Solar light assisted photodegradation of ethidium bromide over titania-based catalysts

The solar light photocatalytic degradation of ethidium bromide (EtBr) in aqueous suspensions has been analyzed over titania-based catalysts. A nanosized titania and an iron-doped TiO2 (with ≈2 wt.% of iron content), synthesized within reverse microemulsions, were compared with a commercial Degussa P-25 titania. Structural and/or light handling properties of a different nature arise upon doping the titania with iron. These include favoring a titania crystal phase transformation from anatase to rutile and lowering the band gap energy. Almost total degradation of EtBr upon solar light assisted photodestruction and with significant total organic carbon (TOC) removal can be achieved over the three studied catalysts although the highest mineralization activity is achieved over the P25 titania sample. The results evidence that heterogeneous photocatalysis can be a promising advanced oxidation process to treat diluted EtBr residues typically generated in biomedical and biomolecular laboratories.