• Mono-aromatic Hydrocarbons such as benzene, toluene, ethylbenzene and xylene are volatile, non-ionic and non-polar compounds that have been used in the vehicles fuel and as solvents in industrial activities. This study was conducted to investigate the performance of clay modified with cationic and non-ionic surfactants in the removal of benzene, toluene, ethylbenzene and xylene from aqueous solutions.

Materials & methods: The experiments were carried outin batch system. The effect of various parameters including surfactant loading (0.2-4 times of clay CEC), contact time (0-24 hr), pH (4-12) and pollutant concentration (10-200 mg/l) was surveyed on the sorption.

• The results showed that the maximum BTEX adsorption occurred in the surfactant loading of two times of cation exchange capacity of the clay. The optimum contact time of the sorption occurred at 24 hr. The sorption capacity of TTAB-Mt and PEG-Mt for BTEX was 22.11 mg/g and 18.77 mg/g, respectively. The Freundlich isotherm and pseudo second-order kinetic models fitted the data better than other isotherm and kinetic models.

Discussion & Conclusion: The sorption capacity of both the sorbents was of no significant differences, but the toxicity and also the cost of non-ionic surfactant is less than cationic surfactant therefore, it is recommended that clay modified by non-ionic surfactant instead of cationic surfactant is used to remove BTEX from aqueous solutions.