Kinetics and Thermodynamics of Heavy Metal Cu(II) Adsorption on Mesoporous Silicates

摘要

Investigations were conducted to study the adsorption behavior of heavy metal Cu(II) on the mesoporous silicate SBA-15 (CONH_2-SBA-15) in aqueous medium by varying parameters such as contact time, temperature, ionic strength, and competing ions. Heavy metal adsorption was broadly independent of initial metal concentration. Competing ions in the aqueous solution had a small effect on the adsorption of Cu(II) on CONH_2-SBA-15. The adsorption data for Cu(II) fit well with the Langmuir and Redlich-Peterson models. Kinetic studies showed that the kinetic data are well described by the pseudo second-order kinetic model. Initial adsorption rate increases with an increase in temperature. The intraparticle diffusion model was the best in describing the adsorption kinetics for the Cu(II) on CONH_2-SBA-15. Thermodynamic analysis indicates that the adsorption is spontaneous and endothermic.