Ma Changdan, Bai Jiali, Hu Xin, Jiang Zhuohan, Wang Linlin
Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, China.
Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, China.
J Environ Sci (China). 2023 Mar;125:533-543. doi: 10.1016/j.jes.2022.03.016. Epub 2022 Mar 20.
In this report, nitrogen-doped porous carbons were synthesized from polyacrylonitrile fiber by a facile two-step synthesis process i.e. carbonization followed by KOH activation. Activation temperature and KOH/carbon ratio are two parameters to tune the porosity and surface chemical properties of sorbents. The as-obtained sorbents were carefully characterized. Special attention was paid concerning the change of sorbents' morphology with respect to synthesis conditions. Under the activation temperatures of this study, the sorbents can still retain their fibrous structure when the KOH/carbon mass ratio is 1. Further increasing the KOH amount will destroy the original morphology of polyacrylonitrile fiber. CO adsorption performance tests show that a sorbent retaining the fibrous shape possesses the highest CO uptake of 3.95 mmol/g at 25°C and 1 bar. Comprehensive investigation found that the mutual effect of narrow microporosity and doped N content govern the CO adsorption capacity of these adsorbents. Furthermore, these polyacrylonitrile fiber-derived carbons present multiple outstanding CO capture properties such as excellent recyclability, high CO/N selectivity, fast adsorption kinetics, suitable heat of adsorption, and good dynamic adsorption capacity. Hence, nitrogen-doped porous carbons with fibrous structure are promising in CO capture.
在本报告中，通过简便的两步合成法，即先碳化再用氢氧化钾活化，由聚丙烯腈纤维合成了氮掺杂多孔碳。活化温度和氢氧化钾/碳比是调节吸附剂孔隙率和表面化学性质的两个参数。对所制备的吸附剂进行了详细表征。特别关注了吸附剂形态随合成条件的变化。在本研究的活化温度下，当氢氧化钾/碳质量比为1时，吸附剂仍能保持其纤维结构。进一步增加氢氧化钾用量会破坏聚丙烯腈纤维的原始形态。一氧化碳吸附性能测试表明,在25°C和1巴条件下，保持纤维形状的吸附剂对一氧化碳的最大吸附量为3.95 mmol/g。综合研究发现，窄微孔率和掺杂氮含量的相互作用决定了这些吸附剂对一氧化碳的吸附能力。此外，这些源自聚丙烯腈纤维的碳具有多种出色的一氧化碳捕获特性，如优异的可回收性、高一氧化碳/氮气选择性、快速的吸附动力学、合适的吸附热和良好的动态吸附容量。因此，具有纤维结构的氮掺杂多孔碳在一氧化碳捕获方面具有广阔前景。
