AQUEOUS OXIDATION OF SODIUM PHOSPHITE BY DISSOLVED OXYGEN USING SULFUR DIOXIDE IN A CATALYTIC RACTION

摘要

Aqueous oxidation of phosphite ions to phosphate ions with dissolved oxygen was examined at 80℃ and pH 4.5 mainly from the stichiometric point of view. Dissolved oxygen alone can not oxidize sodium phosphite in aqueous solution, but when sulfur dioxide is coexistent, cooperative oxidation for both sulfite and phosphite can occur in aqueous solution. Sulfur dioxide itself is well known as a reducing agent, but it also reacts as an oxidation-promoting agent for other species under a certain condition. So sulfur dioxide is a promising cheap reagent for waste phosphite processing.