Selective Desilication, Mesopores Formation, and MTO Reaction Enhancement via Citric Acid Treatment of Zeolite SAPO-34
Selective Desilication, Mesopores Formation, and MTO Reaction Enhancement via Citric Acid Treatment of Zeolite SAPO-34
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通过柠檬酸处理 SAPO-34 沸石进行选择性脱硅、介孔形成和 MTO 反应增强
DOI：
10.1021/acs.iecr.8b00632
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发表时间：
2018
影响因子：
4.2
通讯作者：
Shen Baojian
中科院分区：
文献类型：
--
作者：
Jin Wenlong;Wang Baojie;Tuo Pengfei;Li Cheng;Li Lei;Zhao Hongjuan;Gao Xionghou;Shen Baojian
在SAPO-34分子筛的研究中，除了引入分级孔结构外，调节二氧化硅的组成/结构从而调节酸性是关键因素。本工作采用柠檬酸处理法制备了具有有序介孔结构的分级结构SAPO-34分子筛。介孔呈现出一种新颖的缝隙形状，从晶体表面开始，然后终止于晶体中心。结果表明，柠檬酸处理后，SAPO-34分子筛骨架中Si（OSi）1（OAl）3中的硅物种被选择性萃取，同时SAPO-34分子筛的总刘易斯酸量（NH3-IR）和外表面的Bronsted酸量（吡啶-IR）均明显增加。因此，分级SAPO-34样品在MTO反应中表现出上级催化性能，催化寿命延长了约2.5倍，乙烯和丙烯的选择性提高了近8%;这对于工业过程是非常重要的。
Adjusting the silica composition/structure and thus tuning the acidity besides introducing hierarchical pore structure is the key factor in zeolite SAPO-34 research. In this work, hierarchical zeolite SAPO-34 with well-organized mesopores was prepared via citric acid treatment. The mesopores presented a novel slit shape, which starts from the crystal surfaces then ends at the center of the crystal. It was found that, after citric acid treatment, silicon species of Si(OSi)1(OAl)3 in the SAPO-34 framework were extracted selectively, at the same time that both the total Lewis acid amount (by NH3–IR) and the Bronsted acid amount on the external surface (by Pyridine-IR) of SAPO-34 zeolite obviously increased. Consequently, the hierarchical SAPO-34 sample exhibited superior catalytic performance in the MTO reaction with about 2.5 times prolonged catalytic lifetime and a nearly 8% improvement of selectivity for ethylene and propylene; this is very important for industrial processes.