Evaluation of the Photocatalytic Activity of Copper Doped TiO2 nanoparticles for the Purification and/or Disinfection of Industrial Effluents

In this article, visible light active, copper doped TiO2 nanoparticles are discussed as potential candidates for the tertiary treatment of industrial effluents. Our aim was to develop sustainable photocatalytic materials that exhibit excellent activity and biocompatibility. The photocatalysts were prepared using a two-step procedure: solgel synthesis followed by microwave hydrothermal treatment. Copper (Cu) was chosen as doping agent because it has been previously reported that Cu is a good doping element that improves the photocatalytic performance of TiO2. The incorporation of Cu into the TiO2 matrix was demonstrated by X ray photoelectron spectroscopy and a bandgap reduction down to 2.86 eV was achieved at relatively low doping levels (nominal 2.0%). A moderate photocatalytic activity was observed for the degradation of diclofenac and for the removal of dissolved organic matter contained in an industrial effluent. The removal efficiency of the nanoparticles increased linearly with the amount of copper doping. For instance after 7 h of illumination, diclofenac degradation efficiencies of 21.41, 28.95 and 33.26% were observed for TiO(2)eCu (1.0, 1.5 and 2.0%) respectively. Meanwhile, disinfection of the effluents was attained within five hours of treatment under visible light, in our irradiation conditions. Hydrogen peroxide improved the photocatalytic activity of the nanoparticles since the release of Cu2+ ions give rise to a combined degradation mechanism: photocatalysis + photo-Fenton. The lixiviation of Cu2+ ions was demonstrated by atomic absorption spectroscopy. Moreover, The Cu doped TiO2 nanostructures exhibited excellent antibacterial properties against both gram negative and positive bacteria and do not exert any cytotoxicity to human blood cells. The biocompatibility of the Cu doped TiO2 nanoparticles combined with their photocatalytic activity under room light illumination suits them as excellent candidates for the development of sustainable environmental remediation technologies.