Kinetic and Equilibrium Studies of Cr(VI) Adsorption Using Glutaraldehyde-Crosslinked Chitosan Beads

The increase of pollution in aquifers by heavy metals in Mexico, because of industrialization and urbanization, have had negative effects for the environment and public health. This work aimed to evaluate the kinetic and equilibrium studies of Cr(VI) adsorption using glutaraldehyde-crosslinked chitosan beads in aqueous systems. Glutaraldehyde-crosslinked chitosan beads were prepared, and three different masses (3, 6, 9 g) were evaluated with 5 concentrations of Cr (VI) (20, 30, 50, 80, 100 mg/L). The adsorption mechanisms were studied through the adsorption isotherms of Langmuir and Freundlich, as well as the adsorption kinetics of pseudo-first order, pseudo-second order, and Elovich based on experimental data. Results showed that after 10 min. of exposure, the beads adsorbed more than 50% of the initial concentration of Cr(VI), and after 90 min. it was possible to remove up to 100% of Cr(VI) contained in the water. The adsorption kinetics of pseudo-second order and Elovich showed the best fits compared to pseudo-first order. Based on these results, glutaraldehyde-crosslinked chitosan beads could be proposed as a good alternative for the removal Cr(VI) from aqueous systems.