不同溶剂对Pebax混合基质膜的CO_(2)分离性能影响

Effect of different solvents on performance of Pebax mixed matrix membranes for CO_(2)separation

用N,N-二甲基甲酰胺(DMF)和甲酸作溶剂制备了Pebax/UiO-66-NH_(2)混合基质膜。采用恒体积变压力的方法对膜的气体分离性能进行测试。结果表明,与纯膜相比,在DMF作溶剂时,填料的加入使CO_(2)的渗透系数略微下降,但CO_(2)/N_(2)选择性却大幅提升;在甲酸中CO_(2)渗透系数大幅上升,但CO_(2)/N_(2)选择性只有少量提升。在填料质量分数为2.5%时,DMF铸成的膜在25℃、1.0 MPa测得的CO_(2)渗透系数和CO_(2)/N_(2)选择性分别为126.4 barrer和94.4;而在填料质量分数为7.5%时,甲酸铸成的膜在25℃、0.6 MPa测得的CO_(2)渗透系数和CO_(2)/N_(2)选择性分别为103.5 barrer和104.3。

Pebax/UiO-66-NH_(2)mixed matrix membranes is prepared by using N,N-dimethylformamide(DMF)and formic acid respectively as solvents.The gas separation performance of the membrane is tested by the constant volume and variable pressure method.It is shown that compared with pure membrane,the CO_(2)permeability of the membranes prepared with DMF as solvent decreases slightly with the addition of filler,but the CO_(2)/N_(2)selectivity increases greatly.The CO_(2)permeability of the membranes prepared with formic acid as solvent greatly increases,but the CO_(2)/N_(2)selectivity rises slightly.The CO_(2)permeability and CO_(2)/N_(2)selectivity of the membrane cast in DMF with 2.5 wt%UiO-66-NH_(2)are 126.4 Barrer and 94.4,respectively at 25℃and 1.0 MPa.With 7.5 wt%UiO-66-NH_(2),the CO_(2)permeability and CO_(2)/N_(2)selectivity of the membrane cast in formic acid are 103.5 Barrer and 104.3,respectively at 25℃and 0.6 MPa.