MOF (metal-organic framework) separating layer film and preparation method thereof

Abstract

The invention provides an MOF (metal-organic framework) separating layer film and a preparation method thereof. The preparation method comprises the following steps: a surface modification layer is formed on the surface of a base film through an interfacial polymerization reaction; an MOF separating layer grows secondarily on the surface modification layer, and preparation of the MOF separating layer film is completed. A preparation method of a positively charged MOF separating layer film further comprises the step that acid radical ions in the MOF separating layer film are removed by soaking the prepared MOF separating layer film in methyl alcohol. The MOF separating layer grows secondarily on the surface modification layer, and by means of the pore diameter screening action and a frame charging effect, the MOF separating layer film can effectively realize the effect of selective ion separation; layers of the MOF separating layer film are not formed through simple physical bonding, and accordingly, the defect of separation is overcome.

Description

technical field [0001] The invention belongs to the technical field of ion exchange membranes, and more specifically relates to a metal-organic framework separation layer membrane and a preparation method thereof. Background technique [0002] Metal-organic framework complexes (Metal-Organic Frameworks, MOF) are a new type of porous material with broad application prospects. It is a method of molecular assembly and crystal engineering of transition metal ions or metal clusters and organic ligands. Dimensions and framework of coordination polymers with cavities. In recent years, the research on the design, synthesis, structure and performance of such coordination polymer porous materials has been very active. MOF materials have great application prospects in many fields, especially in adsorption and separate fields. [0003] The research on the adsorption and separation of MOF materials mainly focuses on the adsorption and separation of gas mixtures, while relatively littl...

AI Technical Summary

Problems solved by technology

[0005] 1. In order to improve the ease of use and stability of MOF materials, it is doped into polymer materials to form a mixed matrix membrane, and ions are sieved through the pore size of MOF inside the membrane. The common advantages with MOF improve the applicability of MOF materials, but the two materials are only mixed physically, and there is a fatal defect of phase separation, which will cause holes in the membrane, resulting in the inability to effectively treat ions of different valence states. Sieving, at the same time, will also lead to a reduction in the strength of the membrane itself;

[0006] 2. Grown MOF layer on the surface of inorganic materials. Although the method is simple, the thickness of MOF layer is difficult to control, and too thick separation layer will greatly reduce the ion flux of monovalent ion during membrane separation, thus affecting the separation efficiency of the entire membrane; At the same time, the uncharged MOF layer is not conducive to the transmission of monovalent ions, resulting in greater ion transport resistance, reduced ion flux, and the separation layer also has a phenomenon of shedding.

[0007] Therefore, the ion separation application of existing MOF materials in solution systems is still in the preliminary exploration stage, not only in terms of applicability, but also in its own characteristics, such as the controllability of the pore size of the MOF framework, chargeability, and stability. and the controllability of MOF layer thickness, etc. need to be further studied

However, there are few reports on the precise control of the morphology and size of MOFs for the selective separation of ions.

Images