Impact of Low-Levels of Silver, Zinc and Copper Nanoparticles on Bacterial Removal and Potential Synergy for Point-of-Use Water Treatment Solutions

While Silver (Ag) nanoparticles (NPs) are incorporated into multiple Point-of-Use drinking water solutions, silver is expensive and its disinfection performance over typical storage periods is understudied. Drawing on findings in the medical field of synergy when co-applying Ag with copper (Cu), and zinc (Zn) NPs, this research project investigates the potential for co-applying these NPs for water disinfection. The methodology consisted of using batch-test experiments to assess E. coli disinfection by combinations of Ag-Cu, Ag-Zn and Cu-Zn NPs, at different ratios. The impact of pH and natural water use on disinfection performance were also studied. Results were analyzed using Bliss model and revealed synergy. Synergy degree was: Ag-Zn>Cu-Zn>Ag-Cu, and lower Ag:Zn/Cu ratios yielded higher synergy. pH had insignificant impact on Ag, Ag-Zn and Ag-Cu's disinfection and negatively correlated with Zn-Cu disinfection, and natural water suppressed disinfection. Together results highlight synergy between combinations which can be utilized to optimize CWFs' performance.