乙基纤维素/C60复合膜制备及气体分离性能研究

为制备C60含量不同的乙基纤维素(EC)/C60复合膜,采用UV-可见光谱、AFM和XRD等手段对紫外光辐照前后复合膜结构进行表征,并考察其对气体分离及渗透性能的影响.结果表明,复合膜经紫外光辐照后,C60在膜表面的分布由独立的簇状结构转变为连续平缓的丘陵状结构,膜表面更加致密光滑;复合膜分子链间距未发生明显变化,但对N2、CO2、H2的渗透性能和H2/N2、CO2/N2分离性能产生明显影响.当C60添加量达到1.6%时,未经紫外光辐照的复合膜对CO2及H2的透气系数较纯EC膜分别提高了30%和40%,分别达到61.29Barrer和78.88Barrer,对H2/N2,CO2/N2理想分离系数增至纯EC膜的1.47和1.38倍,分别达到9.979和12.84;经紫外光辐照后,高C60含量的EC/C60复合膜能够保持纯EC膜对CO2和H2的透过水平,而对H2/N2和CO2/N2的分离性能增至纯EC膜的2.30和2.43倍,分别达到17.49和25.60.

Study of preparation and gas separation property of ethyl cellulose/C60 composite membranes

Ethyl cellulose/C60 composite membranes with different C60 content were prepared in this paper.The structure and gas permeation properties of the obtained membranes were investigated by UV-visible specmma,atomic force microscopy,X-ray diffraction and gas permeation tests.The results show that for the ethyl cellulose/C60 composite membranes with the C60 content of 1.6%,the permeation coefficients of CO2,H2 are 61.29 Barrer and 78.88 Barrer,respectively;the separation factors of H2/N2,CO2/N2 are 9.979 and 12.84,respectively.Both gas permeation coefficient and separation factor of the above ethyl cellulose/C60 composite membrane are higher than that of ethyl cellulose membrane.The effect of UV irradiation on the structure and gas permeation properties of the ethyl cellulose/C60 composite membranes was also studied.The results showed that the morphology of C60 on the surface of ethyl cellulose/C60 composite membranes changes from a discrete cluster structure to a continuous gentle hill-like structure during UV irradiation process.UV irradiation process has no noticeable effect on the d-spacing of ethyl cellulose molecular chain.The gas permeation properties of ethyl cellulose/C60 composite membranes,however,are significantly influenced by UV irradiation.By UV irradiation for ten minutes,the H2 and CO2 permeation coefficients of the ethyl cellulose/C60 composite membranes with C60 content of 1.6% nearly reduces by 30%,and the separation factors of H2/N2 and CO2/N2 increase about 2 times.