Abstract:

Porous organic polymers (POPs), with high surface areas and well-developed porosities, were always deemed to be ideal candidates as the adsorbents for CO₂ capture. It is popular to introduce amino groups, the CO₂ chemisorptive sites, onto the POPs for improving the CO₂ capture capacities and selectivities of the POPs.In this study, ethylenediamine (EDA) was successfully doped on the POP (code-named nTPB, with 1,3,5-triphenylbenzene as the monomer) by grafting mode and impregnation, respectively. The effects of different doping modes on the textural properties and the CO₂ adsorption performance of nTPB were studied. It was found that both the surface area and pore volume of nTPB decreased after EDA doping. With the same doping amount of EDA, the pore structure of nTPB was more blocked by impregnation than that of grafting mode. The CO₂ adsorption selectivity of nTPB can be significantly improved by the two doping modes, but only grafting mode can promote the CO₂ adsorption capacity (from 4.4 mmol/g to 5.2 mmol/g at 0℃ and 10⁵ Pa) of nTPB, and that of nTPB doped with impregnation was only 3.4 mmol/g at 0℃ and 10⁵ Pa, due to the pores blocked and EDA buried therein. In addition, the ethylene diamine-doped nTPB grafted showed the same good reusability as the nTPB matrix.

Key words: polymer, CO₂ capture, adsorption, porous material, ethanediamine, triphenylbenzene

摘要：

利用嫁接法和浸渍法分别在以1,3,5-三苯基苯为单体的有机多孔聚合物（nTPB）上成功掺杂乙二胺，分别研究了乙二胺的不同掺杂模式对多孔聚合物的结构性质以及CO₂吸附性能的影响。结果表明，嫁接法和浸渍法皆可在nTPB上均匀掺杂乙二胺，且nTPB的比表面积和孔容均有所下降。在乙二胺掺杂量相同的前提下，由于浸渍法完全利用nTPB的孔道吸收乙二胺，nTPB的孔道堵塞更明显。两种掺杂乙二胺的模式均可显著提升nTPB对CO₂的吸附选择性，但只有嫁接法对nTPB的CO₂吸附量有明显促进（从4.4 mmol/g升高为5.2 mmol/g；0℃，10⁵ Pa）；浸渍法由于过度堵塞nTPB孔道，且乙二胺的吸附位点被包埋，导致CO₂的吸附量反而下降（仅有3.4 mmol/g；0℃，10⁵ Pa）。此外，嫁接法掺杂乙二胺的nTPB表现出与nTPB基质相同的良好重复利用性。

关键词: 聚合物, 二氧化碳捕集, 吸附, 多孔材料, 乙二胺, 三苯基苯