Radiolysis of ground water: Influence of carbonate and chloride on hydrogen peroxide production

Abstract

Small volumes of aqueous solutions have been subjected to α-radiation from a²⁴¹Am source. The irradiated solution was separated from the bulk solution by a glass filter serving as a diffusion barrier. The H₂O₂ concentration in the bulk solution was monitored by a chemiluminescence technique and the overall production of oxidizing species (H₂O₂/O₂) in irradiated ground water was studied by measuring the Fe²⁺-consumption in ground water initially containing 2·10⁻⁶ mol dm⁻³ Fe²⁺. H₂O₂ yields calculated using the computer program CHEMSIMUL are in fair agreement with experimental yields for “pure” water (pH 8) and aqueous methanol solutions (pH 5). Experimentally G(H₂O₂)=1.06±0.1 was obtained in “pure” water. In solutions containing 2·10⁻³ mol·dm⁻³ HCO ⁻₃ and in ground water G(H₂O₂) decreased to 0.69±0.03. A corresponding decrease in G(H₂O₂) was not found in the calculations. The agreement between measured and calculated Fe²⁺ consumption is fair when slow oxidative reactions in the bulk solutions are taken into account.