Chemotherapy drugs are considered a group of emerging pollutants which can possibly impact the aquatic life in the water bodies receiving effluents from wastewater treatment plants. Therefore, the search for alternative methods that will enable the effective removal of drugs from pharmaceutical wastewater and hospital or/and municipal sewage is still a top priority. Photoelectrochemical oxidation is one of the promising method for degradation persistent and toxic organic pollutants from aqueous phase. Based on the literature data and own experience, it could be concluded that the efficiency of the photoelectrochemical treatment system depends mainly on activity of the photoelectrode materials. Thus, one of the challenges in this field is the development of photoactive materials, in the form of thin layer, activated by low powered and low cost irradiation sources (such as sunlight). So far, in such processes, as photoelectrodes were used various types of semiconductors, among which the most frequently used was TiO2. However, pure TiO2 nanostructures are active only under UV radiation. One of the method to enhance the photocatalytic activity under visible light is sensitization of TiO2 nanostructures with narrow-gap semiconducting materials. Sensitization of TiO2 nanostructures with quantum dots (QDs) of narrow-gap semiconductors, such CdS, PbS, SnS will allow for obtain a new materials with photoelectrochemical activity under visible light. The activity of these nanocomposites will depend on their surface and structural properties like type of semiconductors, size and amount QDs.
In the presented study, we prepared photoanodes based on TiO2 nanotubes which were sensitized with QDs of CdS, PbS, SnS and applied them for photoelectrocatalitic removal of selected anticancer drugs. The photoelectrodes differed in type of semiconductor, amount and size of QDs. The structure and morphology of photoelectrodes were investigated. The PEC degradation activity of the prepared electrodes at different values of electric potential, irradiation intensity, pH and drug was determined. The participation of individual oxidants in anticancer drugs degradation was studied based on reactions with scavengers. Moreover, the photoelectrocatalytic degradation pathway of anticancer drugs and the ecotoxicity of the effluents against Lemna minor were investigated.