Cleaning method for ultrafiltration membrane

The molecular weight of ultrafiltration membrane is 1000-20000 daltons. The ultrafiltration membrane can intercept macromolecular impurities (such as protein, pigment, polysaccharide, etc.) and penetrate the target product; The target product can be intercepted and separated through small molecule impurities (inorganic salts, small molecule pigments, monosaccharides, ash, etc.) and water. Different molecular weight target products can also be separated, replacing traditional purification processes such as activated carbon decolorization, resin impurity removal, crystal extraction, etc., to achieve the goals of decolorization, impurity removal, and product classification.

Hongjie Water provides a variety of materials (including silicon carbide membranes) and molecular weight retention roll ultrafiltration membrane components, with a compact structure and reasonable surface area/volume ratio. By using different flow channel networks (13-120mil), the width of the material liquid flow channel can be changed to adapt to various viscosity of the material liquid. In order to meet certain special industry applications, we can provide acid and alkali resistant, high temperature resistant, and pollution resistant film products.

Cleaning method for ultrafiltration membrane:

Advantages: High thermal and chemical stability

Imported raw materials ensure high quality

No dead corner design, less prone to pollution

Easy replacement of membrane components

Various specifications of membrane components are available for selection

The filling density of the membrane core is high, and the cost per unit membrane area is low

Application: Clarification and concentration of fermentation broth in the pharmaceutical and biochemical industries

Concentration of Whey protein, gelatin, Carrageenan, Chondroitin sulfate

Pretreatment of industrial water and purification and sterilization of pure and drinking water

Preparation of medical sterile water and injection water

Separation and Purification of Traditional Chinese Medicine Extracts

Refining of low alcohol Baijiu, clarification and filtration of wine

Oil-water separation

Strong acid and alkali solution

After a long period of operation, the ultrafiltration membrane gradually forms a gel layer and a pollutant deposition layer under the influence of concentration polarization, and is slowly compacted under the effect of pressure difference, so that the fluid resistance increases significantly and the permeable flux drops sharply. If the flux cannot be recovered by physical methods, chemical cleaning agents must be used for cleaning.

However, when cleaning the membrane, two points should be noted: firstly, the composition and nature of pollutants must be clarified in advance. Only in this way can effective cleaning methods be adopted. Secondly, if it is possible to rinse with clean water, it should be done as much as possible. Chemical cleaning methods should only be considered when rinsing with clean water cannot achieve the desired effect. For this purpose, the cleaning of ultrafiltration membranes can be divided into two methods: physical cleaning and chemical cleaning.

Physical cleaning method

The commonly used method in this regard is hydraulic flushing. It can also be divided into reverse flushing, back flushing, and positive flushing depending on the direction of hydraulic flushing.

Reverse flushing

Wash the impurities inside the membrane and at the inlet end face with raw water.

Backwash

The pollutants on the membrane block surface are washed loose and peeled off with ultrafiltration water, and discharged from the water inlet and concentration port respectively (acid, alkali or Sodium hypochlorite and other drugs can be added to enhance the cleaning effect).

Washing and rinsing

Wash the impurities inside and on the end face of the membrane with raw water, and clean the ultrafiltration membrane according to its operating state.

Chemical cleaning method

According to the types of pollutants on the membrane surface, appropriate chemicals are selected to dissolve, oxidize, or undergo other chemical reactions to achieve the purpose of removal. The selection of commonly used chemicals must be based on the properties of membrane materials, such as acids, alkalis, oxidants, fungicides, surfactants, and enzyme added detergents. The method is the same as the normal ultrafiltration process. The cleaning solution enters from the inlet of the original solution, and the concentrated solution and ultrafiltration solution are all returned to the cleaning solution container. After circulation, they are discharged and washed with clean water.

Acid cleaning agents commonly used include 0.1N hydrochloric acid solution, 0.1M oxalic acid solution, 1-3% citric acid, citrate amine, EDTA, etc. This kind of cleaning agent is more effective in removing calcium ions, magnesium ions, fluoride ions and other metal ions and their hydroxides, and inorganic salt gel layer.

Alkaline cleaning agents mainly consist of 0.1~0.5% NaOH aqueous solution. It has good effects on removing protein and oil pollution.

Oxidative cleaning agents, such as 1~1.5% hydrogen peroxide, 0.5~1% NaOCl, 0.05~0.1% sodium Hydrazoic acid, have a significant effect on the removal of organic matter pollution.

Biological enzyme preparations, such as 1% Pepsin and trypsin, are effective in removing protein, polysaccharide and oil pollution. It also has a certain effect on removing organic pollution. When using enzyme cleaning agents, it is better to clean at 55-60 ℃. The length of cleaning time is related to the concentration of enzymes.

Although it is necessary to use chemical cleaning methods for ultrafiltration membranes under specific conditions, caution must be exercised when using them. To avoid chemical cleaning agents damaging the separation performance of the membrane; It is not allowed to deform pollutants and aggravate membrane pollution; The colloidal properties of pollutants should not be disrupted, making them stiff and rigid. In the food and pharmaceutical industries, the residue of cleaning agents should not be allowed to affect product quality.

It is recommended to inspect the ultrafiltration membrane equipment once a month and also check the valve body for leaks. The UF ultrafiltration device checks the inlet water quality according to conventional requirements. Simultaneously detect the production water flow and operating pressure of the UF system.

The above is the "ultrafiltration membrane cleaning method" that Hongjie Water brings to everyone. I hope it can help you!

Shenzhen Hongjie Water Technology Co., Ltd. is an integrated high-tech enterprise specializing in product development, production, sales, engineering design, installation and commissioning, technical consultation, and sales of supporting materials in the field of industrial water treatment and drinking water treatment. Main products: design, manufacturing, installation, commissioning and maintenance of water treatment equipment such as pure water equipment, Ultrapure water equipment, reverse osmosis equipment, GMP purified water equipment, EDI deionized water equipment, domestic sewage equipment, industrial wastewater equipment, softened water equipment and reclaimed water reuse equipment.