Preparation method of amino-modified graphene oxide composite positive permeable film

A technology of graphene compounding and amino modification, applied in chemical instruments and methods, semi-permeable membrane separation, membrane technology, etc., can solve the problems of high salt permeation flux, poor mechanical strength, and low pure water permeation flux, etc. Achieve the effects of good chemical stability, high mechanical strength, and slow membrane fouling

Inactive Publication Date: 2014-06-18
DONGHUA UNIV
3 Cites 26 Cited by

AI-Extracted Technical Summary

Problems solved by technology

However, the current forward osmosis membrane is still in the research and development stage, and the commercially produced forwar...
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Abstract

The invention provides a preparation method of an amino-modified graphene oxide composite positive permeable film. The method is characterized by comprising the following specific steps: mixing graphene oxide, dimethyl formamide, organic amine and dicyclohexyl carbimide, and performing ultrasonic treatment; reacting for 40-50 hours at the temperature of 100-150 DEG C; adding absolute ethyl alcohol, and standing and filtering to obtain a precipitate; washing and drying the precipitate to obtain amino-modified graphene oxide; mixing the amino-modified graphene oxide with a solvent, performing ultrasonic treatment, and adding an additive and a film formation polymer into a mixed solution to prepare a casting film solution; de-foaming to prepare a base film through a phase inversion method, and immersing the base film in pure water for later use; and pouring a metaphenylene diamine solution and trimesoyl chloride to the surface of the base film, performing a contact reaction, washing the surface of the film with an organic solvent, and drying the film to obtain the amino-modified graphene oxide composite positive permeable film. The amino-modified graphene oxide composite positive permeable film is high in mechanical strength, high in chemical stability, large in permeation flux of the pure water, and high in salt rejection rate.

Application Domain

Technology Topic

Examples

  • Experimental program(2)

Example Embodiment

[0018] Example 1
[0019] A method for preparing an amino-modified graphene oxide composite forward osmosis membrane, the specific steps are:
[0020] (1) Add 200g of graphene oxide to 200mL of dimethylformamide, and ultrasonically treat it for 2h at an ultrasonic frequency of 40KHz to obtain a graphene oxide suspension; add 30g of triethylenetetramine to the graphene oxide suspension , 5g dicyclohexylcarboimide, sonicated for 10min under the condition of ultrasonic frequency of 40KHz, reacted at 120℃ for 48h, add 80mL of absolute ethanol, let stand overnight; remove the supernatant of the supernatant, filter with polytetraethylene membrane The lower layer is precipitated and washed with ethanol and deionized water in sequence, and the resulting sample is dried at 80° C. to obtain amino graphene oxide nanoparticles with a particle size of 50-100 nm.
[0021] (2) Add 0.6g of amino graphene oxide nanoparticles to a mixture of 6.2g of dimethylformamide and 2.1g of methylpyrrolidone, and then sonicate for 30 minutes under the condition of an ultrasonic frequency of 40KHz to make the amine graphite Ene nanoparticles are uniformly dispersed; then 0.05g of K30 polyvinylpyrrolidone produced by Aladdin Reagent (Shanghai) Co., Ltd. and 1.65g of ordinary bisphenol A polysulfone produced by Wuhan Nobel Chemical Co., Ltd. are added to the above mixture ( Polyvinylpyrrolidone in the front, polysulfone in the back), formulated into a casting solution. The casting solution was allowed to stand for 24 hours at 25°C to degas. Then, the casting liquid was salivated on the flat glass, scraped into a liquid film with a thickness of 100μm with a spatula, and quickly transferred to a coagulation bath (water) at 20°C for phase inversion; the resulting flat film was transferred to pure Soak in water for 24h to remove residual solvent.
[0022] (3) Pour 50ml of 2wt% m-phenylenediamine aqueous solution on the surface of the flat membrane and let the solution stay on its surface for 2 minutes to ensure that the meta-phenylenediamine monomer can penetrate into the pores of the flat membrane; residual meta-phenylenediamine The water droplets will be scraped off with a rubber roller, and then 50ml of 0.15wt% trimesoyl chloride is poured on the surface of the flat membrane, contacting for 1 min, the trimesoyl chloride solution is scraped off; the unreacted monomer on the surface of the membrane is washed with pure n-hexane After washing, the membrane was first dried naturally at room temperature for 1 min, and then dried at 60°C for 10 min to obtain an amino-modified graphene oxide composite forward osmosis membrane.
[0023] (4) At room temperature, using cross-flow filtration, deionized water as the raw material liquid, and 1.5 mol/L sodium chloride aqueous solution as the draw liquid, the performance of the prepared composite forward osmosis membrane was tested. The measurement method is a forward test, that is, the dense skin layer of the membrane faces the raw material liquid side and the porous support layer faces the draw liquid side; after testing, the flux of the composite forward osmosis membrane prepared without amino-modified graphite oxide is 13.97g/m 2.h, the flux of the composite permeable membrane prepared by adding amino-modified graphene oxide is 33g/m 2.h, the flux increased by 136%; the salt cut-off rate of the composite forward osmosis membrane prepared without amino-modified graphite oxide was 97%, and the salt cut-off rate of the composite permeable membrane prepared with amino-modified graphene oxide was 93.6%. The salinity is only reduced by 3.5%; in addition, the internal concentration polarization of the latter is reduced compared to the former. The mechanical strength of the latter is higher than that of the former.

Example Embodiment

[0024] Example 2
[0025] (1) Add 300g of graphene oxide to 300mL of dimethylformamide, and ultrasonically treat it for 3h at an ultrasonic frequency of 40KHz to obtain a graphene oxide suspension; add 40g of ethylenediamine to the graphene oxide suspension, 10g dicyclohexylcarboimide, sonicated for 5min under the condition of ultrasonic frequency of 40KHz, reacted at 120℃ for 50h, add 100mL absolute ethanol, and let stand overnight; remove the supernatant of the upper layer, filter the lower layer with a polytetraethylene membrane Precipitate and sequentially wash with ethanol and deionized water, and the obtained sample is dried at 70° C. to obtain amino graphene oxide nanoparticles with a size of 500 nm-5um and a thickness of 0.8-1.2 nm.
[0026] (2) Add 1g of amino-graphene oxide nanoparticles to a mixture of 12g of dimethylformamide and 4g of methylpyrrolidone, and then sonicate for 40min under the condition of an ultrasonic frequency of 40KHz to make the amino-graphene oxide nanoparticles The nanoparticles are uniformly dispersed; then 0.1g of K30 polyvinylpyrrolidone produced by Aladdin Reagent (Shanghai) Co., Ltd. and 1g of E6020p polyethersulfone produced by BASF Chemical Co., Ltd. are added to the above mixed solution (polyvinylpyrrolidone first, polyether After sulfone), it is formulated into a casting liquid. The casting solution was allowed to stand for 24 hours at 25°C to degas. Then, the casting liquid was salivated on the flat glass, scraped into a liquid film with a thickness of 140μm with a spatula, and quickly transferred to a coagulation bath (water) at 20°C for phase inversion; the resulting flat film was transferred to pure Soak in water for 24h to remove residual solvent.
[0027] (3) Pour 100ml of 2wt% m-phenylenediamine aqueous solution on the surface of the flat membrane and let the solution stay on its surface for 5 minutes to ensure that the meta-phenylenediamine monomer can penetrate into the pores of the flat membrane; residual meta-phenylenediamine The water droplets will be scraped off with a rubber roller, and then pour 100ml of 0.15wt% trimesoyl chloride on the surface of the flat membrane, contact and react for 5 minutes, and scrape off the trimesoyl chloride solution; rinse the unreacted monomer on the surface of the membrane with pure n-hexane. After washing, the membrane was first dried naturally at room temperature for 3 minutes, and then dried at 80°C for 8 minutes to obtain an amino-modified graphene oxide composite forward osmosis membrane.
[0028] (4) At room temperature, using cross-flow filtration, deionized water as the raw material liquid, and 1.5 mol/L sodium chloride aqueous solution as the draw liquid, the performance of the prepared composite forward osmosis membrane was tested. The measurement method is a forward test, that is, the dense skin layer of the membrane faces the raw material liquid side and the porous support layer faces the draw liquid side; after testing, the flux of the composite forward osmosis membrane prepared without amino-modified graphite oxide is 13.97g/m 2.h, the flux of composite permeable membrane prepared by adding amino modified graphene oxide is 40g/m 2.h, the flux increased by 186%; the salt rejection rate of the composite forward osmosis membrane prepared without amino-modified graphite oxide was 97%, and the salt rejection rate of the composite permeable membrane prepared with amino-modified graphene oxide was 90%. The salinity is only reduced by 7.2%; in addition, the internal concentration polarization of the latter is reduced compared with the former. The mechanical strength of the latter is higher than that of the former.
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PUM

PropertyMeasurementUnit
Thickness0.8 ~ 1.2nm
tensileMPa
Particle sizePa
strength10

Description & Claims & Application Information

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