Biofabrication of Silver Nanoparticles: Development of Low‐Cost SICAF Nanofilters for Portable Water Purification

ABSTRACT Water borne diseases have become serious public health concern in developing countries due to contaminated water. In Pakistan most of the diseases emerge due to water borne pathogens and the fatality rate is high. Water quality can be enhanced by household water treatment by means of silver nanoparticle impregnated clay‐agrowaste nanofilters. In this study, low‐cost technology was used to treat water at household level for 12 months, therefore AgNPs were generated using Aspergillus fumigatus (BTCC10). Before treatment, three parameters were optimized, that is biomass weight (7, 13 and 16 g), NaCl (20%) and sunlight exposure. AgNPs formed were characterized by UV–vis spectrophotometer, Zeta sizer, scanning electron microscopy and Fourier transform infrared (FTIR). After optimization, it was revealed that 13 g biomass had the smallest average size AgNPs (91.7 nm), along with zeta potential of −38.9 mV and polydispersity index (PDI) 0.19 whereas rest of the parameters experienced increase in size. Correspondingly, the functional groups were identified via FTIR as C─H, O─H, C═C, C═O, and N─H acted as capping agents. Later, silver impregnated clay pot filter (CPF), bagasse clay pot filter, and sawdust clay pot filter (SCPF) were prepared. AgNPs‐coated SCPF produced cleaner water as compared to others with reduction by 3 to 4‐fold in contrast to control and proved to be an efficient and sustainable approach for water purification. Additionally, it will also be suitable for areas where water is scarce and unfit for human consumption. Antibacterial activity was also performed against multi‐drug resistant bacterial strains and maximum zones of inhibition (ZOI) for AgNPs against Salmonella typhi was obtained at 16 ± 0.20 d mm whereas Staphylococcus aureus attained ZOI at 14 ± 1.00 b mm with 13 g biomass.