Antimicrobial composites of nanoparticles generated by gamma irradiation supported in clinoptilolite-rich tuff

Abstract

In developing countries, rates of hydric illness in children are high because of the consumption of non-potable water. Therefore, it is important to investigate new methodologies to diminish microorganisms’ concentration in the water that is used in rural areas for drinking. Microbicide agents with a base of natural zeolites can be an alternative to water disinfection instead of using other kinds of disinfectants that produce by-products. Hence, the synthesis and characterization of metallic or oxide-metallic nanoparticles-natural zeolite composites to evaluate the antimicrobial activity in front of Salmonella typhimurium and Candida albicans in this work were investigated. The natural zeolite was in contact with salt solutions of Ag, Cu, or Zn to obtain the modified natural zeolites, and they were then gamma irradiated to generate the nanoparticles. The samples were characterized by different techniques. The Salmonella typhimurium and Candida albicans were suspended in distilled water and put in contact with the composites at different times. The kinetic of the cellular decay was obtained using the Chick model. The chemical species of the nanoparticles obtained were Ag, Cu2O, and ZnO. The kinetic parameter of the cell decay of both Salmonella typhimurium and Candida albicans is the biggest for silver nanoparticles-natural zeolite composite (Z-NpsAgγ). Between two independent experiments of the cellular decay, differences in the k values were observed. The antimicrobial activity of these composites depends on the characteristics of each microorganism, the mass of the composite, the content of the metallic or oxido-metallic nanoparticles in the natural zeolites, their distribution on the zeolitic material surfaces, and the chemical species obtained during the gamma irradiation. The Z-NpsAgγ could be an alternative for water potabilization.