Cation exchangers on a sugar‐beet pulp base. Application for decontaminating radioactive waste water

Abstract

AbstractA cation exchanger suitable for decontaminating low and medium radioactive waste water was sought. Regeneration being considered undesirable, the exchange material had to be cheap and readily obtainable. Sugar‐beet pulp, a weakly acidic cation exchanger, satisfies these conditions. Its capacity is about 0·62 mg eq. per gram of dry matter. In order to study the selectivity of the sugar‐beet pulp exchanger, the equilibrium curve of the reaction equation image was determined.This curve was found to have the shape of the hyperbola proposed by Waterman and Weber for the characterization of the course of simultaneous reactions. Sugar‐beet pulp adsorbs the salts of the alkaline earth metals selectively in the presence of both Na+ and La+++. Sugar‐beet pulp was used to decontaminate a solution containing 140BaCl2 and 140LaCl3 and having an activity of about 10−2 μc/ml. The results were satisfactory.By treating sugar‐beet pulp with formaldehyde and hydrochloric acid, the amount of water bound to the pulp is very much decreased. By this treatment a cation exchanger is produced having a capacity per unit volume about six times greater than that of sugar‐beet pulp. The capacity of this exchanger is about 0·5 mg eq. per gram of dry matter. The selective behaviour of sugar‐beet pulp treated with formaldehyde is similar to that of unmodified sugar‐beet pulp.By treating sugar‐beet pulp with formaldehyde, hydrochloric acid and dilute sulphuric acid, a cation exchanger with very good mechanical and filtration properties is obtained. This exchanger has a capacity of about 1·3 mg eq. per gram of dry matter.It seems possible to employ the cation exchangers obtained by treatment of sugar‐beet pulp with either formaldehyde and HCl or formaldehyde, HCl and H2SO4 also for purposes other than the removal of radioactive cations from water.