多巴胺改性单价选择性阴离子交换膜制备及表征

Preparation and Characterization of Dopamine-modified Monovalent Selective Anion Exchange Membrane

以CuSO4和H2O2为氧化剂,诱导多巴胺(DA)快速聚合,在商品膜表面形成荷负电的聚多巴胺(PDA)电解质层,制备具有1、2价阴离子选择分离功能的离子交换膜。通过扫描电子显微镜、红外光谱仪、Zeta电位分析仪等表征手段对PDA复合膜的表面结构和性质进行了分析,同时还考察了多巴胺含量对膜性能的影响。结果表明,当多巴胺的质量浓度为1 g/L时,PDA聚集物在膜表面均匀分布,PDA复合膜表现出良好的选择透过性(P(Cl^-/SO4^2-)=5.49),对Cl^-与SO4^2-有一定的分离效果;膜面电阻较低(R(Cl^-)=2.61Ω·cm^2、R(SO4^2-))=6.13Ω·cm^2)和较高的离子交换容量(2.19 mmol/g),赋予PDA复合膜一定的实用价值。且在实际运行过程中具有良好的稳定性。

Ion exchange membrane with monovalent-divalent anions selective separation function was prepared by polydopamine(PDA)deposition technology.CuSO4/H2O2 was selected as the oxidizer to induce rapid polymerization of dopamine(DA),forming a negatively charged electrolyte layer on the surface of commercial membrane.The surface structure and properties of PDA composite membrane were characterized by scanning electron microscope,Fourier transform infrared spectroscopy(FT IR)and zeta potential analyzer and other characterization methods.Meanwhile,the effect of dopamine content on the surface morphology was investigated.The results showed that,as the mass concentration of dopamine was 1 g/L,PDA aggregates were uniformly distributed on the membrane surface,modified membrane showed excellent selective permeability(P(Cl^-/SO4^2-)=5.49),and had a certain separation effect on Cl^-and SO4^2-.The lower of membrane surface resistance(R(Cl^-)=2.61Ω·cm^2,R(SO4^2-))=6.13Ω·cm^2)and the higher of ion exchange capacity(2.19 mmol/g)give PDA composite membrane a certain practical value,in addition,the membrane showed remarkable stability.