硅胶固载季鏻离子液体对CO_2的吸附

采用嫁接法制备了硅胶固载季鏻双三氟甲烷磺酰亚胺盐离子液体,并将其用于对CO2的吸附,考察了吸附剂的吸附等温线及循环使用性,并运用均相表面扩散模型(HSDM)研究了吸附动力学。采用FTIR和TG等技术对试样进行了表征。表征结果显示:离子液体已成功固载到硅胶上;煅烧活化硅胶对季鏻离子液体(C-Si O2-P4T)的固载量为5.39%(w);固载试样基本保持了硅胶的孔道特征。实验结果表明:C-Si O2-P4T具有较高的CO2平衡吸附量,且能显著提高CO2/N2吸附选择性,循环使用6次仍保持良好的吸附能力;HSDM可较好地拟合CO2在C-Si O2-P4T内的扩散行为,40℃下的扩散系数在10-7 m2/s数量级,与硅胶同级,优于纯季鏻离子液体。

Adsorption of CO2 on Silica Gel Supported Quaternary Phosphonium Ionic Liquid

The silica gel supported quaternary phosphonium bis（trifluoromethyl）sulfonyl]imide （a kind of phosphonium salt ionic liquid） was prepared by grafting method,and was used for CO₂ adsorption. The adsorption isotherms and reuse performance of the adsorbent were investigated,and the adsorption kinetics was studied using the homogeneous surface diffusion model （HSDM）. The samples were characterized by FTIR and TG and the results show that：The ionic liquid is successfully grafted onto the silica gel;The loading amount of quaternary phosphonium ionic liquid on calcined silica gel （C-SiO₂-P₄T） is 5.39%（w）;The channel characteristics are mainly maintains. The experimental results show that：C-SiO₂-P₄T exhibits a higher adsorption capacity towards CO₂,the CO₂/N₂ selectivity is significantly improved,and its adsorption capacity after 6 times of reuse is good;HSDM is suitable to describe the diffusion of CO₂ in C-SiO₂-P₄T,and the diffusion coefficients at 40 ℃ are all at a level of 10^-7 m²/s,which is the same as that in bare silica gel and better than that in the pure quaternary phosphonium ionic liquid.