A highly hydrophilic and highly oleophobic membrane for oil-water separation

A hydrophilic and oleophobic technology, applied in separation methods, liquid separation, semi-permeable membrane separation, etc., can solve problems such as UF membrane membrane fouling

Inactive Publication Date: 2014-01-22
NAT UNIV OF SINGAPORE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

UF membranes have serious membrane fouling problems

Method used

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  • A highly hydrophilic and highly oleophobic membrane for oil-water separation
  • A highly hydrophilic and highly oleophobic membrane for oil-water separation
  • A highly hydrophilic and highly oleophobic membrane for oil-water separation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Embodiment 1: the preparation of functional polymer

[0052] Poly(vinylidene fluoride-co-chlorotrifluoroethylene) was dissolved in N-methyl-2-pyrpyrrolidone in an airtight flask purged with N2. The mixture was stirred at 200 to 1000 rpm and heated at 60 to 90 °C to obtain a homogeneous viscous polymer solution. The polymer concentration is 10 to 30% by weight.

[0053] CuCl (1 to 5% by weight) and pentamethyldiethylenetriamine (2 to 10% by weight) were added to the above solution, followed by tert-butyl acrylate (10 to 15% by weight).

[0054] The resulting mixture was heated at 50 to 90°C for 0.5 to 4 hours. After cooling, the mixture was poured into water to precipitate the grafted product containing polyacrylate side chains, which was washed with water.

[0055] The grafted product (1 to 10 g) was stirred in toluene p-toluenesulfonate solution (100 mL, 10 to 30% by weight) at 80 to 95° C. for 4 to 8 hours. After cooling, the acidic solution was poured into water,...

Embodiment 2

[0057] Embodiment 2: the preparation of polymer blend solution

[0058] In a sealed container heated to 70 to 100° C., PVDF and the functional polymer prepared in Example 1 were added to dimethylformamide (10 to 30% by weight combination, PVDF:functional polymer=7:3) . The mixture was stirred at 400 to 1000 rpm for 1 to 5 hours and cooled to ambient temperature to obtain a blended solution.

[0059] The blended solution was filtered through a 15 μm stainless steel filter in an airtight stainless steel doping vessel and pressurized by compressed nitrogen at 2 bar pressure.

[0060] The filtered blend solution was degassed by centrifuging the solution at 3000 to 8000 rpm for 5 to 10 minutes.

Embodiment 3

[0061] Embodiment 3: the making of hollow fiber membrane

[0062] Driven by compressed nitrogen, the blended solution of Example 2 was extruded into a water bath using a spinneret with a spinneret of 1.5 / 0.5 OD / ID to form a hollow fiber membrane. Simultaneously, a syringe pump supplies water to the fiber lumen through an annular ring inside the spinneret.

[0063] The air gap is 0.5 cm. The flow rate of the polymer blend solution was maintained at 4 mL / min with compressed nitrogen. Control the flow rate of water to 1 mL / min with a syringe pump. The solidification temperature is 60 to 80°C.

[0064] Finally, the hollow fiber membrane thus obtained was dried in air.

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Abstract

A polymeric membrane for separating oil from water has a pore size of 0.005 [mu]m to 5 [mu]m, a thickness of 50 [mu]m to 1,000 [mu]m, a water contact angle of 0 DEG C to 60 DEG C, an oil contact angle of 40 DEG C to 100 DEG C. The membrane contains a hydrophobic matrix polymer and a functional polymer that contains a hydrophobic backbone and side chains. The side chains each have an oleophobic terminal segment and a hydrophilic internal segment. The weight ratio of the matrix polymer to the functional polymer is 99:1 to 1:9. Also disclosed is a method of making the above described membrane.

Description

Background technique [0001] Polymer membranes can be used to separate dispersed or emulsified oils with droplet volumes less than 150 μm from water. [0002] For example, an ultrafiltration (UF) membrane with a pore size of 0.01-0.1 μm is used to treat oily industrial wastewater. See T. Bilstad and E. Espedal, Membrane Separation of Produced Water, Water Science and Technology 34(9), 239-246 (1996). UF membranes have serious membrane fouling problems. See T. Bilstad and E. Espedal (1996), S.M. Santos and M.R. Wiesner (1997). Membrane fouling occurs when oil deposits on the membrane surface or enters the pores of the membrane in a manner that degrades membrane performance. This is a major obstacle to the widespread use of UF in the treatment of oily wastewater. [0003] Fouling resistant membranes are needed to effectively and economically separate oil from water. Brief description of the invention [0004] The present invention is based on the unexpected discovery of hi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/34B01D71/78B01D71/82B01D61/18C08F259/08C08F214/22C08F214/26C08F214/28
CPCB01D69/087B01D71/32B01D71/34B01D71/40B01D71/78C08L27/16C02F1/40C02F1/444C02F2101/32B01D17/085C08L2205/02B01D71/82C08F259/08C08L51/003C08F220/1804B01D71/401
Inventor 白仁碧朱小萤
Owner NAT UNIV OF SINGAPORE
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