ADSORPTION BEHAVIOR OF NEPTUNIUM ON SILICA GEL IN NITRIC ACID SOLUTION

The adsorption behavior of Np(Ⅳ), Np(Ⅴ) and Np(Ⅵ) on silica gel in nitric acid solutions is studied.The results show that the adsorption equilibrium can be reached within 2 to 4 hours.Adsorption distribution coefficients increase with the increasing of temperature.The concentrations of redox reagents have light effects on adsorption within the studied concentration range.The adsorption isotherm of neptunium on silica gel corresponds to the form of Langmuir isotherm.From the data of adsorption heat it is concluded that the adsorption of neptunium on silica gel in nitric acid solutions belongs to chemical adsorption and the adsorption process is an endothermic reaction.