Preparation and characterization of the antibacterial Zn2+ or/and Ce3+ loaded montmorillonites

A series of modified montmorillonites including Zn(2+) loaded montmorillonite (Zn/MMT), Ce(3+) loaded montmorillonite (Ce/MMT) and Zn(2+) -Ce(3+) loaded montmorillonites (Zn-Ce/MMT) were prepared by an ion-exchange reaction, and characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The specific surface areas, zeta potentials and antibacterial activity of the modified montmorillonites were also investigated. Zinc and cerium were proved to be present as bivalent zinc state and trivalent cerium state in the modified montmorillonites. For the modified montmorillonites, the d(001) basal spacings increased and the particles were formed of irregular shapes. The antibacterial activity of the modified montmorillonites was enhanced with the increase of specific surface areas and zeta potentials, and Zn(2+) -Ce(3+) loaded montmorillonites displayed obvious synergistic antibacterial effect. When Zn/Ce atomic ratio was 1.24, the Zn-Ce/MMT showed high antibacterial efficiency and broad-spectrum antibacterial activity, possessing the MIC against Escherichia coli, Staphylococcus aureus, Candida albicans and Mucor of 1500, 1000, 2000 and 3000 mg.L(-1), respectively.