Silver nanoparticles, because of their small size exhibits high surface area and high surface-to-volume ratio, which enhances their reactivity with organic pollutants such as phenol and its derivatives. Increased surface area provides more active sites for adsorption and catalytic degradation. For instance, AgNPs are used to reduce 4nitrophenol to 4-aminophenol . This makes silver nanoparticles an efficient material for removal of contaminants such as phenol and its derivatives from waste water.