Removal of Cr(VI) using mesoporous alumina with different kinds of pore structures

Three kinds of aluminas with different pore structures, synthesized using different methods, were investigated for the removal of Cr(VI) by batch adsorption tests. And commercial alumina was investigated to compare the removal efficiency. To understand the adsorption process, kinetics studies were performed and the results showed that the kinetics rate was fitted well by the pseudo-2nd-order kinetic model. The adsorption isotherm studies showed that Langmuir adsorption isotherm model fit the experimental data better. Their adsorption rate and capacities of the four kinds of adsorbents were furthermore compared and analyzed. It showed that the adsorption performance varied and depended on the characteristics, surface area, pore type and the surface modification of the adsorbents. The uniform mesopore structures with well-ordered channels have greater advantages over the disordered pores, and meanwhile, the surface area of the adsorbents also played an important role in the adsorption performances.