The deposition of a NaA zeolite layer on porous stainless steel substrates was optimized in order to obtain composite membranes for hydrogen separation. The effect of the silica source on NaA zeolite crystallinity and morphology was studied using two synthesis routes: concentrated gel and clear solution. The optimized synthesis conditions were applied for the synthesis of NaA zeolite layers on top of porous stainless steel disks or on the outer surface of tubular supports. SEM and XRD measurements confirmed that the use of rice husk allowed obtaining defect free and pure phase NaA zeolite membranes. Selectivity values similar to those published for NaA zeolite membranes based on ceramic substrates were obtained using zeolite layers deposited on porous stainless steel tubes. From the curve fitting of the experimental data, the contribution of zeolitic and non-zeolitic flux was estimated. For the membranes synthesized from a concentrated gel, H2 showed a predominated contribution of the zeolitic flux.

中文翻译：

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改性多孔不锈钢载体上的 NaA 沸石膜：不同 SiO2 源的比较研究

NaA沸石层在多孔不锈钢基材上的沉积被优化以获得用于氢分离的复合膜。使用两种合成途径研究了二氧化硅源对 NaA 沸石结晶度和形态的影响：浓缩凝胶和澄清溶液。优化的合成条件用于合成多孔不锈钢圆盘顶部或管状载体外表面上的 NaA 沸石层。SEM 和 XRD 测量证实使用稻壳可以获得无缺陷的纯相 NaA 沸石膜。使用沉积在多孔不锈钢管上的沸石层获得的选择性值类似于基于陶瓷基材的 NaA 沸石膜的选择性值。从实验数据的曲线拟合来看，估计了沸石和非沸石通量的贡献。对于由浓缩凝胶合成的膜，H2 显示出沸石通量的主要贡献。