Okada Chisato, Hou Zongzi, Imoto Hiroaki, Naka Kensuke, Kikutani Takeshi, Takasaki Midori
Nitto Denko Corporation, 1-1-2 Shimohozumi Ibaraki, Osaka 567-8680, Japan.
Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
ACS Omega. 2024 Dec 11;9(51):50466-50475. doi: 10.1021/acsomega.4c07631. eCollection 2024 Dec 24.
To achieve carbon neutrality by 2050, there is a growing need to actively capture carbon dioxide (CO) from the atmosphere. As a method to capture CO directly from the atmosphere, direct air capture (DAC) is attracting attention and amine-based compounds have been extensively studied as CO adsorbents. In this research, we developed thermosetting DAC nanofibers with excellent low-temperature desorption properties and good heat resistance by polymerizing an amine with epoxy. For the fabrication of epoxy-cross-linked amine nanofibers through the electrospinning process, poly(vinyl alcohol) (PVA) was added for the improvement of spinnability, and the direct spin-line heating was conducted for the in situ thermal polymerization. As a result, nanofiber webs with fiber diameters of approximately 300-400 nm were fabricated successfully. The investigation of the CO adsorption and desorption performance of the obtained amine/epoxy/PVA (AE/PVA) nanofiber webs verified the high adsorption amount of 1.8 mmol/g at a CO concentration of 400 ppm. Additionally, 93% of adsorbed CO could be desorbed at a low temperature of 65 °C. These results suggested the possibility of low-energy-consumption CO recovery. By improving the adsorption rate and by making desorption possible at low temperatures, the adsorption/desorption cycle can be repeated more quickly, increasing the amount of CO that can be recovered in a day. The prepared webs also exhibited an excellent adsorption retention ratio of 75% after 100 h of operation at 85 °C, while general amine-filled mesoporous silica usually shows a retention ratio of only 13%. In addition, FT-IR, DSC, and elemental analysis of amine/epoxy/PVA nanofibers were carried out to analyze the reaction mechanism during fiber production. It was revealed that PVA was not involved in the reaction, and as in the bulk state, almost all primary amines were converted to secondary amines due to the in situ polymerization of amines and epoxy to form nanofibers.
为了在2050年实现碳中和，从大气中主动捕获二氧化碳（CO₂）的需求日益增长。作为一种直接从大气中捕获CO₂的方法，直接空气捕获（DAC）备受关注，基于胺的化合物作为CO₂吸附剂已得到广泛研究。在本研究中，我们通过使胺与环氧树脂聚合，开发出了具有优异低温解吸性能和良好耐热性的热固性DAC纳米纤维。为了通过静电纺丝工艺制备环氧交联胺纳米纤维，添加了聚乙烯醇（PVA）以改善可纺性，并进行直接纺丝线上加热以实现原位热聚合。结果，成功制备出了纤维直径约为300 - 400 nm的纳米纤维网。对所得胺/环氧/PVA（AE/PVA）纳米纤维网的CO₂吸附和解吸性能进行研究后发现，在CO₂浓度为400 ppm时，其吸附量高达1.8 mmol/g。此外，在65℃的低温下，93%吸附的CO₂能够被解吸。这些结果表明了低能耗回收CO₂的可能性。通过提高吸附速率并实现低温解吸，吸附/解吸循环可以更快地重复进行，从而增加一天内可回收的CO₂量。制备的纤维网在85℃下运行100小时后，还表现出75%的优异吸附保留率，而一般填充胺的介孔二氧化硅通常仅显示13%的保留率。此外，还对胺/环氧/PVA纳米纤维进行了傅里叶变换红外光谱（FT - IR）、差示扫描量热法（DSC）和元素分析，以分析纤维生产过程中的反应机理。结果表明，PVA未参与反应，并且与本体状态一样，由于胺和环氧原位聚合形成纳米纤维，几乎所有的伯胺都转化为了仲胺。
