The investigation of the removal of a textile dye from aqueous solution by using a chemically modified bentonite

In this study, bentonite was modified with didodecyldimethylammonium bromide which is a surfactant. Then adsorption of Reactive Blue 19 (RM19), which is a textile dye, onto this modified bentonite (MB) was examined. For the characterization studies of modified and natural bentonite (DB), FTIR, XRD, XRF, SEM and zeta potential analysis techniques were used. The adsorption of RM19 onto MB was examined by pH, temperature and contact time parameters and it was seen that the adsorption capacity of MB was considerably higher than that of DB. The maximum adsorption of RM19 for MB and DB was obtained at pH=1.5. Lagergren-first-order, pseudo-second-order, Elovich kinetic and intra-particle diffusion models were examined in the consideration of experimental data and the rate constants were calculated. According to the results, the adsorption of RM19 onto MB was obeyed for the pseudo-second-order kinetic model. Experimental data were applied to isotherm models, and isotherm constants were also deduced for both of Langmuir and Freundlich isotherm models. As a consequence, it was specified that the adsorption of RM19 onto MB was agreed with the Langmuir isotherm model.keywords; Bentonite, Organo-clay, Surfactant, Adsorption, Reactive Blue 19