Research On Electrochemical Reduction Behavior Of Polychlorinated Biphenyls(PCB-77,PCB-101) And Influencing Factors

Polychlorinated biphenyls are typical persistent organic pollutants(POPs) withlow degradability and high biotoxicity and had a great deal of potential risks onboth environment and human beings. In order to degrade the PCBs effectively,searching for the approach to detect the PCBs is becoming the first priority.Electrochemical reduction is an environmental friendly techqinue that displayssome special advantages in dealing with the pollutants in waster water and soilbecause it is time saving and low cost and could be used in on-scene determination.Therefore, the research on the electrochemical reduction behavior of PCBs isessential and of great importance.In this thesis,3,3’,4,4’-tetrachlorobiphenyl(PCB-77) and2,2’,4,5,5’-pentachlorobiphenyl(PCB-101) was used as the representatives toinvestigate the polychlorinated biphenyls. The three tetraalkylammonium salts:tetraethylammonium bromide, tetrabutylammonium bromide, tetrabutylammoniumperchlorate and two imidazolium-based ionic liquids1-methyl-3-propylimid-azoliumiodide (MPII),3-hexyl-1-methylimidazoliumiodide (HMII) were employedas supporting electrolyte. The electrochemical reduction behavior of PCB-77andPCB-101containing different supporting electrolyte at different electrode of Pt, Ag,Cu, Ag50%/Cu50%, Ag72%/Cu28%and Ag85%/Cu15%was investigated by cyclicvoltammetry. Parameters of ambient temperature, scan rate, beneficiation time andnitrogen blow time were studied at the same time. The influence of supportingelectrolyte and electrode on the electrochemical reduction behavior of twopolychlorinated biphenyls was studied by electrochemical impedance spectroscopy.The results showed for the electrochemical reduction of PCB-77and PCB-101,HMII and MPII were much better thn traditional tetraalkylammonium salts as thesupporting electrolytes and Cu and Ag displayed higher catalytic activity than thenoble metal Pt.