Inorganic particulates in removal of toxic heavy metal ions: Part X: Removal behavior of aluminum hydroxide for Hg(II): A radiotracer study

Abstract

The removal behavior of amorphous aluminum hydroxide for Hg(II) ions from aqueous solutions was investigated by employing a radiotracer technique at micro down to trace level concentrations. The batch type experiments were performed to obtain various physico-chemical parameters, viz., effect of sorptive concentration, temperature and pH. It was observed that the increase in sorptive concentration (from 1.10-8 to 1.10-2 mol·dm -3), temperature (from 303 to 333K) and pH (from 3.4 to 10.3) apparently favored the uptake of Hg(II) by this solid. Similarly, the presence of anions (six fold) viz., oxalate, phosphate, glycine and EDTA also enhanced the uptake behavior of aluminum hydroxide for Hg(II). Whereas, the added cations viz., Na+, K+, Ba2+, Sr2+, Mg 2+, Cd2+ and Fe3+ more or less suppressed the removal behavior of the adsorbent. Further, the adsorption process followed the classical Freundlich adsorption isotherm and deductions of various thermodynamic data revealed that the uptake of Hg(II) on aluminum hydroxide followed the ion-exchange type mechanism and thermodynamically it was found to be endothermic in nature. © 2007 Springer Science+Business Media, Inc.