@article{article_97462, title={Removal of Direct Red 81 Dye from Aqueous Solution by Native and Citric Acid Modified Bamboo Sawdust - Kinetic Study and Equilibrium Isotherm Analyses}, journal={Gazi University Journal of Science}, volume={25}, pages={59–87}, year={2012}, author={Ali, İmran and Dahıya, Sarita and Khan, Tabrez}, keywords={Treated Bamboo Sawdust, adsorption, isotherm, kinetic, intra-particle diffusion}, abstract={ Adsorption of Direct Red 81 (DR81) dye was investigated using Bamboo Sawdust (BSD) and Treated Bamboo Sawdust (TBSD) in a batch system with respect to initial dye concentration, adsorbent dose, pH, temperature and contact time. Maximum adsorption capacity ( q m ) obtained from the Langmuir isotherm plots were 6.43 mg/g (89%) (DR81-BSD) and 13.83 mg/g (92%) (DR81-TBSD) at 303 K. Freundlich and Halsey models described the data more appropriately as compared to Langmuir, Dubinin-Kaganer-Radushkevich (DKR), Harkin-Jura and Temkin models. The adsorption dynamics conformed well to pseudo-second order kinetic equation. The adsorption process was controlled by both liquid-film and intra-particle diffusions. Thermodynamic parameters ( Δ G o , Δ H o and Δ S o ) suggested the adsorption process to be spontaneous, endothermic with increase in randomness at solid-solution interface. }, number={1}, publisher={Gazi University}