Biosorptive Color Removal: Applicability of Equilibrium Isotherm Models

Abstract

Models describing adsorption equilibrium have not been derived for the sorption onto the biosorbents including both virgin and immobilized biomasses. Biosorption involves interaction of biopolymer-based surfaces with different types of pollutants which may be different for virgin and immobilized biosorbents. In the present study, 16 different isotherm models have been studied using equilibrium data obtained from biosorbents. Biosorbents, both virgin (prepared from two types of macrofungus biomass) and immobilized forms have been used. Results show that in general the accuracy of models to fit experimental data improves with the degree of freedom. Most widely used isotherm models, i.e., Langmuir and Freundlich, could be used to describe the sorption equilibrium of biosorptive processes for both virgin and immobilized biomasses. Comprehensive equilibrium analysis has assisted in understanding the mechanistic aspects associated with different types of sorbate-sorbent interactions.