Quantification of silver nanoparticles and antimicrobial evaluation in carbon block water filters for household use

Water for human consumption requires treatment to remove pollutants. Carbon block filters, with highly porous activated carbon, adsorb impurities but do not combat microorganisms. Therefore, they are impregnated with silver nanoparticles to reduce the density of microorganisms in the water. Thus, this work aimed to evaluate the antimicrobial activity of carbon blocks impregnated with silver nanoparticles for application in water filters. To this end, the silver content on the surface of the granulated activated carbon was quantified by ICP-OES, the antimicrobial activity of the carbon block was analyzed, a silver leaching test was carried out from the granulated activated carbon, and a toxicity analysis was carried out. The results showed about 1 g of silver per kg in the digested sample and 10 g in the calcined and digested sample. Antimicrobial tests were successful, especially against Staphylococcus aureus, with a 99% reduction in colonies. Leaching showed 0.12 mg/L of silver, above the NBR 16098 limit. However, toxicity was not significant. Thus, using carbon block filters impregnated with silver nanoparticles is promising for this application.