Advanced Photocatalyst Synthesis for Efficient Removal of Emerging Water Contaminants

Abstract

The presence of antibiotics and organic contaminants in aquatic systems is a serious global problem, as these chemicals can persist in water and endanger marine life and human health. One significant source of this contamination is the excretions of unmetabolized drugs through urine or feces, especially in high-density animal farming areas. Traditional methods for removing these contaminants from water are not effective at very low concentrations. To address this problem, advanced oxidation processes (AOP) have been developed, with photocatalysis playing a key role. These methods use highly reactive radicals to break down organic compounds into harmless molecules like water, carbon dioxide and other inorganic species. Bismuth oxyiodide (BiOI) is a promising photocatalyst due to its high capacity, especially under visible light. However, BiOI has limited activity because of the rapid recombination of radicals generated during the process. To improve its effectiveness, researchers are investigating thermal treatment and combining it with other materials. Moreover, enhancing the formation of radicals using oxidizing agents that generate sulphate radicals (SO4·-) is under investigation. Sulphate radicals have a longer lifespan and greater oxidizing power than hydroxyl radicals (OH·). Peroxymonosulphate (PMS) is a potent oxidizing agent that could improve the degradation of organic contaminants in water. Additionally, to enhance the catalytic activity, there is a focus on making the photocatalyst reusable. Researchers are exploring the possibility of making the photocatalysts magnetic to facilitate their recovery after use and prevent their accumulation in aquatic ecosystems. This involves functionalizing these catalysts with magnetic materials, such as BaFe12O19, which also enhances their photocatalytic activity. In summary, current research aims to develop more effective and sustainable materials and methods for removing antibiotic contaminants from water, thereby protecting both the environment and human health.