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Preparation method of polyvinylidene fluoride ultramicro-filtration dry membrane for flat-plate MBR (membrane bioreactor)

A polyvinylidene fluoride, flat-plate technology, applied in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve the problems of filtration failure, membrane structure damage, membrane texture becoming brittle, etc. good mechanical strength and high water yield

Inactive Publication Date: 2012-08-01
广西森淼环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Wet method of the membrane: the most important point is to keep the membrane in a wet state all the time. If the wet membrane is not stored in a good environment, it will shrink and deform due to dehydration, which will greatly reduce the membrane pores or cause the membrane structure to be damaged. At the same time, the texture of the membrane becomes brittle, and even the filtration effect of the membrane is completely invalid.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] 24wt% polyvinylidene fluoride (intrinsic viscosity 2.2dl / g), 70wt% N,N-dimethylacetamide, 2wt% polyethylene glycol (molecular weight 2000), 1wt% ethylene glycol , 0.5wt% Tween-80, and 2.5wt% vinyl chloride vinyl acetate vinyl alcohol copolymer were stirred, dissolved and mixed evenly at a temperature of 90°C to obtain a casting solution, and the resulting casting solution was filtered and vacuum removed After foaming, apply it to polyester non-woven fabric to form a layer of coating film. The thickness of the coating film is controlled at 0.12mm, and the coating speed is 2.0m / min. After the coating film stays in the air for 40s, it is immersed in Component is 30 minutes in the primary coagulation bath of 30wt% glycerol aqueous solution, the temperature of described primary coagulation bath is controlled at 5 ℃, then continuously immersed in the secondary coagulation bath that component is 7wt% sodium chloride aqueous solution for 2 hours , the temperature of the seconda...

Embodiment 2

[0036]19wt% polyvinylidene fluoride (intrinsic viscosity: 3.0dl / g), 54wt% N,N-dimethylformamide, 17wt% N,N-dimethylacetamide, 5wt% polyethylene glycol Alcohol (molecular weight 600), 0.7wt% polyvinylpyrrolidone (average molecular weight distribution 25000-40000), 0.5wt% acetone, 2.8wt% glycerin, 1wt% polystyrene-butyl acrylate at a temperature of 105 Stir, dissolve and mix uniformly under the condition of ℃ to prepare the casting solution. After the obtained casting solution is filtered and vacuum degassed, the casting solution is coated on the polyester non-woven fabric to form a layer of coating film. The thickness of the coating film is Controlled at 0.10mm, the coating speed is 4.5m / min, after the coating film stays in the air for 5s, it is immersed in a primary coagulation bath composed of 20wt% glycerin, 20wt% ethylene glycol and 60wt% water for 15 minutes , the temperature of the first-stage coagulation bath is controlled at 0°C, and then continuously immersed in the se...

Embodiment 3

[0038] 15wt% polyvinylidene fluoride (intrinsic viscosity: 3.8dl / g), 75wt% N,N-dimethylacetamide, 6wt% polyethylene glycol (molecular weight: 400), 1wt% oxalic acid, 0.5 Wt% polyvinylpyrrolidone (molecular weight distribution: 160000-200000), 2.5wt% vinyl chloride vinyl acetate vinyl alcohol copolymer was stirred and dissolved at 110°C to prepare the casting solution, and the obtained casting solution was filtered After vacuum defoaming, the casting solution is applied to the polyester non-woven fabric to form a coating film, the thickness of the coating film is controlled at 0.11mm, and the coating speed is 1.2m / min. After staying in the air for 120s, immerse in the first-level coagulation bath whose composition is 60wt% glycerol aqueous solution for 20 minutes. The temperature of the first-order coagulation bath is 0° C. 1.5 hours in the coagulation bath, the temperature of the second coagulation bath is 25 ℃, and then immersed in the third coagulation bath with water compos...

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PUM

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Abstract

The invention relates to a preparation method of a polyvinylidene fluoride ultramicro-filtration dry membrane for a flat-plate MBR (membrane bioreactor). According to the preparation method, based on the principle combining non-solvent phase inversion with solvent phase inversion, membrane casting liquid is prepared from polyvinylidene fluoride, a solvent, a pore-forming agent and a specific copolymer; after being filtered and defoamed in vacuum, the prepared membrane casting liquid is salivated onto a non-woven fabric support and is prepared into a membrane through three-stage coagulating bath, then the membrane is shaped and the solvent is replaced out of the formed member; then the shaped member enters dry membrane processing liquid continuously and then is dried in a membrane drying system. The prepared dry membrane has pore size from 0.06mu m to 1.5 mu m and porosity from 70%-88% and has good hydrophilia and water permeability. The prepared dry membrane can be used as a flat-plate filtration membrane of an MBR; fed water is municipal sewage, water production yield is 0.4-0.8 m<3> / m<2>.d under the conditions that the pumping negative pressure is 10 Kpa and the temperature is 10 DEG C. in addition, the preparation method can be used for continuous production and the prepared membranes are dry membranes which are preserved and stored conveniently.

Description

technical field [0001] The invention relates to a preparation method of an ultramicrofiltration dry film, in particular to a preparation method of a polyvinylidene fluoride ultramicrofiltration dry film used in a flat MBR. Background technique [0002] MBR (Membrane Bioreactor) technology, as one of the 21st century sewage treatment technologies promoted by the state, has gradually transitioned from laboratory research to practical engineering application in my country. It is an ultra-microfiltration membrane in membrane separation technology. A treatment system formed by combining components with bioreactors in sewage biological treatment. Due to the high-efficiency separation of the membrane, MBR has many outstanding advantages that many traditional biological treatment processes do not have: excellent and stable effluent quality, direct reuse, high volume load, small footprint, compact entire system process, and surplus sludge output Less, easy to operate and manage. The...

Claims

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Application Information

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IPC IPC(8): B01D71/34B01D69/06B01D67/00C02F3/00
Inventor 谢炳玉秦国凤唐智波
Owner 广西森淼环保科技有限公司