Physicochemical characterization and adsorption behavior of Ca/Al chloride hydrotalcite-like compound towards removal of nitrate

The objective of the present research was to synthesize, characterize and to investigate adsorption of nitrate from synthetic nitrate solution by Ca-Al-Cl HTIc. In the present study Ca-Al-Cl HTIc was synthesized by co-precipitation method and was characterized using SEM, XRD, FTIR and TGA-DSC. To assess the practical usefulness, a detailed removal study of nitrate was carried out. The removal of nitrate was 84.6% under neutral condition using 0.35 g of adsorbent in 100 mL of nitrate solution having initial concentration of 10 mg/L. Adsorption kinetic study revealed that the adsorption process followed first order kinetics. Adsorption data were fitted to linearly transformed Langmuir adsorption isotherm with R(2) (correlation coefficient) > 0.99. Thermodynamic parameters were also calculated to study the effect of temperature on the removal process. In order to understand the adsorption type, equilibrium data were tested with Dubinin-Radushkevich isotherm. (C) 2011 Elsevier B.V. All rights reserved.