High Temperature-Resistant Composite Nanofiltration Membrane And Preparation Method Thereof

Abstract

Provided are a high temperature-resistant composite nanofiltration membrane and a preparation method thereof. The high temperature-resistant composite nanofiltration membrane includes a base membrane and a polyamide membrane arranged on the base membrane; wherein the polyamide membrane is prepared from raw materials comprising: an amine, an inorganic salt, a silane additive, a polyacyl chloride, and an oil phase solvent; and the silane additive is at least one selected from the group consisting of 3-aminopropyltriethoxysilane, divinyltriaminopropyltrimethoxysilane, N-cyclohexyl-?-aminopropyltrimethoxysilane, and trimethoxy[3-(phenylamino)propyl]silane.

Claims

1. A high temperature-resistant composite nanofiltration membrane, comprising a base membrane and a polyamide membrane arranged on the base membrane; wherein the polyamide membrane is prepared from raw materials comprising: an amine, an inorganic salt, a silane additive, a polyacyl chloride, and an oil phase solvent; and the silane additive comprises at least one selected from the group consisting of 3-aminopropyltriethoxysilane, divinyltriaminopropyltrimethoxysilane, N-cyclohexyl-?-aminopropyltrimethoxysilane, and trimethoxy[3-(phenylamino)propyl]silane.

2. The high temperature-resistant composite nanofiltration membrane according to claim 1, wherein the inorganic salt comprises at least one selected from the group consisting of sodium chloride, calcium chloride, calcium bromide, and lithium chloride.

3. The high temperature-resistant composite nanofiltration membrane according to claim 2, wherein the amine comprises at least one selected from the group consisting of piperazine, 1,6-hexanediamine, 1,4-diaminocyclohexane, and m-phenylenediamine.

4. The high temperature-resistant composite nanofiltration membrane according to claim 3, wherein the polyacyl chloride comprises at least one selected from the group consisting of trimesoyl chloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, 4,4-biphenyldicarbonyl chloride, succinyl chloride, glutaryl dichloride, adipoyl chloride, and cyclohexyl-1,4-dicarboxylchloride.

5. The high temperature-resistant composite nanofiltration membrane according to claim 1, wherein the oil phase solvent comprises at least one selected from the group consisting of n-hexane, cyclohexane, and heptane.

6. The high temperature-resistant composite nanofiltration membrane according to claim 5, wherein the base membrane is prepared from raw materials comprising: polyethersulfone resin, polybenzimidazole resin, and N-methylpyrrolidone.

7. A method for preparing the high temperature-resistant composite nanofiltration membrane according to claim 6, comprising the following steps: mixing the amine, the inorganic salt, the silane additive, and deionized water evenly at a mass ratio of (0.5-3):(0.5-3):(0.5-3):(91-98.5) to obtain an aqueous phase solution; mixing the polyacyl chloride and the oil phase solvent evenly at a mass ratio of (0.05-1):(99-99.95) to obtain an oil phase solution; immersing the base membrane in the aqueous phase solution to obtain a primary base membrane; immersing the primary base membrane in the oil phase solution to obtain an immersed base membrane; and subjecting the immersed base membrane to a heat treatment to obtain the high temperature-resistant composite nanofiltration membrane.

8. The method for preparing the high temperature-resistant composite nanofiltration membrane according to claim 7, further comprising a step of preparing the base membrane before immersing the base membrane, which is performed as follows: mixing the polyethersulfone resin, the polybenzimidazole resin, and the N-methylpyrrolidone at a mass ratio of 13:2:85 to obtain a mixture, and stirring the mixture for 4 h to 24 h under heating to obtain a uniformly-dispersed casting solution; subjecting the casting solution to filtration and vacuum degassing in sequence to obtain a primary casting solution; coating the primary casting solution evenly onto a non-woven fabric by a membrane casting machine to form a wet membrane; and subjecting the wet membrane to pretreatment and curing in sequence to obtain the base membrane.

9. The method for preparing the high temperature-resistant composite nanofiltration membrane according to claim 8, wherein during preparing the base membrane, the heating is performed at a temperature of 50? C. to 90? C., and the stirring is performed at a rate of 100 rpm to 900 rpm; the pretreatment is performed by subjecting the wet membrane to evaporation at room temperature for 3 s to 10 s to obtain a pretreated wet membrane; the wet membrane has a thickness of 150 ?m to 170 ?m; and the curing is performed by immersing the pretreated wet membrane in ultrapure water at 5? C. to 16? C. for gel curing to form a preformed membrane; and immersing the preformed membrane in water at 20? C. to 40? C. for complete curing to form the base membrane.

10. The method for preparing the high temperature-resistant composite nanofiltration membrane according to claim 9, wherein during preparing the high temperature-resistant composite nanofiltration membrane, the immersing the base membrane in the aqueous phase solution is performed for 15 s to 25 s, and after that, a residual aqueous phase solution on a surface of the base membrane is removed by using a rubber roller to obtain the primary base membrane; the immersing the primary base membrane in the oil phase solution is performed for 10 s to 20 s, and after that, a residual oil phase solution on the surface of the primary base membrane is removed by using the rubber roller to obtain the immersed base membrane; and the heat treatment is performed by subjecting the immersed base membrane to heat preservation in an oven at 30? C. to 90? C. for 1 min to 30 min.

11. The high temperature-resistant composite nanofiltration membrane according to claim 2, wherein the oil phase solvent comprises at least one selected from the group consisting of n-hexane, cyclohexane, and heptane.

12. The high temperature-resistant composite nanofiltration membrane according to claim 3, wherein the oil phase solvent comprises at least one selected from the group consisting of n-hexane, cyclohexane, and heptane.

13. The high temperature-resistant composite nanofiltration membrane according to claim 4, wherein the oil phase solvent comprises at least one selected from the group consisting of n-hexane, cyclohexane, and heptane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIGURE shows a high temperature-resistant composite nanofiltration membrane according to one or more embodiments of the present disclosure; in which 1 represents a base membrane, and 2 represents a polyamide membrane.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] The technical solutions of the present disclosure will be clearly and completely described below in conjunction with specific examples of the present disclosure. Obviously, the described examples are only a part of, not all of, the examples of the present disclosure. All other examples obtained by persons of ordinary skill in the art based on the examples of the present disclosure shall fall within the scope of the present disclosure.

Example 1

[0042] A high temperature-resistant composite nanofiltration membrane consisted of a base membrane and a polyamide membrane arranged on the base membrane; wherein [0043] the polyamide membrane was prepared from an amine, an inorganic salt, a silane additive, a polyacyl chloride, and an oil phase solvent; and [0044] the silane additive was 3-aminopropyltriethoxysilane.

[0045] The inorganic salt was calcium chloride.

[0046] The amine was piperazine.

[0047] The polyacyl chloride was trimesoyl chloride.

[0048] The oil phase solvent was n-hexane.

[0049] The base membrane was prepared from polyethersulfone resin, polybenzimidazole resin, and N-methylpyrrolidone.

[0050] A method for preparing the high temperature-resistant composite nanofiltration membrane was performed as follows: [0051] preparation of an aqueous phase solution: [0052] the amine, the inorganic salt, the silane additive, and deionized water were mixed evenly at a mass ratio of 1:1:1:97 to obtain the aqueous phase solution; [0053] preparation of an oil phase solution: [0054] the polyacyl chloride and the oil phase solvent were mixed evenly at a mass ratio of 0.2:99.8 to obtain the oil phase solution; and [0055] preparation of the high temperature-resistant composite nanofiltration membrane: [0056] the base membrane was immersed in the aqueous phase solution to obtain a primary base membrane, and the primary base membrane was then immersed in the oil phase solution to obtain an immersed base membrane; and the immersed base membrane was subjected to a heat treatment to obtain the high temperature-resistant composite nanofiltration membrane.

[0057] In the method for preparing the high temperature-resistant composite nanofiltration membrane, the base membrane was prepared by the following steps: [0058] the polyethersulfone resin, the polybenzimidazole resin, and the N-methylpyrrolidone were mixed at a mass ratio of 13:2:85, and the resulting mixture was stirred for 6 h under heating to obtain a uniformly-dispersed casting solution; and [0059] the casting solution was subjected to filtration and vacuum degassing in sequence to obtain a primary casting solution, and then the primary casting solution was evenly coated onto a non-woven fabric by a membrane casting machine to form a wet membrane, and the wet membrane was subjected to pretreatment and curing to obtain the base membrane.

[0060] During the preparation of the casting solution, the heating was performed at 70? C. and the stirring was performed at a rate of 600 rpm to obtain the uniformly-dispersed casting solution; [0061] the pretreatment was performed by conducting evaporation on the wet membrane at 25? C. for 3 s to obtain a pretreated wet membrane; and [0062] the wet membrane had a thickness of 150 ?m; and the curing was performed as follows: the pretreated wet membrane was immersed in ultrapure water at 16? C. for gel curing to form a preformed membrane, and then the preformed membrane was immersed in water at 25? C. for complete curing, a cured membrane was washed with water at 75? C. for 3 min (a hot water bath was used to fix membrane pores) to obtain the base membrane, and the base membrane was refrigerated in a freezer at 5? C. for later use.

[0063] During the preparation of the high temperature-resistant composite nanofiltration membrane, the base membrane was immersed in the aqueous phase solution for 20 s, and after the immersing, a residual aqueous phase solution on a surface of the base membrane was removed using a rubber roller to obtain the primary base membrane; after that, the primary base membrane was immersed in the oil phase solution for 15 s, and after the immersing, a residual oil phase solution on the surface of the base membrane was removed using the rubber roller to obtain the immersed base membrane; and [0064] the heat treatment is performed by conducting heat preservation on the immersed base membrane (i.e., a base membrane obtained after immersing in the oil phase solution) in an oven at 70? C. for 5 min.

Example 2

[0065] This example was performed as described in Example 1, except that the amine was 1,6-hexanediamine.

Example 3

[0066] This example was performed as described in Example 1, except that the amine was m-phenylenediamine.

Example 4

[0067] This example was performed as described in Example 1, except that the polyacyl chloride was isophthaloyl chloride.

Example 5

[0068] This example was performed as described in Example 1, except that the polyacyl chloride was terephthaloyl chloride.

Example 6

[0069] This example was performed as described in Example 1, except that the inorganic salt was lithium chloride.

Example 7

[0070] This example was performed as described in Example 1, except that the inorganic salt was calcium bromide.

Example 8

[0071] This example was performed as described in Example 1, except that the silane additive was N-cyclohexyl-?-aminopropyltrimethoxysilane.

Example 9

[0072] This example was performed as described in Example 1, except that the amine, the inorganic salt, the silane additive, and the deionized water were at a mass ratio of 1:1:0.5:97.5.

Example 10

[0073] This example was performed as described in Example 1, except that the amine, the inorganic salt, the silane additive, and the deionized water were at a mass ratio of 1:0.5:1:97.5.

Example 11

[0074] This example was performed as described in Example 1, except that the amine, the inorganic salt, the silane additive, and the deionized water were at a mass ratio of 1:1:3:95.

Example 12

[0075] This example was performed as described in Example 1, except that the amine, the inorganic salt, the silane additive, and the deionized water were at a mass ratio of 1:3:3:93.

Example 13

[0076] This example was performed as described in Example 1, except that the silane additive consisted of divinyltriaminopropyltrimethoxysilane and N-cyclohexyl-?-aminopropyltrimethoxysilane at a mass ratio of 1:1.

Example 14

[0077] This example was performed as described in Example 1, except that the inorganic salt consisted of sodium chloride and lithium chloride at a mass ratio of 1:1.

Example 15

[0078] This example was performed as described in Example 1, except that the amine consisted of 1,6-hexanediamine, 1,4-diaminocyclohexane, and m-phenylenediamine at a mass ratio of 1:1:0.5.

Example 16

[0079] This example was performed as described in Example 1, except that the polyacyl chloride consisted of isophthaloyl chloride, terephthaloyl chloride, and 4,4-biphenyldicarbonyl chloride at a mass ratio of 0.9:1:0.5.

Example 17

[0080] This example was performed as described in Example 1, except that during the preparation of the casting solution, the heating was performed at 75? C.

Example 18

[0081] This example was performed as described in Example 1, except that during the preparation of the base membrane, the evaporation was conducted on the wet membrane at 25? C. for 5 s.

Example 19

[0082] This example was performed as described in Example 1, except that during the preparation of the base membrane, the wet membrane had a thickness of 170 ?m.

Example 20

[0083] This example was performed as described in Example 1, except that the curing was performed as follows: the pretreated wet membrane was immersed in ultrapure water at 12? C. for gel curing to form a preformed membrane, and then the preformed membrane was immersed in water at 25? C. for complete curing to form the base membrane.

Example 21

[0084] This example was performed as described in Example 1, except that during the preparation of the casting solution, the heating was performed at 60? C.

Example 22

[0085] This example was performed as described in Example 1, except that during the preparation of the casting solution, the heating was performed at 80? C.

Comparative Example 1

[0086] This example was performed as described in Example 1, except that no silane additive was used, and the amine, the inorganic salt, the silane additive, and the deionized water were at a mass ratio of 1:1:0:98.

Comparative Example 2

[0087] This example was performed as described in Example 1, except that no polybenzimidazole resin was added, and the polyethersulfone resin, the polybenzimidazole resin, and the N-methylpyrrolidone were at a mass ratio of 15:0:85.

Comparative Example 3

[0088] This example was performed as described in Example 1, except that no inorganic salt was added, and the amine, the inorganic salt, the silane additive, and the deionized water were at a mass ratio of 1:0:1:98.

Comparative Example 4

[0089] This example was performed as described in Example 1, except that the amine, the inorganic salt, the silane additive, and the deionized water were at a mass ratio of 0.4:0.4:0.4:98.8.

Comparative Example 5

[0090] This example was performed as described in Example 1, except that the amine, the inorganic salt, the silane additive, and the deionized water were at a mass ratio of 3.2:3.2:3.2:90.4.

Comparative Example 6

[0091] This example was performed as described in Example 1, except that during the preparation of the casting solution, the heating was performed at 40? C.

Comparative Example 7

[0092] This example was performed as described in Example 1, except that during the preparation of the casting solution, the heating was performed at 100? C.

Comparative Example 8

[0093] This example was performed as described in Example 1, except that during the preparation of the base membrane, the wet membrane had a thickness of 140 ?m.

Comparative Example 9

[0094] This example was performed as described in Example 1, except that during the preparation of the base membrane, the wet membrane had a thickness of 180 ?m.

Comparative Example 10

[0095] This example was performed as described in Example 1, except that during the preparation of the base membrane, no pretreatment was conducted.

Comparative Example 11

[0096] This example was performed as described in Example 1, except that the curing was performed as follows: the pretreated wet membrane was only immersed in water at 25? C. for complete curing to form the base membrane.

[0097] The high temperature-resistant composite nanofiltration membranes prepared in Examples 1 to 22 and Comparative Examples 1 to 11 were separately tested for high-temperature resistance using a cross-flow membrane testing platform:

[0098] (1) a first test conditions: MgSO.sub.4 aqueous solution of 2,000 ppm, an operating pressure of 70 psi, a test temperature of 25? C., and a pH value of 6.5 to 7.5; and

[0099] (2) a second test conditions: the running was carried out for 4 h under a hot water medium of 70? C. and an operating pressure of 70 psi, after that the test was conducted according to the first test conditions.

[0100] The results of the high-temperature resistance test are shown in Table 1.

TABLE-US-00001 TABLE 1 Difference between the results of Results after first Results after second the first test and the second test test conditions test conditions Percentage Percentage Water Retention Water Retention decrease in decrease in Experimental flux rate flux rate water flux retention rate groups (LMH) (%) (LMH) (%) (%) (%) Comparative 38.81 99.01 20.38 98.62 47.49 0.39 Example 1 Comparative 36.61 99.12 22.87 98.51 37.53 0.61 Example 2 Comparative 24.32 99.21 20.43 98.14 16.00 1.07 Example 3 Comparative 45.87 88.14 36.15 50.45 21.19 37.69 Example 4 Comparative 18.93 98.53 16.25 96.27 14.16 2.26 Example 5 Comparative 35.32 90.14 32.78 74.32 7.19 15.82 Example 6 Comparative 10.34 99.12 9.39 98.43 9.19 0.69 Example 7 Comparative 41.58 99.13 30.54 95.14 26.55 3.99 Example 8 Comparative 30.58 99.42 27.18 98.43 11.12 0.99 Example 9 Comparative 40.68 98.14 33.35 96.27 18.02 1.87 Example 10 Comparative 32.87 99.26 26.92 98.59 18.10 0.67 Example 11 Example 1 37.15 99.19 34.77 98.72 6.41 0.47 Example 2 28.91 98.85 26.87 98.52 7.06 0.33 Example 3 25.26 98.27 22.93 98.43 9.22 ?0.16 Example 4 22.64 99.02 19.85 98.87 12.32 0.15 Example 5 24.62 99.18 21.28 98.63 13.57 0.55 Example 6 36.91 99.31 32.93 98.02 10.78 1.29 Example 7 35.86 99.42 30.18 98.04 15.84 1.38 Example 8 30.91 99.31 28.72 98.06 7.09 1.25 Example 9 31.82 98.72 27.33 98.13 14.11 0.59 Example 10 33.75 99.35 30.82 98.71 8.68 0.64 Example 11 35.62 97.18 33.22 97.23 6.74 ?0.05 Example 12 40.22 97.66 32.56 97.22 19.05 0.44 Example 13 32.82 99.25 30.77 98.12 6.25 1.13 Example 14 30.76 99.15 25.31 98.04 17.72 1.11 Example 15 26.72 98.44 22.76 97.99 14.82 0.45 Example 16 27.26 98.62 22.98 97.63 15.70 0.99 Example 17 35.66 99.25 32.33 98.05 9.34 1.2 Example 18 34.11 99.35 31.41 98.13 7.92 1.22 Example 19 33.81 99.03 30.22 98.37 10.62 0.66 Example 20 32.93 99.39 29.11 98.15 11.60 1.24 Example 21 37.45 99.13 32.55 98.43 13.08 0.7 Example 22 35.32 99.43 30.52 98.18 13.59 1.25

[0101] As can be seen from the data in Table 1:

[0102] Comparing with Comparative Examples 1 to 3, in Examples 1 to 22 of the present disclosure, by combining the inorganic salt, silane additive, and polybenzimidazole resin, the composite nanofiltration membranes with higher water flux and high-temperature resistance could be prepared.

[0103] Comparing with Comparative Examples 4 to 5, in Examples 1 and 9 to 12 of the present disclosure, by controlling the amine, inorganic salt, silane additive, and deionized water at appropriate mass ratios, the composite nanofiltration membranes with higher water flux and high-temperature resistance could be prepared.

[0104] Comparing with Comparative Examples 6 to 7, in Examples 1, 17, and 21 to 22 of the present disclosure, by controlling suitable heating conditions during the preparation of the casting solution, the composite nanofiltration membranes with higher water flux and high-temperature resistance could be prepared.

[0105] Comparing with Comparative Examples 8 to 9, in Examples 1 and 19 of the present disclosure, by controlling the appropriate thickness of the wet membrane during the preparation of the base membrane, the composite nanofiltration membranes with higher water flux and high-temperature resistance could be prepared.

[0106] Comparing with Comparative Example 10, in Example 1 of the present disclosure, by conducting the pretreatment during the preparation of the base membrane, the composite nanofiltration membrane with higher water flux and high-temperature resistance could be prepared.

[0107] Comparing with Comparative Example 11, in Example 1 of the present disclosure, by setting suitable curing conditions of the wet membrane during the preparation of the base membrane, the composite nanofiltration membrane with higher water flux and high-temperature resistance could be prepared.

[0108] The above description is merely preferred embodiments of the present disclosure and is not intended to limit the present disclosure, and various changes and modifications of the present disclosure may be made by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present disclosure should be included within the protection scope of the present disclosure.