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利用微乳液及浸渍技术制备了多孔Pd/α-Al2O3催化活性膜.利用透射电镜、扫描电镜和X射线衍射对微乳液中及α-Al2O3陶瓷膜孔结构中纳米Pd颗粒的形貌和分布进行了表征.分析结果表明,通过浸渍技术,微乳液中的纳米Pd颗粒以几百纳米大小的晶体形态均匀负载于陶瓷膜孔中.在“催化接触器”型膜反应器中,以1,5-环辛二烯催化加氢为模型反应,考察了多孔Pd/α-Al2O3膜的活性与选择性,并与Pd-聚丙烯酸(PAA)有机催化膜反应器、悬浮床反应器和固定床反应器中的催化性能进行了比较.结果表明,Pd/α-Al2O3膜反应器的催化活性与目的产物1-环辛烯的选择性远高于Pd-PAA有机膜反应器和固定床反应器.Pd/α-Al2O3膜反应器在强化传质和消除孔内扩散方面效果显著,这与Pd在陶瓷膜孔中的分布及反应物在膜反应器中的高速流动有关.
The porous Pd / α-Al2O3 catalytically active membrane was prepared by microemulsion and impregnation technique. The morphology and distribution of nano-Pd particles in the microemulsion and the pore structure of α-Al2O3 ceramic membrane were characterized by transmission electron microscopy, scanning electron microscopy and X-ray diffraction The results show that by impregnation technology, the nano-Pd particles in the microemulsion are uniformly loaded in the pores of the ceramic membrane in the form of crystal with a size of several hundred nanometers. In the “catalytic contactor” type membrane reactor, 1 , 5-cyclooctadiene catalyzed hydrogenation as a model reaction, the activity and selectivity of the porous Pd / α-Al2O3 membrane was investigated and compared with the Pd-polyacrylic acid (PAA) organic catalytic membrane reactor, suspended bed reactor and fixed The results show that the catalytic activity of Pd / α-Al2O3 membrane reactor is much higher than the selectivity of 1-cyclooctene in the Pd-PAA reactor and the fixed bed reaction The effect of Pd / α-Al2O3 membrane reactor on enhancing mass transfer and eliminating intra-pore diffusion is remarkable, which is related to the distribution of Pd in the pores of ceramic membrane and the high-speed flow of reactants in the membrane reactor.