Modified bentonite adsorption of organic pollutants of dye wastewater

Abstract

Removals of Rhodamine B (RhB) and Acid red 1 using the organic modification of bentonite from aqueous phase were optimized. The organobentonite was synthesized by replacing exchangeable Na+ ions in Na-bentonite (Na-Bt) with cetyl trimethylammonium bromide (CTAB) and systematically explored for its adsorption behavior as an efficient adsorbent for the removal of dyes. Batch adsorption studies manifested that the maximum adsorption capacity of dyes were found to be 173.5 mg/g and 157.4 mg/g for RhB and Acid red 1 at the initial concentration of 300 mg/L at 30 °C and pH 9 and 8, respectively. The investigations of adsorption isotherm and kinetics model showed that the adsorption isotherm data were fitted well to the Langmuir isotherm and the adsorption kinetic was better by pseudo-second-order kinetic model. Besides, the thermodynamic parameters indicate that the adsorption process is spontaneous and endothermic. Furthermore, the properties of the obtained samples were characterized by X-ray diffraction (XRD), Scanning electronic microscopy (SEM), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectrometry (FT-IR) and zeta potential analysis. The results of the characterization provided evidence of the morphological properties and how well the adsorption process performed.