Fabrication Of High Flux,Loose Thin-film Nanocomposite Membrane With Zero Dimensional Nanomaterials

High flux,antifouling nanofiltration membrane has important application.In order to improve the low permeability of nanofiltration membrane,thin film nanocomposite membranes were prepared by the method of interfacial polymerization incorporated zero-dimensional nanomaterials with nano-size,strong hydrophilicity,high stability and good mechanical properties.In this study,three kinds of high flux thin film nanocomposite membranes were prepared by the method of interfacial polymerization using calcium carbonate nanoparticles,graphene quantum dots and titanium dioxide nanoparticles,respectively.We investigated the effects of different nano-sized zero-dimensional materials on the structure and morphology,surface charge of membranes,hydrophilicity and chemical structure,etc.and prepared the high flux membranes.Firstly,the nanocomposite membrane TEPA-CaCO₃/TMC with high flux was prepared by incorporating calcium carbonate nanoparticles into the polyamide separation layer.When the calcium carbonate was introduced into the polyamide layer,the hydrophilicity of the membrane surface was improved and the surface roughness increased due to the hydrophilicity and the size of the calcium carbonate itself,the structure of polyamide layer became loose and thin,and the free volume within the membrane increased.The modified membrane flux increased to 71 L/m²h,which was about 10 times that of the unmodified TEPA/TMC membrane.Secondly,the PIP-GQDs/TMC nanocomposite membranes were prepared by introducing the graphene quantum dots into the polyamide separation layer.Its surface was smooth and low friction,and water molecules could flow quickly through its surface.When the material was introduced into the separation layer,the interfacial polymerization reaction was disturbed,and the surface is became smooth.Membrane flux was 102 L/m²h,which was 6.8 times higher than PIP/TMC membrane,also the antifouling performance greatly improved.Finally,titanium dioxide nanoparticles were introduced into the polyamide separation layer to prepare high flux nanocomposite membranes.The method of in-situ growth titanium dioxide on the support layer reduced the aggregation of hydrophilic nanoparticles in the membrane.The hydrophilicity and roughness of the membrane were improved after modification.In addition,the membrane flux greatly increased to 130 L/m²h,while the dye separation rate of over 95%,salt permeability of 83%.