KH-570修饰的SiO2膜制备及CH4/CO2的分离

采用KH-570代替部分TEOS为前驱物,共水解缩聚反应制得疏水性SiO2膜,通过IR、DTG、SEM、接触角测试仪等手段对KH-570修饰后的SiO2膜进行表征,并对CH4和CO2渗透和分离进行研究。实验结果表明,修饰后(0.8KH-570)SiO2膜接触角达到94.2°,红外光谱分析表明修饰后SiO2膜疏水性增强;(0.8KH-570)SiO2膜具有完整性及在400℃水热稳定性;压差30kPa,分离因子随涂膜次数增加先增大后减小,涂膜5次达最大值2.13,超越了努森扩散理论分离因子1.66,此时分离效果好;对于涂膜5次的SiO2膜,CH4渗透通量随压差增加呈现非线性微增趋势,CH4/CO2分离因子几乎不变。

Preparation of modified silica membranes by KH-570 and separation on CH4/CO2

Hydrophobic silica gas separation membranes were prepared by acid catalysed co-hydrolysis and condensation reaction of TEOS and KH-570 in ethanol,characterized by IR,DTG,SEM,contact angle measuring instrument,and studied by CH4/CO2 gas permeation and separation.The results indicated that the contact angle of(0.8KH-570) silica membrane was 94.2°.The hydrophobicity of modified membrane enhanced by test with infrared spectrum.(0.8KH-570) silica membrane was remarkable integrated and hydrothermally stable until 400℃.As the pressure was 30kPa,the CH4/CO2 separation factor increased within 5 dip-coating times and it decreased afterwards.The separation factor was 2.13 at five dip-coating times,which was larger than the ideal separation factor(1.66) by Knudsen diffusion and the separation performance was the best.For silica membrane at five dip-coating times,methane permeation displayed increase nonlinear with the relative pressure rising.But the CH4/CO2 separation factor hardly had any change.