Medical waste utilization as a carbon source assisting nanothorn ZnIn2S4 for photocatalytic hydrogen evolution and hydrogenation reaction

Background: The COVID-19 pandemic has caused a massive increase of medical waste with the approximate amount of 16,000 tons/day in the worldwide. The generation of such huge medical waste will be serious health and environment issues if the medical waste disposal is not well-treated. Despite the fact that air and water pollutions decrease significantly during the pandemic, the era of post-pandemic could bring back these issues with even worse polluted condition. Methods: Therefore, alternative solutions to overcome the medical waste and pollution issues are urgently needed. In this study, medical waste was treated to obtain carbon combined with ZnIn2S4 photocatalyst for photocatalytic hydrogen evolution reaction (HER) and hydrogenation reaction of azobenzene at mild condition under solar light irradiation. Significant Findings: It was found that with the carbon amount of 0.5 wt%, ZISC-0.5 exhibits the most optimum photocatalytic performances. The amount of generated hydrogen by ZISC-0.5 achieves 86.9 mu mol for 5 h light irradiation. On the other hand, the conversion from azobenzene to aniline by ZISC-0.5 was occurred within 2 h photoreaction as confirmed by UV-Vis spectroscopy and GCMS- analysis.