Feasibility Study of Hydrochar/Zn composites in Heterogeneous Photocatalytic Degradation

Abstract

Water pollution has become an increasingly severe environmental problem. This increase is due to industrial factors and the growing demand for water by the population. This situation is aggravated by the drought problem in Catalonia, which intensifies the pressure on available water resources. With its rich wine-growing tradition, Catalonia generates a large amount of agricultural waste after the grape harvest each year, mainly from the vine shoots. These residues can be converted into hydrochar (HC), a material that is effective in adsorption and photocatalysis processes when combined with other oxides. Considering these factors, interest arises in recycling organic waste into hydrochar (HC) and using it in heterogeneous photocatalytic degradation processes (one of the AOPs techniques) to eliminate emerging pollutants. This approach offers a more sustainable, economical and ecological solution to address drought and improve water quality. This project is proposed to evaluate the feasibility and efficiency of HC and HC/Zn composites in the photodegradation of metoprolol and thiacloprid pollutants under UV irradiation. The aim was to synthesize these composites and analyze their photocatalytic effectiveness and their reusability through multiple degradation cycles. The results showed that individual HC achieved a significant degradation percentage, with 19.91% for metoprolol and 16.89% for thiacloprid after 3 hours of UV illumination. Among the synthesized photocatalysts, HC-HDZn 10% achieved the highest photocatalytic activity, reaching degradation efficiencies of 99.82% for metoprolol and 98.27% for thiacloprid. The study also analyzed the reuse of the optimal photocatalyst in multiple degradation cycles, showing a slight decrease in efficiency but maintaining more than 90% of its initial capacity after three cycles. These results indicate that HC and its composites are promising materials in the photodegradation of organic pollutants, proving successful in environmental remediation applications due to their sustainable, stable character and high efficiency. Future studies could further optimize these materials and explore their application to a wider variety of pollutants.