Development of sustainable and reusable silver nanoparticle-coated glass for the treatment of contaminated water.

Water contaminants like pathogenic microbes and organic pollutants pose a serious threat to human and aquatic life forms; thus, there is an urgent need to develop a sustainable and affordable water treatment technology. Nanomaterials especially metal nanoparticles have extensive applications in wastewater treatment, but the recovery and aggregation of nanoparticles in solution is a major limitation. In the present work, green synthesized silver nanoparticles were covalently immobilized on a glass surface to prevent aggregation of nanoparticles and to enhance their applicability. Fourier transform infrared (FTIR) of silver nanoparticle (AgNP)-coated glass shows peaks of Si-O-Si, Si-O-C, and Ag-O at 1075 cm-1, 780 cm-1, and 608 cm-1 respectively which confirms the immobilization/conjugation of nanomaterial on glass surface. The surface morphology of immobilized AgNP was studied using scanning electron microscopy (SEM) which reveals nanoparticles are spherical and uniformly distributed on glass surface. The AgNP-coated glass was used for the removal of textile dyes in solution; the result indicates approximately 95% of textile dyes were removed after 5 h of treatment. Removal of microbial contaminants from Yamuna River was studied by optical density analysis and confirmed by fluorescence dye staining. The AgNP-coated glass was also studied for their reusability and the data indicates 50% removal of microbes up to the 5th cycle. To further enhance the applicability, the inhibition of bacterial biofilms were analyzed by dark-field illumination with a fluorescence microscope. Thus AgNP-coated glass can be used in the development of food/water storage containers and in textile industries.