In order to study their synergistic catalytic effects in toluene degradation, CuMn_2O_4/HTS-1(HTS-1 was a titanium silicon molecular sieve), Cu_(0.7)Mn_2Y_(0.3)O_x/HTS-1 and Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1 catalysts were prepared by the impregnation method.The textural properties, redox properties and acidity of the catalysts were characterized by X-ray diffractometer(XRD),transmission electron microscopy(TEM), scanning electron microscopy(SEM), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS),frustrated total internal reflection(FT-IR), ammonium temperature-programmed desorption(NH_3-TPD) and pyridine adsorption internal reflection(Py-IR) measurements.The potential roles of Lewis acid sites(activating dioxygen) were discussed, and the experimental results indicated that the most efficient route for toluene degradation over Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1(toluene conversion rate of 90%(T99) = 295℃) was ascribed to regulation of the synergistic effects of redox properties(activating molecular toluene) and Lewis acid sites(activating dioxygen).The Mars–Van–Krevelen(MVK) model was adopted to describe the reaction process of toluene oxidation, which gave an in-depth view into the toluene degradation over CuMn_2O_4/HTS-1, Cu_(0.7)Mn_2Y_(0.3)O_x/HTS-1 and Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1.In addition, the synergistic effects between redox properties and Lewis acid sites were studied in detail. 相似文献
Environmental Science and Pollution Research - Saline loess is an important cause of environmental geo-issues in northwest China. In this research, electrical resistivity of loess with different... 相似文献
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Microplastics (MPs) have become a hot issue of environmental pollution. However, insufficient evidence exists regarding the distributions and fates of MPs in terrestrial environment, especially in farmlands. The distributions of MPs in paddy fields were investigated in Xiangtan City, a typical rice production area in China. The abundance of MPs in paddy seedling raising fields was 3805?±?511 n·kg?1, which increased by approximately 9 times than that in common paddy fields. Transparent films became the dominant forms due to the huge usage of mulching films, corresponding to that the proportion of polyvinyl chloride (PVC) increased to 17% there. Moreover, an industrial plant nearby also contributed considerably to the MP pollution; the proportion of PVC (33%) in the paddy fields nearby increased to approximately 4 times of common paddy fields, while polyvinyl alcohol (PVA; 13%) used as an important chemical raw material to synthesis in various applications was uniquely detected there. These results highlight the input of MPs from agricultural and industrial activities in farmlands. Their contributions to the MP pollution in farmlands should be continuously investigated.
Environmental Science and Pollution Research - A Pyroprobe 5000 pyrolyzer connected to a gas chromatography-time-of-flight mass spectrometry (Py-GC-TOF–MS) was used to analyze the... 相似文献