聚苯胺-蒙脱土复合物改性PVDF超滤膜的制备及性能

Preparation and Properties of PANI-MMT Modified PVDF Ultrafiltration Membrane

以过硫酸铵(APS)为氧化剂,采用原位化学氧化法制备出亲水性的聚苯胺-蒙脱土(PANI-MMT)插层纳米复合物.通过共混的方式将PANI-MMT添加到PVDF/PVP K30/NMP铸膜体系中,利用浸没沉淀相转化法制备出PANI-MMT改性PVDF平板超滤膜,系统考察了PANI-MMT添加量对膜结构和性能的影响.红外光谱(FT-IR)和X射线衍射(XRD)结果表明,聚苯胺(PANI)插层到蒙脱土(MMT)的层状间隙中;扫描电镜(SEM)和原子力显微镜(AFM)结果显示,改性膜内部指状孔数量增加,膜表面粗糙度增大;孔隙率、接触角、水通量及牛血清蛋白(BSA)截留测试等表明,添加PANI-MMT后,PVDF膜的亲水性能显著提升,当添加量为0.5%时,纯水通量达到最大值445.86 L/(m^2·h).改性膜对BSA的截留率无明显变化,均可保持在90%以上;热重分析显示,改性膜具有增强的热稳定性,在600℃条件下不易分解;此外,经PANI-MMT改性的PVDF超滤膜的通量恢复率(FRR)显著提高,5个循环的抗污染性能测试后,M2膜(PANI-MMT添加量为0.5%)的FRR仍保持在85%以上,显示出良好的抗污染稳定性能.

In the current study,PANI-MMT nanocomposites were synthesized by in situ chemical oxidative polymerization with ammonium persulfate(APS)as an oxidant.PANI-MMT was added to the PVDF/PVP K30/NMP casting solution through blending and then the PANI-MMT modified PVDF plate UF membrane were prepared by an immersion precipitation phase inversion method.The effect of PANI-MMT contents on the membrane structure and performance was investigated systematically.Fourier transform infrared spectrum(FT-IR)and X-ray diffraction(XRD)analysis show that PANI has been intercalated into the layered structure of MMT.Scanning electron microscope(SEM)and atomic force microscope(AFM)images indicate that the number of finger-like pores and surface roughness of the modified membranes both increased.The results of the porosity,contact angle,water flux and bovine serum protein(BSA)retention test show that the hydrophilicity of modified PVDF membranes were improved remarkably.When the addition of PANI-MMT was 0.5%,the pure water flux of the composite membrane reached a maximum of 445.86 L/(m^2·h).There is no significant change in the retention rate of BSA by modified membranes,which remains above 90%.Results of TGA show that the modified membrane had enhanced thermal stability,which was difficult to decompose at 600℃.Furthermore,the flux recovery rate(FRR)of the modified membranes were significantly increased.The FRR of M2(0.5%PANI-MMT content)remained above 85%after five anti-fouling tests,which demonstrates good anti-pollution stability.