Enhancing CO_(2)capture of an aminoethylethanolamine-based non-aqueous absorbent by using tertiary amine as a proton-transfer mediator:From performance to mechanism  

作　　者：Xiaobin Zhou DanWang Chao Liu Guohua Jing Bihong Lv Dunqiu Wang 

机构地区：[1]College of Environmental Science and Engineering,Guilin University of Technology,Guilin 541004,China [2]The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control,Guilin University of Technology,Guilin 541004,China [3]College of Chemical Engineering,Huaqiao University,Xiamen 361021,China

出　　处：《Journal of Environmental Sciences》2024年第6期146-156,共11页环境科学学报（英文版）

基　　金：supported by the Natural Science Foundation of Guangxi Province(Nos.2023GXNSFAA026381 and 2020GXNSFBA297071);the National Natural Science Foundation of China(Nos.22006027 and 52260023)。

摘　　要：Non-aqueous absorbents(NAAs)have attracted increasing attention for CO_(2)capture because of their great energy-saving potential.Primary diamines which can provide high CO_(2)absorption loading are promising candidates for formulating NAAs but suffer disadvantages in regenerability.In this study,a promising strategy that using tertiary amines(TAs)as proton-transfer mediators was proposed to enhance the regenerability of an aminoethylethanolamine(AEEA,diamine)/dimethyl sulfoxide(DMSO)(A/D)NAA.Surprisingly,some employed TAs such as N,N-diethylaminoethanol(DEEA),N,N,N’,N’’,N’’-pentamethyldiethylenetriamine(PMDETA),3-dimethylamino-1-propanol(3DMA1P),and N,N-dimethylethanolamine(DMEA)enhanced not only the regenerability of the A/D NAA but also the CO_(2)absorption performance.Specifically,the CO_(2)absorption loading and cyclic loading were increased by about 12.7%and 15.5%-22.7%,respectively.The TA-enhanced CO_(2)capture mechanism was comprehensively explored via nuclear magnetic resonance technique and quantum chemical calculations.During CO_(2)absorption,the TA acted as an ultimate proton acceptor for AEEA-zwitterion and enabled more AEEA to form carbamate species(AEEACOO-)to store CO_(2),thus enhancing CO_(2)absorption.For CO_(2)desorption,the TA first provided protons directly to AEEACOO-as a proton donor;moreover,it functioned as a proton carrier and facilitated the low-energy step-wise proton transfer from protonated AEEA to AEEACOO-.Consequently,the presence of TA made it easier for AEEACOO-to obtain protons to decompose,resulting in enhanced CO_(2)desorption.In a word,introducing the TA as a proton-transfer mediator into the A/D NAA enhanced both the CO_(2)absorption performance and the regenerability,which was an efficient way to“kill two birds with one stone”.

关 键 词：Carbon dioxide capture Non-aqueous absorbent Tertiary amine Proton-transfer mediator Enhanced mechanism 

分 类 号：X701[环境科学与工程—环境工程] TQ028.17[化学工程]