Radical reactions and transient products in water radiolysis at the inter face between water and silica

Kumagai, Yuta   ; Muroya, Yusa*; Saiki, Seiichi; Yamada, Reiji; Nagaishi, Ryuji ; Katsumura, Yosuke*

Peculiar radiation effect at the interface between water and silica has been studied by time-resolved observation of the transient behaviors of radicals produced by irradiation in aqueous solution containing colloidal silica using pulse-radiolysis technique. Scavenging reaction of OH radical by colloidal silica was observed and the reactivity was dependent on pH of aqueous solution. On the other hand, the presence of colloidal silica had no significant effect on the decay kinetics of hydrated electron. Therefore the interaction of the interface with OH radical is expected but not with hydrated election Besides, ESR spectrum of transient radicals in the presence of colloidal silica was measured at 77 K. Change in the spectrum shapes of OH radical and HO radical suggests that there were interactions of colloidal silica with the radicals.