Different approaches for the solar photocatalytic removal of micro-contaminants from aqueous environment: Titania vs. hybrid magnetic iron oxides

摘要

This work reports on the light-induced heterogeneous photodegradation of four micro-contaminants (MCs): Carbamazepine (C), Flumequine (F), Ibuprofen (I), and Sulfamethoxazole (S), using two different heterogeneous advanced oxidation processes. The first one is the semiconductor photocatalysis, run in the presence of the suspension of a home prepared TiO2 (TiO2 HP); the second one is an heterogeneous photo-Fenton process run in the presence of a hybrid magnetic nanomaterial (MB3) with an iron oxides core and an organic shell made of bio-based substances (BBS) isolated from urban biowaste. The two materials work upon two different mechanisms and were already tested (and the action mechanism hypothesized) at the lab scale under model conditions: TiO2 acts as photocatalyst through the photo-generation of hole/electron pairs able to give rise to oxidation and reduction reactions, whereas hybrid magnetic nanomaterial acts in the presence of H2O2 by a photo-Fenton like mechanism. The results evidenced the better performances of TiO2 HP (also better than the well-known reference TiO2 P25). Preliminary photodegradation experiments carried out in a pilot plant under natural solar radiation confirmed the good results obtained with TiO2 HP. Moreover, in the adopted experimental conditions, the Fe(II) leached from MB3 can be considered as responsible of the MCs degradation through a homogeneous photo-Fenton reaction, where MB3 act as iron reservoir.