| The 3% Pt/SiO2 catalyst was prepared by using macroporous silica as the carrier and supportingplatinum via impregnation method, which was used for the catalytic reduction of uranyl(Ⅵ) nitrate to uranium (U(Ⅳ)) with hydrazine nitrate. The effects of catalyst dosage, nitric acid concentration, hydrazine nitrate concentration and reaction temperature on the catalytic reduction of U(Ⅵ) were investigated. The characterization results showed that Pt in the catalyst was mainly deposited on the surface of porous SiO2 carrier in the form of 1~3 nm nanoparticles. The optimal catalytic reaction conditions are as follows: 1.0 mol/L of hydrazine nitrate, 0.8 mol/L nitric acid, 0.9 mol/L uranyl nitrate, a solid-liquid ratio in the reaction solution of 3:100, 60℃ of reaction temperature for 40 min. The conversion rate of U(Ⅵ) was 100% under the optimal conditions. |
