Melamine-based covalent organic frameworks intercalated montmorillonite for photocatalytic and antibacterial applications

Abstract

In the present work, copper oxide materials such as cuprous oxide (Cu2O) and cupric oxide (CuO), as transition metal oxide was successfully included on montmorillonite (Mt)/Covalent organic frameworks (COFs) composite, have been constructed by a facile solvothermal method, and their monomer blocks subsequent assembled into mesoporous COFs, schiff base network-1 (SNW-1), that was intercalated into the montmorillonite layers of a novel nanocomposite (Mt/COF-CuO/Cu2O) for simultaneous antibacterial and heterogeneous photocatalyst performance to degradation of textile important industrially dye such as methyl green (MG) from wastewater. The structures and properties of the resulting materials were then systematically characterized using a series of analytical techniques. The XRD pattern of Mt/COF-CuO/Cu2O nanocomposite confirmed that the formation of CuO and Cu2O nanoparticles in the monoclinic and octahedral phase, respectively. The SEM images of Mt/COF nanocomposite displayed the interfacial connections between irregular spherical grains shape of COF and the layers flat montmorillonite. Mt/COF modified by CuO/Cu2O with plate-shaped morphology and an average width of 50 nm. The diffuse reflectance spectra showed the presence of both Cu2O and CuO nanoparticles in Mt/COF-CuO/Cu2O. The new synthesized photocatalyst showed excellent activity under visible light and was used for the photodegradation of methyl green as target cationic pollutant. The effects of COF incorporation and CuO/Cu2O on the photocatalytic performance have been discussed in detail. In this process, the effects of various parameters such as pH, weight of adsorbent, and concentration of the dye was optimized. The mechanism of separation of the photogenerated electrons and holes at the Mt/COF-CuO/Cu2O nanocomposite was discussed. The antibacterial testing results showed that antibacterial activity of Mt/COF-CuO/Cu2O nanocomposite was more than CuO nanoparticles and Mt/COF against Escherichia coli and Bacillus subtilis.