Preparation, characterization and application of polymeric thin films containing silver and copper nanoparticles with bactericidal activity

The aim of this work was to prepare and characterize self-assembled thin films (SATFs) of poly(allylamine hydrochloride) and poly(acrylic acid) containing silver (AgNPs) and copper nanoparticles (CuNPs) for their subsequent application in the disinfection of an industrial wastewater. The AgNPs and CuNPs were synthesized by direct irradiation of SATFs with ultraviolet light after immersion in silver and copper (II) salt solutions. At the end of the self-assembly procedure, the SATFs were thoroughly characterized by different instrumental techniques, including glow discharge optical emission spectroscopy (GD-OES), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometry (ICP-OES), and transmission electron microscopy (TEM). In general, the GD-OES spectra confirmed the incorporation/formation of AgNPs and CuNPs/copper (II) oxide in the SATFs. Moreover, it was observed through the FESEM and TEM analyses that a change in the salt concentration promoted a variation in the nanoparticle size incorporated into the SATFs (10 - 250 nm for AgNPs, and 10 - 170 nm for CuNPs). The disinfection process of the industrial wastewater with the SATFs reduced the total count of coliforms by 91 and 100 % compared to the raw industrial wastewater (untreated), being the SATF prepared with a concentration of 0.1098 mmol Ag+ L-1 the most efficient material. Finally, the SATFs developed in this work present great potential for a possible application in the tertiary treatment of industrial wastewater due to ease of application, reduced environmental impact, and satisfactory inhibitory action.