Removal of Malachite Green from Aqueous Solutions by Adsorption on to Timber Waste

Sawdust a timber waste has been used as a bio-sorbent for the removal of a cationic dye, malachite green from aqueous solutions. The process of removal has been optimized for different parameters like initial concentration of dye solution and contact time, pH, adsorbent dose, and temperature. pHzpc of the adsorbent was determined. Elemental analysis of the adsorbent was carried out. FTIR was performed to determine various functional groups attached to the adsorbent surface. The experimental results indicate that 5g/L g of sawdust was able to remove 93% of dye from an initial concentration of 20 mg L. Equilibrium was achieved in 100 min. The removal of dye exhibited decreasing trend with increasing temperature and it shows exothermic nature of adsorption. Adsorption data were modelled by Langmuir and Freundlich isotherms. The data was better fitted in Freundlich isotherm model. The maximum adsorption capacity of adsorbent was found to be 13.87 mgg at 298 K. The dye adsorption followed the pseudosecond-order kinetics. The results show that saw dust can be a better alternate for the removal of MG from aqueous solutions and effluents.