Evaluation of antibacterial activity of magnesium oxide nanoparticles in ZSM-12 zeolite obtained from rice husk

Rice husk is an agricultural by-product material comprising about 22% of the weight of rice. Even though some of this husk is converted into end products such as feedstock and adsorbent most is burnt openly, causing environmental and health problems especially in poor and developing countries. Therefore, it is very important to find pathways to fully utilize the rice husk.

In this study, the fabrication and characterization of ZSM-12 zeolite using rice husk ash as an alternative cheap silica source, and synthesis and characterization of magnesium oxide nanoparticles in ZSM-12 matrix by solid state reaction and ion exchange methods is reported. Disk diffusion method and MIC were used to evaluate the antimicrobial activity of nanoparticles on gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) strains of bacteria compared to standard commercial antibiotic disks.

Synthesized samples were evaluated using X-ray diffraction, scanning electron microscopy, energy dispersive X-Ray spectroscopy and transmission electron microscopy. XRD results revealed diffraction peaks for each of the two compounds in the MgO/ZSM-12 nanocomposite.

Transmission electron microscopy image of nanocomposite indicated that nanoparticles size of MgO is ~ 35 nm. Nanocomposite exhibited antibacterial activity with minimal inhibitory concentration of 96 µg/mL against E. coli and S. aureus.