Application of artificial membranes, application of membrane technology

Blood, urine dialysis.

Water purification.

With the continuous development of membrane technology, membrane technology has been widely used in many faces: 1Electricity;

2.Electron; 3.chemical and pharmaceutical;

4.Light; 5.Creature;

6.food and beverage;

7.Municipal; 8.environmental protection and other industries.

It has a wide range of applications and a large degree of industrial relevance. Comparison of the separation range of PF ultrafiltration membrane and microfiltration membrane.

In the field of water treatment, ultrafiltration technology can remove bacteria, viruses, heat sources and other colloidal substances in water, so it is used to prepare ultrapure water in the electronics industry, injections in the pharmaceutical industry, purification of various industrial water and purification of drinking water. In the food industry, ultrafiltration technology is gradually adopted in the production of dairy products, fruit juices, wines, condiments, etc., such as the separation of protein and low molecular weight lactose from water in milk or whey, the clarification and sterilization of fruit juice, the removal of colored proteins, polysaccharides and other colloidal impurities in wine, and the removal of bacteria in soy sauce and vinegar, which shows the advantages of economy, reliability and quality assurance compared with traditional methods.

In pharmaceutical and biochemical production, it is often necessary to separate and purify heat-sensitive substances, and ultrafiltration technology shows its outstanding advantages. Ultrafiltration to separate concentrated bioactive substances (such as enzymes, viruses, nucleic acids, special proteins, etc.) is quite suitable for drugs extracted from animals and plants (such as alkaloids, hormones, etc.), and there are often macromolecules or solid substances in the extract, which can be separated by ultrafiltration in many cases, so that the product quality can be improved.

In the field of wastewater treatment, ultrafiltration technology is one of the successful examples for the treatment of elucent water in electroplating processes. In the production of metal products such as automobiles and furniture, after the paint is deposited on the metal surface by electrophoresis, it is necessary to wash off the plating solution absorbed on the product with clean water. Washing to obtain 1 2% of the coating of the leaching wastewater, with ultrafiltration device to separate the clean water, the paint can be concentrated and reused for electrocoating, the obtained clean water can also be directly used for cleaning, can realize the recycling of water.

At present, most automobile factories at home and abroad use this method to treat electrocoating elument water.

Ultrafiltration technology can also be used for textile mill wastewater treatment. The desizing solution of the textile mill contains polyvinyl alcohol (PVA), which is used with ultrafiltration device **PVA, clean water**, and the concentrated PVA concentrate can be re-sized.

With the development of new membrane materials (functional polymers, inorganic materials), the temperature, pressure and solvent resistance of membranes have been greatly improved, and ultrafiltration technology will be more widely used in petrochemical, chemical industry and more fields.

Applications of microfiltration.

Microfiltration is mainly used to remove ultrafine particles larger than left and right in the solution, and its application is very wide, accounting for the first place in the current sales of membrane process surface industry.

In the process of water purification, microfiltration technology can remove bacteria and solid impurities, which can be used in the production of medicine and beverage water. In the preparation of ultrapure water in the electronics industry, microfiltration can be used for the pretreatment of ultrafiltration and reverse osmosis processes and for the final security filtration of products. Microfiltration technology can also be used to filter various alcoholic beverages such as beer and rice wine to remove yeast, mold and other microorganisms, clarify the product, and extend the storage period.

Microfiltration technology is also widely used in drug sterilization, biological detection and other fields.

Biofilms in living organisms show amazing skills in the separation, transport, and concentration of substances. It is like an excellent "buyer", who welcomes everything he needs and refuses to accept what he doesn't need; For useful nutrients, "only in but not out", and useless waste is "only in and out"; And the speed of the conveyance is impressive. Biofilms are exceptionally selective, highly directional and extremely permeable.

Mimicking the curious capabilities of biofilms could provide new technologies for extracting and enriching elements in a dispersed state. In the 70s, important results were made in the study of simulating the structure and function of biofilms, and the separation technology using artificial membranes was developed - liquid film separation. It has the characteristics of high efficiency, fast and specific, and has an industrial scale in wastewater purification and treatment.

So, how does the liquid membrane achieve wastewater purification? When a small drop of aqueous solution is wrapped in a thin oil film, this small drop of aqueous solution is "protected" by the oil film and can "swim" in other aqueous solutions, and this oil film is called a liquid film. Taking the treatment of phenol-containing wastewater as an example, when the oil beads containing the aqueous solution of sodium hydroxide are put into the phenol-containing wastewater, with the help of surfactant, a surfactant liquid film is formed to separate the water from the wastewater, and the phenol in the wastewater can quickly "drill" into the water droplets through the liquid film and react with sodium hydroxide to form sodium phenol, which can no longer be "returned".

This reaction continuously reduces the concentration of phenols to zero, thus separating the phenols and water in the wastewater efficiently and quickly.

The use of artificial membranes to treat wastewater is just one example of the application of liquid membrane separation technology. In fact, liquid film has been widely used in hydrometallurgy, sodium extraction, organic matter separation, artificial lungs, artificial kidneys, long-acting drugs and antidotes.

Scientists have studied cells and found that animal cells have a very thin membrane called a cell membrane. It isolates the cell from the outside world. The structure of cell membranes is complex. It contains not only proteins, but also phospholipids, sugars, metal ions, and water, among others.

Don't look at this thin film, it can be very effective! In terms of permeability, all kinds of substances are not "treated equally", but are selective. "Green light" for some substances, unimpeded, so that they can enter the cell smoothly; For others, a red light is lit and "no traffic".

It in turn excretes secretions from the cells to the outside of the cells. Here, the cell membrane plays a role in regulating the exchange of substances inside and outside the cell.

The study of biofilms has led to a new technology – membrane technology. As a result, a wide variety of artificial films have emerged. Artificial membranes are widely used in separating liquid mixtures, brackish water and seawater desalination, sewage treatment, gas separation, purification, concentration of certain substances, etc.

The membrane of the glomeruli of the human kidney is an excellent filter, and when the blood flows through, except for red blood cells, white blood cells and macromolecular proteins, everything else flows through the "membrane" to the cyst cavity to form urine. Therefore, the artificial kidney must be designed with a membrane that does the same thing, otherwise, it will not become an artificial kidney. Artificial membranes are also used in the design of artificial gills.

The simple reason is that the gills of fish are actually special membranes that allow only oxygen from the water to pass through. Artificial gills have been made possible by breakthroughs in membrane technology, which can help humans conquer the blue ocean and unravel the mysteries of the underwater world.

Artificial membrane (artificial lipid membrane) A membrane formed artificially using lipids alone. It is widely used as a model for biological body membranes. In lipids, especially phospholipid molecules, there are highly hydrophilic genes such as phosphoric acid and base and hydrophobic groups of fatty acid residues of about 2 nm.

Therefore, when placed in an aqueous solution, the hydrophilic groups are arranged towards the water, and the hydrophobic groups are gathered as far away from the water as possible, so that the membrane is spontaneously formed.

The liquid crystal film or artificial separation film made of polymer polycarbonate combined with liquid crystal being developed in Japan has been applied in the pharmaceutical industry. For example, in medical treatment, the film is made into a capsule, the anti-inflammatory agent is put inside, and then the capsule is buried in the inflamed part, the capsule can be released in time according to the temperature change caused by the inflammation of the affected area, so as to achieve the expected purpose and effect, in the food industry, the use of artificial film can develop the taste sensoror of the "taste recognition robot", and can improve or manufacture the required various food ingredients, and the film technology can concentrate grape juice and improve the taste quality of creeping wine; It can be used to make low-salt soy sauce, purify fruit juice, color food, etc. This can not only improve the quality of food, enhance people's appetite, but also expand the food sales market, and increase the economic benefits of the food industry.

Membrane is an inorganic or polymer material with special selective separation function, which can separate the fluid into two parts that are not connected, so that one or several substances can pass through and separate the other substances. Membrane technology is the preferred technology for environmental protection and environmental remediation. It is also playing an important role in the food industry.

Membranes are at the heart of membrane technology, and the properties and chemical structure of membrane materials play a decisive role in membrane separation performance.

There are seven categories according to the structure:

a.Homogeneous membrane or dense membrane, which is a dense membrane with uniform structure.

b.Symmetrical microporous membrane with an average pore size. According to the different film-forming methods, there are three types of microporous membranes, namely nuclear pore membranes, controlled stretch membranes, and sponge-like structure membranes.

c.Asymmetrical membranes. The membrane section is asymmetrical and is the most widely used membrane in industry.

d.Composite membranes. A dense composite layer of another material is applied to the surface of the porous membrane.

e.Ion exchange membranes.

f.Charged film.

g.Liquid film. It includes a support liquid film and an emulsion film.

According to the shape: flat membrane, tubular membrane, hollow fiber membrane and spiral membrane.

Membrane technology is also increasingly showing its important role and bright prospects in daily life. Since it was discovered that tap water contains trihalomethanes, pesticides, detergents, and secondary pollution from tap water pipes and water towers, it has begun to use reverse osmosis membranes to prepare pure water. However, due to the high production cost of pure water, and while removing harmful substances in the water, it also removes the inorganic salts that are beneficial to the human body.

Therefore, people use pure membrane devices to produce biologically active filtered water that can be directly consumed raw with the advantages of mineral water and pure water.