载胺糖基炭材料吸附CO_(2)机理研究

Study on adsorption mechanism of CO_(2) on amine-loaded sugar-based carbon materials

以葡萄糖为原料制备了一系列糖基炭材料(CMS),并将四乙烯五胺(TEPA)负载到炭材料上,得到载胺糖基炭材料(CMS-xTEPA)用于吸附燃煤烟气中的CO_(2)。研究了TEPA负载量、吸附温度和孔结构对CMS-xTEPA吸附性能的影响,并揭示其吸附机理。结果表明,CMS的CO_(2)吸附能力主要与其微孔孔径和孔容密切关联,介孔结构丰富、孔容较大的炭材料更适合作载胺载体。CMS-xTEPA的CO_(2)吸附能力相较于CMS大幅提高,CMS-xTEPA中胺基与CO_(2)反应生成氨基甲酸酯和氨基甲酸盐类物质,且适宜的吸附温度和TEPA负载量可以提升CMS-xTEPA的CO_(2)吸附能力。CMS-2-30%TEPA在75℃、15%CO_(2)+85%N_(2)气氛下具有较好的CO_(2)吸附性能和良好的循环CO_(2)吸附性能,在5次吸附循环后,仍具有3.04 mmol/g的吸附容量。

A series of sugar-based carbon materials(CMS)are prepared from glucose,and then loaded with tetra-ethylenepentamine(TEPA)to obtain amine-loading sugar-based carbon materials(CMS-xTEPA),which are used for the adsorption of CO_(2) from coal-fired flue gas.The impacts of TEPA loading amount,adsorption temperature and pore structure on the adsorption performance of CMS-xTEPA are investigated,and the adsorption mechanism is revealed.Results show that the adsorption capacity of CMS to CO_(2) has close relation with its microporous pore size and pore volume.Carbon materials with rich mesopore structure and large mesopore volume are more suitable for amine-loading carriers.The adsorption capacity of CMS-xTEPA to CO_(2) is much higher than that of CMS.The amine group in CMS-xTEPA reacts with CO_(2) to form carbamate and carbamate-like substances,and both the appropriate adsorption temperature and TEPA loading amount can enhance the adsorption capacity of CO_(2) by CMS-xTEPA.CMS-2-30%TEPA has good CO_(2) adsorption performance,delivering an adsorption capacity of 3.95 mmol·g^(-1) at 75℃and 15%CO_(2)+85%N2 atmosphere.In addition,it also presents good cyclic adsorption performance to CO_(2),showing an adsorption capacity of 3.04 mmol·g-1 after five adsorption cycles.