阅读说明：本技术 一种氧化石墨烯-二氧化钛-银掺杂哌嗪聚酰胺复合纳滤膜及其制备方法 (Graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane and preparation method thereof ) 是由 陈云强 洪昱斌 方富林 蓝伟光 于 2020-06-12 设计创作，主要内容包括：本发明公开了一种氧化石墨烯-二氧化钛-银掺杂哌嗪聚酰胺复合纳滤膜及其制备方法,包括有机超滤膜支撑体和设于该有机超滤膜支撑体上的有机功能层,该有机功能层以水相溶液和有机相溶液为原料通过界面聚合反应于有机超滤膜支撑体上形成。本发明以负载二氧化钛和银的氧化石墨烯作为添加剂,以哌嗪为水相单体,制备出氧化石墨烯-二氧化钛-银掺杂哌嗪聚酰胺复合纳滤膜,具有良好且平衡的纯水通量、截留率和抗菌性能。(The invention discloses a graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane and a preparation method thereof. According to the invention, the graphene oxide loaded with titanium dioxide and silver is used as an additive, and piperazine is used as an aqueous phase monomer, so that the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane is prepared, and has good and balanced pure water flux, rejection rate and antibacterial performance.)

1. A graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane is characterized in that: the organic functional layer is formed on the organic ultrafiltration membrane support body by taking an aqueous phase solution and an organic phase solution as raw materials through interfacial polymerization reaction;

the aqueous phase monomer in the aqueous phase solution is piperazine, the aqueous phase monomer solution contains an acid acceptor and graphene oxide loaded with titanium dioxide and silver by a hydrothermal method, and the acid acceptor is polyamine;

the organic phase monomer in the organic phase solution is trimesoyl chloride.

2. The graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane of claim 1, wherein: the polyamine is ethylenediamine.

3. The graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane of claim 1, wherein: the pore diameter of the organic ultrafiltration membrane support body is 10-30 KD.

4. The graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane of claim 1, wherein: the mass ratio of the graphene oxide to the titanium dioxide to the silver is 20: 1.

5. The graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane of claim 1, wherein: the mass ratio of the graphene oxide and the piperazine which load titanium dioxide and silver by a hydrothermal method is 0.002-0.004: 1.

6. The preparation method of the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane as claimed in any one of claims 1 to 5, wherein the preparation method comprises the following steps: the method comprises the following steps: and (2) forming the organic functional layer on the organic ultrafiltration membrane support body through interfacial polymerization reaction by taking piperazine as an aqueous phase monomer, phthaloyl chloride as an organic phase monomer, polyamine as an acid acceptor and a mixture of graphene oxide loaded with titanium dioxide and silver by a hydrothermal method as an additive, so as to obtain the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane.

7. The method of claim 6, wherein: the method comprises the following steps:

(1) preparing a graphene oxide aqueous solution by using a modified Hummers method;

(2) preparing graphene oxide loaded with titanium dioxide and silver by using the graphene oxide aqueous solution obtained in the step (1), a mixed solution of titanyl sulfate and silver nitrate and ammonia water as raw materials through a hydrothermal method;

(3) adding the material obtained in the step (2) into a piperazine solution, stirring and mixing uniformly, adding polyamine, and performing ultrasonic treatment to obtain an aqueous phase solution;

(4) soaking the organic ultrafiltration membrane support body washed by ethanol and water in a n-hexane solution of trimesoyl chloride, removing the n-hexane solution of unreacted trimesoyl chloride after room temperature reaction, soaking in the aqueous phase solution, and removing the unreacted aqueous phase solution after room temperature reaction;

(5) and (4) air-drying the material obtained in the step (4), then carrying out heat treatment at 50-80 ℃, and then cooling along with a furnace to obtain the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane.

8. The method of claim 7, wherein: the concentration of the graphene oxide aqueous solution is 2-5/L, and the concentration of the piperazine solution is 1-3 wt%.

9. The method of claim 7, wherein: in the step (4), the concentration of the polyamine in the aqueous phase solution is 0.1-0.5 wt%.

10. The method of claim 7, wherein: the concentration of the n-hexane solution of trimesoyl chloride is 0.1-0.2 wt%.

Technical Field

The invention belongs to the technical field of membrane separation, and particularly relates to a graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane and a preparation method thereof.

Background

The nanofiltration membrane is a novel pressure-driven membrane, the pore size of the membrane is between that of ultrafiltration and reverse osmosis, and the nanofiltration membrane can be used for separating divalent salt and monovalent salt. The nanofiltration membrane has the characteristics of low operating pressure, high flux, energy conservation and the like, so the nanofiltration membrane is widely applied to the fields of bioengineering, medicine, metallurgy, water treatment, electronics and the like. The nanofiltration membrane commonly used in industry is an organic nanofiltration membrane, and has the advantages of high air permeability, low density, good film forming property, low cost, good flexibility and the like.

In the prior art, the nanofiltration membrane technology is used for water purification and has two major problems, namely the problem of flux balancing and interception and the problem of poor antipollution and antibacterial properties of a membrane layer. How to solve the problems becomes a difficult problem of the nanofiltration membrane in the aspect of water purification application.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane.

The invention also aims to provide a preparation method of the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane.

The technical scheme of the invention is as follows:

a graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane comprises an organic ultrafiltration membrane support body and an organic functional layer arranged on the organic ultrafiltration membrane support body, wherein the organic functional layer is formed by taking an aqueous phase solution and an organic phase solution as raw materials and performing interfacial polymerization reaction on the organic ultrafiltration membrane support body;

the aqueous phase monomer in the aqueous phase solution is piperazine, the aqueous phase monomer solution contains an acid acceptor and graphene oxide loaded with titanium dioxide and silver by a hydrothermal method, and the acid acceptor is polyamine;

the organic phase monomer in the organic phase solution is trimesoyl chloride.

In a preferred embodiment of the invention, the polyamine is ethylenediamine.

In a preferred embodiment of the invention, the pore diameter of the organic ultrafiltration membrane support body is 10-30 KD.

In a preferred embodiment of the present invention, the mass ratio of the graphene oxide, the titanium dioxide and the silver is 20: 1.

In a preferred embodiment of the present invention, the mass ratio of the graphene oxide and the piperazine loaded with titanium dioxide and silver by a hydrothermal method is 0.002-0.004: 1.

The preparation method of the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane comprises the following steps: and (2) forming the organic functional layer on the organic ultrafiltration membrane support body through interfacial polymerization reaction by taking piperazine as an aqueous phase monomer, phthaloyl chloride as an organic phase monomer, polyamine as an acid acceptor and a mixture of graphene oxide loaded with titanium dioxide and silver by a hydrothermal method as an additive, so as to obtain the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane.

In a preferred embodiment of the present invention, the method comprises the following steps:

(1) preparing a graphene oxide aqueous solution by using a modified Hummers method;

(2) preparing graphene oxide loaded with titanium dioxide and silver by using the graphene oxide aqueous solution obtained in the step (1), a mixed solution of titanyl sulfate and silver nitrate and ammonia water as raw materials through a hydrothermal method;

(3) adding the material obtained in the step (2) into a piperazine solution, stirring and mixing uniformly, adding polyamine, and performing ultrasonic treatment to obtain an aqueous phase solution;

(4) soaking the organic ultrafiltration membrane support body washed by ethanol and water in a n-hexane solution of trimesoyl chloride, removing the n-hexane solution of unreacted trimesoyl chloride after room temperature reaction, soaking in the aqueous phase solution, and removing the unreacted aqueous phase solution after room temperature reaction;

(5) and (4) air-drying the material obtained in the step (4), then carrying out heat treatment at 50-80 ℃, and then cooling along with a furnace to obtain the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane.

Further preferably, the concentration of the graphene oxide aqueous solution is 2-5/L, and the concentration of the piperazine solution is 1-3 wt%.

Further preferably, in the step (4), the concentration of the polyamine in the aqueous phase solution is 0.1 to 0.5 wt%.

Further preferably, the concentration of the n-hexane solution of trimesoyl chloride is 0.1-0.2 wt%.

The invention has the beneficial effects that: according to the invention, the graphene oxide loaded with titanium dioxide and silver is used as an additive, and piperazine is used as an aqueous phase monomer, so that the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane is prepared, and has good and balanced pure water flux, rejection rate and antibacterial performance.

Detailed Description

The technical solution of the present invention is further illustrated and described by the following detailed description.

The modified Hummers process of the following comparative examples and examples specifically includes:

(1) 1000mL of beaker is cleaned and dried, 3g of crystalline flake graphite is added, and 360mL of concentrated sulfuric acid (98% H) is slowly added under magnetic stirring₂SO₄) And 40mL concentrated phosphoric acid (95% H)₃PO₄) Then 18g of potassium permanganate (KMnO) is slowly added in batches₄) (ii) a The beaker was transferred to a 50 ℃ oil bath and stirred for 12 h. Taking out the beaker, and naturally cooling to room temperature. The reaction solution was slowly poured into 400mL of dilute hydrogen peroxide (containing 18mL of 30% H)₂O₂) On ice, the solution turned bright yellow;

(2) carrying out cross-flow filtration on the solution by using a tubular ceramic membrane with the aperture of 0.05 mu m to remove impurities, and obtaining an oxidized graphene solution after impurity removal; the basic principle is to use the pore size sieving effect of the ceramic membrane, i.e.The size of the aperture of the ceramic tubular membrane filter is smaller than that of the GO sheet layer, so that the GO sheet layer cannot flow out through the tubular ceramic membrane and flows back to the material liquid barrel along with the liquid in the pipeline in a circulating manner, membrane holes cannot be blocked, smoothness of the membrane holes is guaranteed, and the GO sheet layer with larger size is crushed and stripped; the ceramic tubular membrane filtration pore size is larger than the impurity ion size of GO solution, so that H is obtained⁺、K⁺、Mn²⁺The isoacid radicals and metal ions can be easily discharged through the pore diameter of the ceramic tubular membrane. The GO, the waste acid and the K are repeatedly circulated in the way⁺And Mn²⁺Separating metal ions, collecting GO solution, and washing and removing impurities of GO;

(3) and diluting or concentrating according to the required concentration to obtain the graphene oxide aqueous solution with the concentration of 2-5 g/L.

Comparative example 1

(1) Preparing a graphene oxide aqueous solution with the concentration of 2g/L by using a modified Hummers method;

(2) adding the material obtained in the step (1) into a piperazine solution with the concentration of 1 wt%, uniformly stirring and mixing (the mass ratio of the titanium dioxide-loaded graphene oxide to the piperazine is 0.002: 1), adding 0.5 wt% of ethylenediamine, and performing ultrasonic treatment to obtain an aqueous phase solution;

(3) soaking a polyether sulfone support body of 30KD washed by ethanol and water in a n-hexane solution of trimesoyl chloride with the concentration of 2 wt%, removing the n-hexane solution of unreacted trimesoyl chloride after reacting for 10min at room temperature, soaking in the aqueous phase solution, and removing the aqueous phase solution after reacting for 10min at room temperature;

(5) and (4) air-drying the material obtained in the step (4) in a shade place, then carrying out heat treatment at 80 ℃ for 10min, and then cooling along with a furnace to obtain the contrast film.

Testing the performance of the membrane tube: the comparative membrane prepared in this example was tested at room temperature and a pressure of 0.6MPa with a pure water flux of 40LHM, a retention of 95.6% for a 0.2 wt% solution of magnesium sulphate and a reduction of 33% after 3h of immersion in the E.coli culture (tested according to GB 4789.3).

Comparative example 2

(1) Preparing a graphene oxide aqueous solution with the concentration of 2g/L by using a modified Hummers method;

(2) slowly dropwise adding 0.1M ammonia water into 12.5ml of 0.01M titanyl sulfate solution, adjusting the pH value to 10, stirring for 3 hours at 60 ℃, ultrasonically mixing with the graphene oxide solution for 15 minutes, putting the solution into a reaction kettle, and reacting for 1 hour in an oven at 90 ℃ to obtain the graphene oxide loaded with titanium dioxide, wherein the mass ratio of the graphene oxide to the titanium dioxide is 20: 1;

(3) adding the material obtained in the step (2) into a piperazine solution with the concentration of 1 wt%, uniformly stirring and mixing (the mass ratio of the titanium dioxide-loaded graphene oxide to the piperazine is 0.001: 1), adding 0.5 wt% of ethylenediamine, and performing ultrasonic treatment to obtain an aqueous phase solution;

(4) soaking a polyether sulfone support body of 30KD washed by ethanol and water in a n-hexane solution of trimesoyl chloride with the concentration of 2 wt%, removing the n-hexane solution of unreacted trimesoyl chloride after reacting for 10min at room temperature, soaking in the aqueous phase solution, and removing the aqueous phase solution after reacting for 10min at room temperature;

(5) and (4) air-drying the material obtained in the step (4) in a shade place, then carrying out heat treatment at 80 ℃ for 10min, and then cooling along with a furnace to obtain the contrast film.

Testing the performance of the membrane tube: the comparative membrane prepared in this example was tested at room temperature and a pressure of 0.6MPa with a pure water flux of 50LHM, a retention of 95% for a 0.2 wt% solution of magnesium sulphate and a reduction of 34% after 3h of immersion in the E.coli culture (tested according to GB 4789.3).

Comparative example 3

(1) Preparing a graphene oxide aqueous solution with the concentration of 5g/L by using a modified Hummers method;

(2) slowly dropwise adding 0.1M ammonia water into a mixed solution of 12.5mL, 0.01M titanyl sulfate, 15.6mL and 0.01M silver nitrate, adjusting the pH to 10, stirring at 60 ℃ for 3h, ultrasonically mixing with the graphene oxide solution for 15min, putting the solution into a reaction kettle, and reacting in an oven at 90 ℃ for 3h to obtain graphene oxide loaded with titanium dioxide and silver, wherein the mass ratio of the graphene oxide to the titanium dioxide to the silver is 20: 1;

(3) adding the material obtained in the step (2) into a piperazine solution with the concentration of 3 wt%, stirring and mixing uniformly (the mass ratio of the graphene oxide loaded with titanium dioxide and silver to the piperazine is 0.001: 1), adding 0.1 wt% of ethylenediamine, and performing ultrasonic treatment to obtain an aqueous phase solution;

(4) soaking a polyether sulfone support body of 30KD washed by ethanol and water in a normal hexane solution of trimesoyl chloride with the concentration of 1 wt%, removing the normal hexane solution of unreacted trimesoyl chloride after reacting for 10min at room temperature, soaking in the aqueous phase solution, and removing the unreacted aqueous phase solution after reacting for 10min at room temperature;

(5) and (4) air-drying the material obtained in the step (4) in a shade place, then carrying out heat treatment at 50 ℃ for 15min, and then cooling along with a furnace to obtain the contrast film.

Testing the performance of the membrane tube: the comparative membrane prepared in this example was tested at room temperature and a pressure of 0.6MPa with a pure water flux of 52LHM, a retention of 95% for a 0.2 wt% solution of magnesium sulphate and a reduction of 80% after 3h immersion in an escherichia coli culture (test according to GB 4789.3).

Comparative example 4

(1) Preparing a graphene oxide aqueous solution with the concentration of 5g/L by using a modified Hummers method;

(2) slowly dropwise adding 0.1M ammonia water into a mixed solution of 12.5mL, 0.01M titanyl sulfate, 15.6mL and 0.01M silver nitrate, adjusting the pH to 10, stirring at 60 ℃ for 3h, ultrasonically mixing with the graphene oxide solution for 15min, putting the solution into a reaction kettle, and reacting in an oven at 90 ℃ for 3h to obtain graphene oxide loaded with titanium dioxide and silver, wherein the mass ratio of the graphene oxide to the titanium dioxide to the silver is 20: 1;

(3) adding the material obtained in the step (2) into a piperazine solution with the concentration of 3 wt%, uniformly stirring and mixing (the mass ratio of the graphene oxide loaded with titanium dioxide and silver to the piperazine is 0.005: 1), adding 0.1 wt% of ethylenediamine, and performing ultrasonic treatment to obtain an aqueous phase solution;

(4) soaking a polyether sulfone support body of 30KD washed by ethanol and water in a normal hexane solution of trimesoyl chloride with the concentration of 1 wt%, removing the normal hexane solution of unreacted trimesoyl chloride after reacting for 10min at room temperature, soaking in the aqueous phase solution, and removing the unreacted aqueous phase solution after reacting for 10min at room temperature;

(5) and (4) air-drying the material obtained in the step (4) in a shade place, then carrying out heat treatment at 50 ℃ for 15min, and then cooling along with a furnace to obtain the contrast film.

Testing the performance of the membrane tube: the comparative membrane prepared in this example was tested at room temperature and a pressure of 0.6MPa with a pure water flux of 60LHM, a retention of 88% for a 0.2 wt% solution of magnesium sulfate, and a reduction of 97% after 3h immersion of the escherichia coli culture (tested according to GB 4789.3).

Example 1

(1) Preparing a graphene oxide aqueous solution with the concentration of 2g/L by using a modified Hummers method;

(2) slowly dropwise adding 0.1M ammonia water into a mixed solution of 12.5mL, 0.01M titanyl sulfate, 15.6mL and 0.01M silver nitrate, adjusting the pH to 10, stirring at 60 ℃ for 3h, ultrasonically mixing with the graphene oxide solution for 15min, putting the solution into a reaction kettle, and reacting in an oven at 90 ℃ for 1h to obtain graphene oxide loaded with titanium dioxide and silver, wherein the mass ratio of the graphene oxide to the titanium dioxide to the silver is 20: 1;

(3) adding the material obtained in the step (2) into a piperazine solution with the concentration of 1 wt%, stirring and mixing uniformly (the mass ratio of the graphene oxide loaded with titanium dioxide and silver to the piperazine is 0.002: 1), adding 0.5 wt% of ethylenediamine, and performing ultrasonic treatment to obtain an aqueous phase solution;

(4) soaking a polyether sulfone support body of 30KD washed by ethanol and water in a n-hexane solution of trimesoyl chloride with the concentration of 2 wt%, removing the n-hexane solution of unreacted trimesoyl chloride after reacting for 10min at room temperature, soaking in the aqueous phase solution, and removing the aqueous phase solution after reacting for 10min at room temperature;

(5) and (5) placing the material obtained in the step (4) in a shade place for air drying, then carrying out heat treatment at 50 ℃ for 15min, and then cooling along with a furnace to obtain the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane.

Testing the performance of the membrane tube: the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane prepared in the embodiment is tested under the conditions of room temperature and pressure of 0.6MPa, the pure water flux of the composite nanofiltration membrane is 55LHM, the rejection rate of 0.2 wt% magnesium sulfate solution is 96%, and the rejection rate of the composite nanofiltration membrane is reduced by 97% after the composite nanofiltration membrane is soaked in escherichia coli culture solution for 3 hours (tested according to GB 4789.3).

Example 2

Steps (1) and (2) were the same as in example 1;

(3) adding the material obtained in the step (2) into a piperazine solution with the concentration of 3 wt%, stirring and mixing uniformly (the mass ratio of the graphene oxide loaded with titanium dioxide and silver to the piperazine is 0.004: 1), adding 0.5 wt% of ethylenediamine, and performing ultrasonic treatment to obtain an aqueous phase solution;

(4) soaking a polyether sulfone support body of 30KD washed by ethanol and water in a normal hexane solution of trimesoyl chloride with the concentration of 1 wt%, removing the normal hexane solution of unreacted trimesoyl chloride after reacting for 10min at room temperature, soaking in the aqueous phase solution, and removing the unreacted aqueous phase solution after reacting for 10min at room temperature;

(5) and (5) placing the material obtained in the step (4) in a shade place for air drying, then carrying out heat treatment at 50 ℃ for 15min, and then cooling along with a furnace to obtain the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane.

Testing the performance of the membrane tube: the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane prepared in the embodiment is tested under the conditions of room temperature and pressure of 0.6MPa, the pure water flux of the composite nanofiltration membrane is 58LHM, the rejection rate of 0.2 wt% magnesium sulfate solution is 93%, and 99% of the total amount of the graphene oxide-titanium dioxide-silver doped piperazine polyamide composite nanofiltration membrane is reduced by soaking in escherichia coli culture solution for 3 hours (according to GB4789.3 test).

The above description is only a preferred embodiment of the present invention, and therefore should not be taken as limiting the scope of the invention, which is defined by the appended claims.