KH-570修饰的SiO_2膜制备及CH_4/CO_2的分离

Preparation of modified silica membranes by KH-570 and separation on CH_4/CO_2

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。

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.