Organobentonite as an efficient and reusable adsorbent for cationic dyes removal from aqueous solution

Abstract

In the present study, cetyltrimethylammonium bromide (CTAB) was used to modify raw bentonite (Ben) through the replacement of exchangeable cations to form CTAB modified bentonite (CTAB-Ben). Both Ben and CTAB-Ben were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and Brunauer-Emmet-Teller (BET) analysis. Adsorption potential of Ben and CTAB-Ben were explored for the removal of two cationic dyes i.e. Rhodamine B (RB) and Crystal violet (CV) from aqueous solutions. The maximum dye adsorption capacity of CTAB-Ben was found to be 93.15 and 14.76 mg g^-1 for CV and RB, respectively. The adsorption data of both the adsorbents was better explained by Freundlich isotherm whereas the pseudo second order (PSO) model better fitted the kinetics data. Regeneration studies revealed that CTAB-Ben could be reused upto five adsorption-desorption cycles.