阅读说明：本技术 一种聚酰胺复合反渗透膜的制备方法、反渗透膜及其应用 (Preparation method of polyamide composite reverse osmosis membrane, reverse osmosis membrane and application of reverse osmosis membrane ) 是由 刘相宝 沈慧芳 唐文勇 倪凡 赵伟国 孙家宽 于 2020-04-27 设计创作，主要内容包括：本发明提供了一种聚酰胺复合反渗透膜的制备方法、反渗透膜及其应用,上述反渗透膜的制备方法包括以下步骤：a、将聚砜溶于N,N-二甲基甲酰胺中得到铸膜液,将铸膜液均匀刮涂在聚酯无纺布上,在水中固化成型,得到聚砜支撑层；b、将间苯二胺、叶绿酸盐溶于去离子水中配制成水相溶液；将均苯三甲酰氯溶于烷烃溶剂中配制成有机相溶液；c、将聚砜支撑层与水相溶液接触后去除多余水相,然后与有机相溶液接触,经界面聚合形成聚酰胺复合反渗透膜。本发明方法制备得到的反渗透膜具有较高的渗透通量及抗微生物污染性能。(The invention provides a preparation method of a polyamide composite reverse osmosis membrane, the reverse osmosis membrane and application thereof, wherein the preparation method of the reverse osmosis membrane comprises the following steps: a. dissolving polysulfone in N, N-dimethylformamide to obtain a membrane casting solution, uniformly scraping the membrane casting solution on a polyester non-woven fabric, and curing and forming in water to obtain a polysulfone supporting layer; b. dissolving m-phenylenediamine and chlorophyllin in deionized water to prepare an aqueous solution; dissolving trimesoyl chloride in an alkane solvent to prepare an organic phase solution; c. and (3) contacting the polysulfone support layer with a water phase solution, removing the redundant water phase, contacting with an organic phase solution, and carrying out interfacial polymerization to form the polyamide composite reverse osmosis membrane. The reverse osmosis membrane prepared by the method has higher permeation flux and antimicrobial pollution performance.)

1. The preparation method of the polyamide composite reverse osmosis membrane is characterized by comprising the following steps of:

a. dissolving polysulfone in N, N-dimethylformamide to obtain a membrane casting solution, uniformly scraping the membrane casting solution on a polyester non-woven fabric, and curing and forming in water to obtain a polysulfone supporting layer;

b. dissolving m-phenylenediamine and chlorophyllin in deionized water to prepare an aqueous solution; dissolving trimesoyl chloride in an alkane solvent to prepare an organic phase solution;

c. and (3) contacting the polysulfone support layer with a water phase solution, removing the redundant water phase, contacting with an organic phase solution, and carrying out interfacial polymerization to form the polyamide composite reverse osmosis membrane.

2. The method for preparing a polyamide composite reverse osmosis membrane according to claim 1, wherein the chlorophyllin is one or more of iron sodium chlorophyllin, copper sodium chlorophyllin, zinc sodium chlorophyllin, and pheophorbide A.

3. The method for producing a polyamide composite reverse osmosis membrane according to claim 1 or 2, characterized in that the alkane solvent is one or more of n-decane, heptane, n-hexane, cyclohexane, octane, isopar G and isopar L, and further preferably n-decane.

4. The preparation method of the polyamide composite reverse osmosis membrane according to claim 1, characterized in that 15-17 wt% of polysulfone is solid contained in the membrane casting solution, the curing and forming time in water is 5-60 s, preferably 10-30 s, and the thickness of the polysulfone support layer is 20-70 um, preferably 30-50 um.

5. The method for preparing a polyamide composite reverse osmosis membrane according to claim 1, wherein the aqueous solution contains m-phenylenediamine in an amount of 1 to 10 wt%, preferably 1 to 6 wt%, and chlorophyllin in an amount of 0.01 to 10 wt%, preferably 0.5 to 4 wt%.

6. The method for preparing a polyamide composite reverse osmosis membrane according to claim 5, wherein the organic phase solution contains trimesoyl chloride in an amount of 0.05 to 1 wt%, preferably 0.1 to 0.4 wt%.

7. The method for preparing a polyamide composite reverse osmosis membrane according to any one of claims 1 to 6, wherein the contact time of the polysulfone support layer and the aqueous solution is 0.1 to 10min, preferably 0.5 to 4 min; the temperature of the interfacial polymerization reaction is 20-50 ℃, preferably 25-40 ℃, and the reaction time is 0.1-6 min, preferably 0.5-2 min.

8. The preparation method of the polyamide composite reverse osmosis membrane according to claim 1, wherein the polyamide composite reverse osmosis membrane formed by interfacial polymerization is dried at 50-120 ℃, preferably at 60-90 ℃ for 1-10 min, preferably 3-8 min, and then washed with deionized water.

9. A polyamide composite reverse osmosis membrane prepared according to the method of claims 1-8.

10. A polyamide composite reverse osmosis membrane prepared by the method of claims 1-8 or a reverse osmosis membrane according to claim 9, which is used in the field of industrial brackish water desalination.

Technical Field

The invention relates to a reverse osmosis membrane, in particular to a preparation method of a polyamide composite reverse osmosis membrane, the reverse osmosis membrane and application thereof.

Background

The reverse osmosis membrane is used as the core of the reverse osmosis technology, determines the quality of produced water of a reverse osmosis system and plays an important role in system operation. In the actual industrial application process, a large amount of microorganisms exist in reverse osmosis inlet water, secretions of the microorganisms have high viscosity and are easily adsorbed on the surface of a membrane, the growth and reproduction rate of the microorganisms is high, and residual microorganisms can grow at an astonishing speed even if the microorganisms are cleaned by a chemical method, so that irreversible pollution of the reverse osmosis membrane is finally caused, the attenuation degree of selective permeability of the reverse osmosis membrane cannot be recovered, the water yield of a system is reduced, and the energy consumption is increased. Therefore, how to improve the anti-microbial pollution performance of the reverse osmosis membrane is the key point for reducing the energy consumption of the system.

The published literature relates to the following methods for improving the antibacterial ability of reverse osmosis membranes:

yang et al (Chemistry of Materials,2011,23(5): 1263-; wei et al (Journal of Membrane Science,2010,346(1): 152-) -162) graft a hydantoin derivative MDMH onto the surface of a reverse osmosis Membrane, and the halide amine compound formed after chlorination endows the Membrane with extremely strong antibacterial ability; in patent CN105561814B, attapulgite modified by chitosan quaternary ammonium salt is grafted on the surface of a reverse osmosis membrane, so that the antibacterial performance of the reverse osmosis membrane is improved; in patent CN102580579A, a polymer containing hydroxyl nano bactericidal particles is coated on the surface of a reverse osmosis membrane after high-temperature treatment, so that the antibacterial performance of the reverse osmosis membrane is improved; in patent CN101874989A, the surface of the reverse osmosis membrane is coated with a layer of nano inorganic antibacterial particles, so that the microbial pollution resistance of the reverse osmosis membrane is improved.

Although some technical solutions for preparing antibacterial reverse osmosis membranes have been formed in the prior art, most of membrane preparation methods are to prepare nascent reverse osmosis membranes first, and then graft substances with antibacterial properties on the membrane surface by a chemical grafting method or coat some antibacterial substances on the membrane surface to endow the reverse osmosis membranes with certain antibacterial properties, which is generally complicated and difficult to implement in industrial production, so that further attempts and optimization are still needed in the technology of preparing antibacterial reverse osmosis membranes.

Disclosure of Invention

The invention provides a preparation method of a polyamide composite reverse osmosis membrane, a reverse osmosis membrane and application thereof. The reverse osmosis membrane polyamide separation layer prepared by the method contains chlorophyllin, and abundant carboxyl of the chlorophyllin can react with m-phenylenediamine and trimesoyl chloride respectively, so that the crosslinking degree of the polyamide separation layer is reduced, the polyamide separation layer has larger aperture and higher free volume through a self flexible molecular chain, and the permeation flux is improved; more importantly, the metal ions rich in the chlorophyllin endows the reverse osmosis membrane with stronger antibacterial activity, improves the antibacterial performance after long-term use, and is beneficial to maintaining high permeation flux.

A preparation method of a polyamide composite reverse osmosis membrane comprises the following steps:

a. dissolving polysulfone in N, N-dimethylformamide to obtain a membrane casting solution, uniformly scraping the membrane casting solution on a polyester non-woven fabric, and curing and forming in water to obtain a polysulfone supporting layer;

b. dissolving m-phenylenediamine and chlorophyllin in deionized water to prepare an aqueous solution; dissolving trimesoyl chloride in an alkane solvent to prepare an organic phase solution;

c. and (3) contacting the polysulfone support layer with a water phase solution, removing the redundant water phase, contacting with an organic phase solution, and carrying out interfacial polymerization to form the polyamide composite reverse osmosis membrane.

Further, the chlorophyllin is one or more of sodium salt of chlorophyllin iron, sodium salt of copper chlorophyllin, sodium salt of zinc chlorophyllin and pheophorbide A.

Further, the alkane solvent is one or more of n-decane, heptane, n-hexane, cyclohexane, octane, isopar G and isopar L, and n-decane is further preferable.

Further, 15-17 wt% of polysulfone is solid-contained in the membrane casting solution, the curing and forming time in water is 5-60 s, preferably 10-30 s, and the thickness of the polysulfone supporting layer is 20-70 um, preferably 30-50 um.

Further, in the aqueous phase solution, the content of m-phenylenediamine is 1 to 10 wt%, preferably 1 to 6 wt%, and the content of chlorophyllin salt is 0.01 to 10 wt%, preferably 0.5 to 4 wt%.

Further, the content of trimesoyl chloride in the organic phase solution is 0.05-1 wt%, preferably 0.1-0.4 wt%.

Further, the contact time of the polysulfone support layer and the aqueous phase solution is 0.1-10 min, preferably 0.5-4 min, the temperature of interfacial polymerization is 20-50 ℃, preferably 25-40 ℃, and the reaction time is 0.1-6 min, preferably 0.5-2 min.

Further, the polyamide composite reverse osmosis membrane formed by interfacial polymerization is dried for 1-10 min, preferably 3-8 min at 50-120 ℃, preferably 60-90 ℃, and then is washed by deionized water to remove residual solvent.

The invention also provides the polyamide composite reverse osmosis membrane prepared by the method.

The polyamide composite reverse osmosis membrane prepared by the method is applied to the field of industrial brackish water desalination.

The reverse osmosis membrane prepared by the method has the following beneficial effects:

1) the reverse osmosis membrane provided by the invention is simple in preparation method, and excellent antimicrobial pollution performance can be obtained without post-treatment on the reverse osmosis membrane;

2) the reverse osmosis membrane provided by the invention has excellent antimicrobial pollution resistance and can maintain higher permeation flux: under the condition that the pressure is 1.55Mpa in the bitter test recognized in the industry, 2000ppm of sodium chloride is filtered, and the water flux reaches 60-80L/(m)²H), the desalination rate of sodium chloride reaches more than 99.3 percent, and the requirement of industrial brackish water desalination is met.

Detailed Description

The present invention is further illustrated by the following specific examples, which are intended to be illustrative of the invention and are not to be construed as limiting the scope of the invention.

The main raw material sources used in the examples of the present invention and the comparative examples are shown in table 1:

TABLE 1 sources of raw materials

Name of raw materials	Specification and model	Manufacturer of the product
			Polysulfone	P3500 LCD MB7	Solvay Corp
N, N-dimethylformamide	The purity is 99.9 percent	Hualu constancy
			Polyester non-woven fabric	Sanmu 74	Mitsubishi paper company
M-phenylenediamine	The purity is 99.9 percent	Shanghai Oako Chemicals Ltd
			Trimesoyl chloride	The purity is 99.9 percent	Qingdao Sanli bennuo New Material Co.,Ltd.
Chlorophyllin iron sodium salt	Purity of 99%	Wuhan Wanrong science and technology development Limited
			Chlorophyllin copper sodium salt	Purity of 99%	Wuhan Wanrong science and technology development Limited
Chlorophyllin zinc sodium salt	Purity of 99%	Wuhan Wanrong science and technology development Limited
			Pheophorbide A	Purity of 99%	Wuhan Wanrong science and technology development Limited

Other starting materials or reagents are commercially available unless otherwise specified.

Performance evaluation parameters:

the osmotic flux is the volume of water flowing through the unit membrane surface per unit time and is expressed as L/(m)²·h)；

② the salt rejection is the concentration (C) of sodium chloride intercepted by reverse osmosis membrane_P) With the concentration (C) of sodium chloride in the raw material liquid_f) The ratio of (A) to (B):

controlling the concentration of sodium chloride in the feed water raw material solution to be 2000ppm, the pH of the solution to be 7 and the operating pressure to be 1.55 Mpa;

thirdly, evaluating the antimicrobial pollution performance of the reverse osmosis membrane by adopting a bacterial liquid oscillation method: cutting a reverse osmosis membrane into fragments of 10mm multiplied by 10mm by taking escherichia coli and staphylococcus aureus as microorganisms, putting the fragments into a wide-mouth bottle, and pouring 5mL of diluted bacterial liquid and 70mL of 0.03mol/L PBS solution. Another set of samples containing only the bacterial solution and PBS solution without any membrane sample was used as a blank control. And closing the opening of the wide-mouth bottle, and oscillating at 25 ℃ to ensure that the membrane sample is fully contacted with the bacterial liquid. After 24 hours, 100uL of the solution was sampled from the jar, diluted with PBS solution, and viable cell culture count was performed, and the bacteriostatic ratio (K) of the membrane sample was analyzed by comparing the bacterial solution concentration (No) of the blank control with the bacterial solution concentration (Nm) of the membrane sample:

[ example 1 ]

Dissolving polysulfone in N, N-dimethylformamide solution to prepare casting membrane solution (solid content is 17 wt%); uniformly coating the casting solution on a polyester non-woven fabric with the thickness of 90 mu m after vacuum defoaming, and curing in pure water at 25 ℃ for 30s to obtain a polysulfone supporting layer with the thickness of about 135-140 mu m;

immersing the polysulfone support layer in an aqueous solution at 25 ℃ for 30s, wherein the aqueous solution consists of 2.0 wt% of m-phenylenediamine and 0.02 wt% of chlorophyllin copper sodium salt. Taking out the polysulfone supporting layer, removing redundant aqueous phase solution on the surface of the polysulfone supporting layer by using a rubber roller, and then uniformly coating the organic phase solution on the surface of the polysulfone supporting layer, wherein the organic phase solution is 0.10 wt% of trimesoyl solution, the solvent is n-decane, the interfacial polymerization temperature is 35 ℃, and the interfacial polymerization reaction is 30 s; drying the reverse osmosis membrane for 3min by using a 60 ℃ blast drying oven, and finally washing by using deionized water.

[ examples 2 to 12 ]

A reverse osmosis membrane was prepared using the method of example 1, except for the raw material selection and parameter changes shown in table 2.

Comparative examples 1 to 4

A reverse osmosis membrane was prepared by the method of example 1 except that the aqueous solution contained no chlorophyllin and the feed parameters are as shown in table 2.

TABLE 2 control conditions of various parameters of examples and comparative examples

Detailed description of the preferred embodiments	M-phenylenediamine/wt%	Chlorophyllin/wt%	Trimesoyl chloride/wt.%
				Example 1	2.0	Chlorophyllin copper sodium salt, 0.02	0.10
Example 2	2.0	Iron sodium salt of chlorophyllin, 0.5	0.20
				Example 3	2.0	Chlorophyllin zinc sodium salt, 2.0	0.40
Example 4	2.0	Pheophorbide A, 4.0	0.60
				Example 5	4.0	Chlorophyllin copper sodium salt, 1.0	0.10
Example 6	4.0	Iron sodium salt of chlorophyllin, 1.5	0.16
				Example 7	4.0	Sodium salt of zinc chlorophyllin, 4.5	0.20
Example 8	6.0	Chlorophyllin copper sodium salt, 2.0	0.10
				Example 9	6.0	Iron sodium salt of chlorophyllin, 3.5	0.16
Example 10	6.0	Chlorophyllin zinc sodium salt, 6.5	0.20
				Example 11	7.0	Iron sodium salt of chlorophyllin, 5.0	0.05
Example 12	7.0	Chlorophyllin copper sodium salt, 7.5	0.10
				Comparative example 1	2.0	-	0.10
Comparative example 2	4.0	-	0.16
				Comparative example 3	6.0	-	0.10
Comparative example 4	7.0	-	0.05

The reverse osmosis membranes prepared in examples and comparative examples were tested for permeation flux, salt rejection and bacteriostatic ratio, and the test results are shown in table 3.

TABLE 3 test results of permeation flux, salt rejection and bacteriostasis

Detailed description of the preferred embodiments	Permeation flux/L/(m)2·h)	Rate of salt removal/%)	Inhibition rate/%)
				Example 1	67.45	99.38	80
Example 2	68.34	99.34	84
				Example 3	76.42	99.30	88
Example 4	65.43	99.31	87
				Example 5	60.45	99.40	88
Example 6	80.64	99.30	89
				Example 7	67.34	99.38	90
Example 8	60.56	99.35	88
				Example 9	61.43	99.45	89
Example 10	63.45	99.40	91
				Example 11	62.63	99.38	90
Example 12	60.43	99.31	93
				Comparative example 1	50.32	99.49	0
Comparative example 2	55.45	99.53	0
				Comparative example 3	42.72	99.52	0
Comparative example 4	40.23	99.55	0

As shown in the test results in Table 3, the reverse osmosis membrane prepared by adding the chlorophyllin to the polyamide separation layer has better anti-microbial pollution performance, and can maintain higher permeation flux and salt rejection rate.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and additions can be made without departing from the method of the present invention, and these modifications and additions should also be regarded as the protection scope of the present invention.