Piperazine (PZ) and its derivatives are highly regarded as promising amine absorbents for CO₂ capture. However, the high energy demand required for their regeneration poses a significant barrier to their further application in CO₂ capture. In this study, we systematically investigate the regeneration performance of PZ and three N-monosubstituted PZ derivatives, N-ethylpiperazine (EPZ), N-(2-hydroxyethyl)piperazine (HEP), and N-aminoethyl piperazine (AEP), for CO₂ capture at various temperatures. The results indicate that the introduction of ethyl and hydroxyethyl groups can enhance the temperature sensitivity of these absorbents during CO₂ capture, leading to a higher cyclic capacity for EPZ and HEP at reduced regeneration temperatures. In particular, the lower regeneration temperature can significantly reduce the regeneration energy consumption for EPZ to as low as 1.98 GJ·t^–1 of CO₂. Moreover, the structure–activity relationships of N-monosubstituted PZ-based absorbents for CO₂ capture were further elucidated through quantitative nuclear magnetic resonance (NMR) and comprehensive evaluation of the CO₂ capture process. This study provides valuable insights into the application of PZ-based absorbents for more energy-efficient CO₂ capture processes.

中文翻译：

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推进 N-单取代哌嗪基吸收剂在低温下的节能再生，用于 CO2 捕获

哌嗪 （PZ） 及其衍生物被高度认为是有前途的 CO₂ 捕获胺吸收剂。然而，它们再生所需的高能量需求对其在 CO₂ 捕获中的进一步应用构成了重大障碍。在这项研究中，我们系统地研究了 PZ 和三种 N-单取代的 PZ 衍生物 N-乙基哌嗪 （EPZ）、N-（2-羟乙基）哌嗪 （HEP） 和 N-氨基乙基哌嗪 （AEP） 在不同温度下捕获 CO₂ 的再生性能。结果表明，乙基和羟乙基的引入可以提高这些吸收剂在 CO₂ 捕获过程中的温度敏感性，从而在降低的再生温度下提高 EPZ 和 HEP 的循环容量。特别是，较低的再生温度可以显著降低 EPZ 的再生能耗，使其低至 1.98 GJ·t^–1 的 CO₂。此外，通过定量核磁共振 （NMR） 和对 CO₂ 捕获过程的综合评估，进一步阐明了 N-单取代 PZ 基吸收剂用于 CO₂ 捕获的结构-活性关系。这项研究为基于 PZ 的吸收剂在更节能的 CO₂ 捕获过程中的应用提供了有价值的见解。