Adsorption of Calcium(II), Cadmium(II) and Copper(II) Ions from Water by Prepared Silicon-Aluminum-Zirconium Oxide Using Sol-Gel Process

Ternary oxide silica-alumina-zirconia (SiO2/Al2O3/ZrO2) obtained by the sol-gel process was applied as novel adsorbent of ions in aqueous solution. Batch isotherms were performed using standard CuII, CdII and CaII solutions at variable pH and different concentrations. Adsorption capacity was best at weakly acidic pH. The maximum adsorption capacities were 2.28 mg g−1 for CaII, 9.89 mg g−1 for CdII, and 14.88 mg g−1 for CuII. The adsorption data fitted well to the single and dual-site Langmuir-Freundlich isotherm models. However, since the adsorption is very low in the sites with high ene...