In recent years, the design of high-performance nanofiltration membrane materials has become a hot topic in the membrane field. Aiming at the common problems of trade off effect between permeability and selectivity, membrane pollution and separation of substances with similar molecular weight in the development of nanofiltration membrane, Professor Sun Shipeng's team of Nanjing University of technology carried out a series of research work on the subject guest interface enhanced polymer nanofiltration membrane based on the ring-shaped supramolecular cucurbit urea, precisely constructed the separation channel and transmission channel of nanofiltration membrane, and improved the resistance of nanofiltration membrane The pollution performance has realized the efficient interception of small and medium molecular alcohols in water system, which provides a new way to solve the above problems.
1、 Enhanced water transport and SO42 - / Cl - separation by cucurbitamide sub nano separation channel
Using the host guest reaction between cucurbit (6) uril, CB6 and piperazine (PIP) for the first time, a new water soluble rotaxane monomer (pip-cb6) was constructed, and it participated in the interface polymerization process. The application of intrinsic cucurbit in nanofiltration membrane material was realized for the first time (Fig. 1). The introduction of CB6 has successfully constructed two kinds of solvent channels of nanofiltration membrane: one is the traditional polyamide network channel, the other is the rotaxane channel constructed by the hydrophobic cavity of CB6 and pip. In addition, the encapsulation of large-scale CB6 on water-phase monomer PIP limits its diffusion in the interfacial polymerization, making the new nanofiltration membrane selection layer thinner and obtaining lower surface roughness. On the basis of ensuring the excellent selectivity of sulfate and chloride ions, the new structure obtained a pure water permeability (15.5-25.4 l m-2 Bar-1 h-1) 3-5 times higher than the traditional polyamide nanofiltration membrane. In addition, due to the large amount of carbonyl groups at CB6 port significantly enhance the negative electric characteristics of the selective layer, CB6 film can guarantee the SO42 high rejection and the CL permeability greatly improved. Compared with commercial or literature reports of polyamide membrane, CB6 modified nanofiltration membrane shows excellent SO42 - / Cl - separation performance. This achievement was published on AIChE J., [1] the first author of this paper is Cao Xueli, assistant professor of Nanjing University of technology.
Figure 1. Enhanced water transport by cucurbitamide and separation of SO42 - / Cl -
Aiming at the common problems of nanofiltration membrane pollution, the team introduced the dendrimer (PAMAM) on the basis of CB6 modified nanofiltration membrane (Figure 2). The large-scale PAMAM can further reduce the surface roughness of the membrane, and its abundant amino group can improve the hydrophilicity of the membrane surface, both of which are beneficial to improve the anti pollution performance of the membrane surface. The flux recovery rate of cb6-pamam modified nanofiltration membrane after two times of BSA solution pollution and water washing was 99.43% by adjusting the mass ratio of water phase composition of interfacial polymerization without loss of original performance, which proved its great potential to improve the anti pollution performance of membrane. This work was published in J. membr. SCI., [2] the first author is Cai Jing, a postgraduate of Nanjing University of technology.
Figure 2. Pollution resistance of cb6-pamam nanofiltration membrane
2、 Precise design of nano chain pattern on the surface of cucurbitamide induced membrane and efficient separation of isopropanol (IPA) / water
In the process of nanofiltration membrane preparation, the diffusion and reaction characteristics of monomers at the water oil interface determine the structure and properties of the interface polymer layer. Compared with the classical piperazine (PIP), the diffusion rate of polyamines with larger size (polyethyleneimine, triethylenetetramine, etc.) at the interface is slower, thus forming a thinner selective layer. In this work, it was found that the surface structure of nanochains can be accurately controlled by the diffusion inhibition of cucurbitamide cavity to amine monomers, thus establishing a series of methods based on cucurbitamide to regulate the surface microstructure of nanofiltration membrane (Fig. 3). On the one hand, through the construction of deta-cb6 rotane structure with CB6, the self inhibition of deta in the diffusion process is improved, resulting in a large number of nano chain patterns on the membrane surface, effectively improving the permeability of pure water. Further research shows that the precise control of the number and size of nano chains can be realized by adjusting the concentration of cucurbitamide. On the other hand, the construction of CB6 rotaxane channel improved the separation ability of nanofiltration membrane for similar molecular weight substances. For the first time, through nanofiltration technology, isopropanol molecules in water were effectively intercepted, and the low concentration IPA in fermentation broth was concentrated from 0.5wt% to 9wt%. Therefore, the deta-cb6 nanofiltration membrane is expected to be used in the pre concentration process of bio fermentation alcohol, providing a new idea for energy saving and consumption reduction in the production process of bio fuels and other products. This work was published in nano lett. [3] and the first author was Tang Mingjian, a postgraduate of Nanjing University of technology.
Figure 3. Controllable drawing of surface nano chain pattern based on cucurbitamide and corresponding performance
1. Original text (scan or long press QR code, and then go to the original page after identification): the encoding improvement of Polyamid nanofiltration mechanism by cucurial based host – guest chemistryxue Li Cao, Jia Lin Guo, Jing Cai, Mei Ling Liu, Susilo japip, Weihong Xing, Shi Peng sunaiche J., 2020, 66, e16879, DOI: 10.1002/aic.16879
2. Original text (scan or long press QR code, and then go to the original page after identification): the establishment of high-performance anti fouling nanofiltration members via cooperation of artificial supramolecular cubit [6] URI and nominal polyamidoaminejing Cai, Xue Li Cao, Yi Zhao, Fu Yi Zhou, Zaoling Cui, Yong Wang, Shi Peng sunj. Membr. SCI., 2020, 600, 117863, DOI: 10.1016/j.memsci.2020.117863
3. Original text (scan or long press QR code and go to the original page after identification): carefully patterned nanostrand surface of curvature [n] - based nanofiltration membranes for effective alcohol – water condensationming Jian Tang, Mei Ling Liu *, Da An Wang, Dan Dan Shao, Hua Jiang Wang, Zhaoliang Cui, Xue Li Cao, Shi Peng sun * nano lett., 2020, 20, 2717-2723, DOI: 10.1021/acs.nanolett.0c00344
About Professor Sun Shipeng
Sun Shipeng, professor and doctoral supervisor of membrane science and Technology Research Institute of Nanjing University of technology, focuses on nanofiltration membrane materials and processes. Selected in the national overseas high-level talent introduction plan (Youth), Jiangsu outstanding youth fund, Huo Yingdong young teachers fund and other talent plans. He has successively presided over projects of Singapore National Research Foundation and China National Natural Science Foundation. He has published more than 40 papers in AIChE J., nano. Lett., chem. Eng. SCI. IEC & R, J. membr. SCI., J. mater. Chem. A., environ. SCI. Technol., chem. Eng. J. and other journals. We have applied for 24 patents, authorized 11 Chinese and Singapore patents, and transferred 11 patented technologies to 3 companies for industrialization. He was awarded "Singapore young Chemical Engineer Award" by the Institute of Chemical Engineers (IChemE), as well as "Chen Jiageng youth Invention Award" and "outstanding contribution award of Singapore society of engineers". As executive member of the first youth Expert Committee of China desalination and water reuse society, member of the first youth committee of chemical process Strengthening Professional Committee of China Chemical Society, and deputy editor in chief of case studies in chemical and environmental engineering, a journal of Elsevier.
Email: ssp@njtech.edu.cn website: www.sun-membrane.comhttps://www.x-mol.com/university/factory/26706
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