Abstract:
Mimosa tannins were immobilized on goat hair to prepare a sorbent for the adsorption of hexavalent chromium (Cr
6+) in aqueous solution. The results indicate that the redox reaction occurs during the adsorption process. Cr
6+ is firstly reduced to Cr
3+ and then adsorbed on the sorbent. The adsorption capacity is 117.3 mg/g at pH 2.0 and 313 K with the initial Cr
6+ concentration of 300 mg/L. Increasing temperature can promote the adsorption capacity. The solution pH can affect the adsorption capacity significantly because the redox reaction is dependent on pH value, and the optimal pH for the adsorption is 2.0. The adsorption isotherms of the sorbent to Cr
6+ can be well described by the Freundlich model, and the adsorption kinetic data of Cr
6+ fit the pseudo-second-order model. The results of adsorption experiments for the simulated electroplating wastewater indicate that Cr
6+ can be effectively removed using the sorbent when adjusting pH of the solution.