Removal of hexavalent chromium by polyethyleneimine impregnated activated carbon: intra-particle diffusion, kinetics and isotherms

Abstract

Contamination of water by hexavalent chromium generated from man–made activities remains one of the challenges for environmental pollution. Activated carbon impregnated with diluted polyethyleneimine (PEI) solutions was investigated as a possible adsorbent for the remediation of water contaminated with toxic Cr(VI). The activated carbon adsorbents were characterized using Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Parameters that influence the adsorptive removal of Cr(VI) were evaluated, and it was observed that high removal efficiency was achieved at pH 3 with a contact time of 120 min and 1 g L−1 dosage concentration. The data were analyzed by kinetic and isotherm models. The data fitted well into the Elovich and Langmuir models, the latter yielding a maximum adsorption capacity of 114 mg g−1. Overall, the MAC-PEI showed promise as a potential adsorbent to remove noxious Cr(VI) in aqueous solution.

Keywords

• Activated carbon
• Impregnation
• Adsorption
• Hexavalent chromium
• Polyethyleneimine
• Kinetic modelling