Adsorptive removal of triarylmethane dye (Basic Red 9) from aqueous solution by sepiolite as effective and low-cost adsorbent

In this study, the adsorption of Basic Red 9 (BR9) from aqueous solution onto sepiolite was investigated. Batch experiments were carried out to determine the effects of various parameters including contact time, initial dye concentration, temperature and pH on the adsorptive removal of BR9 by sepiolite. Both kinetic and isotherm data were obtained. The kinetic and isotherm data fitted very well with the pseudo second-order kinetic model and Freundlich isotherm model, respectively. The calculated thermodynamic parameters indicated that the adsorption process was spontaneous, favorable, and exothermic. The pH of dye solution and electrostatic interaction do not play an important role on the adsorption process. The increase in the adsorption amount of BR9 led to a decrease in the zeta potential of sepiolite. The interaction between sepiolite and BR9 was investigated by Fourier transform infrared (FTIR) spectroscopy. Desorption of BR9 from spent adsorbent was studied in water, ethyl alcohol and benzyl alcohol. The highest desorption amount was obtained by benzyl alcohol. This study revealed that sepiolite could be used as effective and low-cost adsorbent in the treatment of wastewater contaminated with triarylmethane dyes. (c) 2015 Elsevier Inc. All rights reserved.