Water Disinfection Using Silver and Zinc Oxide Nanoparticles

Abstract

Waterborne disease has changed a basic challenge in human population. recently, the use of nanotechnology and application of nanomaterials for the control of pathogens in water is widely increased in research. Common indicator for microbial quality of water are determine presence of total and fecal coliforms. The purpose of this study was to evaluate the effect of Silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs) and combination of them in removing total and fecal coliform bacteria from contaminated water. In this experimental study a synthetic solution was made by adding effluent to distilled water. In each run, the nano silver (20-100 μg /L) and ZnO NPs (0.25-2 mg/L) were added to contaminated water. The samples were tested by 15-tube series method based on the instruction 9221-B of 21th edition of standard method book on water and wastewater experiments. Bacteria removal efficiency were examined in contact times (15, 30,60, 90 and 120) minutes. Our data indicate a decrease in the number of bacteria (MPN) in the presence of the nanoparticles. Results revealed that the removal percentage of coliform bacteria removal increased with increasing the contact time and concentrations of nanoparticles. Ag NPs at a concentration of 100 μg /L and ZnO NPs at a concentration of 2 mg/L showed the highest percentage of removal bacteria and the combination of ZnO and Ag NPs have been high synergistic behavior against coliform bacteria in contaminated water. therefore, using a combination of ZnO and Ag NPs can become a new and efficient method for the removal of indicator bacteria from contaminated water.