Enhancing morphological and optical properties of montmorillonite/ chitosan-modified cerium oxide nanoparticles for antimicrobial applications

Cerium oxide montmorillonite (CeO2NPs-Mt) nanocomposite has been successfully synthesized using montmorillonite (Mt) as support, Moringa oleifera as a chelating agent, and chitosan as a cross-linking agent with the green hydrothermal method. The molar composition of cerium (Ce) as a precursor and montmorillonite (Mt) as support was varied to 1: 0.5, 1: 1, 1:2, 1:3, and 1:4 to discover the effect of support on morphology, optical properties, and antimicrobial activity of cerium oxide. X-ray diffraction (XRD) analysis result showed the deposition of CeO2NPs on Mt surface. The Fourier transform infra-red (FTIR) analysis revealed the appearance of a Ce-O specific peak in the range of 400-600 cm-1. Based on Transmission electron microscopy (TEM) analysis, the morphology of CeO2NPs-Mt nanocomposite showed reduced agglomeration with nanoparticles dispersed on the support's surface. Scanning electron microscopy (SEM) analysis confirmed that using of Ce: Mt composition of 1:2 resulted in more evenly Ce nanoparticles on Mt support with no agglomeration. Based on the Diffuse Reflectance Spectroscopy UV-Visible (DRS-UV-Vis) analysis result the sample resulted in the largest bandgap energy as well. Nanocomposite Ce: Mt with a molar ratio of 1:2 indicated the good activity of antimicrobial to Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus bacteria, as well as Candida albicans and Aspergillus fumigatus. The result shows that an inhibitory effect of CeO2NPs was increased up to 30% after modification using Mt, showing a highly potential for antimicrobial material to be developed in biomedical applications.