非水吸收剂(NAAs)由于其巨大的节能潜力而吸引了越来越多的人们对CO2捕集的关注。可以提供高CO2吸收负载的伯二胺是用于配制NAA的有希望的候选物,但在再生能力方面具有缺点。在这项研究中,提出了一种有希望的策略,即使用叔胺(TA)作为质子转移介质来增强氨基乙基乙醇胺的可再生性(AEEA,二胺)/二甲基亚砜(DMSO)(A/D)NAA。令人惊讶的是,一些采用的TA,如N,N-二乙基氨基乙醇(DEEA),N,N,N\',N\'\',N\'\'-五甲基二亚乙基三胺(PMDETA),3-二甲基氨基-1-丙醇(3DMA1P),N,N-二甲基乙醇胺(DMEA)不仅提高了A/DNAA的再生能力,而且还提高了CO2吸收性能。具体来说,CO2吸收负荷和循环负荷分别增加了约12.7%和15.5%-22.7%,分别。通过核磁共振技术和量子化学计算,全面探索了TA增强的CO2捕集机理。在CO2吸收过程中,TA充当AEEA-两性离子的最终质子受体,并使更多的AEEA形成氨基甲酸酯物种(AEEACOO-)来存储CO2,从而增强CO2吸收。对于CO2解吸,TA首先直接向AEEACOO-作为质子供体提供质子;此外,它充当质子载体,并促进了从质子化AEEA到AEEACOO-的低能逐步质子转移。因此,TA的存在使AEEACOO-更容易获得质子分解,导致CO2解吸增强。一句话,在A/DNAA中引入TA作为质子转移介质,提高了CO2吸收性能和再生能力,这是“一石二鸟”的有效方法。
Non-aqueous absorbents (NAAs) have attracted increasing attention for CO2 capture because of their great energy-saving potential. Primary diamines which can provide high CO2 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 CO2 absorption performance. Specifically, the CO2 absorption loading and cyclic loading were increased by about 12.7% and 15.5%-22.7%, respectively. The TA-enhanced CO2 capture mechanism was comprehensively explored via nuclear magnetic resonance technique and quantum chemical calculations. During CO2 absorption, the TA acted as an ultimate proton acceptor for AEEA-zwitterion and enabled more AEEA to form carbamate species (AEEACOO-) to store CO2, thus enhancing CO2 absorption. For CO2 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 CO2 desorption. In a word, introducing the TA as a proton-transfer mediator into the A/D NAA enhanced both the CO2 absorption performance and the regenerability, which was an efficient way to \"kill two birds with one stone\".