Preparation Of TEPA@PAN Solid Amine Hollow Fiber And Study On Its Adsorption/desorption Performance Of Low Concentration CO₂

As a greenhouse gas,CO₂ is the main factor causing global warming and climate change,which will have some adverse and lasting effects on the environment and human beings.On the other side,in the confined space,the impact of low concentration CO₂ on the human body cannot be ignored.Due to the particularity of the confined space,the generated CO₂ gas cannot be exchanged with the outside world in time,which makes the CO₂ concentration rise rapidly and seriously threatens human health.In order to solve this problem,it is necessary to develop a technology that can achieve efficient capture under low concentration CO₂.Solid amine adsorbent has the advantages of large adsorption capacity,low regeneration energy consumption and good stability.At present,it has become a hot research field.it is essential to find an efficient solid amine adsorbent.So far,the research on solid amine adsorbent for low concentration CO₂ capture in confined space is still in the initial stage,and there is still great room for development in practical application.In this thesis,a highly porous polyacrylonitrile（PAN）hollow fiber was selected as the carrier,and tetraethylenepentamine（TEPA）was loaded by chemical grafting method to prepare tetraethylenepentamine grafted polyacrylonitrile（TEPA@PAN）solid amine hollow fibers adsorbent for efficient capture of low concentration CO₂ in confined space.The TEPA@PAN hollow fibers were characterized by Fourier transform infrared spectroscopy（FT-IR）,X-ray photoelectron spectroscopy（XPS）,Brunauer-Emmett-Teller（BET）methods and Scan electron microscopy（SEM）.Their CO₂ adsorption capacities at low concentrations（470-5000ppm）were also investigated,indicating the values ranged from 1.70 to 3.66 mmol·g^-1.The CO₂ adsorption capacities fitted well with Langmuir isotherm model.The adsorption kinetic study was performed by using two kinetic models,and pesudo-second model was found fitting better with experimental data.In consideration of their real applications to capture CO₂ from confined space,TEPA@PAN hollow fibers were employed to adsorb CO₂ directly from atmosphere（25℃,470 ppm,RH 25%）,and their CO₂ adsorption capacity reached up 2.03 mmol·g^-1.The used TEPA@PAN hollow fibers after CO₂ adsorption saturation can be regenerated by temperature swing process.Twenty adsorption-desorption cyclic tests were carried out,and no obvious decrease in CO₂ adsorption capacity was observed.which proves that the solid amine adsorbent prepared in this experiment has good adsorption effect and cycle stability for low concentration CO₂.In addition,A scale up experiment was done to prepare TEPA@PAN hollow fiber.The CO₂ adsorption capacity was also examined through direct air capture.It was found that the enlarged solid amine adsorbent could still maintain good CO₂ adsorption capacity.These results indicate TEPA@PAN hollow fiber would be a new choice for CO₂ capture from low concentration sources.