Investigation of heavy metal adsorption in binary system by nanocrystalline cellulose - Bentonite nanocomposite: Improvement on extended Langmuir isotherm model

The preparation of NCC bentonite nanocomposite using waste paper as the source of NCC was conducted in this study. The adsorption performance of the composite was tested for the removal of Pb(II) and Hg(II) from aqueous solution in single and binary systems. Langmuir and Freundlich adsorption isotherms were employed to correlate pure component adsorption isotherm. Langmuir equation can represent the experimental data better than Freundlich, the gin for lead is higher than mercury in both systems (single system q(m) = 0.44 mmol/g (Pb) and 0.23 mmol/g (Hg) for composite). All systems exhibit endothermic process, except for bentonite which shows the exothermic process. The modification of extended Langmuir model for a binary system with the inclusion of fractional loading and heat of adsorption was proposed in this study. The modified extended Langmuir model could represent the experimental data better than original extended Langmuir equation. (C) 2017 Elsevier Inc. All rights reserved.