Efficient photocatalytic removal of drugs in aqueous dispersions by using different TiO2 based semiconductors under UV and simulated solar light irradiation

Abstract

Antibiotics are an important class of environmental pollutants. Due to their widespread use, low metabolism by organisms and persistence in the aquatic environment, they pose a serious risk to human health and environmental quality. The effective removal of pharmaceuticals and their metabolites from aqueous wastewater represents an audacious challenge for the scientific community. Heterogeneous photocatalysis has been applied as an effective technology for the removal of organic pollutants because it can induce their complete mineralization into CO2, H2O and inorganic species when heteroatoms are present in the degraded molecules without giving rise to the so-called secondary pollution. This study is addressed to enhance the efficiency of differently modified commercial and home-prepared TiO2 based photocatalysts (heterojunctions with Cu2O and WO3, and samples doped with N were also prepared) towards some representative drugs (tetracycline, oxytetracycline and lincomycin). N-doped TiO2 revealed high photocatalytic activity under both UV and simulated solar light irradiation, allowing not only the drugs removal but also a higher mineralization degree. O2•− radicals was found to be the main active species in the drugs degradation. Mechanistic investigations revealed a first order kinetics.