Antibacterial and adsorption characteristics of activated carbon functionalized with quaternary ammonium moieties

Activated carbon (AC) was functionalized with two types of quaternary ammonium groups to achieve antibacterial properties. The first route utilized covalently coupled 3-(trimethoxysilyl)propyldimethyloctadecylammonium chloride (QAS) on the AC surface, while the second route employed a polycation, poly(vinyl-N-hexylpyridinium bromide). The successful attachment of these two types of quaternary ammonium was indicated by X-ray photoelectron spectroscopy (XPS) analysis. Both types of functionalized ACs show highly effective antibacterial activities against Escherichia coli and Staphylococcus aureus. Furthermore, the functionalized ACs can be used in repeated antibacterial applications with little loss in efficacy. Using phenol as a model compound, the adsorption capacity of the different ACs was also investigated. The different degrees of decrease in the adsorptive capacity of the two types of functionalized ACs can be related to the changes in the surface area and pore size distribution arising from the different functionalization routes.