Silver GAC

Granular activated carbon (GAC) purifies water by adsorbing organic and inorganic chemicals, thereby improving odour and taste. GAC is a common component of field filters. It may trap but does not kill organisms; in fact, nonpathogenic bacteria readily colonize GAC. For the removal of micro-organisms, our team developed a technology to kill the germs by doping on the surface of the carbon by wet method using Antimicrobial agents which are not harmful and carcinogenic.

Our Nano silver impregnated granular activated carbon (Ag-GAC) has the ability in inhibiting the growth of Escherichia coli (E. coli), a water-borne bacterial pathogen. Ag-GAC was made by impregnating GAC with both colloidal and nano-methodology. Plate assay showed slight inhibition of E. coli, and shake flask tests showed a conspicuous effect only for higher concentrations. Flow tests further indicated that Ag-GAC made from antimicrobial agent caused a desirable three orders of reduction in E. coli number concentration in less than 30 s. An embedded Ag in the final Ag-GAC product was necessary for the requisite complete inhibition of E. coli, killing bacteria in the contact mode for up to the required flow of water. These results prove that Ag-GAC possesses antibacterial properties and can be used for disinfection to produce potable quality water.