Abstract:

A highly efficient CO₂ absorbent, ionic liquid (IL)[P₆₆₆₁₄] [Triz], was impregnated on molecular sieves SBA-15 with two different pore diameters for removing CO₂ in biohythane. The hybrid absorbents were characterized by N₂ adsorption analyzer, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM). Compared to SBA-15 (6.6 nm) -50%[Triz], SBA-15 (4.3 nm) -50%[Triz] had higher CO₂ absorption capacity and absorbing rate by an increase of 12.4% and 95.1%, respectively. The shorter pore length of SBA-15 (4.3 nm) allowed[P₆₆₆₁₄][Triz] inner pores to contact CO₂ during adsorption process, hence SBA-15 (4.3 nm) -50%[Triz] had more IL reactive sites than SBA-15 (6.6 nm) -50%[Triz]. CO₂ absorption in SBA-15 (4.3 nm) -50%[Triz] under different hythane gas flowrate was further studied and fitted with two adsorption kinetic models. The results show that CO₂ adsorption bySBA-15 (4.3 nm) -50%[Triz] follows better with pseudo-second order adsorption dynamic model, indicating that the adsorption process is controlled by chemical adsorption mechanism and CO₂ removal by[P₆₆₆₁₄] [Triz] is a chemical reaction process.

Key words: ionic liquid, molecular sieve, CO₂, kinetic modeling, biohythane

摘要：

以高效吸收CO₂的离子液体（IL）[P₆₆₆₁₄][Triz]作为吸收剂，通过浸渍法负载到两种不同孔径的介孔分子筛SBA-15上，用于脱除生物氢烷气中CO₂，并利用N₂吸附仪、扫描电子显微镜（SEM）和高倍透射电子显微镜（HRTEM）对负载材料进行了表征分析。混合吸收剂SBA-15（4.3 nm）-50%[Triz]的吸收容量和吸收速率比SBA-15（6.6 nm）-50%[Triz]的分别提高了12.4%和95.1%，这是由于SBA-15（4.3 nm）的孔道长度更短，避免了填充在孔道内的[P₆₆₆₁₄][Triz]在反应过程中接触不到CO₂，从而比SBA-15（6.6 nm）-50%[Triz]有更多IL反应活性点参与反应。还研究了不同氢烷气速率下SBA-15（4.3 nm）-50%[Triz]对CO₂的吸收并与2种吸附动力学模型相拟合，结果表明SBA-15（4.3 nm）-50%[Triz]对CO₂的吸收更符合准二级吸附动力学模型，表明吸附过程受化学吸附机理的控制，验证了[P₆₆₆₁₄][Triz]是通过化学反应脱除CO₂。

关键词: 离子液体, 分子筛, CO₂, 动力学模型, 生物氢烷气