Effect of pH, ionic strength, humic substances and temperature on the sorption of Th(IV) onto NKF-6 zeolite

Sorption of Th(IV) from aqueous solution to NKF-6 zeolite as a function of experimental conditions were investigated using batch experiments. The sorption of Th(IV) on NKF-6 zeolite was strongly dependent on pH and ionic strength at pH 6.0. The sorption of Th(IV) on NKF-6 zeolite was mainly dominated by ion exchange or outer-sphere surface complexation at low pH, while by inner-sphere surface complexation at high pH values. The thermodynamic data suggested that the sorption of Th(IV) on NKF-6 zeolite was an spontaneous and endothermic process. The results show that NKF-6 zeolite is a suitable adsorbent for Th(IV) enrichment from large amount of actual effluent.