A new microfiltration photocatalytic reactor for DDT removal

In this paper, a process combining stainless steel membrane and UV/TiO2 is developed to degrade DDT in water. The photocatalyst TiO2 was deposited on a kind of glass cenospheres whose diameters ranged from 20 to 200 μm, so they could be kept in the reactor by microfiltration membrane. The influence of different variables (TiO2 concentration, radiation) on the reaction rate was tested. According to the experiment, the removal was mainly caused by adsorption during the early stages of the reaction and mainly by UV/TiO2 degradation in the later stages. Three sample solutions with DDT concentrations: C0 = 30, 40 and 50 μg/L, were treated in the reactor and the removal rate of DDT was found to be 98.3%, 97.8% and 97.6%, respectively. Adequate dosage of the catalyst increased the generation rate of electron/hole pairs which promoted the formation of OH radicals for enhancing photodegradation.