Study on adsorption of Cd2+ by Ti-pillared montmorillonite-mixed activated carbon

Abstract

In this study, the composite of Ti-pillared montmorillonite-mixed activated carbon (TPM-AC) was prepared by the water immersion method, and the adsorption of Cd2+ was studied under static conditions. A series of single experiments were conducted to determine the effects of the solution pH, adsorption time, initial Cd2+ concentration, and solution temperature on adsorption performance. The adsorption kinetics, isotherms, and thermodynamics behaviours of Cd2+ onto TPM-AC were investigated. The results showed that the Brunauer–Emmett–Teller specific surface area and pore volume of TPM-AC are increased, the crystallinity is greatly improved, and porous structural material with a large specific surface area is formed. The adsorption of Cd2+ by TPM-AC is excellent and better than that of AC and TPM. The adsorption of Cd2+ by TPM-AC, AC, and TPM can be described by the pseudo-second-order kinetic equation, and the adsorption isotherm is more consistent with the Langmuir isotherm model. The RL values of the dimensionless separation constants are all between 0 and 1, indicating that adsorption of Cd2+ is a relatively easy adsorption process. The values of thermodynamic parameters indicated that the adsorption is a reverse spontaneous and endothermic process.