Jang Gyoung Gug, Jung Gang Seob, Seo Jiho, Keum Jong K, Yoon Mina, Damron Josh T, Naskar Amit K, Custelcean Radu, Kasturi Abishek, Yiacoumi Sotira, Tsouris Costas
Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
ChemSusChem. 2024 Jan 22;17(2):e202300735. doi: 10.1002/cssc.202300735. Epub 2023 Nov 15.
Solvent-based CO capture consumes significant amounts of energy for solvent regeneration. To improve energy efficiency, this study investigates CO fixation in a solid form through solvation, followed by ionic self-assembly-aided precipitation. Based on the hypothesis that CO ions may bind with monovalent metal ions, we introduced Na into an aqueous hexane-1,6-diamine solution where CO forms carbamate and bicarbonate. Then, Na ions in the solvent act as a seed for ionic self-assembly with diamine carbamate to form an intermediate ionic complex. The recurring chemical reactions lead to the formation of an ionic solid from a mixture of organic carbamate/carbonate and inorganic sodium bicarbonate (NaHCO ), which can be easily removed from the aqueous solvent through sedimentation or centrifugation and heated to release the captured CO . Mild-temperature heating of the solids at 80-150 °C causes decomposition of the solid CO -diamine-Na molecular aggregates and discharge of CO . This sorbent regeneration process requires 6.5-8.6 GJ/t CO . It was also found that the organic carbamate/carbonate solid, without NaHCO , contains a significant amount of CO , up to 6.2 mmol CO /g-sorbent, requiring as low as 2.9-5.8 GJ/t CO . Molecular dynamic simulations support the hypothesis of using Na to form relatively less stable, yet sufficiently solid, complexes for the least energy-intensive recovery of diamine solvents compared to bivalent carbonate-forming ions.
基于溶剂的二氧化碳捕集在溶剂再生过程中消耗大量能量。为了提高能源效率，本研究通过溶剂化作用，随后进行离子自组装辅助沉淀，研究了以固体形式固定二氧化碳的方法。基于二氧化碳离子可能与单价金属离子结合的假设，我们将钠引入己烷-1,6-二胺水溶液中，在该溶液中二氧化碳形成氨基甲酸盐和碳酸氢盐。然后，溶剂中的钠离子作为与氨基甲酸盐离子自组装的晶种，形成中间离子络合物。反复的化学反应导致由有机氨基甲酸盐/碳酸盐和无机碳酸氢钠（NaHCO₃）的混合物形成离子固体，该离子固体可通过沉淀或离心轻松地从水性溶剂中除去，并加热以释放捕获的二氧化碳。在80-150°C的温和温度下加热固体，会导致固体二氧化碳-二胺-钠分子聚集体分解并释放出二氧化碳。这种吸附剂再生过程每吨二氧化碳需要6.5-8.6 GJ。还发现，不含NaHCO₃的有机氨基甲酸盐/碳酸盐固体含有大量二氧化碳，高达6.2 mmol CO₂/g吸附剂，每吨二氧化碳所需能量低至2.9-5.8 GJ。分子动力学模拟支持了使用钠形成相对不稳定但足够坚固的络合物的假设，与形成二价碳酸盐的离子相比，这样可以以最低的能量强度回收二胺溶剂。
