PI/TiO2纳米复合膜的H2/CH4和H2/N2分离性能

以可溶性聚酰亚胺为基质 ,经乙酸修饰后的钛酸丁酯为TiO2 溶胶前体 ,NMP为共溶剂 ,采用溶胶凝胶法可制得PI/TiO2 纳米复合膜。采用XPS、TEM和气体透气性能测试等手段 ,对复合膜的结构和H2 分离性能进行了表征。结果表明 ,复合膜中钛酸丁酯已转化为TiO2 ,PI与TiO2 两相结合完好。TiO2 以颗粒状均匀分布在PI基质中 ,其颗粒粒径约为 1 0nm。复合膜的H2 ,N2 和CH4 透气系数随着TiO2 含量的增加而明显增加。当TiO2 含量为2 2 3 %时 ,对H2 的透气系数为 1 4 .1Barrer,对H2 /N2 和H2 /CH4 的分离系数分别为 1 87.5和 1 4 3 .2 ,因此 ,该复合膜是一种较为理想的H2 分离和回收膜材料

H2/CH4 and H2/N2 separation propertiesof PI/TiO2 nano-compos ite membrane

The PI TiO 2 nano composite membranes were made from an organic soluble polyimide(PI) and the modified titanium dioxide(TiO 2) precursor tetrabutyl titanate(TBT) in common solvent of NMP by means of sol gel process. The composite structure and separation properties of hydrogen were characterized using the methods of XPS, TEM and measuring the permeability of gases, such as H 2, N 2 and CH 4. The results show that TiO 2 was completely transferred from TBT. The two phases of PI and TiO 2 were attached tightly in the composite. The TiO 2 about 10 nm in size was dispersed well in the PI matrix. The permeability of composite membrane for penetrating gases such as H 2, N 2 and CH 4 was enhanced greatly with the increase in the content of TiO 2. When the content of TiO 2 reached 22.3 percent, the permeability factor was 14.1, and the separation properties for H 2/N 2 and H 2/CH 4 were 187.5 and 143.2 respectively. Thus, PI/TiO 2 nano composite membrane is desirable for separation and recovery of hydrogen in industry.