| Summary: | 碩士 === 國立成功大學 === 化學工程研究所 === 85 === The Pd / Al2O3 composite membranes prepared by electroless - plating technique are studied in this work. The effects of preparation variables, including temperature, concentrations of PdCl2, NaH2PO2, NH4OH and NH4Cl on the plating rate and properties of the composite membranes are investigated. The permeations of H2 and N2 are also studied under temperatures of 100 - 200℃ and pressure differences of 40 ~240 kPa.,
The results show that the Pd plating rate increases with increasing temperature. The activation energy is about 7.3 kcal / mole. The plating rates are increased as the increase in the concentration of PdCL2, NaH2PO2, and NH4Cl. The plating rate is not affected by the NH4OH concentration significantly. High temperature and high concentrations of reactants will lead to the decomposition of bath. Besides, the contents of co - depostied phosphorus are varied in the range of 2.0 - 4.2 wt% depending on the NaH2PO2 concentration.
From the gas permeation test, it shows that the permeations of H2 and N2 through the activated Al2O3 membrane are limited by Knudsen mechanism. On the other hand, the permeations through the Pd / Al2O3 composite membrane can be described by solution - diffusion model, but is slightly deviated from Sievert's law. The separation factor for H2 / N2 is 125 at 200℃.
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