High-intensity ternary gradient structure PVDF tubular ultrafilter membrane and preparation method

Abstract

The invention belongs to the membrane separation material technology field, and discloses a high-intensity ternary gradient structure PVDF tubular ultrafilter membrane and a preparation method. The preparation method is as follows: PVDF powder is sintered in a tubular die, and a support layer tubular prefabricated body with a one-layer structure is formed; then PVDF powder is sintered with the prefabricated body as an outer layer, and a binary PVDF tubular base membrane with a binary gradient structure is formed; then a chemical-bonding functional Al2O3 / PVDF casting membrane solution is employed to carry out coating membrane forming on the inner surface of the tubular base membrane, a separation layer is formed, and a high-intensity ternary gradient structure PVDF tubular ultrafilter membrane is prepared. The provided ultrafilter membrane is prepared through forming methods for three times, the three structures are combined tightly, the provided ultrafilter membrane has advantages of pore diameter gradient distribution, low resistance, large flux, easy reverse cleaning and the like, the mechanical properties and separation performance of the provided ultrafilter membrane are raised greatly, and the provided ultrafilter membrane has good application prospects.

Description

technical field [0001] The invention belongs to the technical field of membrane separation materials, and in particular relates to a high-strength ternary gradient structure PVDF tubular ultrafiltration membrane and a preparation method. Background technique [0002] Membrane separation is a technical means for material separation, concentration and purification. The membrane separation process uses external energy as the driving force, and selectively transmits different substances through the selective permeable membrane, so as to realize the separation, enrichment and purification of liquid or gas mixtures of multiple components. The membrane separation process is relatively simple, less polluting, energy-saving and efficient, can be operated at room temperature, and there is no phase change in the separation process, so it is especially suitable for the separation and concentration of biologically active or heat-sensitive substances. [0003] In industry, membrane separ...

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Problems solved by technology

The filter membrane prepared by sintering has the characteristics of high strength and large porosity, but there are problems such as uneven porosity and small pores are not easy to form

[0008] At present, most PVDF tubular membranes use a composite process of smearing a separation layer on the support material. The support layer and the separation layer are not tightly bonded, and the bonding strength is low, which is easy to cause the peeling phenomenon of the two.

[0009] Therefore, how to maintain the advantage of inorganic modification of PVDF membrane to improve membrane hydrophilicity, avoid its disadvantage of low strength, and have the advantage of high strength of membrane produced by sintering method is a hot issue in the research of membrane material industry.

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