Vietnamese Montmorillonite Supported ZnO: Preparation, Characterization, and Photocatalytic Enhancement in Degradation of Rhodamine B

In this paper, montmorillonite/ZnO (MMT/ZnO) nanocomposite materials are prepared through chemical method with zinc nitrate and sodium alginate as precursors and stabilizers, respectively. Synthesized photocatalysts are used to degrade rhodamine B (RhB) in dye wastewater. The characteristics of photocatalysts in composition, surface morphology and structure are studied by using energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The intermediates after decomposition are identified by liquid chromatography-mass spectrometry (LC-MS). The results reveal that zinc oxide nanoparticles (ZnONP) with hexagonal wurtzite structure are successfully attached to montmorillonite layers according to the pillar-montmorillonite structure. The degradation efficiency of 10 ppm RhB in the presence of 0.1g/L MMT/ZnO under UVC irradiation for 210 min reaches 95.5%. The photocatalytic enhancement of MMT for ZnO is evaluated with different operational parameters such as excitation source, solution pH, catalyst content, initial solution concentration and inorganic scavengers. The mechanism of the photocatalytic degradation of RhB by MMT/ZnO is briefly discussed in this study.