Preparation Of TEPA@PAN Solid Amine Hollow Fiber Membrane And Its Adsorption Performance For Low Concentration CO₂

The concentration of CO₂ in the atmosphere increases year by year,causing serious environmental problems.Therefore,how to reduce the concentration of CO₂in the atmosphere has aroused people's attention.Environmental issues aside,it's easy to overlook the health risks of CO₂ because the concentration of CO₂ in the atmosphere is so low.However,when people stay in a confined space for a long time,CO₂ will be produced due to human respiration,machine operation and other aspects,and the concentration of CO₂ will rise quickly,causing harm to human health.Therefore,it is of great significance to study a safe and feasible low concentration CO₂ adsorption technology.In recent years,CO₂ removal in confined space mostly adopts absorption method and adsorption method,which has some problems such as low selectivity,low thermal stability,low adsorption capacity and high cost.Solid amine adsorbents have become a research hotspot due to their advantages of low energy consumption and strong selectivity.Therefore,it is very important to develop safe,stable,efficient and low consumption solid amine adsorbent to remove low concentration of CO₂ in a confined space.In this paper,a cheap and readily available polyacrylonitrile hollow fiber membrane was selected as the carrier,and TEPA@PAN solid amine hollow fiber membrane was prepared with tetrethylenepentamine(TEPA)as an organic amine.By adjusting the membrane structure,grafting conditions and adsorption conditions,the adsorption performance of low concentration CO₂ was studied,and the main conclusions were as follows:The polyacrylonitrile(PAN)hollow fiber was impregnated in the mixed solution of tetrethylenepentamine-alcohol by chemical grafting method.The reaction vessel was heated to make the reaction,and the TEPA@PAN solid amine hollow fiber was obtained after the reaction.The graft degree and adsorption capacity were changed by adjusting the reaction temperature,reaction time and TEPA concentration.The results showed that when the concentration of tetrethylenepentamine was 1:2,the reaction temperature was 100?,and the reaction time was 18 hours,the grafting rate of amine and the adsorption capacity of CO₂reached the maximum.At this time,the grafting rate was 58.2 wt.%,and the saturation adsorption capacity of 0.3 vol.%CO₂ reached1.32 mmol/g.Polyacrylonitrile hollow fiber membrane was successfully prepared by phase conversion method.In order to further explore the influence of membrane structure on CO₂ adsorption performance,polyacrylonitrile hollow fiber membrane with different structure was prepared under the same preparation conditions by changing the type of pore forming agent and the proportion of pore forming agent in the casting solution.The results showed that:In this experiment,the pore forming agent was selected as polyethylene glycol(PEG-2000),diethylene glycol(DEG),F127 and ethylene glycol monomethyl ether(2-ME).Through CO₂ adsorption test,it was found that the pore forming agent had the largest adsorption capacity of PEG-2000,with the maximum value of 1.29 mmol/g.(2)By changing the proportion of pore-making agent,it was found by CO₂ adsorption test that with the increase of the proportion of pore-making agent,the graft rate gradually increased,but due to the change of membrane structure,the amine utilization rate gradually decreased.In a comprehensive comparison,PAN-PEG-3%had the best adsorption performance for low concentration CO₂,with a saturated adsorption capacity of 1.27 mmol/g and an amine utilization rate of 39.37%.