Preparation method for synthesizing ZIF-8 film in hole

Abstract

A preparation method for synthesizing a ZIF-8 membrane in pores specifically comprises the following steps: introducing a precursor solution into pores of a porous carrier, suspending the carrier in a kettle containing a ligand solution, under a heating condition, enabling the solution in the kettle to form steam, enabling the steam and the precursor solution in the pores to form a membrane at a phase interface, and enabling the formed membranes in the pores not to be in contact with each other to form the complete ZIF-8 membrane. However, each film is formed in the carrier holes, all the holes are complete and thin, no gap exists between the holes and the hole walls and form a complete film together with the hole walls due to the limitation of the hole channels, and the diameter of each carrier hole is less than 50 microns, so that the formed film is small in area, high in strength and good in stability, the problem that defects are easy to occur when the film is formed on the surface of the carrier is solved, and the service life of the carrier is prolonged. Therefore, the separation performance and the permeation flux are relatively high. The method is easy to operate and high in repeatability, the solvent is effectively saved, and compared with a membrane synthesized on the surface under the same condition, the separation factor of the synthesized membrane is improved by 1-3 times, and the permeation flux is improved by 3-8 times.

Description

technical field [0001] The invention belongs to the technical field of separation materials, and relates to the preparation and application of a metal organic framework, in particular to a preparation and application method of zeolite-like imidazole framework compounds. Background technique [0002] my country is the largest coke production, consumption and exporter in the world. A large amount of coke oven gas will be produced in the coke production process. The main components of coke oven gas are methane, hydrogen and a small amount of nitrogen. If the coke oven gas can be fully Utilization will be a considerable economic income. Therefore, it is particularly important to realize the efficient separation of hydrogen and methane. [0003] Membrane separation is an advanced separation technology developed in recent years. It is known as one of the most potential high-end separation technologies. It has the advantages of environmental friendliness, low energy consumption, sma...

AI Technical Summary

Problems solved by technology

At present, membrane materials are mainly divided into two categories: inorganic membranes and organic membranes. Organic polymer membranes are corrosion-resistant and easy to form and process, but have the disadvantages of swelling and poor stability. Due to their excellent thermal and chemical stability, inorganic membranes Compared with the traditional zeolite membrane, the ZIFs series membrane not only has all the advantages of zeolite, but also has adjustable pore size, and the surface is easy to chemical Modified features, is a promising membrane material

[0004] At present, the in situ growth method is commonly used in the synthesis of membranes (Lv Xiaoli, Zhang Chunfang, Bai Yunxiang, Sun Yuping, Gu Jin. ZIF-8 / PAN ultrafiltration membrane prepared by in situ growth method for dye wastewater treatment[J]. Water Treatment Technology, 2016,42(07):30-34.), seed crystal induction method (Zhao Zhenxia, ​​Xu Feng, Li Zhong. Preparation of ZIF-8 film by secondary growth method and its effect on CO 2 / N 2 [J]. Acta Chemical Industry, 2014,65(05):1673-1679.), homologous metal oxide induction (Kong Lingyin. Design and preparation of metal-organic framework ZIF-8 membranes on different porous supports and study on their permeability [D]. Dalian University of Technology, 2015.) and vapor-gel method (Wu Changsong, Li Jiaxin, Sun Qing, Xu Shenghao, Zhao Xuwen, Li Qiuping, Jia Zhijian. Preparation of cerium-doped Miscellaneous ZnO [J]. Journal of Ningbo Institute of Engineering, 2019, 31(01): 12-18.), etc., but whether these methods are used on tubular or flat carriers, they are film-forming on the carrier surface, which is affected by the surface morphology of the carrier and the use of Due to the influence of the conditions in the process, it is not easy to synthesize a thin, continuous and dense film. Even if a continuous and dense film is synthesized, it will cause defects in the film due to the influence of temperature, pressure and other objective factors during use, which will affect its separation performance.

In the process of industrial scale-up preparation, the above-mentioned problems will be further amplified, and more defects will appear, making it more difficult to form a film on the surface of the carrier. In this case, it is difficult to synthesize a dense and thin film. It largely limits its industrial application

[0005] At the same time, the membranes synthesized by the above method generally face problems such as poor repeatability, weak binding force between the membrane and the carrier, and low strength of the membrane. The carrier has extremely high requirements, and it is generally impossible to prepare a complete film on a rough macroporous carrier. The surface of the carrier is required to be flat and the pore size is uniform and below 1 μm. Such a carrier preparation process is difficult and expensive

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