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化学学报
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化学学报 ›› 2009, Vol. 67 ›› Issue (18): 2067-2073. 上一篇    下一篇

研究论文

天然CXN沸石分子筛水热稳定性研究 II. 水蒸汽处理温度对铵型沸石物化性质的影响

何秋平a 程晓维b 鄢 浩*,a 龙英才*,b   

  1. (a上海大学环境与化学工程学院化工系 上海 201800)
    (b复旦大学化学系 上海市分子催化与功能材料重点实验室 上海 200433)
  • 投稿日期:2008-11-27 修回日期:2009-01-04 发布日期:2009-12-31
  • 通讯作者: 龙英才

Hydrothermal Stability of Natural CXN Zeolite II. Influence of Steaming Temperature on the Properties of NH4-Type Zeolite

He, Qiupinga Cheng, Xiaoweib Yan, Hao*,a Long, Yingcai*,b   

  1. (a Department of Chemical Engineering, School of Environment and Chemical Engineering,
    Shanghai University, Shanghai 201800)
    (b Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry,
    Fudan University, Shanghai 200433)
  • Received:2008-11-27 Revised:2009-01-04 Published:2009-12-31
  • Contact: Long, Yingcai

在前文研究天然Stilbite沸石(CXN沸石)水热稳定性影响因素的基础上, 以27Al与29Si MAS NMR, NH3-TPD和低温氮吸附等详细研究了铵型CXN沸石骨架铝配位状态和硅配位状态, 表面酸性与孔性质等与水蒸汽处理温度的关系. 随温度升高, 沸石骨架硅铝比逐渐提高, 并伴随硅羟基缺陷增多. 经750 ℃水蒸汽处理3 h后沸石骨架硅铝比可达到21.3. 沸石总酸量随水蒸汽处理温度的提高而降低, 沸石骨架铝脱除造成沸石孔道部分被堵塞, 但同时形成有利于分子扩散的介孔.

关键词: CXN沸石, STI沸石, 水蒸汽处理, 非骨架铝, 酸性, 孔结构

Based on the investigation of factors influencing the hydrothermal stability of natural Stilbite (CXN) zeolite, the relationship between the steaming temperature and coordinations of Al and Si in the framework of NH4-CXN zeolite has been investigated in detail by 27Al & 29Si MAS NMR characterizations, which indicate that both the framework SiO2/Al2O3 ratios and Si(OH) contents of the zeolite increase with the steaming temperature rising, and 21.3 of the framework SiO2/Al2O3 ratio for the zeolite was obtained by steam treatment at 750 ℃ for 3 h. NH3-TPD shows that the total acid amount of the zeolite decreases with the steaming temperature rising. Nitrogen adsorption data prove that non-framework aluminum obviously blocks part of the zeolite channels and some mesopores appear at the same time.

Key words: CXN zeolite, STI zeolite, steam treatment, non-framework aluminum, acidity, pore structure