From waste to Innovation: Silver-Doped silicate ink coating from waste coal fly ash for hydrophobic antimicrobial fabric and Water-Oil separation

Coal fly ash, a waste byproduct of coal-fired power plants rich in silica, is produced in vast quantities, exceeding 750 million tons annually. This abundance underscores the importance of finding sustainable and value-added applications for its reuse. Silver nanoparticle–silica composites represent a class of inorganically hybrid antimicrobial agents as the protection layer of cotton fabrics. However, prior work has seldom involved in the recycling of waste silica sources or in situ incorporation of well-defined and hierarchical Ag nanostructure. In this study, a new type of hydrophobic and antimicrobial fabric layer composed of silver-doped silicate nanomembrane was fabricated with the extraction of silica particles from waste coal fly ash by physicochemical and hydrothermal method for dual applications in personal protection and oil–water separation. The results from detailed material synthesis, soft flakes of silica extraction and formation of silver nanoparticle-based silicate revealed correlations between SiO₂ and Ag having featured surface morphology and antimicrobial activity without any toxic effect to cells with polydimethoxysilane coatings. The developed fabric shows the satisfactory antimicrobial property increased up to 100% and oil–water separation performance was increased more than 90%, excellent selectivity, reversibility, reusability and stability. The compiled results have great implications for the management of solid waste like coal fly ash to biomedical and textile industry toward the production of personal protective equipment and high-performance nanomembrane for the treatment of contaminated water with oil.