活性位点接枝对聚醚醚酮膜基于溶解-扩散理论的粒子渗透性能的影响

Effect of active site grafting on particle permeability of polyether ether ketone membranes based on dissolution-diffusion theory

为探究聚醚醚酮磺化接枝对水分子和气体分子在膜材料基质渗透过程中的溶解-扩散作用效应,通过与浓硫酸共热在分子主链上接枝-SO_(3)H基团,溶剂挥发法制膜,并通过电镜扫描、BET分析、气体渗透等测试,分析改性膜的微观结构及改性对膜溶解-扩散性能的影响。结果表明,接枝改性后成膜致密均质,机械强度和热稳定性较改性前略微降低,亲水性显著增强。同时,-SO_(3)H活性位点接枝增加膜的O_(2)、CO_(2)、N_(2)的渗透系数及O_(2)/N_(2)和CO_(2)/N_(2)的分离系数,在纯气体渗透试验中,膜的分离系数α_(CO_(2)/N_(2))和α_(O_(2)/N_(2))分别达到21.89~34.36和5.67~6.83;在二元等压气体渗透试验中,α_(CO_(2)/N_(2))和α_(O_(2)/N_(2))分别达到19.93~32.76和5.56~6.69;在三元动态气体渗透试验中,磺化改性也显著降低了动态气调氛围达到平衡的时间。接枝活性位点-SO_(3)H改善了聚醚醚酮膜的亲水性和气体渗透性,尤其是膜的CO_(2)的渗透系数和分离系数有较大提升。

In order to investigate the dissolution-diffusion effect of water molecules and gas molecules in the membrane matrix permeation process after sulfonated grafting,by co-heating with concentrated sulfuric acid,the PEEK molecular chain was grafted with-SO_(3)H,and then the membrane was prepared by solvent volatilization method.The microstructure of the modified membrane and the influence of the modification on the solution-diffusion performance of the membrane were analyzed by scanning electron microscopy,BET analysis,gas permeability and other tests.The results show that PEEK grafted membranes are compact and homogeneous,the mechanical strength and thermal stability of PEEK grafted membranes are slightly lower than those before modification and the hydrophilicity is significantly enhanced.At the same time,-SO_(3)H active site grafting increases the permeability coefficient of O_(2),CO_(2),N_(2) and the separation coefficient of O_(2)/N_(2) and CO_(2)/N_(2) of the PEEK membrane.In the pure gas permeation experiment,the separation coefficient of α_(CO_(2)/N_(2) )and α_(O_(2)/N_(2)) in PEEK membrane is 21.89~34.36 and 5.67~6.83,respectively;in the binary isobaric gas permeation experiment,α_(CO_(2)/N_(2)) and α_(O_(2)/N_(2)) reach 19.93~32.76 and 5.56~6.69,respectively.In the ternary dynamic gas permeation experiment,sulfonation modification also significantly reduces the time for the dynamic atmosphere to reach equilibrium.The grafting active site-SO_(3)H improves the hydrophilicity and gas permeability of the polyetheretherketone membrane,especially the permeability coefficient and separation coefficient of CO_(2) of the membrane.