Designing Of Amine-functionalizedized Solid Adsorbent For Carbon Dioxide Capture

Fossil fuels such as coal,oil and natural gas have been the main source of energy for human activity for centuries.Carbon in fossil fuels is converted into CO₂ through combustion reactions,which are directly emitted into the atmosphere,thereby aggravating the greenhouse effect,leading to global climate change and the destruction of ecological balance.CO₂,as an important source of carbon,is widely applied for industrial purpose.Therefore,capturing and utilizing CO₂ from the tail gas of fossil fuel combustion can not only alleviate the greenhouse effect,but also convert the captured CO₂ into profitable products,achieving a win-win situation in both environmental and economic benefits.Carbon capture technologe emerged and the liquid absorption method to capture CO₂ is most widely used.One of the most mature is the use of alkanolamines to absorb carbon dioxide.However,its strong corrosiveness and high regeneration energy consumption limit its industrial application.Ionic liquid can combat with strong corrosiveness and high energy consumption of alkanolamine CO₂absorption,and the solid adsorbent can effectively solve the problem of high viscosity of ionic liquid adsorption.Based on the advantages and disadvantages of different adsorbents,our study designed and synthesized a series of amine-functionalizedized solid adsorbents and systematically investgated their CO₂ capture performance.The details are as follows:Firstly,a simple amino acid ionic liquid（AAIL）was synthesized using glycine and tetraethylammonium hydroxide to introduce basic amino groups to realize the chemical absorption of CO₂ according to the weak acidity of CO₂.In order to design an amine-functionalized solid adsorbent,a mesoporous polymer polydivinylbenzene（PDVB）was synthesized from diethylbenzene,and the liquid adsorbent was dispersed in the solid material to construct an amine-functionalized solid adsorbent.The amine-functionalizedized solid adsorbent designed in our work utilizes AAIL to provide active sites for CO₂ capture,and PDVB provides mesoporous conditions for well-dispersed AAIL,which showed a fantastic CO₂ capture performance.The research results show that the CO₂adsorption capacity of the adsorbent is 1.55mmol/g at 75℃and 10vol.%CO₂,and the utilization efficiency of the adsorbent[N₂₂₂₂][Gly]is close to the theoretical value.Besides,the adsorbent can achieve selective capture CO₂ from the dilution source and the performance of the adsorbent still worked well after being reused for many times.Secondly,the electron-withdrawing property of the amine group of AAILs reduces the activity of its carboxyl group.In order to improve the ability of AAILs to capture CO₂,two aminopolycarboxylate ionic liquids（APC-ILs）were synthesized using ethylenediamine-N,N’-diacetic acid and iminodiacetic acid（anion sources）and tetraethylammonium hydroxide（cation source）.There are two carboxyl groups in the synthesized APC-ILs,and an additional carboxylic acid group was introduced into the amine group of AAILs to offset the electron-withdrawing property of the amine group,which realized the additional chemical absorption of CO₂ by the carboxyl group in ILs.APC-ILs was dispersed into PDVB to construct amine-functionalized solid adsorbents for efficient CO₂ capture.The research results indicated that the CO₂ capture efficiency of APC-ILs is greatly improved,and it can chemically react with CO₂ in a stoichiometric ratio of 1:2.Besides,the adsorbent can achieve selective and high-capacity capture of CO₂ from a diluted source,and the performance remains well after reused for multiple times.Finally,in order to seek higher CO₂ adsorption capacity,polyamine——pentaethylene hexamine（PEHA）with high amino density was selected as the absorbent to construct amine-functionalizedized solid adsorbent.In order to realize the concept of green and sustainable development,a kind of fibrous carbon microspheres（FCMs）was synthesized from low-cost and environmentally friendly chitin to provide mesoporous conditions for PEHA dispersion.Because PEHA has a high content of active CO₂ capture sites,FCMs provides good mesoporous conditions for dispersing PEHA.Therefore,the amine-functionalized solid adsorbent constructed in this work shows high CO₂ capture performance.The results show that at 75℃and 10 vol.%CO₂,the CO₂ adsorption capacity of adsorbent is 3.90mmol/g.Besides,the adsorbent can selectively capture CO₂ from the dilution source,and the adsorbent performs well in the long-term cycle experiment.In conclusion,our study synthesized a series of amine-functionalizedized solid adsorbents by a green and simple method,and the designed adsorbents acheieved the efficient and reversible selective capture of CO₂,which has a good industrial application prospect.