ADSORPTION CHARACTERISTICS OF CETYLTRIMETHYLAMMONIUM BROMIDE MODIFIED BENTONITE FOR REMOVAL OF ACID ORANGE

Large amount of acid orange, a member of azo dye family, has been discharged into the environment due to its wide use. Adsorption is an efficient treatment method to remove acid orange. In this work, cetyltrimethylammonium bromide modified bentonite (CTAMB-B), belonging to a new adsorbent was firstly prepared and characterized by FT-IR, TEM and cation exchange capacity (CEC). In adsorption experiments, the influence of the factors including pH, temperature, contact time, initial concentrations of CTMAB-B and acid orange were all taken into consideration. The results showed that pH and temperature had no obvious influence on the adsorption of acid orange with CTAMB-B. However, the adsorption of acid orange increased slowly along with the increase of CTAMB-B dosage and contact time, respectively, but remained constant when the adsorption equilibrium was reached. Hence, the prime contact time and CTMAB-B dosage were 30 min and 0.3 g/L, respectively. It was noticeable that initial concentration of acid orange exerted the most significant influence on the adsorption capacity of CTMAB-B. Furthermore, the adsorption process was in agreement with both pseudo-first-order kinetics and pseudo-second-order kinetics. Meanwhile, the adsorption isotherm of CTMAB-B was described well by both Langmuir model and Freundlich model.