The impregnation of ZnO onto ZSM-5 derived from red mud for photocatalytic degradation of methylene blue
Hellna Tehubijuluw, Riki Subagyo, Yuly Kusumawati, Didik Prasetyoko
Abstract
Abstract Photocatalytic degradation of Methylene Blue (MB) by zinc oxide/zeolite socony mobile-5 (ZnO/ZSM-5) composites was investigated. The ZSM-5 material was synthesized from red mud by a two-step hydrothermal method to which ZnO loadings at different mass ratios were subsequently performed. Characterizations using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, and scanning electron microscopy were carried out to identify the formation of ZSM-5 and ZnO/ZSM-5. ZSM-5 and ZnO/ZSM-5 have cubic microcrystallite morphologies. ZnO loading in the ZnO/ZSM-5 composites was successfully performed and confirmed by the appearance of wurtzite peaks in the XRD spectra that matched the Joint Committee on Powder Diffraction Standards data. The presence of ZnO in ZSM-5 leading resulted in a decrease in the surface area and pore size as confirming by nitrogen adsorption-desorption isotherm experiments. The band gap of the samples was measured using UV-Vis diffuse reflectance spectroscopy. The optimum photocatalytic degradation of MB was observed at a ZnO loading of 34% w/w dubbed 34-ZnO/ZSM-5. The influence of the initial concentration of MB was also investigated at 80, 90, and 100 mg L − 1 using 34-ZnO/ZSM-5 and ZSM-5. Liquid chromatography–mass spectrometry characterization was performed to analyze the degradation products.