碳纳米管界面改性超滤膜的抗污机理解析

以碳纳米管(CNT)为核心改性材料,采用喷涂法对聚醚砜(PES)超滤膜进行界面改性,研究改性膜的抗污染性能.结果表明:改性膜经聚乙烯醇交联稳定后,呈现微弱的通透性降低和明显的亲水性提升,CNT交织网状层提高了界面粗糙度;在牛血清白蛋白(BSA)污染试验中,CNT-10改性膜的抗污性能最好,在20mg/L BSA试验后,...

Anti-fouling mechanism for ultrafiltration membrane of modified surface by carbon nanotubes

Carbon nanotubes (CNTs) as the core modification material was spray-coated on polyether sulfone (PES) ultrafiltration membrane towards enhanced anti-fouling property. The permeability of the modified membrane decreased slightly and the hydrophilicity increased obviously, and the layer of woven CNT fibre also increased the membrane roughness. In the presence of bovine serum albumin (BSA) of 20mg/L, the CNT-10membrane exhibited a high flux recovery rate up to 95.7% with the reversible fouling ratio nearly 60%. Then, applying electrical impedance spectroscopy (EIS) to measure membrane fouling extents provided the membrane real- imaginary impedance, conductance and capacitance. The Nyquist curve of CNT-10exhibited less horizontal shift (real impedance increases) towards the right side, and the radius of the curve was not significantly expanded after contamination test, in consistent with the slightly decreased conductance and relatively stable capacitance. It was concluded that the modified membrane has less foulant adhesion, agreeing with the flux variation. The discussion on frequency division of frequency-conductance diagram showed that BSA contaminated the entire surface and membrane of PES-V, but did not pollute the entire surface and membrane of CNT-10. The free energy analysis of the interfacial interaction between CNT modified layer and BSA was only half that for the control, indicating small membrane-foulant attraction, which explained the excellent anti-fouling performance of the CNT modified membrane by thermodynamics.