Kinetic and Equilibrium Studies of Adsorption of Dye Congo Red from Aqueous Solutions on Bagasse Charcoal and Banana Peels

Batch adsorption experiments were carried out for the removal of dye congo red (CR) from aqueous solutions using bagasse charcoal (BC) and banana peels (BP). Experiments were carried out as a function of contact time, initial dye concentration, adsorbent dose and ionic strength. The results showed that the amount of dye adsorbed increased with increasing initial dye concentration and contact time. The kinetics of basic dye adsorption nicely followed the pseudo second-order rate expression and demonstrates that intraparticle diffusion plays a significant role in the adsorption process. The adsorption data fitted well with Langmuir, Freundlich, Temkin, Dubinin and Radushkevich and Generalized isotherms. The characteristic parameters for each model have been determined. The Langmuir isotherm gave the best correlation for the adsorption of dye congo red on both the adsorbents. The monolayer saturation capacity was found to be 45.3 and 44.4 mg/g for BC and BP respectively. The value of separation factor (R_L) insinuates that BC and BP can be used as effective adsorbents. The results of the present study corroborate that BC and BP are promising adsorbents for the removal of toxic dye CR.