Electrolytic control of hydrogen peroxide release from calcium peroxide in aqueous solution.

The in situ generation of hydrogen peroxide (H 2 O 2 ) for water treatment is more practical than the use of liquid H 2 O 2 , which is costly to store and transport. Calcium peroxide (CaO 2 ), a solid carrier of H 2 O 2 , can release H 2 O 2 on dissolution in water. However, the constant H 2 O 2 release rate of CaO 2 has been a bottleneck constraining its wider application. In this study, a practical electrochemical method using a divided cell is developed to control the rate of release of H 2 O 2 from CaO 2 . The results show that the rate of H 2 O 2 release from CaO 2 is enhanced in the anolyte. The increase in H 2 O 2 release is positively correlated with the current. Under a current of 100 mA, the H 2 O 2 concentration was 2.5 times higher after 30 min of electrolysis than in the control experiment in which no current was applied. Water electrolysis in the anodic compartment generates protons that not only: (i) enhance dissolution of CaO 2 and release of H 2 O 2 , but also (ii) neutralize the alkaline pH resulting from CaO 2 dissolution, thus providing new advantages for the use of CaO 2 . This effective technique may be suitable for the sophisticated control of H 2 O 2 release in environmental applications. [ABSTRACT FROM AUTHOR]