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What is the double-layer gradient structure of the microporous filtration membrane? what are the pro

Issuing time:2023-08-21 10:42

The double-layer gradient structure of microporous membranes refers to two layers of membranes with different pore sizes, usually arranged such that the layer with larger pore size is on the "upstream" side (feed layer) and the layer with smaller pore size is on the "downstream" side (filter discharge). layer), in this kind of microporous membrane with double-layer gradient structure, two layers are arranged in a gradient or gradual transition from one layer to another, and the upper layer is usually called a pre-filter or protective layer, which usually has a more Large pores, or more open structures, can be used to trap larger particles or pollutants and prevent them from reaching the layer below.

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The lower layer is used as a precision filter layer, which usually has smaller pores or a tighter structure. It can be used as the main filter barrier to effectively remove smaller particles, microorganisms or other target pollutants in the filtered fluid. The gradient structure Designed to efficiently remove particles of all sizes.

Microporous membranes of this type of gradient structure are usually produced by a phase inversion process, in which the polymer is dissolved in a solvent to form a solution, the solution is cast into a film, and then the film is immersed in a coagulation bath to precipitate the polymer and form Porous structure, and the difference between the upper and lower layers of the gradient pore size is controlled by the choice of polymer and solvent, the concentration of the solution, the temperature of the coagulation bath, and other factors. In this process, in order to create a double-layer gradient structure, you can press Performing two phase inversion processes sequentially, using different conditions to create the upper two layers with different pore sizes, this design is commonly used in a variety of filtration processes, including water purification, air filtration, pharmaceutical manufacturing, and laboratory filtration.

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What are the advantages and disadvantages of the double-layer gradient structure of the microporous membrane?

1. Advantages

Characterized by high capacity, the larger pores on the upstream side allow the membrane to capture and retain more particles without clogging, which increases the overall capacity of the filter.

The gradient structure is protective, with the large pore size upstream layer trapping larger particles, protecting the downstream layer from damage and helping it maintain its performance.

It can increase the flow rate of filtration, and having larger pores on the upstream side can also increase the flow rate by reducing the flow resistance, enhance the overall filtration capacity, improve flow dynamics, increase the dirt holding capacity, and extend the service life of the membrane by preventing premature clogging

2. Disadvantages

For a more complicated manufacturing process, creating a double-layer gradient structure may be more complicated and costly than creating a single-layer membrane, because it requires precise control of the phase inversion process to create a two-layer structure with different pore sizes. With the investment in manufacturing costs, then , the membrane cost is relatively high.

There is the possibility and risk of layer separation. Under certain conditions, such as high pressure or high temperature, there is a risk of separation between the upper and lower layers, which may damage the performance of the filtration membrane and filtration system.

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The microporous membrane with double-layer gradient structure has great advantages in application, and its advantages also reflect its value. Therefore, under the correct use method, its disadvantages are negligible. Moreover, the specific configuration of the double-layer gradient structure And characteristics can be adjusted according to the intended application and the materials used in the membrane structure, which greatly enhances its application range.

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