Adsorption of Eriochrome black-T from aqueous environment by raw Montmorillonite

Abstract

ABSTRACT The present study aimed to investigate the removal of the azo dye, Eriochrome black-T (EBT) from the synthesised effluents using the Montmorillonite (MM) raw clay. MM is a soft phyllosilicate group of minerals and has been used as a low-cost adsorbent for the removal of pollutants from the environment. In this regard, the effect of several factors, such as contact time, pH, adsorbent dose, initial dye concentration, solution ion strength, and temperature in the batch system was assessed. Fourier transformed infrared (FTIR) spectroscopy and X-ray diffractometer (XRD) techniques were also employed to examine the MM. Adsorption capacity of EBT in equilibrium time equal to 20 min was attained 57.88 mg/g. Removal of EBT by the MM illustrated that the data had a good fit with the models of pseudo-second-order and Freundlich isotherm. The contact time and pH were also optimised at 20 min and pH = 3, respectively. The maximum adsorption capacity (72.71 mg/g) was obtained for pH value of 3. Based on the value of RL in this study (RL = 0.70), the adsorption process of EBT removal using MM was favourable. The results from this study confirmed the effectiveness of MM as an inexpensive and eco-friendly option for the adsorption and removal of EBT from polluted water.