Kinetics of hydrogen peroxide consumption in aqueous phase at different hydrogen partial pressures

The reaction between aqueous hydrogen peroxide solutions and hydrogen has been studied at room temperature and in the absence of catalytic products. The concentrations of the hydrogen peroxide solutions used are in the level expected to be obtained by water radiolysis in the vicinity of spent nuclear fuel surface. On the other hand, different hydrogen pressures were used, with a maximum of 48 bars, which mimics the maximum pressure postulated as a result of iron-steel containers anoxic corrosion. The reaction evolution has been determined by the decrease of hydrogen peroxide concentration with time. A clear effect has been observed, and the rate of reaction is found to be enhanced as the hydrogen pressure is increased. From the experiments performed, a kinetic constant k = 0.029 +/- 0.009 dm(3) mol(-1) s(-1) has been determined for the reaction H2O2 + H-2(g) -> 2H(2)O based on a second-order overall kinetics reaction (first order with respect to hydrogen peroxide and first order with respect to hydrogen).