A method of the unsaturation salting liquid crystallization based on carbon-based materialTechnical field
The method for the unsaturation salting liquid crystallization based on carbon-based material that the present invention relates to a kind of.
Background technique
With the burgeoning population in the whole world and industrialization, freshwater resources are increasingly deficient, and the urgent status be expected toThe desalination of water purifies to obtain effectively solution (Nature 452,2008,301~310).
The carbon-based materials such as graphene oxide membrane gradually show filter membrane of new generation with its fast and accurate desalination characteristicPotentiality (Science 343,2014,752~754；Science 333,2011,712~717；Science 332,2011,674~676；Adv.Funct.Mater.23,2013,3693~3700；Chem.Soc.Rev.44,2015,5016~5030).CarbonSill is the rapid osmotic and salt ion of water in the formation and its channel of aquaporin as the vital factor of filter membraneRetention.When hydrone penetrates into aquaporin, due to the hydrophobic effect on carbon material aromatic ring surface, can be formed almost without frictionRapid osmotic water flow, infiltration rate several orders of magnitude higher than traditional filter membrane achieve the purpose that high efficiency filter(Adv.Mater.28,2016,2287~2310).However when graphene oxide membrane for salting liquid infiltration screening after,The residual (Science 343,2014,752~754) that the salting liquid of high concentration is had found in film, goes out on carbon-based material surfaceThe enrichment (Sci.Rep~Uk 3,2013,3436) of the salt ion of high concentration is showed.High salt concentration is enriched in aquaporin in film, hasIt may cause channel block.
Currently, it is rich to cannot achieve high local concentrations salt far below the salting liquid of saturated concentration under conditions of normal temperature and pressureCollection is so that precipitate crystal.This problems demand solves.
Summary of the invention
The technical problem to be solved by the present invention is to overcome in the prior art under conditions of normal temperature and pressure far below saturationThe defect of crystallization can not be precipitated in the salting liquid of concentration, provide a kind of side of unsaturation salting liquid crystallization based on carbon-based materialMethod.Method of the invention can make unsaturated salting liquid that crystallization be precipitated at normal temperatures and pressures, achieve the purpose that the desalination purification of water.
The present invention solves above-mentioned technical problem by following technical proposals.
The method for the unsaturation salting liquid crystallization based on carbon-based material that the present invention provides a kind of comprising following step:
Carbon-based material is immersed in 10~120min in salting liquid, until precipitating crystal；Wherein, the salting liquid is non-Saturated solution, molar concentration >=1mol/L of the salting liquid.
In the present invention, the oxidation of graphene oxide film, partial reduction that the carbon-based material preferably independently supportsGraphene film, with filter membrane support graphene oxide membrane or containing the carbon-based material of aromatic ring structure.
In the present invention, the carbon-based material is known in this field to be made by 1 drop-coating of method and/or 2 suction method of method,The drop-coating is the drop-coating of this field routine, and the suction method is the suction method of this field routine.Preferably, the independenceThe preparation method of the graphene oxide film of support preferably uses drop-coating (method 1) comprising following steps: will aoxidize stoneBlack alkene solution drop coating is drying to obtain the graphene oxide membrane independently supported in smooth hydrophobic paper surface.By the independence of above-mentioned acquisitionThe graphene oxide membrane of support carries out hydro-thermal reaction to get partial reduction graphene oxide membrane.
The graphene oxide with filter membrane support preferably uses suction method (method 2) comprising following steps:Graphene oxide solution is filtered, filter membrane is drying to obtain the graphene oxide membrane with filter membrane support；Wherein, described to filter as filterFilm filters.The graphene oxide membrane that filter membrane support is had described in above-mentioned acquisition is subjected to hydro-thermal reaction to get partial reduction oxygenGraphite alkene film.
In method 1 or method 2, the graphene oxide solution is graphene oxide solution commonly used in the art.InstituteThe graphene oxide that the graphene oxide in graphene oxide solution is this field routine is stated, improvement is preferably passed throughThe graphene oxide of Hummers method preparation.The solvent of the graphene oxide solution is commonly used in the art for matchingThe solvent of graphene oxide solution is set, can be organic solvent or water, the organic solvent is preferably ethyl alcohol, acetone, dimethylSulfoxide (DMSO) etc. can also be the mixed solvent of several organic solvents.The concentration of the graphene oxide solution is that this field is normalThe concentration of the graphene oxide solution used is advised, preferably, the mass concentration of the graphene oxide solution is 0.1~10mg/ML is more preferably 5mg/mL.
In method 2, the filter membrane is filter membrane commonly used in the art, preferably water phase filter membrane, the hole of the filter membraneDiameter is preferably 0.22 μm.
In method 1 or method 2, the operation of the drying and condition are the operation and condition of the drying of this field routine,If do not damage the drying condition of the property of film, such as: in drying basin air drying, frozen drying, in baking ovenThe methods of the dry drying means that can be used as film of normal-temperature vacuum, it is dry preferably in baking oven, the temperature of the drying compared withIt is goodly 60~80 DEG C, is more preferably 70 DEG C.The time of the drying is preferably 6~10 hours, is more preferably 8 hours.
In method 1 or method 2, the hydro-thermal reaction is the hydro-thermal reaction of this field routine, preferably in deionized waterMiddle carry out hydro-thermal reaction.The dosage of the deionized water of the hydro-thermal reaction do not do it is specifically limited, as long as being able to carry out hydro-thermal reaction, preferably 20~50mL is more preferably 30mL.The temperature of the hydro-thermal reaction is preferably 160~200 DEG C, more preferablyGround is 180 DEG C.
In the present invention, flatness, thickness and the surface area size of the film of the carbon-based material will not influence crystal precipitation.InstituteThe thickness for stating the film of carbon-based material is preferably 0.2 micron~100 microns, is more preferably 25 microns.
In the present invention, the carbon-based material is known in this field can vacuum oven at normal temperatures and pressures, lower than 180 DEG CInterior or ion concentration is that the salting liquid of 0.1~5.0mol/L can save for a long time.
In the present invention, the salting liquid is salting liquid commonly used in the art, preferably potassium salt soln and/or sodium saltSolution, example sodium salt as mentioned can be sodium sulphate, sodium carbonate, sodium fluoride, sodium chloride, sodium bromide, sodium iodide, and the sylvite canFor potassium sulfate, potassium carbonate, potassium fluoride, potassium chloride, potassium bromide, potassium iodide；Salt in the salting liquid can also be calcium chloride, chlorinationMagnesium or ammonium chloride etc..
In the present invention, the salting liquid is preferably inorganic salt solution or organic slat solution；The inorganic salt solutionSolvent is water；The solvent of the organic slat solution is the solvent of organic slat solution commonly used in the art, such as ethyl alcohol, firstAlcohol, acetone, glycerol, dichloroethanes, trichloro ethylene, chloroform or toluene etc..
In the present invention, the salting liquid is unsaturation solution, and " unsaturation solution " this concept those skilled in the art are equalKnow that its meaning, ie in solution concentration are less than the concentration of saturated solution.The molar concentration of the salting liquid of the invention be 1mol/L extremelyThe concentration of the saturated solution of the salt.
In the present invention, the molar concentration of the salting liquid is preferably 2.5mol/L.
In the present invention, the salting liquid is preferably sodium-chloride water solution, when the carbon-based material is to pass through the suction filtrationMade from method when the graphene oxide membrane of the partial reduction, the molar concentration of the sodium-chloride water solution is preferably 1.0~4.0mol/L, such as 1.0mol/L, 1.5mol/L, 2.0mol/L, 2.5mol/L, 3.0mol/L, 4.0mol/L；When described carbon-basedWhen material is the graphene oxide membrane as made from the drop-coating, the molar concentration of the sodium-chloride water solution is preferablyFor 2.5~4.5mol/L, such as 2.5mol/L, 4.0mol/L, 4.5mol/L.
In the present invention, the time of the immersion is preferably 0.5 hour.
On the basis of common knowledge of the art, above-mentioned each optimum condition, can any combination to get each preferable reality of the present inventionExample.
The reagents and materials used in the present invention are commercially available.
The positive effect of the present invention is that:
Method for crystallising of the invention can make unsaturated salting liquid that crystallization be precipitated at normal temperatures and pressures, and the desalination for reaching water is netThe purpose of change.
Detailed description of the invention
Fig. 1 is the graphene film in the embodiment of the present invention 1 and 2, wherein (A) is suction method preparation in the embodiment of the present invention 1With filter membrane support graphene oxide membrane, (B) be the embodiment of the present invention 1 in suction method preparation partial reduction oxidation stoneBlack alkene film, (C) are the graphene oxide membrane of drop-coating preparation in the embodiment of the present invention 2 independently supported.
Fig. 2 is that the XRD of the graphene oxide membrane of the partial reduction in the embodiment of the present invention 1 after salting liquid immersion detects figure.
Fig. 3 is the XRD detection of the graphene oxide filter membrane independently supported in the embodiment of the present invention 2 after salting liquid immersionFigure.
Fig. 4 is that the WAXS of the graphene oxide membrane of the partial reduction in the embodiment of the present invention 1 after salting liquid immersion detects figure.
Fig. 5 is salt water, the salinity of the graphene oxide filter membrane independently supported in the embodiment of the present invention 2 after salting liquid immersionAdsorbance and film in salinity.
Specific embodiment
The present invention is further illustrated below by the mode of embodiment, but does not therefore limit the present invention to the realityIt applies among a range.In the following examples, the experimental methods for specific conditions are not specified, according to conventional methods and conditions, or according to quotientThe selection of product specification.
In following embodiments 1 with filter membrane support graphene oxide film, partial reduction graphene oxide membrane withAnd the graphene oxide membrane independently supported in embodiment 2 is all the graphene oxide using the Hummers method preparation of improvementIt is obtained, but the graphene oxide of equally applicable other methods preparation.
Embodiment 1
The graphene oxide membrane of graphene oxide membrane and partial reduction with suction method preparation with filter membrane support.
Taking 1mL concentration is 5mg/mL graphene oxide water solution, is diluted to 10mL with deionized water, carries out filter membrane suction filtration,It is put into the drying 8 hours of 70 DEG C of baking oven later, the graphene oxide membrane with filter membrane support can be obtained, with a thickness of 25 microns；
The preparation of partial reduction graphene oxide: above-mentioned acquisition is had to the graphene oxide membrane of filter membrane support, is put into and containsHave and carry out 180 DEG C of hydro-thermal reactions in the reaction kettle of 30mL deionized water, partial reduction graphene oxide membrane can be obtained, with a thickness of 25Micron.
Will with filter membrane support graphene oxide membrane be separately immersed in molar concentration be 0.25mol/L, 0.5mol/L,In the NaCl aqueous solution of 1.0mol/L, 1.5mol/L, 2.0mol/L, 2.5mol/L, 3.0mol/L, 4.0mol/L and 5.0mol/LIt 0.5 hour, takes out carry out XRD test later, detect NaCl crystal peak.
By the graphene oxide membrane of partial reduction be separately immersed in molar concentration be 0.25mol/L, 0.5mol/L,In the NaCl aqueous solution of 1.0mol/L, 1.5mol/L, 2.0mol/L, 2.5mol/L, 3.0mol/L, 4.0mol/L and 5.0mol/LIt 0.5 hour, takes out carry out XRD test later, detect NaCl crystal peak.
Embodiment 2
The graphene oxide membrane independently supported is prepared with drop-coating.
Taking 1mL concentration is 5mg/mL graphene oxide water solution drop coating in smooth hydrophobic paper surface, enters 70 DEG C of dryings 8 of baking ovenHour, the graphene oxide membrane independently supported can be obtained, with a thickness of 100 microns.
By the graphene oxide membrane independently supported be separately immersed in molar concentration be 0.1mol/L, 0.25mol/L,In the NaCl aqueous solution of 0.5mol/L, 1.0mol/L, 2.0mol/L, 2.5mol/L, 4.0mol/L, 4.5mol/L and 5.0mol/L0.5 hour, soaking solution was removed later and is centrifuged disengaging film surface absorption water, wet film weighing is taken out, is subsequently placed into baking oven later60 DEG C drying 6 hours, take out dry film weighing.
Calculate salting liquid, the adsorbance of salinity and film in the graphene oxide filter membrane absorption salting liquid caudacoria independently supportedInterior salinity.
Effect example 1
(1) XRD (X-ray diffraction) test result
Fig. 2 is that the XRD of the graphene oxide membrane of partial reduction in embodiment 1 detects figure, as seen from Figure 2, works as chlorinationWhen sodium water solution molar concentration >=1.5mol/L, there is diffraction maximum at (200) in diffraction curve.Fig. 3 is independently to prop up in embodiment 2The XRD of the graphene oxide filter membrane of support detects figure, as seen from Figure 2, as sodium-chloride water solution molar concentration >=2.5mol/LWhen, there is diffraction maximum at (200) in diffraction curve.XRD test result is shown soaks in the sodium-chloride water solution of respective concentrationThe graphene oxide membrane of the graphene oxide film independently supported after bubble and partial reduction, inside there are XRD crystal diffraction peak,(200) face of its main peak and corresponding sodium chloride salt crystal coincide, and shows to have formd significant crystal structure in film.
(2) synchronous wide-angle scatters WAXS (shanghai light source) test result
The WAXS test result of Fig. 4 shows that the graphene oxide membrane of the partial reduction in embodiment 1 is dense at different molesThere are crystal diffraction peak, main peak and (200) faces for corresponding to salt crystal to coincide for inside after impregnating in the NaCl aqueous solution of degree, tableSignificant crystal structure is formd in bright film, which is consistent with the XRD testing result in (1)；In addition, being scattered from WAXSRing is it is known that crystal illustrates still to contain more moisture in film in two-dimensional orientation distribution in film；In Fig. 4, A is partial reductionGraphene oxide membrane dry film, B are the NaCl crystal being precipitated in saturated solution, and C is the NaCl aqueous solution of 0.25mol/L (low concentration)Wet film after immersion, D are the wet film after the NaCl aqueous solution soaking of 2.5mol/L (high concentration).
(3) salting liquid absorption result
Fig. 5 is the salinity in embodiment 2 in the salt water of graphene oxide membrane, the adsorbance of salinity and film, molten with saltLiquid adsorbance characterizes ion enrichment degree.The graphene oxide membrane independently supported shows the absorption weighing result of NaCl aqueous solution, after the NaCl aqueous solution soaking of different molar concentrations, the increment of salt water adsorption amount, film inner salt in film be increased,It is found after conversion film forming inner salt water molar concentration, when 2.5mol/L (concentration of the saturated solution of 0.5 times of salt) concentration is impregnated,Concentration has reached supersaturation in film, has reached the condition of crystallization.
It can be seen from above-mentioned test result at normal temperatures and pressures, the lower sodium-chloride water solution of concentration (1.0~Crystallization 4.5mol/L) is precipitated in the presence of the graphene oxide membrane of the graphene oxide film and partial reduction that independently support.
Although specific embodiments of the present invention have been described above, it will be appreciated by those of skill in the art that this is onlyFor example, protection scope of the present invention is to be defined by the appended claims.Those skilled in the art without departing substantially fromUnder the premise of the principle and substance of the present invention, many changes and modifications may be made, but these change andModification each falls within protection scope of the present invention.