Determination of the selenium (VI)/(IV) standard redox potential by cyclic voltammetry

Doi, Reisuke  

To obtain the reliable standard potential of Se(VI/IV), a study by cyclic voltametry was performed in Se pure system where the elements other than Se have no effects on the system. High pH solutions were used to make all the tetravalent Se species SeO in the bulk solution. Instead of the measured pH of high-ionic-strength solutions, pH was correctly estimated. The half-wave potentials were determined varying molality of Na. Experimental data have been interpreted by using SIT to give the following data, E (SeO/SeO) = 0.82270.0032 V vs. SHE, = 0.590.12 kg/mol. This E (SeO/SeO) agreed with the corrected value for OECD/NEA's and could make a contribution to more reliable prediction of speciation especially in the oxidizing ground water than OECD/NEA's.