Bio-polymer adsorbent for the removal of malachite green from aqueous solution.

A simple, economical and green methodology has been developed for the adsorption of malachite green using cellulose powder as the adsorbent. Batch experimental procedures were conducted to investigate the adsorption ability of this bio-polymer to remove malachite green from aqueous medium. The adsorbed dye on cellulose was characterized by Fourier transform-infrared spectroscopy (FT-IR). The various analytical parameters such as the effect of contact time, pH, temperature, etc. were optimized. The adsorption was efficient at a neutral pH (7.2) and both Langmuir and Freundlich isotherm models showed good fit into the experimental data. The adsorption kinetics indicated that the adsorption proceeds according to pseudo-second-order model. The adsorption of malachite green was found to be exothermic and it was accompanied by decrease in the entropy. Column studies were performed and the regeneration of the adsorbent was done easily using environmentally benign polyethylene glycol-400.