Simultaneous removal of Cr(VI) and Amido black 10B (AB10B) from aqueous solutions using quaternized chitosan coated bentonite.

Abstract In this study, simultaneous removal of Cr(VI) and Amido Black 10B (AB10B) using quaternized chitosan coated bentonite was investigated by a batch method. The factors affecting adsorption process such as pH, adsorbent dosage, contact time and initial concentration and the interaction of two components in binary solutions have been studied. The results showed that the antagonism effect existed between Cr(VI) and AB10B in binary systems. The equilibrium time for Cr(VI) adsorption was less than the one for AB10B adsorption. The maximum adsorption capacities of the modified bentonite, according to the Langmuir isotherm model were 847.5 mg/g for AB10B and 66.6 mg/g for Cr(VI) at 298 K. The experimental results demonstrated that both Cr(VI) and AB10B were well described by the pseudo-second-order model. Thermodynamic study depicted that the adsorption of Cr(VI) and AB10B onto the modified bentonite was both spontaneous. The adsorption for Cr(VI) was exothermic while the one for AB10B was endoth- ermic in nature.