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用不同浓度的盐酸溶液对纳米ZSM-5分子筛进行脱铝改性,采用X-射线衍射(XRD)、X-射线荧光光谱(XRF)、扫描电子显微镜(SEM)、氮气物理吸附、傅里叶变换红外光谱(FTIR)、~(27)Al MAS NMR和NH_3程序升温脱附(NH_3-TPD)等方法对酸处理前后的样品进行了表征,并考察了盐酸浓度对改性前后纳米ZSM-5分子筛的结构、酸性及其催化对二氯苯(p-DCB)异构化反应性能的影响。结果表明,通过改变盐溶液的浓度可以选择性地脱除ZSM-5分子筛的非骨架铝及骨架铝,形成二次介孔,并对分子筛的酸性进行调变。改性后的纳米ZSM-5分子筛在对二氯苯异构化反应中的催化活性略有降低,但是间二氯苯的选择性得到显著提高。
The ZSM-5 zeolites were modified by dealuminization with different concentrations of hydrochloric acid solution. X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), physical adsorption of nitrogen (FTIR), ~ (27) Al MAS NMR and NH_3 temperature-programmed desorption (NH_3-TPD) were used to characterize the samples before and after acid treatment. Structure, Acidity and Catalytic Effects of Zeolite on Isomerization Reaction of Dichlorobenzene (p-DCB). The results show that by changing the concentration of the salt solution, the non-framework aluminum and framework aluminum of ZSM-5 zeolite can be selectively removed to form secondary mesopores, and the acidity of the zeolite can be modified. The catalytic activity of the modified nano-ZSM-5 zeolite in the isomerization of p-dichlorobenzene slightly decreased, but the selectivity of m-dichlorobenzene was significantly improved.