Fabrication Of High Flux,Antifouling Nanofiltration Membranes With Zwitterionic Monomer And Hybrid Materials

The target of the thesis is to fabricate high flux and antifouling nanofiltration?NF?membranes,which were prepared by using a zwitterionic amine monomer,incorporating inorganic attapulgite?ATP?and inorganic-organic hybrid POSS-PEG in interfacial polymerization process,respectively.We investigated the effect of different types of modifiers on the physical and chemical structure of the membranes.By adjusting the monomers concentrations,the concentration of added modifier added,we optimized separation performance of NF membranes.The antifouling properties of the NF membranes were also tested.The details of this study were summarized as follows:A kind of novel electro-neutral NF membrane at neutral pH was fabricated by interfacial polymerization from a novel zwitterionic amine monomer PEI-g-SBMA.The zwitterionic amine endowed the resultant NF membrane with an electro-neutral separation layer under neutral condition and enhanced antifouling property via regulation of surface charge balance.The hydrophilcity of the membranes was also enhanced due to the watery surface,which was in favor of the improvement of flux and antifouling properties.The electro-neutral zwitterionic NF membranes?PEI-gSBMA/TMC?showed a high waterflux of 132 L/?m²h MPa?,i.e.over 2 times higher than that of the PEI/TMC membranes without grafted SBMA.The PEI-g-SBMA/TMC membrane exhibited a high dye rejection?90.6% for Orange GII?but a low salt rejection?7.1% for NaCl and 50.4% for Na₂SO₄?.Meanwhile,the antifouling properties against bovine serum albumin?BSA?,sodium alginate?SA?and humic acid?HA?were significantly improved compared with the PEI/TMC membranes.A kind of novel hybrid NF membrane PIP-ATP/TMC was fabricated by incorporating inorganic ATP nanorods in interfacial polymerization process.The hydrophilic ATP provided preferentially trans-membrane channel for water molecules,enhancing the flux of the resultant NF membranes.The element of Al,Mg in ATP can combine a large amount of water molecules by hydration to construct hydrophilic membrane surface,enhancing the antifouling properties and flux.Without reducing the dye and salt rejection,the PIP-ATP/TMC NF membrane water flux was 229.5 L/?m²h MPa?,i.e.over 2.2 times higher the unmodified PIP/TMC membrane.Meanwhile,the antifouling properties against BSA,SA and HA were significantly improved compared with the PIP/TMC membranes.A kind of novel hybrid NF membrane PIP-?POSS-PEG?/TMC was fabricated by incorporating inorganic-organic hybrid POSS-PEG in interfacial polymerization process.The PEG segment in POSS-PEG can constructe watery membrane surface to enhance the antifouling properties.The watery surface also provided water molecules the prior channel to enhance the flux.The density of the polyamide separation layer was reduced due to the incorporatin of POSS-PEG,enhancing the flux of the asfabricated membranes.Without reducing the salt rejection,the PIP-?POSS-PEG?/TMC NF membrane water flux was 193.5 L/?m²h MPa?,i.e.over 1.9 times higher the unmodified PIP / TMC membrane.Meanwhile,the antifouling properties against BSA,SA and HA were significantly improved compared with the PIP/TMC membranes.