Research progress of CO₂ separation technology by solvent absorption

College of Chemical Engineering, Huaqiao University, Fujian, 361021, China

^* Corresponding author’s e-mail:2026201009@stu.hqu.edu.cn

Abstract

The combustion of fossil fuels emits a large amount of CO₂, which causes the greenhouse effect and leads to global warming and poses a serious threat to life on earth. CO₂ capture technology can effectively reduce the concentration of CO₂ in the atmosphere, alleviate the greenhouse effect, and improve the environment. CO₂ capture technologies include absorption, membrane separation and adsorption separation, among which chemical absorption and separation have the advantages of high efficiency, low cost and easy availability of materials. In this paper, the advantages and disadvantages of three main chemical absorption and separation methods (inorganic reagents, organic amines and ionic liquids) adsorb CO₂ are summarized. Among inorganic adsorbents, NH₃·H₂O can achieve rapid and efficient absorption of CO₂, and it is relatively stable and not easy to degrade. Common types of organic amine adsorbents are monoethanolamine, methanolamine, and sterically hindered amine. However, it is difficult for a single organic amine adsorbent to meet the requirements of high absorption rate, high absorption capacity and low reaction heat at the same time. Therefore, mixing organic amine absorbents with different characteristics can improve their performance in absorbing CO₂. Ionic liquids have the advantages of good thermal stability, very low saturation vapor pressure, and designable structure, and are a new type of CO₂ adsorbent, but ionic liquids have high viscosity themselves. Combining ionic liquids with organic or inorganic porous materials to form loaded ionic liquid materials, which can be used as CO₂ adsorbent not only to improve the separation effect, but also to avoid the problem of high viscosity caused by direct absorption of ionic liquids, thus improving CO₂ adsorption efficiency.