CN112999870A - Carbon nitride modified Janus acid-resistant nanofiltration membrane as well as preparation method and application thereof - Google Patents
Carbon nitride modified Janus acid-resistant nanofiltration membrane as well as preparation method and application thereof Download PDFInfo
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
- B01D61/027—Nanofiltration
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D2325/00—Details relating to properties of membranes
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
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- C02F2101/20—Heavy metals or heavy metal compounds
Abstract
A carbon nitride modified Janus acid-resistant nanofiltration membrane and a preparation method and application thereof are provided, the preparation method of the carbon nitride modified Janus acid-resistant nanofiltration membrane comprises the steps of immersing an ultrafiltration base membrane into a prepared water phase solution for reaction, and drying to obtain an ultrafiltration base membrane I; immersing the ultrafiltration basement membrane I into the oil phase solution for reaction to obtain an ultrafiltration basement membrane II; carrying out heat treatment on the ultrafiltration basement membrane II to obtain an ultrafiltration basement membrane III; and (3) performing three-acid treatment on the ultrafiltration base membrane to obtain the carbon nitride modified Janus acid-resistant nanofiltration membrane. The invention adds two-dimensional carbon material carbon nitride (C)3N4), providing a narrow, smooth and interconnected two-dimensional channel, blocking the passage of macromolecular substances and reducing the transport resistance of water molecules; by interfacial polymerizationThe method is to add a two-dimensional carbon material C3N4The composite functional layer is firmly loaded on the surface of the ultrafiltration basal membrane, and the flux of the nanofiltration membrane prepared by the invention is obviously improved on the premise of ensuring the acid resistance and the retention rate of multivalent cations.
Description
Technical Field
The invention relates to the technical field of membrane preparation, in particular to a carbon nitride modified Janus acid-resistant nanofiltration membrane as well as a preparation method and application thereof.
Background
The nanofiltration membrane is used as a separation membrane with charged surface, can separate substances with different molecular weights by screening, can selectively separate solutes by electrostatic repulsion, has lower operating pressure than a reverse osmosis membrane, reduces larger energy consumption, and is a resource recovery method with simple process and obvious advantages. Therefore, in recent years, nanofiltration membrane separation technology has been widely applied to a plurality of fields such as pure water preparation, seawater desalination and desalination, micromolecular organic matter recovery and removal, heavy metal enrichment and recovery, industrial wastewater treatment and the like. However, most of the traditional nanofiltration membranes are polyamide membranes, are not tolerant in extreme environments (strong acid, strong alkali, strong oxidation, high temperature and the like), are easy to hydrolyze, and limit the wide application of the nanofiltration membranes in the extreme environments. In the actual chemical process, the acidic wastewater is the most common industrial wastewater in China, such as mine wastewater, smelting wastewater, electroplating wastewater, sulfuric acid method titanium dioxide acidic wastewater and the like. The acid-resistant nanofiltration membrane can realize the synchronous separation and resource recovery of heavy metal ions and acid in the acidic wastewater, so the development of the acid-resistant nanofiltration membrane has important significance.
At present, most of acid-resistant nanofiltration membranes are negatively charged nanofiltration membranes, the retention rate and the acid permeability of multivalent cations need to be improved, and the flux is low. The preparation of positively charged and Janus nanofiltration membranes is one of the important methods for improving the rejection rate of the nanofiltration membranes on polyvalent metal ions. At present, the nano-filtration membrane is prepared by the interfacial polymerization reaction of polyvinylamine substances and cyanuric chloride, and although the acid resistance and the acid permeation rate of the nano-filtration membrane prepared by the process are improved, the reaction rate is low, the reaction time is long, and the flux needs to be further improved. Therefore, the invention is necessary to invent the nanofiltration membrane with simple process, short reaction time and high water flux and multivalent salt metal ion rejection rate.
Disclosure of Invention
In view of the above, one of the main objectives of the present invention is to provide a carbon nitride modified Janus acid-resistant nanofiltration membrane, and a preparation method and an application thereof, so as to at least partially solve at least one of the above technical problems.
In order to achieve the above object, as an aspect of the present invention, there is provided a method for preparing a carbon nitride modified Janus acid-resistant nanofiltration membrane, comprising:
s1: immersing an ultrafiltration basement membrane into the prepared aqueous phase solution for reaction, and drying to obtain an ultrafiltration basement membrane I; wherein the aqueous phase solution comprises an aqueous phase monomer A, an acid-binding agent, a two-dimensional nano material B and a surfactant;
s2: immersing the ultrafiltration basement membrane I into the oil phase solution for reaction to obtain an ultrafiltration basement membrane II;
s3: carrying out heat treatment on the ultrafiltration basement membrane II to obtain an ultrafiltration basement membrane III;
s4: and (3) performing three-acid treatment on the ultrafiltration base membrane to obtain the carbon nitride modified Janus acid-resistant nanofiltration membrane.
As another aspect of the invention, the invention also provides a carbon nitride modified Janus acid-resistant nanofiltration membrane obtained by adopting the preparation method.
As a further aspect of the invention, the application of the carbon nitride modified Janus acid-resistant nanofiltration membrane in the field of water quality purification is also provided.
Based on the technical scheme, compared with the prior art, the carbon nitride modified Janus acid-resistant nanofiltration membrane and the preparation method and application thereof have at least one or part of the following advantages:
1. the invention is technically characterized in that the carbon nitride (C) is added into the two-dimensional carbon material3N4) Narrow, smooth and mutually communicated two-dimensional channels are provided, macromolecular substances are blocked from passing through, and water molecule transportation resistance is reduced; adding a two-dimensional carbon material C by adopting an interfacial polymerization method3N4The composite functional layer is firmly loaded on the surface of the ultrafiltration basal membrane, so that the water flux is obviously improved and the C with high flux (51-213LMH/MPa) is prepared on the premise of ensuring the acid resistance and the retention rate of multivalent cations3N4Modified Janus acid-resistant nanofiltration membranes;
2. in the preparation method of the invention, C is controlled3N4The concentration and the subsequent treatment process accelerate the reaction rate of the water phase and the oil phase, reduce the reaction time, and the obtained composite functional layer has a loose structure, thereby being beneficial to improving the water flux;
3. the nanofiltration membrane prepared by the invention improves the membrane flux by 100-150% on the premise of ensuring the acid resistance and the salt rejection rate, and the prepared nanofiltration membrane is a Janus membrane, has enhanced rejection performance on multivalent cations compared with a negatively charged nanofiltration membrane, and has improved anti-pollution performance on negatively charged pollutants compared with a positively charged nanofiltration membrane, so that the acid-resistant nanofiltration membrane has a wider application range and a wider application field;
4. high throughput C prepared by the method of the invention3N4The modified Janus acid-resistant nanofiltration membrane is mainly applied to the recovery treatment of acid wastewater containing heavy metal ions.
Drawings
FIG. 1 is high throughput C in example 13N4Modified Janus acid-resistant nanofiltration membrane pair 2g/LMgCl2The retention rate of the soaking liquid is compared with a curve of the soaking time;
FIG. 2 shows the results of example 5 in which C was not added3N4And is added with C3N4Prepared Janus acid-resistant nanofiltration membrane pair is 2g/LMgCl2The retention rate of (D) is compared with the change curve of the reaction time;
FIG. 3 is a graph comparing flux (bar graph) and rejection (dot line graph) of the nanofiltration membranes of examples 1-4 and comparative examples 1-2.
Detailed Description
In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.
The invention discloses a high-flux C3N4A preparation method of a modified Janus acid-resistant nanofiltration membrane belongs to the technical field of membrane preparation. Firstly, poly is carried outEthylene imine, sodium dodecyl sulfate, graphite phase C3N4Sequentially adding the solids into deionized water to prepare an aqueous phase solution; dissolving cyanuric chloride in an organic solvent to prepare an oil phase solution, finally carrying out contact reaction on an ultrafiltration basement membrane with a water phase solution under normal pressure, removing redundant solution, carrying out contact reaction with the oil phase solution for a period of time, carrying out heat treatment, washing with deionized water, and storing in the deionized water to obtain the high-flux C3N4Modified Janus acid-resistant nanofiltration membrane. The invention adds two-dimensional nano material C into aqueous phase solution3N4The powder improves the flux of the nanofiltration membrane on the premise of ensuring that the acid resistance and the retention rate of multivalent cations are not changed, and the flux is improved by 100 to 150 percent. In addition, the prepared nanofiltration membrane is a Janus membrane, and compared with a negatively charged nanofiltration membrane, the rejection performance of divalent and multivalent cations is enhanced, and compared with a positively charged nanofiltration membrane, the anti-pollution performance of negatively charged pollutants is enhanced; the membrane preparation method is simple, easy to operate, easy to realize industrial production and has wide application prospect; high throughput of preparation C3N4The modified Janus acid-resistant nanofiltration membrane is mainly applied to the fields of water quality purification and industrial wastewater treatment, and is particularly applied to the treatment of acid wastewater containing heavy metal ions.
The invention discloses a preparation method of a carbon nitride modified Janus acid-resistant nanofiltration membrane, which comprises the following steps:
s1: immersing an ultrafiltration basement membrane into the prepared aqueous phase solution for reaction, and drying to obtain an ultrafiltration basement membrane I; wherein the aqueous phase solution comprises an aqueous phase monomer A, an acid-binding agent, a two-dimensional nano material B and a surfactant;
s2: immersing the ultrafiltration basement membrane I into the oil phase solution for reaction to obtain an ultrafiltration basement membrane II;
s3: carrying out heat treatment on the ultrafiltration basement membrane II to obtain an ultrafiltration basement membrane III;
s4: and (3) performing three-acid treatment on the ultrafiltration base membrane to obtain the carbon nitride modified Janus acid-resistant nanofiltration membrane.
In some embodiments of the invention, in step S1, the concentration of aqueous phase monomer A in the aqueous phase solution is 5 to 25g/L, such as 5g/L, 6g/L, 7g/L, 8g/L, 10g/L, 12g/L, 15g/L, 18g/L, 20g/L, 22g/L, 25 g/L;
in some embodiments of the invention, in step S1, the concentration of the acid-binding agent in the aqueous solution is 0.1 to 5 wt%, such as 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%;
in some embodiments of the invention, in step S1, the concentration of the two-dimensional nanomaterial B in the aqueous solution is 0.01 to 10 wt%, such as 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%;
in some embodiments of the invention, in step S1, the concentration of the surfactant in the aqueous phase solution is 0.02 to 0.08 wt%, such as 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%.
In some embodiments of the invention, in step S1, the aqueous phase monomer a includes any one or more of polyethyleneimine, polyvinylamine, polyvinylaniline, polyphenylmethylamine, diethylenetriamine, polyethylenepolyamine;
in some embodiments of the invention, in step S1, the acid-binding agent includes any one or more of triethylamine, pyridine, 4-dimethylaminopyridine, N-diisopropylethylamine, sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, potassium bicarbonate, and potassium carbonate.
In some embodiments of the invention, in step S1, the two-dimensional nanomaterial B is graphite phase C3N4Solid or solution.
In some embodiments of the present invention, in step S1, the surfactant includes any one or more combination of commonly used surfactants such as sodium dodecylbenzene sulfonate, sodium dodecylsulfonate, sodium dodecylsulfate, hexadecyldimethylbenzyl ammonium chloride, octadecyl trimethyl ammonium chloride, trioctylmethyl ammonium chloride, benzyltriethyl ammonium chloride, tetrabutyl ammonium chloride, etc.;
in some embodiments of the invention, in step S1, the ultrafiltration membrane comprises any one or more combination of polyethersulfone, polysulfone, and polyisophthaloyl metaphenylene diamine.
In some embodiments of the invention, in step S1, the reaction time is 2 to 20min, for example 2min, 4min, 6min, 8min, 10min, 12min, 15min, 18min, 20 min.
In some embodiments of the invention, in step S2, the reaction time is 30 to 600S; the reaction temperature is 15 to 35 ℃ and is, for example, 15 ℃, 18 ℃, 20 ℃, 22 ℃, 25 ℃, 28 ℃, 30 ℃, 32 ℃ and 35 ℃; reaction humidity is 20 to 60%, e.g. 20%, 30%, 40%, 50%, 60%;
in some embodiments of the present invention, in step S2, the oil phase solution includes a solute and a solvent;
in some embodiments of the invention, the solute comprises at least one of cyanuric chloride, cyanuric fluoride, cyanuric bromide, cyanuric iodide, or oligomers of the above;
in some embodiments of the invention, the solute is at a concentration of 0.01 to 10g/L, e.g., 0.01g/L, 0.02g/L, 0.05g/L, 0.08g/L, 1g/L, 2g/L, 3g/L, 4g/L, 5g/L, 6g/L, 7g/L, 8g/L, 10 g/L;
in some embodiments of the invention, the solvent comprises any one or combination of n-hexane, cyclohexane, toluene, benzene, ethyl acetate.
In some embodiments of the invention, in step S3, the heat treatment temperature is 50 to 150 ℃, for example 50 ℃, 60 ℃, 80 ℃, 100 ℃, 120 ℃, 150 ℃; the heat treatment time is 2-150min, such as 2min, 5min, 8min, 10min, 20min, 30min, 50min, 80min, 100min, 120min, 140min, and 150 min.
In some embodiments of the invention, in step S4, the concentration of the acid in the acid treatment step is 2 to 15 wt%, such as 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%;
in some embodiments of the present invention, in step S4, the acid treatment temperature in the acid treatment step is 25 to 65 ℃, for example, 25 ℃, 30 ℃, 35 ℃, 45 ℃, 55 ℃, 65 ℃;
in some embodiments of the present invention, in step S4, the acid treatment time in the acid treatment step is 1 to 20min, such as 1min, 2min, 4min, 6min, 8min, 10min, 12min, 15min, 18min, 20 min;
in some embodiments of the invention, in step S4, the acid in the acid treatment step includes any one or more of citric acid, hydrochloric acid, sulfuric acid, and acetic acid.
The invention also discloses a carbon nitride modified Janus acid-resistant nanofiltration membrane obtained by the preparation method.
The invention also discloses application of the carbon nitride modified Janus acid-resistant nanofiltration membrane in the field of water quality purification.
In a preferred embodiment of the present invention, the present invention adopts, for example, the following technical solutions:
high-flux C3The preparation method of the N4 modified Janus acid-resistant nanofiltration membrane comprises the following steps:
(1) preparing an aqueous solution: sequentially adding a water-phase monomer A, an acid-binding agent, a modified two-dimensional nano material B and a surfactant into deionized water, uniformly dispersing the monomers, the acid-binding agent, the modified two-dimensional nano material B and the surfactant, and preparing a water-phase solution; wherein the concentration of the aqueous phase monomer A in the formed aqueous phase solution is 5-25 g/L; the acid-binding agent has a concentration of 0.1-5 wt%; the concentration of the modified two-dimensional nano material B is 0.01-10 wt%; the concentration of the surfactant is 0.02-0.08 wt%.
Wherein the aqueous phase monomer A is multifunctional amine substances such as polyethyleneimine, polyvinylamine, polyvinylaniline, polystyrene methylamine, diethylenetriamine, polyethylene polyamine and the like and any combination thereof, preferably polyethyleneimine, the molecular weight is 30000, preferably 1800, the concentration of the polyethyleneimine is 5-25g/L, and the concentration is preferably 10 g/L;
more preferably, the aqueous phase monomer is a mixture of mixed polyethyleneimines having molecular weights of 600, 1800, 10000, 25000, and the like, respectively.
Wherein the acid-binding agent is one or more of triethylamine, pyridine, 4-dimethylaminopyridine, N-diisopropylethylamine, sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, potassium bicarbonate and potassium carbonate, triethylamine is preferred, and the concentration is preferably 0.5 wt%.
Wherein the surfactant is one or more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, hexadecyl dimethyl benzyl ammonium chloride, octadecyl trimethyl ammonium chloride, trioctyl methyl ammonium chloride, benzyl triethyl ammonium chloride, tetrabutyl ammonium chloride and other common surfactants. Among them, sodium dodecylsulfate is preferable, and the concentration is preferably 0.05 wt%.
Wherein the two-dimensional nano material B is a graphite phase C3N4Solid or solution, preferably at a concentration of 0.875 wt%.
Wherein the ultrafiltration basal membrane is one of ultrafiltration membranes such as polyethersulfone, polysulfone and polyisophthaloyl metaphenylene diamine, preferably polyethersulfone; the molecular weight cut-off is between 30 and 100kDa, preferably 30 kDa.
(2) Preparing an oil phase solution: dissolving cyanuric chloride in solution of one or more organic solvents selected from n-hexane, cyclohexane, toluene, benzene and ethyl acetate, wherein the concentration of cyanuric chloride is 0.01-10 g/L; the cyanuric chloride may be cyanuric chloride, cyanuric fluoride, cyanuric bromide, cyanuric iodide, oligomers thereof, etc.
Wherein, the oil phase solvent is preferably n-hexane, and the concentration of the oil phase is preferably 0.01-2g/L, and most preferably 0.1 g/L.
(3) And (3) interfacial polymerization process: immersing the ultrafiltration basement membrane into the water phase solution for 2-20min, taking out and airing, immersing the ultrafiltration basement membrane into the oil phase solution at 15-35 ℃ and under the humidity of 20-60% for reaction for 30-600 s;
wherein, the temperature in the step (3) is 15-35 ℃, preferably 25 ℃, and the humidity is 20-60%, preferably 40%.
(4) And (3) heat treatment: and (3) carrying out heat treatment on the film obtained in the step (3), wherein the heat treatment temperature is 50-150 ℃, preferably 70 ℃, and the treatment time is 2-150min, preferably 5 min.
(5) And (3) citric acid treatment: performing citric acid treatment on the membrane obtained in the step (4) for 1-20min at the concentration of 2-15 Wt% to obtain C3N4Modified Janus acid-resistant nanofiltration membrane.
Wherein, the concentration of the citric acid is preferably 15 wt%, the citric acid treatment temperature is preferably 25 ℃, and the treatment time is 10 min. The citric acid can also be hydrochloric acid, sulfuric acid, acetic acid and various organic acids.
The technical solution of the present invention is further illustrated by the following specific embodiments in conjunction with the accompanying drawings. It should be noted that the following specific examples are given by way of illustration only and the scope of the present invention is not limited thereto.
The chemicals and raw materials used in the following examples were either commercially available or self-prepared by a known preparation method.
Example 1
Preparing 100ml of aqueous phase solution: weighing 1g of polyethyleneimine with molecular weight of 1800, 0.05g of sodium dodecyl sulfate and 0.175g of C3N4Adding deionized water into the powder to 100ml, fully dispersing and stirring the powder for 3 hours;
preparing 100ml of oil phase solution: weighing 0.015g of cyanuric chloride, dissolving the cyanuric chloride in 100ml of n-hexane solvent, and fully stirring for 3 hours; soaking the polyethersulfone ultrafiltration membrane soaked in deionized water in an aqueous phase solution for 5min, taking out and airing, soaking the polyethersulfone ultrafiltration membrane in an oil phase solution at 25 ℃ for reaction for 90s, carrying out heat treatment at 70 ℃ for 5min, cleaning the polyethersulfone ultrafiltration membrane by using deionized water, then soaking the polyethersulfone ultrafiltration membrane in 15 wt% of citric acid in a water bath at 50 ℃ for 10min, and then cleaning the polyethersulfone ultrafiltration membrane again by using deionized water.
At ambient temperature, the flux was measured to be 51LMH/MPa, and the flux was measured to be 2g/LMgCl2The retention rate of (2) was 96%, and the high flux C was measured3N4The modified Janus acid-resistant nanofiltration membrane was immersed in 3 wt% hydrochloric acid at 25 ℃ and measured for 2g/LMgCl2The retention rate of the sodium ion membrane is changed along with the change of the soaking time, as shown in figure 1, the result shows that the prepared nanofiltration membrane is MgCl2The retention rate of (A) does not significantly decrease with time, indicating the high passQuantity C3N4The modified Janus acid-resistant nanofiltration membrane has good acid resistance.
Example 2
Preparing 100ml of aqueous phase solution: weighing 1g of polyethyleneimine with molecular weight of 1800, 0.05g of sodium dodecyl sulfate and 0.105g of 0.105g C3N4Adding deionized water into the powder to 100ml, fully dispersing and stirring the powder for 3 hours;
preparing 100ml of oil phase solution: weighing 0.015g of cyanuric chloride, dissolving the cyanuric chloride in 100ml of n-hexane solvent, and fully stirring for 3 hours; soaking the polyethersulfone ultrafiltration membrane soaked in deionized water in an aqueous phase solution for 5min, taking out and airing, soaking the polyethersulfone ultrafiltration membrane in an oil phase solution at 25 ℃ for reaction for 120s, carrying out heat treatment at 70 ℃ for 5min, cleaning the polyethersulfone ultrafiltration membrane with deionized water, then soaking the polyethersulfone ultrafiltration membrane in 15 wt% of citric acid in a water bath at 50 ℃ for 10min, and then cleaning the polyethersulfone ultrafiltration membrane with deionized water again.
The flux was measured at room temperature at 72LMH/MPa, and measured for 2g/LMgCl2Has a retention rate of 96 percent, which is 2g/LNa2SO4The retention of the solution was 24%.
Example 3
Preparing 100ml of aqueous phase solution: 0.75g of polyethyleneimine with molecular weight of 1800, 0.05g of sodium dodecyl sulfate and 0.0175g of C are weighed respectively3N4Adding deionized water into the powder to 100ml, fully dispersing and stirring the powder for 3 hours;
preparing 100ml of oil phase solution: weighing 0.01g of cyanuric chloride, dissolving the cyanuric chloride in 100ml of n-hexane solvent, and fully stirring for 3 hours; soaking the polyethersulfone ultrafiltration membrane soaked in deionized water in an aqueous phase solution for 5min, taking out and airing, soaking the polyethersulfone ultrafiltration membrane in an oil phase solution at 25 ℃ for reaction for 90s, carrying out heat treatment at 70 ℃ for 5min, cleaning the polyethersulfone ultrafiltration membrane by using deionized water, then soaking the polyethersulfone ultrafiltration membrane in 15 wt% of citric acid in a water bath at 50 ℃ for 10min, and then cleaning the polyethersulfone ultrafiltration membrane again by using deionized water.
The flux was measured at room temperature to be 131LMH/MPa, and it was measured for 2g/LMgCl2The retention of the solution was 85%, which is 2g/LNa2SO4The retention of the solution was 20%.
Example 4
Preparing 100ml of aqueous phase solution: weighing 1g of polyethyleneimine with molecular weight of 1800, 0.05g of sodium dodecyl sulfate and 0.175g C3N4Adding deionized water into the powder to 100ml, fully dispersing and stirring the powder for 3 hours;
preparing 100ml of oil phase solution: weighing 0.005g of cyanuric chloride, dissolving the cyanuric chloride in 100ml of n-hexane solvent, and fully stirring for 3 hours; soaking the polyethersulfone ultrafiltration membrane soaked in deionized water in an aqueous phase solution for 5min, taking out and airing, soaking the polyethersulfone ultrafiltration membrane in an oil phase solution at 25 ℃ for reaction for 120s, carrying out heat treatment at 70 ℃ for 5min, cleaning the polyethersulfone ultrafiltration membrane with deionized water, then soaking the polyethersulfone ultrafiltration membrane in 15 wt% of citric acid in a water bath at 50 ℃ for 10min, and then cleaning the polyethersulfone ultrafiltration membrane with deionized water again.
The flux was measured at room temperature at 213LMH/MPa for 2g/LMgCl2Has a rejection of 78%, which is 2g/LNa2SO4The retention of the solution was 18%.
Example 5
100ml of a solution containing C3N4Aqueous phase solution of (a): weighing 1g of polyethyleneimine with molecular weight of 1800, 0.05g of sodium dodecyl sulfate and 0.175g C3N4Adding deionized water into the powder to 100ml, fully dispersing and stirring the powder for 3 hours;
100ml of a C-free solution was prepared3N4Aqueous phase solution of (a): respectively weighing 1g of polyethyleneimine with the molecular weight of 1800 and 0.05g of sodium dodecyl sulfate, adding deionized water to 100ml, and fully dispersing and stirring the mixture for 3 hours;
preparing 100ml of oil phase solution: weighing 0.015g of cyanuric chloride, dissolving the cyanuric chloride in 100ml of n-hexane solvent, and fully stirring for 3 hours; respectively soaking the polyethersulfone ultrafiltration membrane soaked in the deionized water in the two aqueous phase solutions for 5min, taking out and airing; immersing the ultrafiltration membranes taken out of the two water phase solutions into the oil phase solution respectively for reaction for 30s, 60s, 90s, 120s and 150s, then carrying out heat treatment on the ultrafiltration membranes at 70 ℃ for 5min, and cleaning the ultrafiltration membranes by using deionized water to obtain 5 sheets of non-C3N4Modified Janus sodiumFilter Membrane and 5 sheets C3N4Modified Janus nanofiltration membranes.
As shown in FIG. 2, the pair of 2g/LMgCl was measured at normal temperature2The retention of (A) does not proceed with C as the reaction time increases3N4Modified Janus nanofiltration membrane to MgCl2The retention rates of the solutions are respectively 75%, 89%, 92%, 95% and 94%; carry out C3N4Modified Janus nanofiltration membrane to MgCl2The retention rates of the solutions were 90%, 95%, 98%, 95%, and 94%, respectively.
Comparative example 1
Preparing 100ml of aqueous phase solution: respectively weighing 1g of polyethyleneimine with the molecular weight of 1800 and 0.05g of sodium dodecyl sulfate, adding deionized water to 100ml, and fully dispersing and stirring the mixture for 3 hours;
preparing 100ml of oil phase solution: weighing 0.015g of cyanuric chloride, dissolving the cyanuric chloride in 100ml of n-hexane solvent, and fully stirring for 3 hours; soaking the polyethersulfone ultrafiltration membrane soaked in deionized water in an aqueous phase solution for 5min, taking out and airing, soaking the polyethersulfone ultrafiltration membrane in an oil phase solution at 25 ℃ for reaction for 120s, carrying out heat treatment at 70 ℃ for 5min, cleaning the polyethersulfone ultrafiltration membrane with deionized water, then soaking the polyethersulfone ultrafiltration membrane in 15 wt% of citric acid in a water bath at 50 ℃ for 10min, and then cleaning the polyethersulfone ultrafiltration membrane with deionized water again.
The flux was measured at ambient temperature, 33LMH/MPa, for 2g/L MgCl2Has a retention rate of 95% and is suitable for a gas flow rate of 2g/LNa2SO4The retention of the solution was 50%.
Comparative example 2
Weighing 5g of polyethyleneimine with the molecular weight of 1800, 1.0g of triethylamine and 0.15g of sodium dodecyl sulfate, adding deionized water to 500ml, and fully dispersing and stirring the mixture for 12 hours; weighing 0.1g of cyanuric chloride, dissolving the cyanuric chloride in 500ml of n-hexane solvent, and fully stirring for 12 hours; soaking the polyethersulfone ultrafiltration membrane soaked in deionized water in an aqueous phase solution for 10min, taking out and airing, soaking the polyethersulfone ultrafiltration membrane in an oil phase solution at 25 ℃ for reaction for 2min, performing heat treatment at 30 ℃ for 120min, and then cleaning the polyethersulfone ultrafiltration membrane by using deionized water, wherein the flux of the prepared acid-resistant nanofiltration membrane is 40LMH/MPa and 2g/LMgCl2The retention rate of (a) was 91%.
Adopting a membrane performance evaluation instrument, wherein the size of the retention rate represents the compactness of the composite functional layer formed by the interfacial polymerization reaction: the higher the retention rate is, the more compact the formed composite functional layer is; the faster the change in rejection rate, indicating the faster the rate of formation of the dense composite functional layer, the time required for the rejection rate to reach 90% can be considered as the reaction completion time.
Nanofiltration membranes prepared in examples 1-3 and comparative example 1 (without C)3N4Modified Janus nanofiltration membrane), comparative example 2 to 2g/LMgCl2Solution and Na2SO4The flux and retention of the solution were tested and the results are shown in table 1 and figure 3.
TABLE 1 comparison of separation Performance between examples 1-4 and comparative examples 1 and 2
| Flux (LMH/MPa) | MgCl2Retention (%) | Na2SO4Retention (%) | |
| Comparative example 1 | 33 | 95 | 50 |
| Comparative example 2 | 40 | 91 | —— |
| Example 1 | 51 | 90 | 28 |
| Example 2 | 72 | 96 | 24 |
| Example 3 | 131 | 85 | 20 |
| Example 4 | 213 | 78 | 18 |
As shown in table 1, the flux of the acid-resistant nanofiltration membrane obtained in the embodiment of the invention is in the range of 51-213LMH/MPa, and the flux of the carbon nitride modified nanofiltration membrane (embodiment 2) is increased by 118% compared with that of the unmodified nanofiltration membrane (comparative example 1); due to the trade-off effect of flux and rejection, as the flux of the nanofiltration membrane increases, for MgCl2The rejection rate of (a) is somewhat reduced, but still above 75%. With the combination of the figure 1, and after 96h of soaking in HCl solution, the higher magnesium salt rejection rate is still maintained, which shows that the flux of the nanofiltration membrane is improved on the premise that the prepared nanofiltration membrane ensures the acid resistance and the rejection rate of multivalent cations.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A preparation method of a carbon nitride modified Janus acid-resistant nanofiltration membrane comprises the following steps:
s1: immersing an ultrafiltration basement membrane into the prepared aqueous phase solution for reaction, and drying to obtain an ultrafiltration basement membrane I; wherein the aqueous phase solution comprises an aqueous phase monomer A, an acid-binding agent, a two-dimensional nano material B and a surfactant;
s2: immersing the ultrafiltration basement membrane I into the oil phase solution for reaction to obtain an ultrafiltration basement membrane II;
s3: carrying out heat treatment on the ultrafiltration basement membrane II to obtain an ultrafiltration basement membrane III;
s4: and (3) performing three-acid treatment on the ultrafiltration base membrane to obtain the carbon nitride modified Janus acid-resistant nanofiltration membrane.
2. The method according to claim 1, wherein the reaction mixture,
in step S1, the concentration of the aqueous phase monomer A in the aqueous phase solution is 5 to 25 g/L;
in step S1, the concentration of the acid-binding agent in the aqueous phase solution is 0.1 to 5 wt%;
in step S1, the concentration of the two-dimensional nanomaterial B in the aqueous phase solution is 0.01 to 10 wt%;
in step S1, the concentration of the surfactant in the aqueous phase solution is 0.02 to 0.08 wt%.
3. The method according to claim 1, wherein the reaction mixture,
in step S1, the aqueous phase monomer a includes any one or a combination of more of polyethyleneimine, polyvinylamine, polyvinylaniline, polystyrene-based amine, diethylenetriamine, and polyethylenepolyamine;
in step S1, the acid-binding agent includes one or more of triethylamine, pyridine, 4-dimethylaminopyridine, N-diisopropylethylamine, sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, potassium bicarbonate, and potassium carbonate;
in step S1, the two-dimensional nanomaterial B is graphite phase C3N4Solid or solution.
4. The method according to claim 1, wherein the reaction mixture,
in step S1, the surfactant includes any one or a combination of a plurality of common surfactants such as sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, hexadecyl dimethyl benzyl ammonium chloride, octadecyl trimethyl ammonium chloride, trioctyl methyl ammonium chloride, benzyl triethyl ammonium chloride, tetrabutyl ammonium chloride, etc.;
in step S1, the ultrafiltration membrane includes any one or more of polyethersulfone, polysulfone, and polyisophthaloyl metaphenylene diamine.
5. The method according to claim 1, wherein the reaction mixture,
in step S1, the reaction time is 2 to 20 min.
6. The method according to claim 1, wherein the reaction mixture,
in step S2, the reaction time is 30 to 600S; the reaction temperature is 15 to 35 ℃; the reaction humidity is 20 to 60 percent;
in step S2, the oil phase solution includes a solute and a solvent;
wherein the solute comprises at least one of cyanuric chloride, cyanuric fluoride, cyanuric bromide, cyanuric iodide or oligomers thereof;
wherein the concentration of the solute is 0.01 to 10 g/L;
wherein, the solvent comprises any one or a combination of more of n-hexane, cyclohexane, toluene, benzene and ethyl acetate.
7. The method according to claim 1, wherein the reaction mixture,
in step S3, the heat treatment temperature is 50 to 150 ℃; the heat treatment time is 2 to 150 min.
8. The method according to claim 1, wherein the reaction mixture,
in step S4, the concentration of the acid in the acid treatment step is 2 to 15 wt%;
in step S4, the acid treatment time in the acid treatment step is 1 to 20 min;
in step S4, the acid treatment temperature in the acid treatment step is 25 to 65 ℃;
in step S4, the acid in the acid treatment step includes any one or more of citric acid, hydrochloric acid, sulfuric acid, and acetic acid.
9. A carbon nitride modified Janus acid-resistant nanofiltration membrane obtained by the preparation method of any one of claims 1 to 8.
10. The application of the carbon nitride modified Janus acid-resistant nanofiltration membrane as claimed in claim 9 in the field of water quality purification.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114471161A (en) * | 2022-01-24 | 2022-05-13 | 中国科学院城市环境研究所 | High-performance titanium carbide composite nanofiltration membrane and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101468299A (en) * | 2007-12-27 | 2009-07-01 | 中国科学院生态环境研究中心 | Method for preparing fragrant polyamide hollow fiber nano filter membrance |
| CN107930412A (en) * | 2017-10-09 | 2018-04-20 | 浙江大学 | A kind of anti-acid gathers（Acid amides atrazin）The preparation method of Nano filtering composite membrane |
| CN109999666A (en) * | 2019-04-30 | 2019-07-12 | 中国科学院生态环境研究中心 | High-throughput charged positive electricity anti-acid nanofiltration membrane, preparation method and application |
| US20190282967A1 (en) * | 2018-02-07 | 2019-09-19 | Zhejiang University | Semipermeable membrane and preparation method thereof |
| CN111517981A (en) * | 2020-04-23 | 2020-08-11 | 青海大学 | Zwitterion functionalized carbon nitride nanosheet and positively charged nanofiltration membrane |
-
2021
- 2021-03-22 CN CN202110304738.7A patent/CN112999870A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101468299A (en) * | 2007-12-27 | 2009-07-01 | 中国科学院生态环境研究中心 | Method for preparing fragrant polyamide hollow fiber nano filter membrance |
| CN107930412A (en) * | 2017-10-09 | 2018-04-20 | 浙江大学 | A kind of anti-acid gathers（Acid amides atrazin）The preparation method of Nano filtering composite membrane |
| US20190282967A1 (en) * | 2018-02-07 | 2019-09-19 | Zhejiang University | Semipermeable membrane and preparation method thereof |
| CN109999666A (en) * | 2019-04-30 | 2019-07-12 | 中国科学院生态环境研究中心 | High-throughput charged positive electricity anti-acid nanofiltration membrane, preparation method and application |
| CN111517981A (en) * | 2020-04-23 | 2020-08-11 | 青海大学 | Zwitterion functionalized carbon nitride nanosheet and positively charged nanofiltration membrane |
Non-Patent Citations (2)
| Title |
|---|
| JIANXIN CHEN等: "Synthesis and characterization of g-C3N4 nanosheet modified polyamide nanofiltration membranes with good permeation and antifouling properties", 《ROYAL SOCIETY OF CHEMISTRY》 * |
| ZONGYAO ZHOU ET AL.: "Tuning the Surface Structure of PolyamideMembranes Using Porous Carbon Nitride Nanoparticles for High-Performance Seawater Desalination", 《MEMBRANES》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114471161A (en) * | 2022-01-24 | 2022-05-13 | 中国科学院城市环境研究所 | High-performance titanium carbide composite nanofiltration membrane and preparation method thereof |
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