Professor Xu Zhikang of Zhejiang University made a series of new advances in the group "Polymer filtration membrane based on controlled table interface engineering"

China Coatings Online News Information:
-filter membrane with aperture of about 1 nanometer is usually prepared with interface polymerization of ultrafiltration subfilm surface, and has a wide range of applications in drinking water depth purification, multi-price ion removal, organic small molecule concentration and so on. However, the classical triamide/diamine interface polymerization is a non-equilibrium process in thermodynamics, the reaction is very fast, can be completed in seconds, dynamics can not be controlled. With the support of the key project of NSF, "Polymer filtration membrane based on controlled table interface engineering", Professor Xu Zhikang of Zhejiang University led the "polymer separation membrane and its table interface engineering" task force to make a series of progress from the following two aspects."top-down" construction of selective cortical layer, to achieve the multi-functionalization of the filtration membrane team doctoral student Zhang Chao-early found that trace CuSO4/H2O2 can promote the rapid oxidation of dopamine polymerization, forming a stable, uniform, controllable coating (Angew. Chem. Int Ed., 2016, 55, 3054-3057)。 Further in-depth studies have shown that the polydopamine coating, which reduces roughness, increases the refractive index, and the interference principle makes it a bright color rather than a dim black color. The paper was published in J. Mater. Chem. C (IF s 5.066) and was selected as the outer cover paper.:Zhang, Bai-Heng Wu, Yong Du, Meng-Qi Ma and Zhi-Kang Xu; Mussel-inspired Polydopamine Coatings for Large-scale and Angle-independent Structural Colors. J. Mater. Chem. C, 2017, 5, 3898-3902.Ph.D. student Zhang Chao, in cooperation with Ph.D. student Lu Wei, analyzed the structure of this coating on the surface of the ultrafiltration substation in detail using electron annihilation, and found that the coating has two types of aperture, 0.5 nanometers and 0.9 nanometers, and can be used as a selected cortical layer of thin layer composite nanofiltration film, not only with outstanding water phase desalination performance, but also from the organic phase efficient recovery of nanocatalysts. The paper was published in ACS Appl. Mater.Interfaces (IF s 7.145).paper information: Chao Zhang,??? Yan Lv,? Wen-ZeQiu, Ai He, and Zhi-Kang Xu*; Polydopamine Coatings with Nanopores for Versatile Molecular Separation. ACS Appl.Mater.Interfaces, 2017, DOI: 10.1021/acsami.7b03115.On the basis of the work of developing polydhopamine (PDA)/polyethylene subamine (PEI) co-deposit selective cortical layer in the early stage, Dr. Lu Wei ofproposed that siO2 nanoparticles with a diameter of about 10 nanometers in the PDA/PEI cortical layer can not only improve the acoustics of the composite nanofiltration membrane, but also significantly enhance its surface mechanical properties and structural stability. The paper was published in ACS Appl. Mater.Interfaces (IF s 7.145).paper information:Lv, Yong Du, Wen-ZeQiu, and Zhi-Kang Xu; Nanocomposite Membranes via the Codeposition of Polydopamine/Polyethyleneimine with Silica Nanoparticles for Enhanced Mechanical Strength and High Water Permeability.ACS Appl. Mater. Interfaces, 2017, 9, 2966?2972.。 Ph.D. student Lu Wei and Ph.D. student Zhang Chao further collaborated with Professor Seth Darling of Agung National Laboratory in the United States to build a class of composite nanofiltration membranes with photocatalytic degradation by using bionic mineralization to generate b-hydroxy iron oxide nano-bars on the surface of such nanofiltration membranes. Under visible light, the film completely removes the chroma of the printing and dyeing wastewater, and the catalyst of the load can degrade the dye on the surface of the membrane efficiently and steadily through the photofinton reaction, showing excellent self-cleaning ability. The paper will be published in Adv. Funct. Mater. (IF-11.382). :Lv?, Chao Zhang?, Ai He, Shang-Jin Yang, Guang-Peng Wu, Seth B. Darling, Zhi-Kang Xu; Photocatalytic Nanofiltration Membranes with Self-Cleaning Property for Wastewater Treatment.Adv. Funct. Mater., 2017, in press." Bottom-up "regulating interface aggregation to achieve a thinner separation layer and higher water flow In addition to thermodynamics and dynamics are difficult to regulate, the unevenness of the surface of the ultrafiltration membrane is also an important factor affecting the interface polymerization. Ph.D. student Zhang Wei and Ph.D. student Yang Xi used polyphenols and dopamine and polyethylene subamine, respectively, in the ultrafiltration sub-film moderate co-deposition, to build a hydro-hydro, evenly distributed middle layer, to a certain extent, make the superfiltration sub-film surface homogenization, capillary action caused upward Laplace Force will make more amine monosomes in the water phase are evenly distributed on the surface of the substitin to participate in interface polymerization, thus successfully reducing the thickness of the selected cortical layer from the original 100-120 nanometers to about 50 nanometers, effectively reducing the water's cross-membrane resistance, while giving the cortical layer better uniformity. Under the premise of ensuring the intercepting effect, the water flow of the composite nanfiltration membrane is significantly increased, the intercept rate of Na2SO4 under 0.6MPa is greater than 97%, and the water ratio is as high as 60 L/m2h. The papers were published in ACS Appl.Mater.Interfaces (IF=7.145) and Langmuir (IF=3.993). :Zhang, Yan Lv, Hao-Cheng Yang, Yong Du, Zhi-Kang Xu; "Polyphenol Coating as An Interlayer for Thin-Film Composite Membranes with Enhanced Nanofiltration Performance. ACS Appl. Mater. Interfaces, 2016, 8(47), 32512–32519.。 Xi Yang, Yong Du, Xi Zhang, Ai He and Zhi-Kang Xu*; Nanofiltration Membrane with A Mussel-Inspired Interlayer for Improved Permeation Performance. Langmuir,2017,33(9), 2318–2324.。 Master's student Wang Jingjing introduced natural cellulose nanocrystals as the intermediate layer on the surface of the microfiltration subfilm, effectively regulated the interface polymerization process and obtained the ultra-thin polyamide separation layer. At the same time, the super-hydrophobicity of the middle layer of cellulose nanocrystalline also significantly promotes the penetration of water and realizes the preparation of high-performance composite nanofiltration membrane. At the same time that the intercept rate of Na2SO4 is 97%, its penetration ratio can reach up to 204 Lm-2h-1, which is the highest reported in the literature.related papers were published in J. Mater. Chem. A (IF-8.262).paper information: -Jing Wang, Hao-Cheng Yang, Ming-Bang Wu, Xi Zhang and Zhi-Kang Xu; Nanofiltration Membranes with Cellulose Naocrytals as An Interlayer for Unprecedented Performance.J. Mater. Chem. A, 2017, DOI: 10.1039/c7ta00501f.
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