Cm(III) sorption by silica: effect of alpha hydroxy isobutyric acid

Abstract

Abstract Sorption of Cm(III) on silica surface from aqueous solutions of varying pH was investigated in absence and presence of alpha hydroxy isobutyric acid (HIBA) by employing batch sorption and surface complexation modeling (SCM). Cm(III) sorption on silica increased with the pH of the suspension and remained constant above pH∼6. With increase in HIBA concentration, the sorption edge shifted to higher pH. The effect of addition order of HIBA and Cm(III) on the sorption was studied and higher shift in sorption edge, as compared to binary system, was observed when HIBA was added to silica suspension prior to Cm(III). The sorption data could be satisfactorily explained by SCM in all the systems. The results have been compared with that reported earlier on the effect of HIBA on sorption behaviour of Eu(III) by silica. Further, the use of small organic molecules as model compounds of humic acid (HA) has been evaluated by comparing the influence of HA and HIBA on sorption of Cm(III) on to silica.