陶瓷中空纤维内表面动态水热合成NaA分子筛膜及其表征

Synthesis and Characterization of NaA Zeolite Membranes on the Inner Side of Hollow Fiber Support by a Dynamic Hydrothermal Process

采用动态水热法在氧化铝陶瓷中空纤维内表面原位合成了NaA分子筛膜。利用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)表征了分子筛膜的物相及微观形貌,通过渗透汽化测试考察了膜的乙醇/水分离性能,研究了合成工艺参数对成膜过程及膜质量的影响。结果表明,动态下合成的分子筛膜,晶体交联紧致,膜层薄且连续性好,厚度约4μm;提高动态速度有利于降低载体内外合成液的温差和浓度差,缩短晶化时间。在温度343K下,分离质量分数90%的乙醇/水体系,膜的渗透通量和分离因子可达1.03kg/(m2·h)和3 781,对乙醇/水表现出良好的分离效果和可重复性。

NaA zeolite membranes coated on the inner surface of hollow fiber support were synthesized directly in dynamic state by in-situ hydrothermal synthesis method. The phase, morphology and alcohol/water separation were characterized by X-ray diffraction （XRD）, field emission scanning electron microscopy （FE-SEM） and pervaporigation, respectively. The influences of the dynamic state hydrotherrnal condition on the quality of the as-synthesized membranes were investigated. The results show that NaA zeolite membranes fabricated in the dynamic state hydrothermal condition exhibit an excellent continuity, intersecting twin-crystal structure without obvious ecological gravity deposition crystal. The membranes thickness is about 4μm. The improvement of rotation speed is beneficial to decrease the difference of temperature and concentration in both sides of carrier wall, and reduce crystallization time. In addition, the as-synthesized membrane exhibit 90% ethanol/water pervaporation performance and technology repeatability at 343 K. The permeation flux and the separation factor of the membranes are over 1.03 kg/（m^2·h） and 3 781, respectively.