PDMS/PEI Composite Membranes Filed With ZIF-8 For Gas Separation

Separating and capturing CO2, has very important significance for the sustainable development of human civilization.Membrane separation technology as an efficient, clean and environmentally friendly new separation technology, is a new separation technology that has a good prospect of application.The zeolitic imidazole compounds (ZIFs) ZIF-8 has a great specific surface area and porosity, and has a strong adsorption capacity to CO2 than traditional metal organic framework compounds (MOFs).Besides, ZIFs has better hydrothermal stability, this paper will make this material with poly (dimethyl siloxane)/poly (ether imide) composite membrane(PDMS/PEI) for blending modification research.As the product yield in the traditional literatures of ZIF-8 is lower, in the The first two parts is to find a way of expending the yield of ZIF-8,getting expand three times yield more than the methods in the literature, the method to 300ml ammonia and 10 ml of methanol as solvent,2-methyl imidazole and Zn(OH)2 raw material ratio of 4:1, then characterizing the new products.The effects of different containers on the synthesis of ZIF-8 was also investigated. The results showed that the synthesized ZIF-8 crystal was more regular and the particle size was more uniform in the glass and other hydrophobia containers.The modified PDMS/PEI composite film was prepared by adding the ZIF-8 crystal in the casting solution. The effects of ZIF-8 on the properties of the modified films were investigated by the filling amount of ZIF-8, the pressure of raw materials and the preparation of different conditions. The results show that under the same temperature and pressure, increase the ZIF materials filling amount, gas separation coefficient showed the first increase after declining trend, in less than 15% with increasing the filler content, the separation performance of the membrane gradually increased. Using ammonia water as solvent,15%ZIF-8 filling the volume down, CO 2 permeability than the blank film increased by 181% and CO2/N2 separation coefficient than the unmodified membrane increase 43.75%; increased raw material air force also helped to improve the pervaporation performance of separation of PDMS/PEI composite membrane; in addition, ZIF-8 crystals prepared by the comparisonof the three kinds of solvent system, prepared by ammonia of zif-8 crystal filling effect best.