The study of an azo dye removal from liquid medium by modified clay

In this batch study, montmorillonite was modified by a cationic surfactant [hexadecyltrimethylammonium bromide (HDTMA-MMT)] and used as sorbent to remove bromocresol green (BCG) from aqueous solutions. The effect of several factors such as surfactant loading rate onto the clay, contact time, pH, adsorbent dosage, dye concentration, and ion strength were investigated on the sorption. The equilibrium time for BCG sorption was reached at contact time of 20 minutes. Fitting the experimental data to different kinetic and isotherm models showed that the experimental data are well described by pseudo-second-order kinetic (R2 > 0.99) and Freundlich isotherm (R2 > 0.99) models. According to the results of this study, HDTMA-MMT can be considered as a low-cost, eco-friendly, and highly effective option for the sorption of BCG from aqueous solutions.