Metabolically inactive Trichoderma harzianum mediated adsorption of synthetic dyes: Equilibrium and kinetic studies

The feasibility of using metabolically inactive biomass of Trichoderma harzianum for the adsorption of synthetic dyes from aqueous solution was investigated at various contact time, adsorbent dosage and pH. Greater percentage of dye was removed with decrease in the initial concentration of dyes and increase in amount of adsorbent used. The pH of 8 and 4 was found to be effective for the removal of Rhodamine 6G and Erioglaucine respectively. The Langmuir and Freundlich adsorption isotherms were applied to study the equilibrium relationships between adsorbent and adsorbate. Adsorption of dyes onto fungal biomass satisfied the Langmuir and Freundlich adsorption isotherms. The extent and rate of adsorption of dyes were analyzed using first- and second-order rate kinetics. Compared to the first-order, the second-order kinetics gave a much higher degree of correlation with the experimental adsorption data and suggested that adsorption system follows the second-order rate kinetics. IR spectroscopic studies revealed the participation of the functional groups in the adsorption mechanism. Utilization of the autoclaved biomass for bioremediation is much secure as it does not pose any jeopardy to the environment as well living system because they are metabolically inactive cells.