Silver nanoparticles impregnated with polyamide-66 to disinfect drinking water

Abstract

The importance of the preservation of water resources has resulted in the application of technologies such as nanostructured materials, which are able to minimize the impact associated with water contamination. This work evaluated the application of polyamide-66 (PA) pellets functionalized with silver nanoparticles (AgNPs) at polymer mass percentages of 0.05, 0.10 and 0.50% to disinfect of drinking water. Studies were carried out in three stages. The first stage was the synthesis of the silver nanoparticles by using silver nitrate as a metal precursor and sodium borohydrate as a reduction agent. The colloidal dispersion was characterized by UV-Vis spectrophotometry and transmission electron microscopy (MET). Afterwards, the nanostructures were incorporated into a polyamide-66 polymeric matrix. In the second stage, the silver ions leached from the polymer matrix in the water after a three-hour period were quantified in order to evaluate the limit established by Conama Resolution 357/2005, which imposes a concentration limit of 0.010 mg L^-1. The best results were obtained with the application of 0.05% AgNPs in the polymeric matrix, yielding an average concentration of silver ions lixiviated of 0.008 mg L^-1. The last step comprised the quantification of the antibacterial activity of the polymer matrix containing 0.05% of AgNPs against the microorganism E. coli using the Standard Test Method for Determining the Antimicrobial Agents Under Dynamic Contact Conditions. The samples containing 0.05% of AgNPs exhibited an antibacterial reduction of 97.89% after 24 h of incubation under stirring at room temperature (25°C).