Adsorption of Acid Red G Dye from Solutions by Raw Bentonite and Bentonite-Cationic Starch Composite

Abstract

The adsorption of acid red G dye onto raw bentonite/cationic starch (RB/CS) and raw bentonite (RB) was investigated in aqueous solution in a bath system with respect to the adsorption kinetics and adsorption isotherms, respectively. For RB and RB/CS composite, the kinetic data showed that the kinetics of adsorption was best described by a pseudo-second-order expression than the pseudo-first-order. Adsorption isotherms of acid red G dye onto RB and RB/CS composite were determined with common isotherm equations such as the Langmuir and Freundlich models. The results showed that for RB/CS composite, the Langmuir model agreed very well with the experimental data, whereas the RB was fitted to both Langmuir and Freundlich models. In summary, the results showed that RB/CS could be employed as low-cost materials for the removal of acid red G dye from effluents compared to RB.