Synthesis and characterization of inorganic mixed metal oxide nanoparticles derived from Zn-Al layered double hydroxide and their antibacterial activity

Inorganic metal oxides represent a class of materials that have been used for health applications. In this research, a series of novel environmental-friendly mixed metal oxide nanoparticles with general formula ZnO/MAl2O4 (M= Cu, Ni, Co and Mg) were synthesized by mixing Zn-Al layered double hydroxide as precursor with various metal nitrate salts. For this purpose, in the first step, the Zn-Al layered double hydroxide (Zn-Al LDH) as precursor was synthesized by a simple and rapid chemical co-precipitation method. In the second step, by simple mixing of Zn-Al LDH compound as precursor with related metal nitrate salts M (NO3)2. xH2O (M= Cu, Ni, Mg and Co), the mixed metal oxide nanoparticles of ZnO/CuAl2O4, ZnO/NiAl2O4, ZnO/CoAl2O4, and ZnO/MgAl2O4 were synthesized and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV-vis diffusive reflectance spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). Furthermore, the antibacterial activity of the synthesized mixed metal oxides was evaluated against the gram-negative bacterial species Escherichia coli and the gram-positive bacterial species Staphylococcus aureus. The crystallite size and play a critical role. Thus, the antibacterial activity of the mixed metal oxides was demonstrated to be in the following order: ZnO/NiAl2O4 > ZnO/CuAl2O4 > ZnO/MgAl2O4 > ZnO/CoAl2O4.