ZEOLITE MEMBRANE AND PREPARATION METHOD THEREOF

Abstract

A zeolite membrane and a preparation method thereof are provided. The method includes: adding an organic binder solution dropwise to zeolite, and thoroughly grinding and stirring; blade-coating a resulting mixture on a substrate at a given thickness; and drying to obtain the zeolite membrane. The preparation of a zeolite membrane does not require a complicated hydrothermal crystal growth process, and the membrane can be prepared directly from natural zeolite or artificial zeolite. A prepared zeolite membrane has the characteristics of simple preparation process, low cost, prominent water permeability, high contaminant rejection rate and high zeolite load. The zeolite membrane, when used for the rejection of contaminants in water, can not only remove macromolecular contaminants in water, but also efficiently remove ammonia nitrogen by way of ion exchange, which is suitable for advanced treatment of wastewater.

Claims

1. A method for preparing a zeolite membrane, comprising the following steps: 1) adding an organic binder solution dropwise to a zeolite to obtain a mixture, and thoroughly grinding and stirring the mixture; 2) blade-coating the mixture obtained in step 1) on a substrate to obtain the substrate with a zeolite membrane matrix; and 3) drying the substrate with the zeolite membrane matrix obtained in step 2) at 40° C. in air for 12 h to obtain the zeolite membrane.

2. The method for preparing the zeolite membrane according to claim 1, wherein the zeolite used in step 1) is at least one selected from the group consisting of a natural zeolite and an artificial zeolite, and the zeolite has a particle size less than 100 μm.

3. The method for preparing the zeolite membrane according to claim 1, wherein a solute in the organic binder solution is at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC).

4. The method for preparing the zeolite membrane according to claim 1, wherein a solvent in the organic binder solution is at least one selected from the group consisting of N-methyl pyrrolidone (NMP), N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), triethyl phosphate (TEP), and dimethyl sulfoxide (DMSO).

5. The method for preparing the zeolite membrane according to claim 1, wherein an organic binder has a mass concentration of 0.1% to 30% in the organic binder solution.

6. The method for preparing the zeolite membrane according to claim 1, wherein the organic binder solution and the zeolite in step 1) have a mass ratio of 0.1:1 to 6:1.

7. The method for preparing the zeolite membrane according to claim 1, wherein the substrate used in step 2) is at least one selected from the group consisting of a non-woven fabric, a metal mesh with a pore size less than 0.1 mm, a microfiltration (MF) membrane and an ultrafiltration (UF) membrane; wherein the MF membrane or the UF membrane comprises a polyacrylonitrile (PAN) membrane, a polyvinyl chloride (PVC) membrane, a polyethersulfone (PES) membrane, a polypropylene (PP) membrane, a polysulfone (PSF) membrane, a polytetrafluoroethylene (PTFE) membrane, and a polyvinylidene fluoride (PVDF) membrane.

8. A zeolite membrane prepared by the method according to claim 1, wherein the zeolite membrane has a thickness of 0.1 mm to 1.5 mm.

9. The zeolite membrane according to claim 8, wherein a filtration using the zeolite membrane requires an operating pressure of 0 kPa to 150 kPa, and the zeolite membrane has a water flux of 20 L.Math.m.sup.−2.Math.h.sup.−1 to 4,000 L.Math.m.sup.−2.Math.h.sup.−1.

10. The zeolite membrane according to claim 8, wherein the zeolite used in step 1) is at least one selected from the group consisting of a natural zeolite and an artificial zeolite, and the zeolite has a particle size less than 100 μm.

11. The zeolite membrane according to claim 8, wherein a solute in the organic binder solution is at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC).

12. The zeolite membrane according to claim 8, wherein a solvent in the organic binder solution is at least one selected from the group consisting of N-methyl pyrrolidone (NMP), N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), triethyl phosphate (TEP), and dimethyl sulfoxide (DMSO).

13. The zeolite membrane according to claim 8, wherein an organic binder has a mass concentration of 0.1% to 30% in the organic binder solution.

14. The zeolite membrane according to claim 8, wherein the organic binder solution and the zeolite in step 1) have a mass ratio of 0.1:1 to 6:1.

15. The zeolite membrane according to claim 8, wherein the substrate used in step 2) is at least one selected from the group consisting of a non-woven fabric, a metal mesh with a pore size less than 0.1 mm, a microfiltration (MF) membrane and an ultrafiltration (UF) membrane; wherein the MF membrane or the UF membrane comprises a polyacrylonitrile (PAN) membrane, a polyvinyl chloride (PVC) membrane, a polyethersulfone (PES) membrane, a polypropylene (PP) membrane, a polysulfone (PSF) membrane, a polytetrafluoroethylene (PTFE) membrane, and a polyvinylidene fluoride (PVDF) membrane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in more detail below with reference to the examples and the drawings. Particularly:

[0024] FIG. 1A shows an image of the real zeolite membrane prepared in Example 1 of the present invention;

[0025] FIG. 1B shows an image of the real zeolite membrane prepared in Example 1 of the present invention from another view; and

[0026] FIG. 2 is a diagram showing a relationship between water flux of the zeolite membrane prepared in Example 1 of the present invention and pressure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solutions in the present invention are clearly and completely described below with reference to the examples of the present invention. Apparently, the described examples are merely some rather than all of the examples of the present invention. All other examples obtained by a person of ordinary skill in the art based on the examples of the present invention without creative efforts shall fall within the protection scope of the present invention.

EXAMPLE 1

[0028] This example provided a method for preparing a zeolite membrane, specifically as follows:

[0029] 10 g of a solution of PVDF in NMP with a mass concentration of 6% is added dropwise to 10 g of natural clinoptilolite; a resulting mixture is thoroughly ground and stirred, and then blade-coated on a non-woven fabric at a thickness of 0.5 μm; and then the non-woven fabric is dried to obtain the zeolite membrane. Images of the real zeolite membrane prepared are shown in FIGS. 1A-B.

EXAMPLE 2

[0030] This example provided a method for preparing a zeolite membrane, specifically as follows:

[0031] 10 g of a solution of PVDF in NMP with a mass concentration of 8% is added dropwise to 10 g of natural clinoptilolite; a resulting mixture is thoroughly ground and stirred, and then blade-coated on a non-woven fabric at a thickness of 0.7 μm; and then the non-woven fabric is dried to obtain the zeolite membrane.

EXAMPLE 3

[0032] This example provided a method for preparing a zeolite membrane, specifically as follows:

[0033] 15 g of a solution of PVDF in NMP with a mass concentration of 10% is added dropwise to 10 g of artificial zeolite; a resulting mixture is thoroughly ground and stirred, and then blade-coated on a non-woven fabric at a thickness of 0.9 μm; and then the non-woven fabric is dried to obtain the zeolite membrane.

EXAMPLE 4

[0034] This example provided a method for preparing a zeolite membrane, specifically as follows:

[0035] 10 g of a solution of PVDF in NMP with a mass concentration of 8% is added dropwise to 10 g of artificial zeolite; a resulting mixture is thoroughly ground and stirred, and then blade-coated on a stainless metal mesh with a pore size of 0.025 mm at a thickness of 0.7 μm; and then the stainless metal mesh is dried to obtain the zeolite membrane.

EXAMPLE 5

[0036] This example provided a method for preparing a zeolite membrane, specifically as follows:

[0037] 10 g of a solution of PVDF in DMF with a mass concentration of 6% is added dropwise to 10 g of natural zeolite; a resulting mixture is thoroughly ground and stirred, and then blade-coated on a stainless metal mesh with a pore size of 0.05 mm at a thickness of 0.5 μm; and then the stainless metal mesh is dried to obtain the zeolite membrane.

EXAMPLE 6

[0038] This example provided a method for preparing a zeolite membrane, specifically as follows:

[0039] 10 g of a solution of PVDF in NMP with a mass concentration of 4% is added dropwise to 10 g of natural zeolite; a resulting mixture is thoroughly ground and stirred, and then blade-coated on a PVDF UF membrane at a thickness of 0.3 μm; and then the PVDF UF membrane is dried to obtain the zeolite membrane.

EXAMPLE 7

[0040] The water flux of the zeolite membrane prepared in Example 1 is tested at an operating pressure of 0 kPa to 100 kPa and a height of 0.1 m that a liquid level is above the zeolite membrane, and results are shown in FIG. 2. The zeolite membrane has a water flux up to 47 L.Math.m.sup.−2.Math.h.sup.−1, and even up to 3,370 L.Math.m.sup.−2.Math.h.sup.−1 at an operating pressure of 100 kPa, indicating that this zeolite membrane has excellent water permeability.

EXAMPLE 8

[0041] The contaminant rejection performance of the zeolite membrane prepared in Example 1 is tested at a height of 0.1 m that a liquid level is above the zeolite membrane, and bovine serum albumin (BSA) has a concentration of 0.1 g.Math.L.sup.−1 in inlet water. Results shows that the zeolite membrane has a BSA rejection rate of 22%.

EXAMPLE 9

[0042] The NH.sub.4.sup.+ rejection performance of the zeolite membrane prepared in Example 1 is tested at a height of 0.1 m that a liquid level is above the zeolite membrane, and NH.sub.4.sup.+ has a concentration of 10 mg.Math.L.sup.−1 in inlet water. Results shows that the zeolite membrane has a NH.sub.4.sup.+ rejection rate of 65%.

[0043] The above examples are merely intended to describe the technical solutions of the present invention, rather than to limit the present invention. Although the present invention is described in detail with reference to the above examples, persons of ordinary skill in the art should understand that modifications may be made to the technical solutions described in the above examples or equivalent replacements may be made to some or all technical features thereof, which do not make the essence of corresponding technical solutions depart from the scope of the technical solutions in the examples of the present invention.

[0044] In addition, those skilled in the art can understand that, although some examples herein include some features included in other examples but no other features, a combination of features of different examples falls within the scope of the present invention and forms a different example. For example, in the claims, any one of the claimed examples can be used in any combination. The information disclosed in this background section is only intended to deepen the understanding of the general background of the present invention, and should not be regarded as an acknowledgement or any form of suggestion that this information constitutes the prior art commonly known to those skilled in the art.