Removal of Cerium from Aqueous Solutions by Amino Phosphate Modified Nano TiO2: Kinetic, and Equilibrium Studies

Abstract

Adsorption of Ce(III) from aqueous solution by amino phosphate modified nano TiO2 was investigated. Effects of pH of solution, adsorbent dose, contact time, initial metal concentration and temperature were examined. Experimental data were fitted well by the pseudo second order model. Adsorption was well described by Freundlich isotherm model with a maximum adsorption capacity of 25 mg g-1. According to the obtained thermodynamic parameters, the adsorption was a spontaneous and endothermic process. Effect of interfering cations was studied. The presence of Ca and Mg ions up to 150 mg L-1 showed no considerable effect on the adsorption of Ce(III). Regeneration of adsorbent was performed using HNO3 with efficiency greater than 84%. The quantities of distribution coefficient (Kd), the affinity of metal for retention onto solid phase, was the higher for Ce(III) than La(III). Due to the high sorption capacity, being plentiful and low cost it is concluded that the use of amino phosphate mofified nano titania as an appropriate adsorbent is promising for the removal of lanthanides especially Ce(III) from contaminated sites.