Abstract:

Commercial coal-based activated carbon was used as raw material, roasted with low concentration of oxygen, oxidized and modified with H₂O₂, and impregnated with tetraethylenepentamine (TEPA) to obtain an amine-loaded composite oxidized activated carbon, which was used to simulate flue gas [(15%(vol) CO₂ + 85%(vol) N₂) +10%(vol) H₂O] adsorption of CO₂. After low concentration oxygen modification, activated carbon showed highest specific surface area of 1421.82 m²/g and highest pore volume of 0.83 cm³/g. The content of oxygen-containing groups on the activated carbon surface and mesoporous volume increased through composited oxidation, resulting higher CO₂ adsorption performance on TEPA-impregnated composited oxidized activated carbon. Compared different adsorbents, the sample COAC-4-40TEPA prepared through 4 h oxidation, H₂O₂ oxidation and 40% TEPA impregnation, showed highest CO₂ adsorption capacity of 2.45 mmol/g, which is 2.02 times of AC-40TEPA. Moreover, the CO₂ adsorption capacity could maintain 92.24% after ten adsorption cycles. The deactivation model analysis showed that initial adsorption rate of COAC-4-40TEPA was 1.64 times of AC-40TEPA, and the deactivation rate was lower.

Key words: activated carbon, oxidation, carbon dioxide, adsorption, TEPA, regeneration

摘要：

以商业煤基活性炭为原料，经低浓度氧气焙烧、H₂O₂氧化改性，并以四乙烯五胺（TEPA）浸渍，得到胺负载复合氧化活性炭，用于模拟烟道气[(15%(体积)CO₂+85%(体积)N₂）+10%(体积)H₂O]中CO₂吸附。低浓度氧气焙烧后，活性炭的最大比表面积和孔体积分别为1421.82 m²/g、0.83 cm³/g。经复合氧化改性后，活性炭的介孔体积增大，表面含氧官能团增加，使得TEPA负载复合氧化活性炭的CO₂吸附性能提高。焙烧时间为4 h，H₂O₂氧化、负载40%TEPA的样品COAC-4-40TEPA，在60℃时CO₂饱和吸附量最高为2.45 mmol/g，是TEPA负载未改性活性炭AC-40TEPA的2.02倍。经过十次吸附循环后，COAC-4-40TEPA的 CO₂饱和吸附量可维持在92.24%，而TEPA的浸出量仅有0.67%。失活模型研究表明，COAC-4-40TEPA的初始吸附速率常数是AC-40TEPA的1.64倍，且失活速率常数低于AC-40TEPA。

关键词: 活性炭, 氧化, 二氧化碳, 吸附, 四乙烯五胺, 再生