Simultaneous production of sodium peroxodisulfate and sodium dithionite, useful as bleach, e.g. for pulp, involves anodic oxidation of sodium sulfate in cell with cation exchange membrane and sodium dithionite formation in cathode chamber

摘要

Simultaneous production of sodium peroxodisulfate (I) and sodium dithionite (II) is carried out in a divided electrolysis cell at current densities of 1.5-6 kA/m2 and 20-60 deg C. The process comprises (i) anodic oxidation of sodium sulfate in aqueous solution to (I); and (ii) cathodic production of (II) from sodium ions, which are liberated at the anode and pass through the cation exchange membrane, and added sulfur dioxide at pH 4-6.