Introduction to microfiltration membranes, what is microfiltration membranes?

Microfiltration membranes trap particles between microns. Microfiltration membranes allow macromolecules and dissolved solids (inorganic salts) to pass through, but retain suspended solids, bacteria, and large molecular weight colloids. The operating pressure of the microfiltration membrane is generally as follows:

Microfiltration membrane filtration is the earliest membrane technology developed and applied in the world, using natural or synthetic polymer compounds as membrane materials. For microfiltration membranes, the separation mechanism is mainly sieving retention.

Microfiltration membranes are divided into inorganic membranes and organic polymer membranes according to film-forming materials, inorganic membranes are divided into ceramic membranes and metal membranes, and organic polymer membranes are divided into natural polymer membranes and synthetic polymer membranes; According to the form of the membrane, it is divided into flat membrane, tubular membrane, rolling membrane and hollow fiber membrane; According to the principle of film making, the preparation methods of polymer membranes are divided into dissolution method (dry-wet method), stretching pore forming method, phase conversion method, thermal phase method, dip coating method, irradiation method, surface chemical modification method, nuclear track method, dynamic formation method, etc. The preparation methods of inorganic membranes mainly include sol-gel method, sintering method, chemical precipitation method, etc. According to the size of the micropores, the filter membrane is divided into four forms: microfiltration membrane (MF), ultrafiltration membrane (UF), nanofiltration membrane (NF) and reverse osmosis membrane (RO).

Microfiltration is a precision filtration technology that sits somewhere between conventional filtration and ultrafiltration. Filtration is generally divided into depth filtration and screen filtration. Conventional filtration mostly belongs to depth filtration, and the media it uses such as paper, asbestos, glass fiber, ceramics, cloth, felt, etc., are some porous bodies with extremely irregular pore shapes, and the pore size distribution range is wide, and its pore size cannot be marked.

The rejection rate decreases with the increase of pressure, because the medium is thick, the capacity of particles is large, and the corresponding rejection rate is also high, which is mainly used for general clarification filtration. The filter media used in microfiltration has a sieve-like structure, which is made of natural or synthetic polymer materials, with a neat porous structure and a uniform pore size distribution. When filtration, all particles with large diameter are intercepted on the surface of the filter membrane, and the fluctuation of pressure will not affect its filtration effect.

Compared with general depth filtration media, it has the following characteristics.

1) Uniform pore size and high filtration accuracy Microporous filter membrane can make a relatively uniform pore size, which is one of its most important features. During filtration, it can make all particles and bacteria larger than the pore size be intercepted on the surface of the filter membrane, so it is often used as a means of guarantee, and is called "absolute filtration".

2) High porosity and fast flow rate There are millions of micropores on the microporous filter membrane, and the volume of the micropores accounts for about 70% and 80% of the total volume of the membrane. Due to the high porosity and thin membrane, the resistance is very small, and the filtration speed of liquids and gases can be dozens of times faster than other commonly used media with the same cross-sectional area.

3) The thickness of the microporous filter membrane is generally 100 150 m). The adsorption capacity of the filter membrane for solutes is very small, so it is suitable for the filtration of trace solutions and valuable particles.

4) No medium shedding Microfiltration membrane is a uniform and continuous overall structure, no debris shedding, while the general depth filtration media may shed debris or fibers and pollute the filtrate again.

5) Small particle capacity, easy to clog The microporous filter membrane has a thin texture and uniform pore size, and the retention is limited to the surface, so it is easy to be blocked by particles or gel substances similar to the pore size in the filtrate. Therefore, the microporous filter membrane is mainly used for precision filtration, and for liquids containing more impurities, it must be combined with depth filtration or other pretreatment methods to obtain good filtration effect and prolong the service life of the membrane.

Microfiltration is currently required in the production of purified water, used as fine filtration, as a reverse osmosis membrane and as a security filter prior to filling.

A filter membrane that can filter substances with a molecular weight of 10W-50W!

A membrane that can filter out impurities in the micron range.

Microporous membrane is made by using polymer chemical materials and pore-forming additives applied to the support layer after special treatment. In the application of membrane separation technology, microporous filter membrane is one of the most widely used membrane varieties, which is simple and fast to use, and is widely used in many fields such as scientific research, food testing, chemical industry, nanotechnology, energy and environmental protection. The microporous membrane is mainly made of refined nitrocellulose, acetone, n-butanol, ethanol, etc., hydrophilic, non-toxic and hygienic, is a porous membrane filter material, the pore size distribution is relatively uniform and penetrating micropores, and the absolute pore size of microporosity is as high as 80.

It is mainly used for the filtration of aqueous solution, so it is also called aqueous membrane. Flat sheet membranes, hollow fiber membranes, and tubular membranes. Among them, the flat thin paper filter membrane can be further subdivided into two types: "flat thin paper filter without support" (unsupported) and "supported flat thin paper filter membrane" (supported) according to its structural differences.

According to the requirements of the technology required for the manufacture of the two, the production process of "flat tissue paper filter without support" is more sophisticated and complex than that of "flat thin paper filter with support".

Microporous filtration is a screening process and belongs to precision filtration. Microporous precision filtration refers to the filtration technology that removes particles down to 10 m, and generally speaking, the filtration mechanism is divided into two types: surface type and deep type. Microporous filtration is a screening process and belongs to precision filtration.

MF membranes manufactured by advanced technology have a surface filtration mechanism. Because the filter pore size is fixed, the accuracy and reliability of filtration can be ensured. Depth filtration is divided into non-fixed irregular pore size and fixed irregular pore size, the former such as chemical fiber winding filter element, generally only used as a relatively rough pre-filtration.

A microporous membrane is a type of membrane with a very small pore size, such as an ultrafiltration membrane. Now some. For example, it is used in industry to semi-permeable membranes and so on. Microporous membranes are generally used to filter bacteria.

The microporous membrane is actually a tool for fine filtration, which means that it can carry out deep filtration.

What is a microporous filter membrane A microporous membrane is a kind of membrane that filters water or taro paste.

That's all kinds of filtration membranes, through filtration to receive water, I use it to remove impurities.

And I'm talking about a filtering thing that allows them to sort out some filtering and things like that.

In chemical experiments, most of the filter membranes are pain from work breaks? He can pass through small molecule substances.

Ceramic microfiltration membrane, also known as inorganic ceramic membrane, is an asymmetric membrane formed by the preparation of inorganic ceramic materials through a special process. The wall of the ceramic membrane tube is densely covered with micropores, and under the action of pressure, the raw material liquid flows inside or outside the membrane, and the small molecule substances pass through the membrane, and the macromolecular substances are intercepted by the membrane, so as to achieve the purposes of separation, concentration, purification and environmental protection. Ceramic membrane has many advantages such as high separation efficiency, stable effect, good chemical stability, acid and alkali resistance, organic solvent resistance, bacterial resistance, high temperature resistance, pollution resistance, high mechanical strength, good regeneration performance, simple separation process, low energy consumption, easy operation and maintenance, long service life, etc., and has been successfully used in many fields such as food, beverage, traditional Chinese medicine, plant deep processing, biomedicine, fermentation, fine chemicals, etc., and can be used for separation, clarification, purification, concentration, sterilization, desalination, etc. in the process of processing.

Ceramic microfiltration membranes are used in the fine chemical industry.

1. Chemical intermediates: p-aminobenzenophorol, hydroquinone, cyclolap mold hexanone, oxime branches.

2. Ultrafine particles: titanium dioxide.

3. Metal salts: copper sulfate, primary brine (sodium chloride), potassium nitrate.

1. Filtration and sterilization in the pharmaceutical industry.

2. Application in food industry (clarification of gelatin, clarification of glucose, clarification of fruit juice, clarification of liquor, ** beer residue, sterilization of white beer, milk skimming, production of drinking water, etc.).

3. Application in paint industry.

4. Application in biotechnology industry.

5. Pretreatment of reverse osmosis and nanofiltration process.

6. Removal of algae and particulate impurities in surface water such as reservoirs, lakes and rivers.

7. Filter membrane module of household water dispenser.

8. Microfiltration membranes such as PP and PTFE also have the function of filtering acidic or alkaline water, and their pH range is 1-14

1. Separation efficiency is the most important performance characteristic of microporous membranes, which is controlled by the pore size and pore size distribution of the membrane. Because the microporous membrane can achieve a relatively uniform pore size, the filtration accuracy of the microfiltration membrane is higher and the reliability is higher.

2. The surface porosity is high, which can generally reach 70%, which is at least 40 times faster than the filter paper with the same retention capacity.

3. The thickness of the microfiltration membrane is small, and the loss caused by the liquid adsorption by the filter medium is very small.

4. The polymer microfiltration membrane is a uniform continuum, and there is no medium falling off during filtration, which will not cause secondary pollution, so as to obtain high-purity filtrate.