Organic filter membrane is F membrane, which mostly refers to PVDF (polyvinylidene fluoride filter membrane), nylon (polyamide) and PTFE (polytetrafluoroethylene filter membrane). When the filter membrane is at 25℃. According to the actual production, the ratio of filter membrane to solvent is 5000 times. After soaking in organic solvents such as alcohols, esters, ketones and 30% sodium hydroxide solution for 72 hours, no soluble substances enter the solution, which proves that the physicochemical properties of filter membrane are stable in organic solvents and strong alkaline solutions. Organic solvent-resistant reinforced nylon microporous filter amine is a kind of screen-type precision filter material resistant to various organic solvents, which is made of polymer under special process conditions. Besides all the advantages of ordinary nylon microporous filter membrane, it also has the advantages of good strength, wide amplitude and arbitrary length. It can separate, purify and enrich particles, foreign matter, flying dust and aerosol in liquid phase and gas phase, and is widely used in medical and health, biochemistry, microelectronics industry, environmental protection and other departments.
Microporous filter membrane is made of aliphatic nylon, which has good hydrophilicity and resistance to proper concentration of acid and alkali. It is not only suitable for aqueous solutions containing acid and alkali, but also suitable for organic solvents, such as alcohols, hydrocarbons, ethers, esters, ketones, benzene and benzene homologues, dimethylformamide, dimethyl sulfoxide, etc. It is one of the most widely used microfiltration membranes. The principle of aperture selection is the same as that of mixed fiber membrane, that is, nominal apertures of 0.65, 0.8 and 1.2 microns are used for particle removal and 0.45, 0.3 and 0.22 microns for sterilization. When there are many particles or bacteria in the filtrate, it must be pre-filtered, and the principle is the same as that of mixed fiber membrane. If filtered for a short period of time [several hours], this product is resistant to formic acid with a concentration of 20%, hydrochloric acid with a concentration of 30%HCL and other acids with the same acidity, and alkali with a concentration of 3% sodium hydroxide. However, long-term contact with acid and alkali with the above concentration will cause the nylon amide bond to break and make the membrane brittle, so it should only be used at the lower limit of acid and alkali with the above concentration. The lower the using temperature, it will not become brittle when meeting acid and alkali. Before use, it should be cleaned, soaked in distilled water and then put in a filter, while the organic solvent filter is soaked in ethanol for cleaning. For occasions with high requirements, for example, the filtration of chromatographic samples or reagents, if it is water system, it is washed with distilled water, and then pre-filtered with distilled water; if it is organic system, it is best to soak this product in pure toluene and more than 95% ethanol overnight, then pre-filter with pure toluene and pure ethanol, and then thoroughly clean the membrane before use. This product becomes brittle obviously after being immersed in water, and the intensity of organic solvent decreases slightly. Therefore, this product should be used with 60-100 mesh nylon net or metal net under the membrane, so that there is no danger of membrane breakage. There are two sides of this product, the one with strong light is the opposite side, the one with weak light is the positive side, and the aperture in the membrane gradually decreases from the front side to the opposite side. When in use, it should face the filtrate, that is, the filtrate flows in from the side with weak light, and the filtered solution flows out from the side with strong light. The particles to be intercepted are equivalent to being blocked by multi-layer filter membranes with large to small pore sizes, which can significantly prolong the service life. When using, the front and back sides should be recognized before membrane treatment (the light can be compared from the side of the membrane), and the front side will be difficult to distinguish after entering the water.
1. When selecting filter membrane, please first find out the minimum size of particles or bacteria to be trapped, and then select the membrane with required pore size according to the following table.
2. Nylon filter membrane can be sterilized by any of the following methods before use:
(1) steam sterilization at 121℃ for 30 minutes, and then soaking and wetting with ethanol.
(2) Sterilize with 2.5Mradr—-ray or ultraviolet radiation, and then soak in ethanol for wetting.
(3) 90% ethylene oxide+10% carbon dioxide, at a pressure of 1kg/cm2 and a dosage of 800g /m3, for 4 hours, and then soaked and wetted with ethanol.
(4) Soak in 3% methanolic solution for 24 hours, then wash with filtered distilled water with pore size of 0.45μm, and then soak and wet with ethanol. 3. Nylon filter membrane was soaked in 30% sodium hydroxide solution for 72 hours at 25℃ according to the ratio of filter membrane to solvent of 5,000 times in actual production, and the images of the solution before and after soaking were completely coincident by liquid chromatography, which showed that no dissolved substances entered the solution after soaking, and the physical and chemical properties of ZN filter membrane were stable in organic solvent and strong alkaline solution. 4. The product has strong electrostatic charge and can absorb dust in the air. When not in use, it should be wrapped and put in a dry and clean place.
High-quality nylon filter membrane is suitable for the filtration of aqueous solution and most organic solvents, and is also suitable for the preparation of many biological agents and other unusable situations. Nylon membrane is hydrophilic, and it does not need to be prewetted with extractable solvent when filtering aqueous solution. Moreover, it is flexible, durable, torn and can be autoclaved at 121℃. After soaking the filter membrane in the following chemical solution at room temperature for 72 hours, check that the appearance does not swell, dissolve, deform, destroy or deteriorate.
(1) Acids: 1% nitric acid, 1% sulfuric acid, 1% hydrochloric acid, 20% phosphoric acid, 25% acetic acid and 4- aminosalicylic acid.
(2) Alkalis: 50% sodium hydroxide, 75% potassium acetate and 25% ammonium hydroxide.
(3) Alcohols: methanol, ethanol, n-butanol, n-amyl alcohol, glycerol and dodecyl alcohol.
(4) Esters: methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, isopropyl myristate, methyl glycol acetate, diphenyl toluene phosphate, tricresyl phosphate,
(5) Ketones: acetone, cyclohexane, methyl hexanone, methyl isopropyl ketone and methyl propyl ketone.
(6) Hydrocarbons: pentane, hexane, benzene, toluene, kerosene, gasoline, decalin,
(7) Halogenated hydrocarbons: dichloromethane, dichloroethane, chloroform, carbon tetrachloride, trichloroethylene, perchlorethylene, benzene monochloride, benzene trichloride and carbon tetrachloride.
(8) Organic oxygen-containing compounds: yi ether, tetrahydrofuran, dioxane and 1,4- dioxane.
(9) Oils: peanut oil, castor oil and silicone oil.
(10) Others: aminopenicillin sodium solution, penicillin butyl acetate secondary extract, jet engine fuel, developer, developer diluent, photoresist, freon and 98% dimethylformamide.(1) Acids: 1% nitric acid, 1% sulfuric acid, 1% hydrochloric acid, 20% phosphoric acid, 25% acetic acid and 4- aminosalicylic acid.
(2) Alkalis: 50% sodium hydroxide, 75% potassium acetate and 25% ammonium hydroxide.
(3) Alcohols: methanol, ethanol, n-butanol, n-amyl alcohol, glycerol and dodecyl alcohol.
(4) Esters: methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, isopropyl myristate, methyl glycol acetate, diphenyl toluene phosphate, tricresyl phosphate,
(5) Ketones: acetone, cyclohexane, methyl hexanone, methyl isopropyl ketone and methyl propyl ketone.
(6) Hydrocarbons: pentane, hexane, benzene, toluene, kerosene, gasoline, decalin,
(7) Halogenated hydrocarbons: dichloromethane, dichloroethane, chloroform, carbon tetrachloride, trichloroethylene, perchlorethylene, benzene monochloride, benzene trichloride and carbon tetrachloride.
(8) Organic oxygen-containing compounds: yi ether, tetrahydrofuran, dioxane and 1,4- dioxane.
(9) Oils: peanut oil, castor oil and silicone oil.
(10) Others: aminopenicillin sodium solution, penicillin butyl acetate secondary extract, jet engine fuel, developer, developer diluent, photoresist, freon and 98% dimethylformamide.