Water disinfection via controlled release of biocides for reduced toxicity and extended shelf life: a review

Abstract

The excessive release of biocidal agents and their consecutive impact are critical issues that can lead to secondary toxicity, and decreased longevity of the water disinfection process. Various antimicrobial agents, such as chlorine, biocidal salts, nanoparticles, etc., have been used for water purification. However, ensuring the longevity and stability of the material becomes a vital concern when dealing with long-term disinfection. This review explores diverse approaches to mitigate excessive biocide release, offering applications in point-of-use disinfection treatment with a controlled release phenomenon. Comprehensive literature is highlighted, emphasizing the use of biocides in various forms, including filters, resins, membranes, hydrogels, antimicrobial films, tablets, etc. Techniques such as carrier-modulated and stimuli-responsive methods, which aim to modify the biocide's inherent structural and chemical properties, are focused on enhancing selectivity and functionality for a prolonged effect with minimal leaching. The controlled-release action phenomena on reduced disinfection by-products are also highlighted, and a perspective toward reduced secondary toxicity is provided. Additionally, a strength, weakness, opportunity, and threat (SWOT) analysis is conducted to evaluate the potential of these systems for real-world applications. Such systems can pave a roadmap for long-term disinfection operations and potentially enhance the shelf-life of materials.