Synthesis and photocatalytic activity of montmorillonite/TiO<sub>2</sub> nanocomposites for rhodamine B degradation under UVC irradiation
Bang Tam Thi Dao, Hà Mạnh Tuấn, Trung Do Nguyen, Hon Nhien Le, Tien Trung Vu, Huu Truong Nguyen, Chi Nhan Ha Thuc
Abstract
Abstract The increasing contamination of water by organic dyes causes water pollution in the enviroment. Factories discharge untreated effluents into nearby water courses adding to the existing water pollution; this poses a significant environmental challenge. Hence there is a pressing demand to develop efficient technology for wastewater treatment, and photocatalysis has emerged as an advanced oxidation process with a green chemical approach for such treatment. This study aims to synthesize montmorillonite/TiO 2 (Mnt/TiO 2 ) photocatalysts and clarify the effect of montmorillonite content on the photodegradation of the organic dye rhodamine B (RhB). Mnt/TiO 2 was prepared by a chemical method with various mass ratios of m Mnt : m TiO2 based on the cation exchange capacity (CEC) of Mnt. The physicochemical properties of the samples prepared were determined by the following methods: energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The photocatalytic degradation efficiency of the RhB solution of Mnt/TiO 2 was investigated by UV-Vis spectroscopy under UVC irradiation. Liquid chromatography-mass spectrometry (LCMS) was used to identify the photocatalytic by-products. The results showed that the structure of the nanocomposites has a ‘house-of-cards’ form with TiO 2 nanoparticles randomly distributed on the surface and sheets of clay minerals. The best mass ratio of m Mnt : m TiO2 is 10:1, corresponding to a 10 ppm RhB solution decolorization efficiency of 91.5% in 210 min. In this study, Mnt/TiO 2 successfully cleaved the dye chromophore structure and broke the RhB rings into small and broken-ring compounds.