Biosorption of methylene blue from aqueous solutions on β-cyclodextrin grafting wood flour copolymer: kinetic and equilibrium studies

The preparation, characterization, and environmental application of β -cyclodextrin/citric acid/wood flour ( β -CD/CA/WF) graft copolymer wood-based biosorbent for methylene blue (MB) biosorption were investigated in this paper. The Fourier transform infrared spectroscopy and the technique of phenolphthalein probe were used to characterize the grafting β -CD. Furthermore, the biosorption behavior of MB on β -CD/CA/WF graft copolymer was studied under various conditions of pH, contact time, and initial MB concentration. The results indicated that the biosorption of MB was dependent on both the initial MB concentration and the initial pH. Langmuir isotherm model fitted the isotherm data better than the Freundlich model. The adsorption kinetics followed the pseudo-second-order kinetic model, and intraparticle diffusion was one of the effective rate-controlling steps for the entire biosorption period. Equilibrium and kinetic results have implied that β -CD/CA/WF graft copolymer could be considered as a promising material for the adsorption of dye from aqueous solutions.