Removal of Hexavalent Chromium from Aqueous Solutions using N-octyl Quaternized Poly(4-vinylpyridine): Kinetic and Equilibrium Studies

The removal of chromium(VI) from aqueous solutions by poly(N-octyl-4-vinylpyridinium bromide) copolymer was investigated. Batch adsorption experiments were used to study the effect of experimental parameters on the equilibrium adsorption of chromium(VI). The adsorption characteristics of copolymer toward Cr(VI) in dilute aqueous solution were followed using UV-Vis spectrophotometry. The effect of concentration of chromium(VI) in solution on the metal uptake behavior of copolymer and the contact time were studied. It has been observed that the capacity of chromium adsorption on copolymer increases with initial metal concentration. Adsorption equilibrium was reached within 10 min. Equilibrium modeling of the process of Cr(VI) removal was carried out by using the Freundlich and Langmuir isotherms. The maxima adsorption capacity of chromium(VI) was found to be 26.31 mgg−1. Results also showed that the kinetic of adsorption is best described by a pseudo-second-order expression than a first-order model.