Formation of bromates at a titanium anode

The production of sodium bromate by electrolysis of concentrated sodium bromide solution (300 g dm-3 NaBr) in a cell without a diaphragm, by the use of a RuO2/TiO2 titanium anode (DSA), has been investigated. The current efficiency was high (98% – 99%) when the pH value of the solution was maintained between 8.5 and 9.5 and in the presence of Na2Cr2O7 (3.0 g dm-3). The theoretical calculations of the influence of pH on the current efficiency confirm the dependence obtained experimentally.