The decomposition of hydrocarbons using combined advanced oxidation methods is largely considered owing to abundant production of OH radicals and the potential economic advantages. In this study, the synergetic effect of ozonation on photocatalytic oxidation of chloroform and chlorobenzene over expanded graphite- -TiO2 &ZnO Nano composite was investigated. The effect of introduced ozone concentration and residence time was also examined on removal effi ciency. The results showed that the removal effi ciency was signifi cantly enhanced by the combined system resulting from the additional oxidation process causing active species to be increased. Increasing the introduced ozone concentration which generates more reactive compounds had a greater effect on the removal effi ciency than that of residence time. However, from the mineralization point of view, the residence time had a dominant effect, and the selectivity towards CO2 was dramatically declined when the fl ow rate increased. Based on these results, the combined system is preferred due to higher removal effi ciency and complete mineralization.
