Adsorptive removal of diclofenac and ibuprofen from aqueous solution by organobentonites: Study in single and binary systems

Organobentonite adsorbents were prepared by treating raw bentonite (RB) with three different cetyltrimethylammonium bromide concentrations (0.5, 1 and 2CEC). The prepared adsorbents were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Thermogravimetric analysis (TGA) and Specific surface area (BET). The adsorbents were then tested for their ability to remove diclofenac (DIC) and ibuprofen (IBU) from aqueous solution at different conditions (pH, adsorbent dosage, initial drug concentration, and contact time) in order to determine the optimum conditions for adsorption. The kinetics in single drug solution follows pseudo-second order kinetic model. The adsorption isotherms of the two drugs obeyed both the Langmuir and Freundlich isotherm models with the saturation adsorption amount onto 2CECRB of 600.6 and 194.9 mg/g for DIC and IBU, respectively. In adsorption from mixed drug solutions, DIC and IBU show competitive adsorption. Hydrophobic interactions play an important role during the sorption process. In addition, 2CECRB could be regenerated and reused after four cycles.