Jump to main content
Jump to site search


Synergistic antibacterial activity of a combination of silver and copper nanoparticle impregnated activated carbon for water disinfection

Abstract

Silver and copper nanoparticle, impregnated separately, on plasma treated, activated carbon (AC) (named Ag-AC and Cu-AC, respectively), when mixed in an optimized 50:50 weight ratio, shows synergistic water disinfection, compared to only Ag-AC or only Cu-AC. Time-dependent cryo-SEM imaging and reactive oxygen species (ROS) measurement of E. coli proves that (in both batch and continuous flow-column), Cu-AC forms pits faster on the cell-membrane compared to Ag-AC, which together with the latter, facilitates faster cell death. The composite of Ag-AC and Cu-AC in batch mode showed 4 log reduction of live E. coli cells in the treated water, in 8 minutes itself, confirmed by both plate count and fluorescence spectroscopy. Scaling up this result in a continuous flow-column (of 8 cm diameter and 25 cm height, packed with the composite), one could achieve zero live cell concentration in only 7 minutes of contact time, translating into a very high flow rate of 5.32 L/h of treated water. Therefore, plate- count, fluorescence spectroscopy, time-dependent ROS measurement and cryo-SEM imaging establishes the mechanism of synergy and contact time required for cell-death. The disinfection performance to zero live E. coli cells could be maintained with even higher, inlet E. coli concentration of 106 CFU/ml (albeit at a lower throughput from the column, as expected) and also non-stop for at least 5 days, demonstrating potential long-term performance, with more than adequate Ag and Cu left in the column. Finally, the steady state concentration of Ag and Cu in the treated water were 23 and 56.4 µg/L, respectively, which are well-within the permissible limits of 100 and 1000 µg/L for Ag and Cu, respectively. Therefore, synergistic antibacterial activity of the composite resulted in production of decontaminated water at the highest throughput over a long time-period.

Back to tab navigation

Supplementary files

Publication details

The article was received on 12 May 2017, accepted on 05 Oct 2017 and first published on 06 Oct 2017


Article type: Paper
DOI: 10.1039/C7EN00427C
Citation: Environ. Sci.: Nano, 2017, Accepted Manuscript
  •   Request permissions

    Synergistic antibacterial activity of a combination of silver and copper nanoparticle impregnated activated carbon for water disinfection

    P. Biswas and R. Bandyopadhyaya, Environ. Sci.: Nano, 2017, Accepted Manuscript , DOI: 10.1039/C7EN00427C

Search articles by author

Spotlight

Advertisements