Kinetics of uranium(VI) ion sorption by cryogranulated hydroxides of magnesium, cadmium, cobalt, and nickel

The kinetics of uranium ion sorption from 0.005 M UO2(NO3)2 and UO2F2 solutions by cryogranulated hydroxides of several bivalent metals is studied. A mathematical model is proposed to describe the sorption process under the conditions of the hydroxo compound phase formation as a thin layer on the hydroxide particle (granule) surface. The role of the diffusion processes is shown. The temperature dependences for the sorption rate are obtained as equations of the type 1n (dMy/dt) = A - BT-1. The activation energy of the sorption process for the hydroxides lies within 43-50 kJ/mole, which shows that the chemical stage makes a significant contribution to the rate of the overall process