Luminescence quenching of uranyl ion adsorbed in nafion membrane by alcohols and vinyl monomers

The luminescence quenching of ∗UO22+ ion adsorbed in hydrated Nafion membrane by methanol, ethanol, 2-propanol, 2-propen-1-ol (allyl alcohol), acrylic acid, methacrylic acid, vinyl acetic acid, and vinyl acetate are studied and compared with experiments with reactants in homogeneous aqueous solution. The luminescence quenching rate constants are enhanced in Nafion by a factor of about 3 and 7.5 for alcohols and vinyl monomers, respectively. The increase in reactivity is ascribed to a combination of favorable partition of the organic compounds in the Nafion membrane and cage effect that reduces the rate of dissociation of bimolecular complexes in the mechanism of the photo-oxidation processes involving ∗UO22+ ion and the organic compounds.