Effect of acid leaching on the microstructure and adsorption properties of ground montmorillonite powder

Montmorillonite powder was treated by grinding, and then, it was subjected to acid leaching with variable concentrations of HCl for different periods of time. The effects of these two activations on the crystal structure, specific surface area, pore structure, and adsorption properties of the clay were explored by Fourier transform infrared spectra, X-ray diffraction (XRD), Brunauer-Emmett-Teller, and UV/visible techniques. An increase in surface area from 78 to 490m(2)/g, specific micropore volume from 101.3 to 121.1 x 10(-5)cm(3)/g has been attained. Factorial design was used to determine main factors affecting microstructure and textural properties of the activated clay. Based on the analysis of the factorial design of experiments, acid concentration was the most significant factor for the amelioration of specific surface area. The adsorption efficiency of activated sample for phenol was tested. It showed that the adsorption followed Langmuir isotherms and it was enhanced owing to the increase in specific surface area.