Efficient mineralization of paracetamol using the nanocomposite TiO2 /Zn(II) phthalocyanine as photocatalyst

Abstract

The photocatalytic performance of a composite based on the association of TiO2 and 2.5 wt.% of zinc(II) phthalocyanine (TiO2 /ZnPc) was evaluated towards the mineralization of paracetamol and compared to that observed for the bare oxide in different pH and H2 O2 concentrations. The results show that the photocatalytic performances were influenced by the pH, with maximum efficiency around the isoelectric point. Mineralization efficiencies between 86-91% was obtained using TiO2 /ZnPc in pH 5.5-6.8, with 33 mg L-1 of H2 O2 , ca. 15% higher than that observed with TiO2 . The mineralization efficiencies using bare TiO2 and TiO2 /ZnPc were respectively 112 and 18% lower in the absence of H2 O2 . The better performance of TiO2 /ZnPc is related to its extended light absorption and non-uniform coating of the TiO2 surface by ZnPc aggregates. Above pH 6.8, the mineralization efficiencies decrease for both photocatalysts, although the consumption of H2 O2 remains above 90%, due to its decomposition in alkaline pH.