Effect of Al2O3 Nanoparticles on Radiolytic H2O2 Production in Water

The yields of H2O2 have been determined in aqueous slurries in the pH range of 1-13 with various amounts of added Al2O3 nanoparticles. The addition of Al2O3 generally decreases H2O2 yields at all pH values within this range in the gamma radiolysis of both deaerated and aerated slurries, except at pH above 11. Very little effect of pH is observed in the gamma radiolysis of deaerated systems in the pH range of 3 8, whereas a large increase in H2O2 yields is observed in aerated Al2O3 slurries as the pH increases or decreases from neutral. Results with 5 MeV H and He ions for H2O2 yields in aerated Al2O3 slurries above pH 4 have similar trends as in gamma radiolysis, except with different absolute yields. Scavenger capacity studies using methanol as an OH center dot radical scavenger show that the decrease in H2O2 yields with added Al2O3 occurs at relatively long time scales and is probably due to reaction of the solid nanoparticles with OH center dot radicals.