CN105797603A

CN105797603A - Hydrophilic hollow fiber ultra-filtration membrane and preparation process thereof

Info

Publication number: CN105797603A
Application number: CN201610227301.7A
Authority: CN
Inventors: 张晓姮; 李剑
Original assignee: Emate(shanghai) Environmental Technology Inc
Current assignee: Emate(shanghai) Environmental Technology Inc
Priority date: 2016-04-13
Filing date: 2016-04-13
Publication date: 2016-07-27

Abstract

The invention discloses a hydrophilic hollow fiber ultra-filtration membrane and a preparation process thereof.The ultra-filtration membrane is prepared from, by mass, 32%-36% of polyvinylidene fluoride, 8%-12% of polysulfone, 45%-50% of organic solvent, 5%-7% of poly methacrylic and 2%-4% of inorganic modifier.The preparation process includes the steps that a gel phase conversion method is adopted, dried polyvinylidene fluoride and polysulfone are dissolved in the organic solvent, the inorganic modifier and poly methacrylic are added into the mixed solution, a uniform membrane casting solution is formed after stirring is completed, and then the solution is defoamed in a constant-temperature water bath; the defoamed mixed solution is fed into a spinning machine, extrusion is conducted through a spinning nozzle, hollow fibers are formed and stand, after part of the solvent in the fibers evaporates, the fibers are immersed in a water solution coagulating bath, the liquid fibers are solidified into solid hollow fibers, and the ultra-filtration membrane is obtained after surface treatment.The hydrophilic performance of the provided ultra-filtration membrane is greatly improved, meanwhile, the anti-contamination capacity is remarkably improved, and the membrane pore-forming rate is obviously increased.

Description

A kind of hydrophilic hollow fiber ultrafiltration membrane and preparation technology thereof

Technical field

The invention belongs to ultrafilter membrane field, be specifically related to a kind of hydrophilic hollow fiber ultrafiltration membrane and preparation technology thereof.

Background technology

Ultrafilter membrane is one of membrane separation technique of studying at present and being most widely used, it is with film pressure at both sides difference as motive force, with ultrafilter membrane as medium, under pressure, the material that in trap water, colloid, bulky grain and molecular weight are of a relatively high, it is allowed to water and little particles of solute pass through the separation process of film.

The performance of ultrafilter membrane is mainly determined by the material of film, Kynoar (PVDF) is the novel polymeric membrane material that a kind of chemical stability is good, thermostability is strong, but its surface can be extremely low, hydrophobicity is the strongest, on the make need during hollow fiber film to add substantial amounts of water wetted material, make ultrafilter membrane have hydrophilic, through use after a while, surface hydrophilic material can fall off, and makes the flux of ultrafilter membrane decline.Polysulfones is the filming polymer of a class excellent performance, has good chemical stability, resistance to water, thermostability, and good film property and mechanical strength, it is widely used in the preparation of ultrafilter membrane, but its price comparison is high, and average price per ton is at 12～180,000 yuan, and use cost is prohibitively expensive.At present, lack a kind of cheap, and the ultrafiltration membrane material that strainability is superior.

Summary of the invention

To be solved by this invention is that existing ultrafiltration membrane material is because using Vingon so that it is ultrafiltration membrane surface can be low, and after adding water wetted material, water wetted material is easy to fall off, the problem making ultrafiltration flux depression.

In order to solve the problems referred to above, the invention provides a kind of hydrophilic hollow fiber ultrafiltration membrane, it is characterized in that, it is made up of following raw material by percentage to the quality: Kynoar (PVDF) 32%-36%, polysulfones (PS) 8%-12%, organic solvent 45%-50%, polymethyl (PMMA) 5%-7%, and inorganic modifier 2%-4%.

Preferably, described organic solvent is N,N-dimethylacetamide (DMAC).

Preferably, described inorganic modifier is SiO₂。

Present invention also offers the preparation technology of above-mentioned hydrophilic hollow fiber ultrafiltration membrane, it is characterised in that use gel phase conversion method, specifically comprise the following steps that

Step 1): dried Kynoar and polysulfones are dissolved in organic solvent, mixes to be completely dissolved；

Step 2): adding inorganic modifier and polymethyl in mixed liquor, stirring is to being completely dissolved；

Step 3): form uniform casting solution, then water bath with thermostatic control deaeration at 25 ± 2 DEG C after using magnetic stirrer at 30 ± 2 DEG C；

Step 4): sent in spinning-drawing machine by the mixed liquor after deaeration, be extruded into hollow form fiber with spinning head, stands, and after fiber middles divides solvent evaporation, immerses aqueous coagulation bath, and liquid fibre solidification becomes the doughnut of solid-state, and surface treated forms ultrafilter membrane.

Preferably, in described step 3), the mixing time of magnetic stirring apparatus is 4h, and inclined heated plate is 24h.

Preferably, the external diameter of the doughnut in described step 4) is 0.85mm, and internal diameter is 0.5mm.

Preferably, the rejection of described ultrafilter membrane is 94%-96%, and membrane flux is 90-96L/(m²H).

The invention provides a kind of hydrophilicity good, rejection and membrane flux are high, chemical stability is good and the hydrophilic hollow fiber ultrafiltration membrane of advantage of lower cost, compared with prior art, ultrafilter membrane hydrophilicity provided by the present invention is greatly promoted, contamination resistance is obviously enhanced simultaneously, and film becomes porosity the most substantially to increase.

Detailed description of the invention

For making the present invention become apparent, hereby with preferred embodiment, it is described in detail below.

Embodiment 1

Composition of raw materials: (table 1)

Table 1

Component	Mass percent
		Kynoar	36%
Polysulfones	8%
		DMAC N,N' dimethyl acetamide	45%
Polymethyl	7%
		Nano-meter SiO_2₂	4%

Embodiment 2

Composition of raw materials: (table 2)

Table 2

Component	Mass percent
		Kynoar	34%
Polysulfones	12%
		DMAC N,N' dimethyl acetamide	45%
Polymethyl	7%
		Nano-meter SiO_2₂	2%

Embodiment 3

Composition of raw materials: (table 3)

Table 3

Component	Mass percent
		Kynoar	32%
Polysulfones	10%
		DMAC N,N' dimethyl acetamide	50%
Polymethyl	6%
		Nano-meter SiO_2₂	2%

Comparative example

Composition of raw materials: (table 4)

Table 4

Component	Mass percent
		Kynoar	36%
DMAC N,N' dimethyl acetamide	50%
		Polymethacrylates	6%

According to table 1-4 each constituent mass mark, using gel phase conversion method, prepare the composite modified ultrafilter membrane of different formulations, concrete preparation method is as follows:

(1) dried PVDF and polysulfones are dissolved in organic solvent N,N-dimethylacetamide, mix to be completely dissolved；

(2) adding inorganic modifier nanosized SiO_2 and polymethyl in mixed liquor, stirring is to being completely dissolved；

(3) magnetic stirrer 4h is used to form uniform casting solution, then water bath with thermostatic control 24h deaeration at 25 DEG C at 30 DEG C；

(4) mixed liquor after deaeration is sent in spinning-drawing machine, be extruded into hollow form fiber with spinning head, stand, after fiber middles divides solvent evaporation, immersing aqueous coagulation bath, liquid fibre solidification becomes the external diameter of solid-state to be 0.85mm, internal diameter is 0.5mm doughnut, and surface treated forms ultrafilter membrane.

Ultrafilter membrane performance prepared by embodiment 1-3 is with the contrast of non-modified ultrafilter membrane performance indications as shown in table 5.

Table 5

Performance indications	Rejection (%)	Water flux L/ (m²·h)
			Embodiment 1	96.02	96
Embodiment 2	94.35	95
			Embodiment 3	94.13	90
Unmodified ultrafiltration	89.02	75

Seeing from table 5, the rejection of embodiment 1 and water flux, compared with the height of embodiment 2 with embodiment 3, illustrate inorganic modifier Nano-meter SiO_2₂Ultrafilter membrane hydrophilicity and rejection can be obviously improved；The water flux of embodiment 2 relatively embodiment 3 is relatively big, illustrates that ultrafilter membrane hydrophilic improves along with polysulfones proportion increases.

Claims

1. a hydrophilic hollow fiber ultrafiltration membrane, it is characterised in that by following raw material system by percentage to the quality Become: Kynoar 32%-36%, polysulfones 8%-12%, organic solvent 45%-50%, polymethyl 5%-7%, And inorganic modifier 2%-4%.

2. hydrophilic hollow fiber ultrafiltration membrane as claimed in claim 1, it is characterised in that described organic solvent For N,N-dimethylacetamide.

3. hydrophilic hollow fiber ultrafiltration membrane as claimed in claim 1, it is characterised in that described inorganic modifier For SiO₂。

4. a preparation technology for the hydrophilic hollow fiber ultrafiltration membrane described in claim 1-3 any one, its feature It is, uses gel phase conversion method, specifically comprise the following steps that

Step 1): dried Kynoar and polysulfones are dissolved in organic solvent, mix to completely Dissolve；

Step 3): form uniform casting solution after using magnetic stirrer at 30 ± 2 DEG C, then exist Water bath with thermostatic control deaeration at 25 ± 2 DEG C；

Step 4): the mixed liquor after deaeration is sent in spinning-drawing machine, is extruded into hollow form fiber with spinning head, Standing, after fiber middles divides solvent evaporation, immerse aqueous coagulation bath, liquid fibre solidification becomes the hollow of solid-state Fiber, surface treated forms ultrafilter membrane.

5. the preparation technology of described hydrophilic hollow fiber ultrafiltration membrane as claimed in claim 4, it is characterised in that Described step 3) in the mixing time of magnetic stirring apparatus be 4h, inclined heated plate is 24h.

6. the preparation technology of described hydrophilic hollow fiber ultrafiltration membrane as claimed in claim 4, it is characterised in that Described step 4) in the external diameter of doughnut be 0.85mm, internal diameter is 0.5mm.

7. the preparation technology of described hydrophilic hollow fiber ultrafiltration membrane as claimed in claim 4, it is characterised in that The rejection of described ultrafilter membrane is 94%-96%, and membrane flux is 90-96L/ (m²·h)。