The presence of pharmaceutical agents in the environment is a growing concern as their production and consumption increases year by year. As a result, their excretion into the environment is also increasing. Conventional purification methods in wastewater treatment plants are not successful in removing pharmaceuticals. Therefore, research is focused on combining biological and chemical treatment with advanced oxidation processes, which include photocatalytic decomposition. In heterogeneous photocatalysis, ZnO has been shown to be a potentially effective photocatalyst due to its unique physical and chemical properties. This work involves the hydrothermal synthesis of ZnO nanoparticles, their coating with nickel clusters, and subsequent calcination, to optimize and compare the photocatalytic efficiency of the prepared materials in the degradation of pharmaceuticals. To confirm the success of the synthesis, I characterized the prepared photocatalysts using various techniques. I investigated the photocatalytic degradation of five model pharmaceutical agents, namely sulfamethoxazole, phenytoin, naproxen, ibuprofen, and diclofenac, as they are present in relatively large amounts in wastewater. To compare their persistence with that of endocrine disruptors, which are also of environmental concern, I also studied the photocatalytic degradation of the well-known endocrine disruptor bisphenol A. Photocatalysis occurs only in the presence of light, so I also compared the difference in degradation efficiency when using ultraviolet or visible light as the light source. As expected, Ni-grafted ZnO proved to be the most efficient photocatalyst because nickel grafting decreases the rate of charge recombination and increases the activity. However, additional calcination of ZnO leads to a decrease in activity due to an increase in particle size. Photocatalysis has been shown to be much more efficient in the presence of ultraviolet light.
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