Pesticides Removal from Wastewater Using a Pilot-scale Photocatalytic Reactor

Today, the increase in agricultural practices leads to pesticide pollution, which has become a threat to both water sources and humans. Various techniques to degrade pesticides have been used, but heterogeneous photocatalysis in presence of semiconductor nanoparticles has proven to be more efficient because it can degrade many persistent organic compounds. However, for practical and industrial applications, it is necessary to immobilize the photocatalyst on the surface or within macroscopic supports to avoid the post-treatment step to separate the photocatalyst in powder form from the treated water at the end of the process. In this work, monolithic polymer/photocatalyst composite aerogels based on syndiotactic polystyrene (sPS) and two different photocatalysts, N-doped TiO2 (NdT) and ZnO/NdT, were prepared to obtain easily recoverable materials for cost-saving processes. The aerogels were tested in the degradation of two target pesticides, atrazine (ATZ) and thiacloprid (THI), using a pilot-scale photoreactor. The experimental data showed a pollutant degradation higher than 90% after 180 min for ATZ and over 90% after 60 min of irradiation for THI. These results indicate that the heterogeneous photocatalytic process based on composite aerogels could be an efficient technology for pesticide degradation.