Removal of phenol from water by adsorption–flocculation using organobentonite

Bentonite modified with short chain cationic surfactant might be the basis of a new approach to removing organic pollutants from water. The treatment process involves dispersing bentonite to the contaminated water and then adding a small cationic surfactant so as to result in flocs which are agglomerates of organobentonite and bound organic pollutants. The flocs are then removed from the solution by sedimentation. Experimental results indicate that BTMA-bentonite displays a high affinity for phenol, possibly because phenol molecules interact favorably with the benzene ring in BTMA ion through increased π–π type interactions. Under appropriate operating conditions, 90% phenol removal and nearly 100% bentonite recovery could be achieved by the adsorption–flocculation process using BTMA-bentonite. Additionally, the insensitivity of the process to the changing ionic strength of the solution and rapid adsorption kinetics made adsorption–flocculation with BTMA-bentonite attractive for continuous treatment of large volumes of industrial wastewater. The bentonite may function as a recyclable surfactant support for the adsorption and subsequent combustion of organic pollutants.