A nanofiltration membrane regeneration method

Abstract

The invention discloses a nanofiltration membrane regenerating method, relating to the field of viscose recovery. The method mainly comprises the steps of circularly cleaning demineralized water to adjust the demineralized water to be neutral, circularly cleaning an oxalic acid solution to remove hemicelluloses and impurities, and cleaning the demineralized water to adjust the demineralized water to be neutral again. By utilizing the washing-acid pickling-washing process, hemicelluloses accumulated in nanofiltration membrane holes can be effectively removed, divalent ions such as calcium, magnesium, ferrum and silicon form a complex to deposit the nanofiltration membrane subjected to secondary pollution in the cleaning process, so that the cleaned nanofiltration membrane achieves more than 93% of a rated value, and the regeneration of the nanofiltration membrane can be realized.

Description

technical field [0001] The invention relates to the field of viscose fiber recovery, in particular to a nanofiltration membrane regeneration method. Background technique [0002] Roll-type nanofiltration membrane: the pore size is above 1nm, generally 1-2nm. It is a functional semi-permeable membrane that allows solvent molecules or some low-molecular-weight solutes or low-priced ions to pass through. The molecular weight of its intercepted organic matter is about 150-500, and the ability to intercept soluble salts is between 2-98%. It has been widely used in pharmaceuticals, drinking water and sewage treatment, waste acid, waste alkali and other fields, and produces extreme great economic benefits. The original nanofiltration membrane regeneration process uses 60m 3 The / h material pump pumps desalted water at 50°C into the membrane equipment to wash out the impurities in the membrane layer and the half-fibers stuck inside. However, the interval between the membrane lay...

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Problems solved by technology

[0004] In the existing technical scheme of nanofiltration membrane regeneration, the traditional desalinated water cleaning is only to use the pressure provided by the pump to wash away the half fiber blocked in the membrane layer. However, the pressure provided by the material pump is 6bar, and the dead angle of the membrane layer or blockage The more serious fiber crystal blocks cannot be cleaned by the pressure of the pump, resulting in the final blockage of the membrane layer and the scrapping of the membrane core. Using alkaline cleaning solution and the principle that lye can dissolve hemicellulose, select the best alkali The optimal temperature makes the hemicellulose blocked in the membrane layer dissolve in the lye and take out the membrane layer, but this cleaning requires a lot of lye consumption, and the residual calcium, magnesium, iron, silicon in the nanofiltration membrane Divalent positive ions will form complex precipitation in alkaline solution, which is not conducive to removal

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