concentration of 15 mg/L,the pH value of 1,the working current of 10 mA.After 180 min of electrochemical reductive dechlorination,the pentachlorophenol removal rate could reach 84.5%.(4)In conclusion,the dechlorination ability of the prepared electrodes is Pd/Ag/Foam-Ni > Pd/Fosm-Ni > Ag/Foam-Ni > Foam-Ni.