Electrochemical Reduction of Selenium ( + 4 ) in Acidie Perchlorate Solutions

The mechanism of selenium(+4) electrocbemical reduction in acidic perchlorate solutions was studied. Dropping mercury and hanging mercury drop electrodes were used in direct current, alternating current, pulse and differential pulse polarographic and voltammetric measurements. Potentiostatic electrolysis experiments on mercury electrode were also performed. Precipitates formed on the electrode surface were identified using the x-ray diffraction and x-ray fluorescence. At the mercury electrode surface, depending on selenium concentration in the solution, mercury selenide 01' elemental selenium was accumulated. The results were greatly influenced by the presence of Hg2+ions in the perchlorate medium. The potential of the peak is pH dependent. Surface active substances supress the peak height, while the cupric ions significantly enhance ito