In this paper, dodecylamine (DDA) is used as the template, and ethyl orthosilicate (TEOS) is used as the silicon source. The HMS molecular sieve is prepared by in situ synthesis and modified by Cu, Ce, and Cu/Ce. The Cu/Ce-HMS molecular sieve catalyst was synthesized for the first time. Scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and Fourier transform infrared spectrometer (FTIR) were used to characterize the synthesized composite molecular sieve. The results showed that the metal was loaded on the HMS intact and did not change the morphology of the HMS. A mixture of n-hexane and dibenzothiophene (DBT) was used as the model oil, and the oxidation removal of DBT in the model oil was used as a probe reaction to study the photocatalytic oxidative desulfurization performance of the composite catalyst. The results show that the desulfurization rate after modification is Cu/Ce-HMS molecular sieve > Cu-HMS molecular sieve > Ce-HMS. Finally, we explored the reaction mechanism of catalyst desulfurization. The results of ultraviolet diffuse reflectance showed that the modified molecular sieve Cu/Ce-HMS had a smaller band gap, greater reaction activity, and stronger photocatalytic performance, which is benefit to improve the desulfurization efficiency. We report a simple and effective preparation method of composite molecular sieve catalyst, which provides a certain reference for future desulfurization research.
In this paper, phenol was used as the material to be treated, and HMS molecular sieve was used as the catalyst for the catalytic treatment of the material. HMS, Ti-HMS, Ce-HMS and composite modified Ce/Ti-HMS molecules were used to prepare sieved catalysts. Simulated phenol-containing wastewater with phenol as the main component is treated. The structure of the molecular sieve and its elements and contents were characterized by field emission scanning electron microscope; the morphology of atoms or molecules in the material was characterized by X-ray diffractometer; the chemical bonds in the molecular structure were characterized by Fourier transform infrared spectroscopy. The change of vibration peak was analyzed, and the change of surface and skeleton structure was analyzed; the absorbance of the substance to be tested to visible light was measured by ultraviolet-visible diffuse reflectance method. The experiment was optimized by response surface methodology, and the oxidation of Ce3+ was detected by infrared tracking, and the reaction mechanism of phenol catalytic degradation was analyzed. The active sites that determine the catalytic performance of the composite catalyst were studied by DFT calculations, which further confirmed that the bimetallic modified zeolite has better catalytic effect.
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