Preparation And Performance Of Pd/Al₂O₃ Composite Hollow Fiber Membrane

With the aggravating of energy shortage and environmental pollution, the development of new clean energy is drawing more and more interest. As a green energy carrier, H2 has attracted intense research interests in production and purification. Pd membrane has attracted more attention on H2 separation and purification due to its high permeability, good mechanical stability and thermal stability. On the other hand, Pd membrane has also been used in hydrogenation, dehydrogenation, oxidation and some hydrogen related reactions, which made the research of Pd membrane more significant in academic and industry.In this paper, Pd/Al2O3 composite hollow fiber membranes were prepared by electroless plating method. The morphology and hydrogen permeability of the Pd/Al2O3 composite hollow fiber membranes were characterized by SEM, XRD, EDX and high temperature permeation tests. The main contents and results are as follows:1.The palladium membrane was prepared on the alumina support using the electroless plating method. The effect of substrates, plating temperature, plating time and times on the microstructure and performance of Pd/Al2O3 composite membrane was investigated. The results showed that the compact Pd membrane could be prepared on the alumina tube with pore size of 2μm. The ideal Pd membrane could be obtained at 318 K. A uniform and continous Pd layer could be obtained by electroless plating for 4h. The deposited Pd and the thickness of membrane increased with increasing the plating times. A thin and continuous Pd membrane could be prepared after two plating times.2.Al2O3 sol was modified by PVA introduction and a layer of γ-Al2O3 was prepared by sol-gel dip coating and sintering technique. The tightness and mechanical strength of modified alumina hollow fiber membranes elevated with increasing the amount of PVA, while the water flux and porosity decreased. Modified Al 2O3 hollow fiber membranes with good performance could be fabricated when the amount of PVA reached 33%.3. A compact and continuous Pd layer was obtained on the surface of α-Al2O3 membrane modified by sol-gel technology. The H2 flux and H2/N2 ideal selectivity of Pd/γ-Al2O3 composite hollow fiber membranes were 0.04 mol/m2·s and 410 at 823 K and ΔP0.5=1. Moreover, Pd/Al2O3 composite hollow fiber membrane showed high stability during the 150 h experiment with 25 times pressure cycles between 50 KPa and 100 KPa at 673 K and 8 times temperature cycles between 623K-723 K.