[Reproduced] Lin Zhang in Zhejiang University, Science: With this super nanofiltration membrane, is desalination still far away?
1. Developed an interfacial polymerization process for preparing nano-turing nanofiltration membranes with nano-Turing structure, and its desalination and water purification performance exceeded that of traditional nanofiltration membranes by more than three times.
2. It is found that there are active sites with high permeability in the Turing structure, which greatly enhances the water permeability.
In 1952, Turing published "The Chemical Basis of Morphogenesis" (The Chemical Basis of Morphogenesis), which theoretically explained how two chemical substances diffuse and react under specific reaction conditions to form a space-time stable structure. It was not until 40 years after the paper was published that no one confirmed his theory experimentally. Since the publication of the thesis, Turing's theory has begun to show unique guidance to basic research. The design and development of Turing structures play an important role in the practical application of chemistry and biology.
Turing structure often appears in the reaction-diffusion process that is thermodynamically unbalanced. When the diffusion rate is unbalanced, the fast-moving inhibitor controls the movement of the slow-moving activator, resulting in a Turing structure. The steady-state system formed by the Turing structure is very sensitive to tiny heterogeneous disturbances.
In order to obtain the Turing structure, there are two commonly used methods:
1) The introduction of PVA and other macromolecules can be reversibly combined with the activator.
2) Adopt a homogeneously dispersed heterogeneous multiphase reaction system to keep the activator in the low-speed moving phase.
In view of this, the research group of Professor Zhang Lin of Zhejiang University combined theory and experiment and reported a polyamide nanofiltration membrane with nano Turing structure, which has excellent desalination and water purification performance.
Figure 1. Interfacial polymerization to form a nano Turing structure
The researchers used an interfacial polymerization strategy to grow polyamide films. During the growth process, the polymerization reaction occurred at the oil-water interface. The morphology of the film is controlled by controlling the reaction conditions to ensure that the formed film has a bubble and tubular structure.
The researchers added the inhibitor TMC to the oil phase and added the activator polyvinyl alcohol to the water phase. PVA combines hydrogen bonds with activators to enhance solution viscosity and slow down the diffusion rate of monomers. Compared with the traditional nanofiltration membrane, the nano-Turing nanofiltration membrane produced by this method has more protrusions, more voids and more island-like structures.
Figure 2. Film with Turing structure
The polyamide membrane with nano Turing structure has better water purification and desalination performance due to its unique structural characteristics. Both the water permeability and the water-salt separation performance surpass the traditional thin nanofiltration.
In addition, the researchers also found that there are active sites in the Turing structure that allow water to pass through at high speed, which greatly enhances water permeability.
Figure 3. The spatial distribution of water permeability sites in the film
In short, the research has developed a nano-turing nanofiltration membrane, which has important practical prospects in the fields of seawater desalination and industrial wastewater desalination.
Lin Zhang is a professor at Zhejiang University. He is also the deputy director of the National and Local Joint Engineering Laboratory of Industrial Biocatalysis, and the deputy director of the Engineering Research Center of the Ministry of Education of Membrane and Water Treatment Technology.
In recent years, with the major needs of air, water resources and energy as the research background, we are committed to the key scientific issues of membrane science and technology in the above-mentioned fields to carry out research work, through the design of nanocomposite functional materials to improve and improve membrane performance, and build membranes Bioreactors are the main research content to enhance process separation and transfer efficiency, and innovative results have been achieved. Won 1 Second Prize of Natural Science Award from Ministry of Education, 1 First Prize of Zhejiang Province Science and Technology Progress Award, “Outstanding Contribution Award for Youth in Science and Technology” of China Petrochemical Federation, 1 Excellent Patent Award of National Intellectual Property Office, 2nd Prize of Marine Science and Technology 1 item. Selected into the second level of the Zhejiang Province "151" Talent Training Program, and received funding from the Zhejiang Outstanding Youth Fund; concurrently serves as the editorial board member of the SCI journal "Environmental Technology", the core journal "Water Treatment Technology", and "Membrane Science and Technology", Zhejiang Province Standing director of the Society of Chemical Engineering, Deputy Secretary-General of Zhejiang Membrane Society, Deputy Secretary-General of Zhejiang Membrane Industry Association; as the project leader, he has undertaken and completed a number of national-level projects including the National Natural Science Foundation of China and the "863" plan goal-oriented project. A number of research papers have been published in TOP chemical journals such as AIChE J, Chem. Eng. Sci., I&ECR, J. of Membrane Sci., Polymer, etc. More than 110 SCI papers have been published, and he has cited more than 2,000 times. The H-index is 26. Four research results successfully realized the transfer of intellectual property rights. In 2011, he was invited to participate in the 14th Asian Chemistry Conference held in Thailand, and made an invited report on high-throughput nanocomposite membranes at the Membranes for Molecular Separation branch. A basic research system for applications in water treatment, biomass energy, environmental purification and other fields with nanocomposite materials as membranes and membrane bioreactors as processes has been formed.
Author: Zhe Tan
Corresponding author: Zhang Lin
The first unit: Zhejiang University
Zhe Tan, Lin Zhang et al. Polyamide membranes with nanoscale Turing structures for water purification. Science 2018, 360, 518-521.
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