Fabrication And Performance Study Of Hydrophilic Self-cleaning Ultrafiltration Membranes

Inspired by the antifouling prototype in nature and in order to improve resistance of ultrafiltration membranes to various foulants,hydrophilic groups and low surface energy groups were introduced onto membrane surfaces by the surface segregation and electrostatic self-assembly method.Therefore,the membrane surface properties were regulated neatly and the dual-defense mechanisms were strengthened,so that the pollution resistance of membrane was enhanced and its long-term stability was improved.TEOS hydrolyzed and condensed to produce in-situ SiO₂ nanoparticles under PFSA polymer as catalyst,and the synergetic surface segregation process was controlled by the hydrogen bonding between PFSA polymer and SiO₂ nanoparticles.The hydrophilic microdomains and low surface energy microdomains were introduce onto membrane surfaces to regulate surface chemical composition and surface properties,so that the resistance of PVDF/PFSA/SiO₂ membrane surfaces to foulants was enhanced.The polyethylamine modified grapheme oxide?PEI-GO?was prepared firstly,then the synergetic suface segregation process was controlled through the electrostatic interaction between PFSA polymer and PEI-GO nanosheets.The composite modifiers successfully improved the physical morphology of membranes and regulated membrane surface properties such as Zeta potential and surface free energy.Through strengthening the"fouling-resistant"and"fouling-release"mechanisms,the resistance of PVDF/PFSA/PEI-GO membrane to foulants was improved,and the surface properties and chemical composition of the membrane were stable.By means of electrostatic self-assembly,PEI and PFOS were introduced onto the surface of HPAN membrane,and the modification process had no obvious effect on the surface and section structure of membranes.The introduction of PEI and PFOS regulated the contact angle,surface energy,Zeta potential and etc of membranes,and the dual-defense mechanisms were strengthened,so that the HPAN-PEI-PFOS membrane showed low flux decline?8%-11.5%?and high flux recovery?above 98%?during the filtration of oil-in-water emulsion and BSA solution.