Preparation Of Pebax-based Membrane And Application For CO₂ Separation

Highly efficient CO₂ capture technology is the key to achieve energy gas purification and mitigate the effect of greenhouse. Compared with traditional CO₂ separation method, membrane separation technology has been rapid development due to its advantages of high separation efficiency and low power consumption, and it has become one of the major technologies in CO₂ separation. Membrane material is the core section of membrane separation technology, and the membrane material directly related to the membrane separation performance. It has important theory value in developing high permeability and high selectivity membrane materials for CO₂ separation. In this study, in order to obtain high performance membrane for CO₂ separation, a series of fillers were designed and prepared based on transport sites, tubular morphology and platelet morphology to construct CO₂ transport passageways in Pebax matrix. The details were summarized as follows:The preparation of Pebax/PEG4000-MMT membrane and application for CO₂separation: based on the transport sites in polymer-inorganic hybrid membrane, polyethylene glycol was introduced into the interlayer of montmorillonite, and the product was selected as the filler to construct CO₂ transport passageways in Pebax matrix. The introduction of polyethylene glycol increased the content of ether group in membrane, and ether group has a good affinity for CO₂, increasing CO₂ solubility. Simultaneously, the introduction of polyethylene glycol increased the interlayer spacing of MMT, providing transport passageways for CO₂ permeability. The optimum separation performance was achieved at the PEG4000-MMT content of 0.5 wt% with selectivity of 37 for CO₂/CH4 and a CO₂ permeability of 375 Barrer.The preparation of Pebax/PPy-MWCNT membrane and application for CO₂separation: based on the tubular morphology of fillers in polymer-inorganic hybrid membrane, polypyrrole modified multiwalled carbon nanotubes were selected as the filler to construct CO₂ transport passageways in Pebax matrix. The smooth internal surfaces of multiwalled carbon nanotubes possess, providing accessible transport passageways for CO₂ permeability. Polypyrrole endow multiwalled carbon nanotubes with alkaline, enhancing CO₂ adsorption and increasing CO₂ permeability. The optimum separation performance was achieved at the PPy-MWCNT content of 5 wt% with selectivity of 34 for CO₂/CH4 and a CO₂ permeability of 442.91 Barrer.The preparation of Pebax/Fe₃O₄-GO membrane and application for CO₂separation: based on the platelet morphology of fillers in polymer-inorganic hybrid membrane, magnetic modified graphene oxide were selected as filler, and added to Pebax polymer matrix, construct CO₂high-speed transport passageways by the directional arrangement of filler in the presence of magnetic field conditions. Compared with directional arrangement in different ways, the vertical arrangement of filler shown the best performance. The optimum separation performance wasachieved at the Fe₃O₄-GO content of 3 wt% with selectivities of 47 and 75 for CO₂/CH4 and CO₂/N2, respectively, and a CO₂ permeability of 538 Barrer.