Application of ZnO nanoparticles synthesized using Inula helenium plant extract for the sustainable removal of paracetamol from water

Paracetamol (PARA) is one of the most widely used pharmaceutically active compounds with analgesic and antipyretic properties and is frequently found in aquatic systems. Exposure to PARA can cause hepatotoxic, nephrotoxic, and genotoxic effects in humans, while in aquatic organisms it induces oxidative stress, DNA damage, and behavioral disorders. Heterogeneous photocatalysis is a green method characterized by simplicity, environmental friendliness, and the use of semiconductor nanomaterials as photocatalysts for the degradation of organic pollutants in water. Accordingly, increasing attention has been directed toward the green synthesis of metal oxide nanoparticles, as it reduces the use of hazardous chemicals, contributes to the development of environmentally friendly photocatalytic materials and support the principles of green chemistry.

The aim of this study was to evaluate the efficiency of a newly synthesized photocatalyst based on Inula Helenium plant extract for the photocatalytic degradation of PARA in aqueous suspension under simulated solar irradiation. In addition, a comparison between the efficiencies of photolysis and photocatalysis was performed. The results demonstrated that photocatalysis is a more efficient process than photolysis. Namely, after 180 min of irradiation, direct photolysis did not lead to any measurable degradation of PARA. Additionally, the influence of catalyst loading of the newly synthesized ZnO, ranging from 0.5 to 2.0 mg/cm³, on PARA degradation was also examined. Highest activity was achieved at a catalyst loading of 0.5 mg/cm³, resulting in 43% of PARA removal after 180 min of irradiation. Overall, these results highlight the importance of catalyst loading as a very important operational parameter in the photocatalytic degradation process and confirm that green-synthesized ZnO nanoparticles are effective photocatalysts for removing emerging contaminants from water systems.

Acknowledgements

The financial support of the Ministry of Science, Technological Development and Innovation of the Republic of Serbia (Grant No. 451-03-33/2026-03/ 200125 and 451-03-34/2026-03/ 200125).