On the Removal of the Cr(VI) in Water by an Ordered Mesoporous Carbon Material: Kinetic and Isotherm Studies

In this work, an ordered mesoporous carbon material CMK-3 was synthesized and tested in the adsorption of Cr(VI) in water with an activated carbon material (AC) as the control. Properties of CMK-3 have been characterized by means of Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. In the adsorption of Cr(VI) in water, the adsorption rate and adsorption capacity of CMK-3 were found to be better than that of AC. A careful study on the adsorption kinetics and isotherms of Cr(VI) on CMK-3 was taken. The adsorption data of Cr(VI) on CMK-3 had been analyzed by pseudo-first-order, pseudo-second-order, particle diffusion, Elovich, Double constant, and Exponential function kinetic models, which revealed that the kinetic adsorption of Cr(VI) on CMK-3 is well accorded with pseudo-second-order kinetic model. The corresponding parameters for each model are obtained. According to the fitting of Langmuir, Freundlich, and Temkin models, the adsorption of Cr(VI) on CMK-3 was well described by Langmuir model to be a single-molecule layer adsorption. The adaptation of the adsorption of Cr(VI) on CMK-3 to Langmuir adsorption model and pseudo-second-order model suggests that the adsorption of Cr(VI) on CMK-3 can be highly affected by its chemical property although its textural properties also can remarkably affect its adsorption behavior.