A preparation process of acid and alkali water treatment membrane material

Abstract

The invention discloses a preparation process of an acid-resistant and alkaline water treatment membrane material, comprising the following steps: step S1, dissolving zinc chloride in anhydrous alcohol to obtain an anhydrous alcohol suspension; step S2, dissolving a furfuryl alcohol prepolymer in a furfuryl alcohol monomer, mixing to form a furfuryl alcohol prepolymer-furfuryl alcohol monomer resin solution; step S3, gradually adding the anhydrous alcohol suspension into the furfuryl alcohol prepolymer-furfuryl alcohol monomer resin solution to obtain a hydrophilic furfuryl alcohol resin; step S4, coating a polypropylene non-woven fabric with the hydrophilic furfuryl alcohol resin obtained in step S3, and then baking the polypropylene non-woven fabric to solidify the hydrophilic furfuryl alcohol resin to form a porous material layer; step S5, forming a separation layer on the porous material layer to obtain an alkali-resistant membrane. The invention solves the problem that a traditional reverse osmosis membrane and a nanofiltration membrane cannot be used under a strong alkaline condition, and can be applied to the fields of acid and alkaline material recovery.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment membrane material preparation, and in particular to a preparation process of an acid-resistant and alkali-resistant water treatment membrane material. Background Art

[0002] Water treatment membranes such as reverse osmosis membranes and nanofiltration membranes use the static pressure difference on both sides of the membrane as a driving force to separate the mixture. Nanofiltration is used to separate substances with relatively small molecular weights, such as inorganic salts or small molecular organic substances such as glucose and sucrose, from solvents. Nanofiltration, also known as low-pressure reverse osmosis, is an emerging field of membrane separation technology. Its separation performance is between reverse osmosis and ultrafiltration, allowing some inorganic salts and certain solvents to pass through the membrane, thereby achieving the effect of separation.

[0003] The core of membrane separation technology is high-performance membrane materials. Conventional reverse osmosis membranes and nanofiltration membranes on the market generally use polyethylene terephthalate non-woven fabrics as the supporting layer of porous materials and polyamide as the separation layer. However, under strong acid and alkaline conditions, the ester bonds in polyethylene terephthalate and the amide bonds in polyamide will hydrolyze, causing the performance of the membrane material to decline rapidly. Therefore, it is difficult to apply membrane separation technology under strong alkaline conditions. Taking DuPont's reverse osmosis membrane component products as an example, the continuous operating conditions generally allowed by its conventional membrane element products are generally pH2-11. Summary of the invention

[0004] Purpose of the invention: The purpose of the invention is to solve the deficiencies in the prior art and provide a preparation process for acid and alkaline water treatment membrane materials.

[0005] Technical solution: It comprises the following components: a polypropylene non-woven fabric as a porous material support layer, a furfuryl alcohol resin porous material layer coated on the polypropylene non-woven fabric, and a separation layer generated by in-situ polymerization of furfuryl alcohol using sulfuric acid as a catalyst. The furfuryl alcohol resin porous material layer is a hydrophilic membrane layer. The hydrophilic furfuryl alcohol resin membrane layer is prepared by mixing and curing furfuryl alcohol prepolymer and furfuryl alcohol monomer. During the curing process, small molecules generated by the polycondensation reaction escape, and finally a porous polymer-based membrane with interpenetrating networks or finger-like pores is generated to support the subsequent polyfurfuryl alcohol separation layer. The specific preparation steps are as follows:

[0006] Step S1, dissolving zinc chloride in anhydrous alcohol, and stirring to obtain an anhydrous alcohol suspension of zinc chloride;

[0007] Step S2, dissolving the furfuryl alcohol prepolymer in the furfuryl alcohol monomer, and mixing to form a furfuryl alcohol prepolymer-furfuryl alcohol monomer resin solution;

[0008] Step S3, gradually adding an anhydrous alcohol suspension of zinc chloride into the furfuryl alcohol prepolymer-furfuryl alcohol monomer resin solution, stirring, to obtain a hydrophilic furfuryl alcohol resin;

[0009] Step S4, coating the hydrophilic furfuryl alcohol resin obtained in step S3 on the polypropylene non-woven fabric, and then baking the polypropylene non-woven fabric to solidify the hydrophilic furfuryl alcohol resin to form a porous material layer;

[0010] Step S5, forming another separation layer on the porous material layer obtained in step S4, so as to obtain an alkali-resistant membrane;

[0011] The step S5 comprises the following sub-steps:

[0012] Step S5-1, preparing an aqueous solution of furfuryl alcohol monomer, wherein the aqueous solution also contains sulfuric acid as a catalyst;

[0013] Step S5-2, immersing the porous material layer in an aqueous solution to absorb the aqueous solution in step S4-1;

[0014] Step S5-3, baking in an oven, generating a separation layer in situ after heating.

[0015] A further improvement of the present invention is that in the step S2, the weight proportion of the furfuryl alcohol resin prepolymer is 15-60%, and the weight proportion of the furfuryl alcohol monomer is 38-83%.

[0016] A further improvement of the present invention is that in the step S1, the weight proportion of the zinc chloride is 1%, and the weight proportion of the anhydrous alcohol is 1%.

[0017] A further improvement of the present invention is that in step S4, the baking temperature is 100° C. to 180° C., and the baking time is 10 seconds to 300 seconds.

[0018] A further improvement of the present invention is that in step S5-1, the content of furfuryl alcohol monomer in the aqueous solution is 0.1-5%, and the content of sulfuric acid is 0.1-0.5%.

[0019] A further improvement of the present invention is that in step S5-3, the baking temperature is 120°C to 180°C, and the baking time is 10 seconds to 300 seconds.

[0020] A further improvement of the present invention is that in step S5, the obtained alkali-resistant membrane is placed in a sodium hydroxide aqueous solution for testing, the pH value of the sodium hydroxide aqueous solution is 13.5, and the test pressure is 1.55 MPa.

[0021] A further improvement of the present invention is that in step S5, the obtained alkali-resistant film is placed in a sodium sulfate solution for testing, the sodium sulfate solution is prepared at a concentration of 1000 ppm and the test pressure is 1.55 MPa.

[0022] Compared with the prior art, the preparation process of the acid-resistant and alkaline water treatment membrane material provided by the present invention achieves at least the following beneficial effects:

[0023] The present invention uses polypropylene non-woven fabric as the supporting layer of the porous material, which solves the problem that the traditional polyethylene terephthalate non-woven fabric is easy to hydrolyze under alkaline conditions; furfuryl alcohol resin is used as the porous material layer, which is easier to adsorb furfuryl alcohol monomer, which is conducive to the generation of the polyfurfuryl alcohol separation layer; the furfuryl alcohol monomer is used to generate the polyfurfuryl alcohol separation layer by in-situ polymerization. Furfuryl alcohol resin, as a typical furan resin, has the characteristics of stable chemical properties, good alkali resistance, and strong corrosion resistance, which solves the problem that the traditional polyamide desalination layer generated by the reaction of m-phenylenediamine or piperazine with trimesoyl chloride is not alkali-resistant; the present invention solves the problem that traditional reverse osmosis membranes and nanofiltration membranes cannot be used under strong alkaline conditions, and the material can be applied to the fields of acid and alkaline material recovery. DETAILED DESCRIPTION

[0024] It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0025] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention and its application or use. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be considered part of the specification.

[0026] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0027] Example 1

[0028] A preparation process of an acid-resistant and alkaline water treatment membrane material comprises, in sequence, a polypropylene non-woven fabric support layer, a furfuryl alcohol resin porous material layer and a separation layer. The furfuryl alcohol resin porous material layer has a porous structure, and the main body is a hydrophilic furfuryl alcohol resin membrane layer. The hydrophilic furfuryl alcohol resin membrane layer is prepared by mixing and curing furfuryl alcohol prepolymer and furfuryl alcohol monomer.

[0029] The preparation method specifically comprises the following steps:

[0030] Step S1: dissolving zinc chloride in anhydrous alcohol, and stirring to obtain an anhydrous alcohol suspension of zinc chloride;

[0031] Step S2: dissolving the furfuryl alcohol prepolymer in the furfuryl alcohol monomer, and mixing to form a furfuryl alcohol prepolymer-furfuryl alcohol monomer resin solution;

[0032] Step S3: then gradually adding the anhydrous alcohol suspension of zinc chloride to the furfuryl alcohol prepolymer-furfuryl alcohol monomer resin solution, stirring, to obtain a hydrophilic furfuryl alcohol resin;

[0033] The weight ratio of each component is: 49% furfuryl alcohol resin prepolymer, 49% furfuryl alcohol monomer, 1% zinc chloride and 1% anhydrous alcohol.

[0034] Step S4: scrape a 20 μm thick layer of hydrophilic furfuryl alcohol resin on the polypropylene non-woven fabric; bake the non-woven fabric coated with the hydrophilic furfuryl alcohol resin at 120° C. for 60 seconds to solidify the furfuryl alcohol resin to form a porous material layer; then put it into water as a base film to moisten it and store it for later use.

[0035] Step S5: forming another separation layer on the porous material layer obtained in step 4, the specific steps are as follows:

[0036] Step S5-1, preparing an aqueous solution of furfuryl alcohol monomer, wherein the aqueous solution also contains sulfuric acid as a catalyst, wherein the furfuryl alcohol monomer content is 2% and the sulfuric acid content is 0.2%;

[0037] Step S5-2, immersing the base film in the aqueous solution to absorb the aqueous solution;

[0038] Step S5-3, generating a separation layer in situ after heating, the baking temperature is 140° C., and the baking time is 60 seconds.

[0039] A sodium sulfate solution with a concentration of 1000ppm was prepared, and the pH value of the aqueous solution was adjusted to 13.5 with sodium hydroxide. The aqueous solution was used as the test water source. Under the test pressure of 1.55Mpa, the sodium sulfate removal rate of the water treatment membrane was measured to be 98.53%, and the water production was 37.0L*m-2*h-1.

[0040] It can be seen from the above embodiments that the preparation process of the acid- and alkaline-resistant water treatment membrane material provided by the present invention achieves at least the following beneficial effects:

[0041] The invention discloses a preparation process of an acid- and alkaline-resistant water treatment membrane material. A polypropylene non-woven fabric is used as a supporting layer of a porous material, and a furfuryl alcohol resin is used as a porous material layer, so that the furfuryl alcohol monomer is more easily adsorbed, which is beneficial to the generation of a polyfurfuryl alcohol separation layer. The furfuryl alcohol monomer is in-situ polymerized to generate the polyfurfuryl alcohol separation layer. As a typical furan resin, the furfuryl alcohol resin has the characteristics of stable chemical properties, good alkali resistance and strong corrosion resistance. The problem that a traditional polyethylene terephthalate non-woven fabric is easy to hydrolyze under alkaline conditions is solved, and the problem that a traditional polyamide desalination layer generated by the reaction of m-phenylenediamine or piperazine with trimesoyl chloride is not alkali-resistant is solved. The invention can be applied to the fields of acid and alkaline material recovery, and the problem that a traditional reverse osmosis membrane and a nanofiltration membrane cannot be used under strong alkaline conditions is solved.

[0042] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A process for preparing an acid-resistant and alkaline water treatment membrane material, characterized in that: The invention comprises the following components: a supporting layer of a porous material using a polypropylene non-woven fabric, a porous material layer of a furfuryl alcohol resin coated on the polypropylene non-woven fabric, and a separation layer generated by in-situ polymerization of furfuryl alcohol using sulfuric acid as a catalyst. The porous material layer of the furfuryl alcohol resin is a hydrophilic membrane layer. The hydrophilic furfuryl alcohol resin membrane layer is prepared by mixing and curing a furfuryl alcohol prepolymer and a furfuryl alcohol monomer. During the curing process, small molecules generated by the polycondensation reaction escape, and finally a porous polymer-based membrane with an interpenetrating network or finger-like pores is generated to support the subsequent polyfurfuryl alcohol separation layer. The specific preparation steps are as follows: Step S1, dissolving zinc chloride in anhydrous alcohol, and stirring to obtain an anhydrous alcohol suspension of zinc chloride; Step S2, dissolving the furfuryl alcohol prepolymer in the furfuryl alcohol monomer, and mixing to form a furfuryl alcohol prepolymer-furfuryl alcohol monomer resin solution; Step S3, gradually adding an anhydrous alcohol suspension of zinc chloride into the furfuryl alcohol prepolymer-furfuryl alcohol monomer resin solution, stirring, to obtain a hydrophilic furfuryl alcohol resin; Step S4, coating the hydrophilic furfuryl alcohol resin obtained in step S3 on the polypropylene non-woven fabric, and then baking the polypropylene non-woven fabric to solidify the hydrophilic furfuryl alcohol resin to form a porous material layer; Step S5, forming another separation layer on the porous material layer obtained in step S4, so as to obtain an alkali-resistant membrane; The step S5 comprises the following sub-steps: Step S5-1, preparing an aqueous solution of furfuryl alcohol monomer, wherein the aqueous solution also contains sulfuric acid as a catalyst; Step S5-2, immersing the porous material layer in an aqueous solution to absorb the aqueous solution in step S4-1; Step S5-3, baking in an oven, generating a separation layer in situ after heating.

2. The process for preparing the acid and alkali water treatment membrane material according to claim 1, characterized in that: In the step S2, the weight proportion of the furfuryl alcohol resin prepolymer is 15-60%, and the weight proportion of the furfuryl alcohol monomer is 38-83%.

3. The process for preparing the acid and alkali water treatment membrane material according to claim 1, characterized in that , In the step S1, the weight proportion of the zinc chloride is 1%, and the weight proportion of the anhydrous alcohol is 1%.

4. The process for preparing the acid and alkali water treatment membrane material according to claim 1, characterized in that , In the step S4, the baking temperature is 100° C. to 180° C., and the baking time is 10 seconds to 300 seconds.

5. The process for preparing the acid and alkali water treatment membrane material according to claim 1, characterized in that: In the step S5-1, the content of furfuryl alcohol monomer in the aqueous solution is 0.1-5%, and the content of sulfuric acid is 0.1-0.5%.

6. The process for preparing the acid and alkali water treatment membrane material according to claim 1, characterized in that: In the step S5-3, the baking temperature is 120°C to 180°C, and the baking time is 10 seconds to 300 seconds.

7. The process for preparing the acid and alkali water treatment membrane material according to claim 1, characterized in that: In the step S5, the obtained alkali-resistant membrane is placed in a sodium hydroxide aqueous solution for testing, the pH value of the sodium hydroxide aqueous solution is 13.5, and the test pressure is 1.55 MPa.

8. The process for preparing the acid and alkali water treatment membrane material according to claim 1, characterized in that , In the step S5, the obtained alkali-resistant film is placed in a sodium sulfate solution for testing, the sodium sulfate solution is prepared at a concentration of 1000 ppm and a test pressure of 1.55 MPa.