The Ion Exchange Properties of Silica Gel I. The Sorption of Na+, Ca2+, Ba2+, UO22+, Gd3+, Zr(IV) + Nb, U(IV), and Pu(IV).

Abstract

The metal ion sorption on silica gel was investigated. The silica gel acts in this respect as an ion exchanger of the weakly acid type and in the case of a monovalent cation the exchange reaction can be written as Si - OH + Me/sup +/ (?) Si - OMe + H/sup +/. For this equilibrium the law of mass action seems to be valid. Moreover an amount of hydrogen ions equivalent to the amount of metal ions sorbed is set free at the sorption on silica gel that is saturated with hydrogen ions. The amount of metal ion sorbed depends strongly on the pH of the solution. At the sorption of strongly hydrolyzed (presumably high molecular) ions the equilibrium is reached slowly, whereas the sorption of nonhydrolyzed (low molecular) ions is quite rapid, the equilibrium usually being reached within five minutes. (auth)