Enhancing cadmium ion removal from contaminated water using functionalized fly ash-alumina/copper oxide nanocomposites

Aluminum oxide and fly ash-alumina/copper oxide nanocomposites (FA-alumina/CuO NCS) were prepared by a simple process using a common precipitate and an extract of Salvia officinalis leaves. The effectiveness of these materials in adsorption and desorption of cadmium ions Cd(II) was investigated. The best adsorption results were obtained with an adsorbent dose of 0.5 g/L, a pH of 8.4, a Cd(II) concentration of 200 mg/L and an equilibrium time of 3 h. These results led to a removal of 94.9 % and 97.8 % for the two adsorbents, respectively. The kinetic analysis showed that the adsorption follows a pseudo-second order model, with correlation values (R2) of 0.9896 and 0.994. At 303 K, the Freundlich isotherm model (R2 = 0.991) provided an accurate description of the adsorption process. According to the thermodynamic studies, the process is endothermic, which also gave negative values for Gibbs free energy (Delta G degrees) and positive changes in entropy (Delta S degrees = 0.542 and 0.987 kJ/mol) and enthalpy (Delta H degrees = 147.32 and 302.54 kJ/mol). The novel use of alumina nanoparticles and FA-alumina/CuO NCS provides a breakthrough opportunity for the effective removal of Cd(II).