Preparation and Characterization of Silver/Organo-clay Nanocomposites

Abstract

This study investigated the application of organo-clay as a support in the synthesis of silver nanoparticles with increased antimicrobial activity – the Ag-montmorillonite nanocomposite (Ag-MMT). This technology is utilized to improve the antibacterial function of materials, especially those used in polymeric nanocomposites. This purpose fulfils the recently increasing public concerns on hygiene and brings solutions to health, safety, and microbial protection. The experimental steps consisted of purification with hydrogen peroxide to remove organic matter and modification with Cetyl trimethyl ammonium bromide to increase basal spacing in the clay. The purified Ag-MMT nanocomposites were obtained from organo-clay and silver nitrate (AgNO₃) as the silver precursor in the concentrations of 0.005 M, 0.01 M, 0.02 M, 0.05 M, and 0.1 M. The nanocomposites' properties were analyzed as a function of the sodium borohydride (NaBH₄) concentration, the reducing agent. The X-ray diffraction analysis showed that the structure of the purified MMT was gradually exfoliated with increasing concentrations of AgNO₃ while the organo-clay structure remained intact. Samples of Ag⁺-MMT were reduced with NaBH₄ to produce Ag^o; the UV-vis spectra showed which particle diameters were dependent on the NaBH₄ concentration. The Ag-MMT organo-clay nanocomposite showed the highest antimicrobial activity against Escherichia coli as the result of its high concentration of silver nanoparticles.