Anti-microbial efficiency of nano silver–silica modified geopolymer mortar for eco-friendly green construction technology
2015
Adak, Dibyendu | Sarkar, Manas | Maiti, Moumita | Tamang, Abiral | Mandal, Saroj | Chattopadhyay, Brajadulal
A silver–silica nano composite based geopolymer mortar has been developed by simple adsorption of silver in a suitable amount of a colloidal silica suspension for anti-bacterial property development. The silver nanoparticles (3–7 nm) were attached on the surface of 20–50 nm sized silica nanoparticles. The silver–silica nano-composite was characterized by Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) and energy dispersive X-ray spectral analysis. Mechanical strength, durability and mechanistic anti-bacterial activity of the silver–silica nano composite modified geopolymer mortar (GMAg–Sᵢ) were investigated and compared to nano silica modified geopolymer mortar (GMSᵢ) and control cement mortar (CM). To accesses the anti-microbial efficacy of the samples, 99% mortality for Gram positive and Gram negative bacteria was calculated. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values were determined from batch cultures. The addition of 6% (w/w) of the silver–silica nano composite in the geopolymer mortar cured at ambient temperature shows substantial improvement in mechanical strength, durability and anti-bacterial property. Reactive Oxygen Species (ROS) generation and cell wall rupture as observed from fluorescence microscopy and Field Emission Scanning Electron Microscopy (FESEM) may be possible reasons behind the anti-bacterial efficacy of silver–silica nano composite modified geopolymer mortar.
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