Cu2+ removal from aqueous solution by modified chitosan hydrogels

BACKGROUND: The adsorption of Cu2+ from aqueous solution using crosslinked chitosan hydrogels impregnated with Congo Red (CR) by ion-imprint technology was systematically investigated with particular reference to the effects of contact time, pH, and initial concentration on adsorption. RESULTS: The adsorption capacity of the crosslinked chitosan without impregnation was only 68.68 mg g-1 for Cu2+. However, the adsorption capacity increased from 77.42 (without imprint ion) to 84.54 mg g-1 (imprint ion content 0.5 mmol) after the chitosan was impregnated with a ratio of 1/12 of CR to chitosan. The as-prepared adsorbents were found to be pH-dependent and the process of adsorption agreed well with the Freundlich isotherm. The loaded adsorbents could be regenerated and reused without the appreciable loss of capacity. CONCLUSION: Chitosan hydrogels impregnated with CR showed higher Cu2+ adsorption capacities compared with those prepared conventionally without imprint ion, and thus developed a good approach to increase Cu2+ adsorption efficiency in the treatment of waste-water. Copyright (c) 2012 Society of Chemical Industry