Molybdenum oxide disulfide doped piperazine polyamide composite ceramic nanofiltration membrane and preparation method thereof
阅读说明：本技术 一种氧化二硫化钼掺杂哌嗪聚酰胺复合陶瓷纳滤膜及其制备方法 (Molybdenum oxide disulfide doped piperazine polyamide composite ceramic 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二硫化钼掺杂哌嗪聚酰胺复合陶瓷纳滤膜及其制备方法,包括多孔陶瓷膜支撑体和设于该多孔陶瓷膜支撑体上的有机功能层,该多孔陶瓷膜支撑体的表面负载有硅烷偶联剂,该有机功能层以水相单体、有机相单体和酸接受剂为原料通过界面聚合反应于多孔陶瓷膜支撑体上形成。本发明通过在负载有交联剂的无机陶瓷膜上制备有机无机哌嗪聚酰胺复合陶瓷纳滤膜,对硫酸镁溶液具有较高的脱盐率,纯水通量高且耐酸碱性能良好。(The invention discloses a molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane and a preparation method thereof. According to the invention, the organic-inorganic piperazine polyamide composite ceramic nanofiltration membrane is prepared on the inorganic ceramic membrane loaded with the cross-linking agent, so that the magnesium sulfate solution has high desalination rate, high pure water flux and good acid and alkali resistance.)
1. The molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane is characterized in that: the organic functional layer is formed by taking a water phase monomer, an organic phase monomer and an acid acceptor as raw materials and performing interfacial polymerization reaction on the porous ceramic membrane support;
the water phase monomer contains molybdenum disulfide oxide and piperazine;
the organic phase monomer is trimesoyl chloride;
the acid acceptor is polyamine;
the amino group on the silane coupling agent reacts with trimesoyl chloride to be connected.
2. The molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane of claim 1, wherein: the polyamine is diethylamine.
3. The molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane of claim 1, wherein: the aperture of the porous ceramic membrane support is 10-100 nm.
4. The molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane of claim 1, wherein: the material of the porous ceramic membrane support body is alumina, titanium oxide or zirconium oxide.
5. The molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane of any one of claims 1 to 4, wherein: the mass ratio of the piperazine to the molybdenum disulfide oxide to the polyamine is 0.2-3: 0.01-0.05: 1.
6. The preparation method of the molybdenum disulfide oxide doped piperazine polyamide composite ceramic 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: preparing molybdenum disulfide oxide by an improved Hummers method; and (2) taking the mixture of the molybdenum disulfide oxide and the piperazine as an aqueous phase monomer, taking phthaloyl chloride as an organic monomer, taking polyamine as an acid acceptor, and forming the organic functional layer on the porous ceramic membrane support body activated by strong alkali and grafted with the silane coupling agent through interfacial polymerization, wherein amino on the silane coupling agent reacts with trimesoyl chloride to be connected, so that the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane is obtained.
7. The method of claim 6, wherein: the method comprises the following steps:
(1) preparing an aqueous solution of molybdenum disulfide oxide by using a modified Hummers method;
(2) fully mixing the molybdenum disulfide oxide aqueous solution, the piperazine aqueous solution, PEG1000 and polyamine to obtain an aqueous phase solution;
(3) after ultrasonic treatment, soaking the ceramic membrane support body in a strong alkali solution for activation treatment, and then drying to obtain an activated ceramic membrane support body;
(4) soaking the activated ceramic membrane support body in a silane coupling agent solution, then cleaning with ethanol and water, and drying to obtain a grafted ceramic membrane support body;
(5) soaking the grafted ceramic membrane support body in a n-hexane solution of trimesoyl chloride, carrying out soaking and blow-drying after room temperature reaction, soaking in the water phase solution prepared in the step (2), and carrying out soaking and blow-drying after room temperature reaction; repeating the step at least 1 time;
(6) and (3) drying the material obtained in the step (5) in the shade, then carrying out heat treatment at 50-80 ℃, and then cooling along with a furnace to obtain the molybdenum oxide disulfide doped piperazine polyamide composite ceramic nanofiltration membrane.
8. The method of claim 7, wherein: in the aqueous phase solution, the concentration of the piperazine is 0.2-3 wt%, the concentration of the molybdenum disulfide oxide is 0.01-0.05 wt%, and the concentration of the polyamine is 1 wt%.
9. The method of claim 9, wherein: in the aqueous phase solution, the concentration of the PEG1000 is 0.8-1.2 wt%.
10. The method of claim 7, wherein: the concentration of the n-hexane solution of trimesoyl chloride is 2-10 wt%.
Technical Field
The invention belongs to the technical field of membrane separation, and particularly relates to a molybdenum oxide disulfide doped piperazine polyamide composite ceramic nanofiltration membrane and a preparation method thereof.
Background
The nanofiltration membrane technology is a means for effectively solving the problem of water purification due to simple operation and high efficiency. The nanofiltration membrane operates at lower pressure and higher flux than RO membranes. The nanofiltration membrane technology is used for water purification and has two major problems, namely the problem of flux and interception needs to be balanced, and the problem of pollution resistance of a membrane layer. How to solve the problems becomes a difficult problem of the nanofiltration membrane in the aspect of water purification application.
The research of the nanofiltration membrane in recent years shows that the most widely used organic nanofiltration membrane at present has the advantages of high air permeability, low density, good film forming property, low cost, good flexibility and the like, but loses use value in many fields due to poor high temperature resistance, organic solvent resistance and acid and alkali resistance; the inorganic nanofiltration membrane has the advantages of high mechanical strength, corrosion resistance, solvent resistance, high temperature resistance, stronger pollution resistance than an organic membrane and the like, but has higher preparation cost, large brittleness and difficult processing. Therefore, how to combine the advantages of inorganic materials and organic materials into one, and the preparation of the anti-pollution composite nanofiltration membrane with high flux and high rejection rate becomes a hot focus of attention.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a molybdenum oxide disulfide doped piperazine polyamide composite ceramic nanofiltration membrane.
The invention also aims to provide a preparation method of the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane.
The technical scheme of the invention is as follows:
the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane is characterized in that: the organic functional layer is formed by taking a water phase monomer, an organic phase monomer and an acid acceptor as raw materials and performing interfacial polymerization reaction on the porous ceramic membrane support;
the water phase monomer contains molybdenum disulfide oxide and piperazine;
the organic phase monomer is trimesoyl chloride;
the acid acceptor is polyamine;
the amino group on the silane coupling agent reacts with trimesoyl chloride to be connected.
In a preferred embodiment of the invention, the polyamine is diethylamine.
In a preferred embodiment of the present invention, the pore size of the porous ceramic membrane support is 10 to 100 nm.
In a preferred embodiment of the present invention, the material of the porous ceramic membrane support is alumina, titania or zirconia.
In a preferred embodiment of the invention, the mass ratio of the piperazine, the molybdenum disulfide oxide and the polyamine is 0.2-3: 0.01-0.05: 1.
The other technical scheme of the invention is as follows:
the preparation method of the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane comprises the following steps: preparing molybdenum disulfide oxide by an improved Hummers method; and (2) taking the mixture of the molybdenum disulfide oxide and the piperazine as an aqueous phase monomer, taking phthaloyl chloride as an organic monomer, taking polyamine as an acid acceptor, and forming the organic functional layer on the porous ceramic membrane support body activated by strong alkali and grafted with the silane coupling agent through interfacial polymerization, wherein amino on the silane coupling agent reacts with trimesoyl chloride to be connected, so that the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane is obtained.
In a preferred embodiment of the present invention, the method comprises the following steps:
(1) preparing an aqueous solution of molybdenum disulfide oxide by using a modified Hummers method;
(2) fully mixing the molybdenum disulfide oxide aqueous solution, the piperazine aqueous solution, PEG1000 and polyamine to obtain an aqueous phase solution;
(3) after ultrasonic treatment, soaking the ceramic membrane support body in a strong alkali solution for activation treatment, and then drying to obtain an activated ceramic membrane support body;
(4) soaking the activated ceramic membrane support body in a silane coupling agent solution, then cleaning with ethanol and water, and drying to obtain a grafted ceramic membrane support body;
(5) soaking the grafted ceramic membrane support body in a n-hexane solution of trimesoyl chloride, carrying out soaking and blow-drying after room temperature reaction, soaking in the water phase solution prepared in the step (2), and carrying out soaking and blow-drying after room temperature reaction; repeating the step at least 1 time;
(6) and (3) drying the material obtained in the step (5) in the shade, then carrying out heat treatment at 50-80 ℃, and then cooling along with a furnace to obtain the molybdenum oxide disulfide doped piperazine polyamide composite ceramic nanofiltration membrane.
Further preferably, in the aqueous phase solution, the concentration of the piperazine is 0.2 to 3 wt%, the concentration of the molybdenum disulfide oxide is 0.01 to 0.05 wt%, and the concentration of the polyamine is 1 wt%.
Still more preferably, the concentration of the PEG1000 in the aqueous phase solution is 0.8 to 1.2 wt%.
Further preferably, the concentration of the n-hexane solution of trimesoyl chloride is 2-10 wt%.
The invention has the beneficial effects that: according to the invention, the organic-inorganic piperazine polyamide composite ceramic nanofiltration membrane is prepared on the inorganic ceramic membrane loaded with the cross-linking agent, so that the magnesium sulfate solution has high desalination rate, high pure water flux and good acid and alkali resistance.
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 taken, cleaned and dried, 3g of molybdenum disulfide 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) performing cross-flow filtration on the solution by using a tubular ceramic membrane with the aperture of 0.05 mu m to remove impurities to obtain a material after impurity removal
(3) And (3) diluting or concentrating the material obtained in the step (2) according to the required concentration to obtain molybdenum oxide disulfide aqueous solutions with different concentrations.
Comparative example 1
(1) Preparing a molybdenum disulfide oxide aqueous solution with the concentration of 3mg/mL by using a modified Hummers method;
(2) fully mixing a piperazine aqueous solution, PEG1000 and polyamine to obtain an aqueous phase solution, wherein the content of the piperazine, the PEG1000 and the diethylamine in the aqueous phase solution is 1 wt%, 1 wt% and 1 wt% in sequence;
(3) ultrasonically treating an alumina ceramic membrane tube with the aperture of about 50cm after cutting for 5 hours, soaking the alumina ceramic membrane tube with the aperture of 100nm for 24 hours by using 2mol/L sodium hydroxide, drying the tube for 10 hours at the temperature of 100 ℃, washing the ceramic membrane tube by using cellulose after cooling, then washing the ceramic membrane tube by using ethanol and deionized water for a plurality of times in sequence, drying the tube for 12 hours at the temperature set value of 100 ℃ in a drying oven, and cooling the tube along with the oven to obtain an activated ceramic membrane support body;
(4) soaking the activated ceramic membrane support body in a 2 mmol/L3-aminopropyltriethoxysilane ethanol solution, reacting for 12 hours at room temperature, washing with ethanol and deionized water for several times, drying for 12 hours in a drying oven at a set temperature of 150 ℃, and cooling with the oven to obtain a grafted ceramic membrane support body;
(5) soaking the grafted ceramic membrane support body in a n-hexane solution of trimesoyl chloride with the concentration of 2 wt%, carrying out soaking and blow-drying after reacting for 10min at room temperature, soaking in the water phase solution prepared in the step (2), and carrying out soaking and blow-drying after reacting for 10min at room temperature; repeating the step for 1 time;
(6) and (5) placing the material obtained in the step (5) in a shade place for air drying, then placing the material in a 50 ℃ oven for heat treatment for 15min, and then cooling along with the oven to obtain the contrast film.
Testing the performance of the membrane tube: the comparison made in this comparative example was tested at room temperature and a pressure of 0.6MPa with a pure water flux of 35LHM and a rejection of 93% for a 0.2 wt% solution of magnesium sulfate.
And (3) acid and alkali resistance test: after the comparative membrane prepared in the comparative example is respectively soaked in a nitric acid solution with the pH value of 2 and a sodium hydroxide solution with the pH value of 12 for 168 hours at the temperature of 85 ℃, the pure water flux is respectively 33 and 32LHM, the retention rates are respectively 92.3 percent and 91.8 percent, and the performance is basically kept unchanged.
Comparative example 2
(1) Preparing a molybdenum disulfide oxide aqueous solution with the concentration of 3mg/mL by using a modified Hummers method;
(2) fully mixing the molybdenum disulfide oxide aqueous solution, the piperazine aqueous solution, PEG1000 and polyamine to obtain an aqueous phase solution, wherein the contents of the molybdenum disulfide oxide, the piperazine, the PEG1000 and the diethylamine in the aqueous phase solution are 0.008 wt%, 1 wt% and 1 wt% in sequence;
(3) ultrasonically treating an alumina ceramic membrane tube with the aperture of about 50cm after cutting for 5 hours, soaking the alumina ceramic membrane tube with the aperture of 100nm for 24 hours by using 2mol/L sodium hydroxide, drying the tube for 10 hours at the temperature of 100 ℃, washing the ceramic membrane tube by using cellulose after cooling, then washing the ceramic membrane tube by using ethanol and deionized water for a plurality of times in sequence, drying the tube for 12 hours at the temperature set value of 100 ℃ in a drying oven, and cooling the tube along with the oven to obtain an activated ceramic membrane support body;
(4) soaking the activated ceramic membrane support body in a 2 mmol/L3-aminopropyltriethoxysilane ethanol solution, reacting for 12 hours at room temperature, washing with ethanol and deionized water for several times, drying for 12 hours in a drying oven at a set temperature of 150 ℃, and cooling with the oven to obtain a grafted ceramic membrane support body;
(5) soaking the grafted ceramic membrane support body in a n-hexane solution of trimesoyl chloride with the concentration of 2 wt%, carrying out soaking and blow-drying after reacting for 10min at room temperature, soaking in the water phase solution prepared in the step (2), and carrying out soaking and blow-drying after reacting for 10min at room temperature; repeating the step for 1 time;
(6) and (5) placing the material obtained in the step (5) in a shade place for air drying, then placing the material in a 50 ℃ oven for heat treatment for 15min, and then cooling along with the oven to obtain the contrast film.
Testing the performance of the membrane tube: the comparative film obtained in this comparative example was tested at room temperature and a pressure of 0.6MPa, and had a pure water flux of 40LHM and a rejection of 94% for a 0.2 wt% solution of magnesium sulfate.
And (3) acid and alkali resistance test: after the comparative membrane prepared in the comparative example is respectively soaked in a nitric acid solution with the pH value of 2 and a sodium hydroxide solution with the pH value of 12 for 168 hours at the temperature of 85 ℃, the pure water flux is respectively 38 LHM and 39LHM, the retention rates are respectively 93.2 percent and 93.6 percent, and the performance is basically kept unchanged.
Comparative example 3
(1) Preparing a molybdenum disulfide oxide aqueous solution with the concentration of 3mg/mL by using a modified Hummers method;
(2) fully mixing the molybdenum disulfide oxide aqueous solution, the piperazine aqueous solution, PEG1000 and polyamine to obtain an aqueous phase solution, wherein the contents of the molybdenum disulfide oxide, the piperazine, the PEG1000 and the diethylamine in the aqueous phase solution are 0.07 wt%, 1 wt% and 1 wt% in sequence;
(3) ultrasonically treating an alumina ceramic membrane tube with the aperture of about 50cm after cutting for 5 hours, soaking the alumina ceramic membrane tube with the aperture of 100nm for 24 hours by using 2mol/L sodium hydroxide, drying the tube for 10 hours at the temperature of 100 ℃, washing the ceramic membrane tube by using cellulose after cooling, then washing the ceramic membrane tube by using ethanol and deionized water for a plurality of times in sequence, drying the tube for 12 hours at the temperature set value of 100 ℃ in a drying oven, and cooling the tube along with the oven to obtain an activated ceramic membrane support body;
(4) soaking the activated ceramic membrane support body in a 2 mmol/L3-aminopropyltriethoxysilane ethanol solution, reacting for 12 hours at room temperature, washing with ethanol and deionized water for several times, drying for 12 hours in a drying oven at a set temperature of 150 ℃, and cooling with the oven to obtain a grafted ceramic membrane support body;
(5) soaking the grafted ceramic membrane support body in a n-hexane solution of trimesoyl chloride with the concentration of 2 wt%, carrying out soaking and blow-drying after reacting for 10min at room temperature, soaking in the water phase solution prepared in the step (2), and carrying out soaking and blow-drying after reacting for 10min at room temperature; repeating the step for 1 time;
(6) and (5) placing the material obtained in the step (5) in a shade place for air drying, then placing the material in a 50 ℃ oven for heat treatment for 15min, and then cooling along with the oven to obtain the contrast film.
Testing the performance of the membrane tube: the comparative film obtained in this comparative example was tested at room temperature and a pressure of 0.6MPa, and had a pure water flux of 53LHM and a rejection of 90% for a 0.2 wt% solution of magnesium sulfate.
And (3) acid and alkali resistance test: after the comparative membrane prepared in the comparative example is respectively soaked in a nitric acid solution with the pH value of 2 and a sodium hydroxide solution with the pH value of 12 for 168 hours at the temperature of 85 ℃, the pure water flux is respectively 50 and 510LHM, the retention rates are respectively 88.5 percent and 87.6 percent, and the performance is basically kept unchanged.
Example 1
(1) Preparing a molybdenum disulfide oxide aqueous solution with the concentration of 3mg/mL by using a modified Hummers method;
(2) fully mixing the molybdenum disulfide oxide aqueous solution, the piperazine aqueous solution, PEG1000 and polyamine to obtain an aqueous phase solution, wherein the contents of the molybdenum disulfide oxide, the piperazine, the PEG1000 and the diethylamine in the aqueous phase solution are 0.02 wt%, 1 wt% and 1 wt% in sequence;
(3) ultrasonically treating an alumina ceramic membrane tube with the aperture of about 50cm after cutting for 5 hours, soaking the alumina ceramic membrane tube with the aperture of 100nm for 24 hours by using 2mol/L sodium hydroxide, drying the tube for 10 hours at the temperature of 100 ℃, washing the ceramic membrane tube by using cellulose after cooling, then washing the ceramic membrane tube by using ethanol and deionized water for a plurality of times in sequence, drying the tube for 12 hours at the temperature set value of 100 ℃ in a drying oven, and cooling the tube along with the oven to obtain an activated ceramic membrane support body;
(4) soaking the activated ceramic membrane support body in a 2 mmol/L3-aminopropyltriethoxysilane ethanol solution, reacting for 12 hours at room temperature, washing with ethanol and deionized water for several times, drying for 12 hours in a drying oven at a set temperature of 150 ℃, and cooling with the oven to obtain a grafted ceramic membrane support body;
(5) soaking the grafted ceramic membrane support body in a n-hexane solution of trimesoyl chloride with the concentration of 2 wt%, carrying out soaking and blow-drying after reacting for 10min at room temperature, soaking in the water phase solution prepared in the step (2), and carrying out soaking and blow-drying after reacting for 10min at room temperature; repeating the step for 1 time;
(6) and (5) placing the material obtained in the step (5) in a shade place for air drying, then placing the material in a 50 ℃ oven for heat treatment for 15min, and then cooling along with the oven to obtain the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane.
Testing the performance of the membrane tube: the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane prepared in the embodiment is tested under the conditions of room temperature and 0.6MPa, the pure water flux is 62LHM, and the rejection rate of 0.2 wt% magnesium sulfate solution is 98%.
And (3) acid and alkali resistance test: the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane prepared in the embodiment is respectively placed in a nitric acid solution with the pH value of 2 and a sodium hydroxide solution with the pH value of 12, after the nanofiltration membrane is soaked for 168 hours at the temperature of 85 ℃, pure water fluxes are respectively 60 and 59LHM, retention rates are respectively 95.7% and 96.4%, and performances are basically kept unchanged.
Example 2
(1) Preparing a molybdenum disulfide oxide aqueous solution with the concentration of 1mg/mL by using a modified Hummers method;
(2) fully mixing the molybdenum disulfide oxide aqueous solution, the piperazine aqueous solution, PEG1000 and polyamine to obtain an aqueous phase solution, wherein the contents of the molybdenum disulfide oxide, the piperazine, the PEG1000 and the diethylamine in the aqueous phase solution are 0.01 wt%, 3 wt%, 1 wt% and 1 wt% in sequence;
(3) ultrasonically treating an alumina ceramic membrane tube with the aperture of 80nm and the length of about 50cm after cutting for 10 hours, soaking the alumina ceramic membrane tube in 5mol/L sodium hydroxide for 24 hours, drying the tube for 10 hours at the temperature of 100 ℃, washing the ceramic membrane tube by using cellulose after cooling, then washing the ceramic membrane tube by using ethanol and deionized water for a plurality of times in sequence, drying the tube for 12 hours at the temperature of 100 ℃ in a drying oven, and cooling the tube along with the oven to obtain an activated ceramic membrane support body;
(4) soaking the activated ceramic membrane support body in a 2 mmol/L3-aminopropyltriethoxysilane ethanol solution, reacting for 12 hours at room temperature, washing with ethanol and deionized water for several times, drying for 12 hours in a drying oven at a set temperature of 150 ℃, and cooling with the oven to obtain a grafted ceramic membrane support body;
(5) soaking the grafted ceramic membrane support body in a n-hexane solution of trimesoyl chloride with the concentration of 2 wt%, carrying out soaking and blow-drying after reacting for 3min at room temperature, soaking in the water phase solution prepared in the step (2), and carrying out soaking and blow-drying after reacting for 3min at room temperature; repeating the step for 1 time;
(6) and (3) placing the material obtained in the step (5) in a shade place for air drying, then placing the material in an oven at 80 ℃ for heat treatment for 15min, and then cooling along with the oven to obtain the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane.
Testing the performance of the membrane tube: the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane prepared in the embodiment is tested under the conditions of room temperature and 0.6MPa, the pure water flux of the nanofiltration membrane is 60LHM, and the rejection rate of 0.2 wt% magnesium sulfate solution is 97%.
And (3) acid and alkali resistance test: the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane prepared in the embodiment is respectively placed in a nitric acid solution with the pH value of 2 and a sodium hydroxide solution with the pH value of 12, after the nanofiltration membrane is soaked for 168 hours at the temperature of 85 ℃, pure water fluxes are respectively 58 and 57LHM, retention rates are respectively 95.3% and 96.2%, and performances are basically kept unchanged.
Example 3
(1) Preparing a molybdenum disulfide oxide aqueous solution with the concentration of 5mg/mL by using a modified Hummers method;
(2) fully mixing the molybdenum disulfide oxide aqueous solution, the piperazine aqueous solution, PEG1000 and polyamine to obtain an aqueous phase solution, wherein the contents of the molybdenum disulfide oxide, the piperazine, the PEG1000 and the diethylamine in the aqueous phase solution are 0.05 wt%, 0.2 wt%, 1 wt% and 1 wt% in sequence;
(3) ultrasonically treating an alumina ceramic membrane tube with the length of about 50cm and the aperture of 10nm after cutting for 10 hours, soaking the alumina ceramic membrane tube in 2mol/L sodium hydroxide for 24 hours, drying the tube for 10 hours at the temperature of 100 ℃, washing the ceramic membrane tube by using cellulose after cooling, then washing the ceramic membrane tube by using ethanol and deionized water for a plurality of times in sequence, drying the tube for 12 hours at the temperature of 100 ℃ in a drying oven, and cooling the tube along with the oven to obtain an activated ceramic membrane support body;
(4) soaking the activated ceramic membrane support body in a 2 mmol/L3-aminopropyltriethoxysilane ethanol solution, reacting for 12 hours at room temperature, washing with ethanol and deionized water for several times, drying for 12 hours in a drying oven at a set temperature of 150 ℃, and cooling with the oven to obtain a grafted ceramic membrane support body;
(5) soaking the grafted ceramic membrane support body in a normal hexane solution of trimesoyl chloride with the concentration of 10 wt%, carrying out soaking and blow-drying after reacting for 15min at room temperature, soaking in the aqueous phase solution prepared in the step (2), and carrying out soaking and blow-drying after reacting for 15min at room temperature; repeating the step for 1 time;
(6) and (5) placing the material obtained in the step (5) in a shade place for air drying, then placing the material in a 50 ℃ oven for heat treatment for 15min, and then cooling along with the oven to obtain the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane.
Testing the performance of the membrane tube: the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane prepared in the embodiment is tested under the conditions of room temperature and 0.6MPa, the pure water flux is 58LHM, and the rejection rate of 0.2 wt% magnesium sulfate solution is 98.5%.
And (3) acid and alkali resistance test: the molybdenum disulfide oxide doped piperazine polyamide composite ceramic nanofiltration membrane prepared in the embodiment is respectively placed in a nitric acid solution with the pH value of 2 and a sodium hydroxide solution with the pH value of 12, after the nanofiltration membrane is soaked for 168 hours at the temperature of 85 ℃, pure water fluxes are respectively 57.3 and 57.5LHM, retention rates are respectively 96.8% and 97.2%, and performances are basically kept unchanged.
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.