The frequency of filter membrane cleaning is related to the perfection of pretreatment measures. The more complete the pretreatment measures, the longer the cleaning interval; conversely, the higher the cleaning frequency.
How to clean membrane filter?
1. The chemical cleaning cycle depends on the degree of membrane fouling. 2. The common cleaning liquid formula is as follows: Alkali washing solution: 0.1 ~ 0.5% NaOH solution. Acid pickling solution: 0.2% HCI or 1% citric acid solution (selected according to the actual situation). Oxidant solution: 500 ~ 1000mg / L (effective chlorine concentration) NaClO solution. 3. According to the instructions of the cleaning solution above, prepare the cleaning solution according to the proportion in the chemical cleaning box, and mix thoroughly to control the pH and temperature. 4. Reduce the liquid level in the membrane tank to the lowest level, or drain the water in the membrane tank. 5. In the way of backwash, the chemical cleaning solution penetrates the membrane from the inside of the hollow fiber under the pressure of the cleaning liquid pump and accumulates in the membrane tank until the membrane module is flooded. 6. Let the cleaning solution soak the membrane filaments in the membrane tank for 2 ~ 4 hours, while soaking, it can be aerated to enhance the cleaning effect. 7. First perform alkaline washing, then acid washing, and finally, wash with oxidant solution. 8. During the cleaning process, observe the pH change of the cleaning solution at any time and add an appropriate amount according to the change to achieve the pH value in the cleaning plan. When the pH value of the cleaning solution changes greatly and the cleaning solution is dirty, it should be shut down and replaced in time. 9. Increasing the temperature of the cleaning liquid can enhance the cleaning effect, and the temperature of the cleaning liquid must not exceed 40℃. 10. After each step of chemical cleaning, drain the chemical solution in the membrane tank and the medicine washing box, add pure water to the medicine washing box to clean or ultra-filter the produced water, turn on the washing pump, and perform a reverse washing of the system.
Generally, 2 ~ 3 times, until the cleaning solution and pollutants in the system are flushed out (the pH value of the cleaning solution is neutral).
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For instance, nylon membrane filter, polypropylene membrane filter is compatible with aqueous and alcoholic solutions and solvents; suitable for HPLC, with high protein binding capacity, including many specifications, 0.1um, 0.22um, 0.45um, 0.8um, 1.0um, 3.0um, 5.0um, and 10.0um.
There are also two different shapes, round, and square. Round one is indicated by its diameter. The diameters are: 13; 25; 47; 90; 142; 293mm. The rolling membrane is rectangular rolled together, expressed in width. The widths are: 254, 260; 270; 280; 310mm, with inner core: 22mm.
The nylon membrane material is aliphatic nylon, which has good hydrophilicity and resistance to appropriate concentrations of acids and bases. It is not only suitable for aqueous solutions containing acid and alkali, but also for organic solvents, for instance, esters, ketones, benzene and benzene homologs, dimethylformamide, dimethylsulfoxide, etc., which is one of the most widely used microporous membranes. (Belongs to a terminal filtration membrane).