Imidazolium-based Ionic Liquids Impregnated in Silica and Alumina Supports for CO2 Capture

Ionic liquids (ILs) physical immobilization in solid materials is a key strategy for developing efficient and low cost CO2 capture processes. In this work, two porous commercial substrates with different characteristics (silica and alumina) were impregnated with ILs by physical wet method. Imidazolium based IL combined with [Br]- and [Tf2N]- anions were used in impregnation process. CO2 sorption capacity and selectivity (CO2/N2) of these materials were investigated. The best results regarding CO2/N2 selectivity and CO2 sorption were obtained with [Tf2N]- anion. In relation to solid support, commercial alumina exhibited enhanced CO2 uptake and higher selective capacity (CO2/N2) (6.1 (± 0.1)). Combination of commercial alumina as support and 20 wt% of mbmim [Tf2N] resulted in higher CO2/N2 selectivity of 9.5 ± 1.0. In addition, this material also showed fast sorption kinetics when compared to pure IL besides reuse capacity.离子液体（Ionic Liquids, ILs）在固体载体中的物理固定化，是开发高效低成本二氧化碳（CO₂）捕获工艺的关键策略。本研究采用物理湿法浸渍工艺，将ILs负载至两种特性各异的商用多孔载体（二氧化硅与氧化铝）中。实验选用了咪唑类离子液体，分别搭配[Br]⁻与[Tf₂N]⁻两种阴离子开展浸渍。研究考察了所得材料的CO₂吸附容量与CO₂/N₂选择性两项性能指标。结果表明，搭配[Tf₂N]⁻阴离子的材料在CO₂/N₂选择性与吸附容量方面均表现最优。就固体载体而言，商用氧化铝载体展现出更优异的CO₂吸附量与选择性，其CO₂/N₂选择性可达6.1 ± 0.1。以商用氧化铝为载体、负载20 wt%的mbmim [Tf₂N]时，所得材料的CO₂/N₂选择性可达9.5 ± 1.0。此外，相较于纯ILs，该材料不仅具备良好的循环复用能力，还展现出更快的吸附动力学特性。