Photodegradation of eight miscellaneous pesticides in drinking water after treatment with semiconductor materials under sunlight at pilot plant scale

Heterogeneous photocatalysis with different semiconductor materials such as zinc oxide (ZnO), titanium dioxide (TiO2), tungsten (VI) oxide (WO3), tin (IV) oxide (SnO2) and zinc sulphide (ZnS) in aqueous suspensions has been investigated for the removal of eight miscellaneous pesticides (ethoprophos, isoxaben, metalaxyl, metribuzin, pencycuron, pendimethalin, propanil and tolclofos-methyl). The experiments were carried out at pilot plant scale using compound parabolic collectors under natural sunlight, comparison of catalysts showed that ZnO is the most efficient for catalyzing the removal of these compounds. The photocatalysis of these compounds using ZnO followed first-order kinetics. The residual levels at the end (240 min) of the ZnO experiment were lower than 0.8 μg L−1.

► Heterogeneous photocatalytic oxidation of pesticides in water.
► ZnO and TiO2 strongly enhances photodegradation.
► The treatment cost was estimated to be 27.18 €/m3 for ZnO.
► Half lives ranged from 9 to 38 min by use of the tandem ZnO/Na2S2O8.