Preparation And Performance Study Of Hollow Fiber Membrane-based Solid Amine For Removing Low-concentration CO₂

CO2 is the most important greenhouse gas and the increment of concentration will bring a series of adverse effects.Compared with the global warming problem,the air quality problem caused by the increment of indoor CO2 concentration is easily overlooked.CO2 mainly comes from people's respiratory metabolism in room,which is lower than the concentration produced by industry.If they can't ventilate with the outside,the concentration of CO2 in the closed chamber will rise very quickly,so many researchers have begun looking for effective ways to capture carbon dioxide directly from the air.On the basis of summarizing the commonly used CO2 removal technology,this paper studies the removal of CO2 in a confined space by using a hollow fiber membrane with asymmetric structure as the carrier.The performance of the multi-level discussion,found that the prepared solid amine has a significant advantage in low concentration CO2 capture.This provides a new research idea for the preparation and application of solid amine adsorbents in the future.The main conclusions of this paper are as follows:The tetraethylenepentamine(TEPA)film was firstly loaded into the porous layer of the asymmetric polysulfone(PSF)hollow fiber membrane by the impregnation method to obtain the PSF-TEPA solid amine adsorbent,which has simple process and convenient operation.With TEPA loading of 47.11 wt%,the CO2 breakthrough adsorption capacity and saturated adsorption capacity reached 1.29 mmol· g-1 and 1.93 mmol·g-1 at 20 ?.When the temperature was raised to 50 ? and the CO2 concentration was increased to 0.55 vol%,adsorption performance was further enhanced,and the saturated adsorption amount reached 2.32 mmol g'1.After 5 adsorption-desorption cycles,there is a CO2 adsorption capacity of 74.02%of fresh solid amine,which has certain cycle stability.In order to further prepare a film-based solid amine with high cycle stability,the amino group in N-(2-aminoethyl)-3-aminopropyltrimethoxysilane(AEAPS)was fixed on the inner and outer surfaces of the porous Al2O3 hollow fiber ceramic membrane by grafting to form an Al2O3-AEAPS solid amine adsorbent.After 8 cycles of regeneration,the saturated adsorption amount was only reduced by 6.81%,and it had excellent cycle stability.Adsorption of CO2 on the membrane wall can effectively improve the adsorption performance of CO2.When the amine graft ratio was 37.15%at 20 ?,the adsorption capacity of 0.55 vol%CO2 reached 0.54 mmol g,.When the temperature rises to 45 ?,the ability of Al2O3-AEAPS to adsorb CO2 begins to decrease because of thermodynamic factors.When mixed with 0.45 vol%of water vapor,the amount of adsorption can be increased by 0.3 times compared to the dry state,and has certain indoor application potential.