Effective removal of maxilon red grl from aqueous solutions by walnut shell: Nonlinear kinetic and equilibrium models



The feasibility of walnut shell as a waste biomaterial for removing Maxilon Red GRL (MR GRL) dye from aqueous solutions was investigated in this work. The biosorption was studied as a function of pH, ionic strength, biosorbent dosage, particle size, temperature, initial dye concentration, and contact time. Nonlinear kinetic equations including the pseudo-first order, pseudo-second order, and Logistic were applied to the experimental data for describing the biosorption kinetics. The Logistic model showed the best correlation with the experimental data. Besides, intraparticle diffusion was not the sole rate-controlling factor. The Langmuir, Freundlich, Hill, and Dubinin-Radushkevich nonlinear isotherms were fitted to the equilibrium data, and the Hill model presented the best fit. Thus, this research highlights the potential of walnut shell as an effective biosorbent for the removal of MR GRL from aqueous media. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 396–401, 2014