| 초록 |
Electrochemical cell performance of a divided cell with electrogeneration of Ag2 from Ag in 6 M HNO3 anolyte has been studied with 6 M HNO3 or 3 M H2SO4 as the catholyte. This work arose because in mediated electrochemical oxidation (MEO) processes with Ag(II)/Ag(I) redox mediator, generally HNO3 is used as catholyte, which, however, produces NOx gases in the cathode compartment. The performance of the cell with 6 M HNO3 or 3 M H2SO4 as the catholyte has been compared in terms of (i) the acid concentration in the cathode compartment, (ii) the Ag to Ag2 conversion efficiency in the anolyte, (iii) the migration of Ag from anolyte to catholyte across the membrane separator, and (iv) the cell voltage. Studies with various concentrations of H2SO4 catholyte have been carried-out, and the cathode surfaces have been analyzed by SEM and EDXA; similarly, the precipitated material collected in the cathode compartment at higher H2SO4 concentrations has been analyzed by XRD to understand the underlying processes. The various beneficial effects in using H2SO4 as the catholyte have been presented. A simple cathode surface renewal method relatively free from Ag deposit has been suggested. |
