Controlled carbonation of [formula omitted] surface and its application as an antibacterial particle

Abstract

Most commercially available disinfectants cause serious health side effects. This study investigates controlled carbonation of Ca(OH)2by mixing with dry ice and the use of the resultant particles as a more health friendly antimicrobial agent. In one mixing scheme, alternate layering of Ca(OH)2 and dry ice is used with no additional mixing, while in another a Hamilton Beach mixer is utilized. X – ray diffraction confirmed the identity of the resultant particles and thermogravimetry measured their bulk composition. Fourier transform infrared spectroscopy displayed different surface composition than Ca(OH)2suggesting a core – shell structured product. Commercial Ca(OH)2−CaCO3 core – shell (CSCC) particles prepared under quiescent conditions and the particles prepared in this work displayed different extent of aggregated structures, despite the different mixing strategies. Thicker CaCO3 shell and CSCC particle aggregation corresponded to higher content of CaCO3 as estimated by acid/base titration. The antibacterial activity of the CSCC particles was evaluated using a novel strategy where cells are mixed with a fixed density of particles as a slurry. Both gram – negative; namely P.aeruginosa and E.coli, and gram – positive; namely S.aureus, bacteria were tested. The results confirmed the superior antibacterial properties of the in – house prepared CSCC particles, where at least 2 times more effective particles than Ca(OH)2 and commercial particles were reported against gram-positive bacteria. The antibacterial properties of the particles were correlated to their morphology.