Solubility of ThO2·xH2O(am) in the presence of gluconate

Abstract

AbstractThorium complexation with gluconate has been studied from solubility experiments at gluconate concentrations between 10−6and 10−1 mol/l, with pHcbetween 9 and 13 andI=0.5 M (NaClO4). Solubility experiments indicate the formation of a 1:1 thorium:gluconate complex. The stability constant for this species, extrapolated toI=0 by using the SIT (specific interaction theory), has been determined to be log10Kº=−11.5 ± 0.6 for the reaction: Th4++ GH4−+ 2H2O = Th(OH)2(GH2)−+ 4H+. In the presence of ThO2·xH2O, sorption of the organic ligand onto solid surface seems to limit thorium dissolution.