An insight into the photochemical generation of uranous ions U(IV) in uranyl nitrate solutions

[Display omitted] •Uranous ions have been generated via photochemical route in uranyl nitrate solution.•Conversion of uranyl to uranous ions was higher in the presence of 1 N HNO3.•The formation of uranous ions was very fast in the photoirradiation with Sunlight and 395 nm LED. The photochemical generation of uranous ions U(IV) in the aqueous solution containing 40 mM uranyl nitrate, 1% (v/v) 2-propanol and/or 1% (v/v) acetone, in the presence of different concentrations of nitric acid has been investigated. The formation of U(IV) was investigated in six different light irradiations, (i) 350 nm uv lamps, (ii) 395 nm LED lamps, (iii) 300 nm uv lamps, (iv) fluorescent lamps visible light, (v) 100 W tungsten lamp and (vi) Sunlight. The formation kinetics of U(IV) was followed by monitoring the absorbance at 648 nm from the absorption spectra of the solution recorded at different photo-irradiation time intervals. It was observed that the maximum conversion of U(VI) to U(IV) was about 72% in the case of solution containing 40 mM UO2(NO3)2, 1% 2-propanol and 1 N HNO3 under 350 nm uv light and it was stable for several days in de-aerated condition.