| With the development of economy, enrichment of atmospheric greenhouse gases, mainly carbon dioxide, resulted from human activities has increased global mean temperature. So the research on how to effectively capture CO2 is of great significance to reduce emissions of greenhouse gases. Compared with the traditional methods such as absorption and adsorption, membrane separation has advantages of low energy consumption, simple investment for equipment, small investment and environmentally friendly. So it is widely used in CO2 capture area. In this study, a novel microgel particle layer which could improve CO2 permselectivity performance was constructed by casting the microgel solutions on the asymmetric polysulfone substrate membrane. Immobilized water remained in the water-swollen microgels can promote CO2 permeation through the membrane. There was reversible reaction between the tertiary amino groups contained in the microgel particles and CO2 gas molecules. We combined with microgel and PSF to prepare a novel composite membrane which could lead to an increase in CO2 separation performance.In this study, we report that an aqueous solution of temperature-responsive microgel particles consisting of N-isopropylacrylamide (NIPAm) and N-[3-(dimethylamino) propyl]methacrylamide (DMAPMA) by a emulsion polymerization process. The global shape of the microgel particles were characterized by scanning electron microscopy and transmission electron microscopy. CO2 desorption and absorption behavior of microgels was investigated by quantifying the percentages of CO2 content captured and released during the temperature swing process. The results show that amine-containing microgels can reversibly capture and release carbon dioxide via temperature-induced volume phase transition and reversible reaction between the tertiary amino groups and CO2.A functional film layer with composed of temperature-responsive microgel particles on polysulfone (PSF) substrate membrane (PSF/MGs) for CO2 separation. The influence composition and morphology of coated amino-containing microgel particles on the composite membrane structure was were investigated by attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The gas separation performance property of the PSF/MGs membrane was investigated by studying the permselectivity varying with feed gas pressure and reversible reaction between mixture gas and composite membrane. Furthermore, the effect of several factors such as microgel particles concentration, copolymerized tertiary amino content and microgel swelling ratio on composite membrane morphology and performance were investigated. For CO2/N2 gas mixture (15/85 by volume%), the membrane prepared with 1 wt% of MGs and 20 mol% of tertiary amino group content displayed a significant enhancement. CO2 permeance and CO2/N2 selectivity increased from 7.41 GPU and 10.85 to 19.16 GPU and 25.31 at 4 bar feed pressure, respectively. PSF/MGs composite membranes exhibited excellent thermal adaptation between room temperature and 50℃. The enhancement for CO2 permselectivity performance of composite membrane was mainly attributed to the properties of water facilitated transport and CO2 reversible reaction in the amino-containing microgel particle film layer. Additionally, long-term performance of PSF/MGs composite membranes preferable due to water-swollen ability, protonation of the tertiary amino group and stable structure.
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