Preparation and evaluation of quaternary imidazolium-modified montmorillonite for disinfection of drinking water

• Quaternary imidazolium was synthesized and used to modify montmorillonite.
• Dioctylimidazolium-modified montmorillonite displayed excellent disinfection properties.
• Disinfection occurred after contact between the modified montmorillonite and E. coli cells.
• There was no regrowth of E. coli after disinfection of drinking water.
• Leaching of the quaternary imidazolium salts from the modified montmorillonite was not observed.

Quaternary imidazolium salts with varying alkyl chain lengths (octyl, decyl, dodecyl, tetradecyl, hexadecyl) were synthesized and characterized with nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy. Antibacterial screening experiments revealed that the activity decreased with increasing alkyl chain length. Quaternary imidazolium salts with alkyl chains, such as octyl and decyl, were used for the modification of montmorillonite (Mt). The characterization of the modified Mts was performed using XRD, TGA and TEM, and results showed that the surfactants were successfully intercalated in the Mt interlayer space. The selected quaternary imidazolium salt-modified Mts were evaluated for water disinfection using distilled, borehole and river water inoculated with Escherichia coli. Mt modified with surfactants carrying the octyl chains displayed excellent disinfection properties for all three water types. The TEM results showed that the mechanism of inactivation occurred through rupturing of the cell membrane after the E. coli cells came into contact with the modified Mt. In summary, the quaternary imidazolium-modified Mt has great potential to be used for household water disinfection.

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