It is a kind of with the metal-organic framework for being selectively adsorbing and separating anionic dye performance
Material and its preparation method and application
Technical field
The present invention relates to metal-organic framework materials synthesis technical fields, and in particular to an example is based on positive charge (1,3-
Two (4- carboxyl phenyl) imidazoles villaumites are that cationic metal-organic framework materials of main ligand are used for anion as adsorbent
The quick adsorption of dyestuff with separate.
Background technique
Metal-organic framework (Metal-Organic Framework, MOFs), also known as Porous coordination polymer
(Porous CoordinationPolymers, PCPs) is to pass through coordination key-shaped by metal ion or metal cluster and organic ligand
At one kind there is the crystalline state porous framework material of periodic network structure, because of its high-specific surface area, the spies such as porous, structure is adjustable
Property, there is potential application prospect in terms of the adsorbing separation of gas, catalysis, sensing and proton.Referring to:
Nandasiri,M.I.;Jambovane,S.R.;McGrail,B.P.; Schaef,H.T.;Nune,
S.K.Coord.Chem.Rev.2016,311,38-52;H.Furukawa,N.Ko, Y.B.Go,N.Aratani,S.B.Choi,
E.Choi,A.Yazaydin,R.Q.Snurr,M.O'Keeffe, J.Kim,O.M.Yaghi,Science 2010,329,
424. are used as a polyporous materials, and MOFs has become research main-guest chemistry due to the Scalability in its duct and cage
Focus.In recent years, it is based on ion exchange and Subjective and Objective electrostatic interaction, constructs the MOFs of ionic for different charges
The report of Dye Adsorption separation is more and more, but in the ionic MOFs of these reports, the sun based on organic ligand building
The metal-organic framework materials of ionic are more rare.Referring to: Han, Y.;Sheng,S.;Yang,F.;Xie,Y. B.;Zhao,
M.J.;Li,J.R.Journal ofMaterials ChemistryA.2015,3,12804;Song,B. Q.;Wang,X.L.;
Zhang,Y.T.;Wu,X.S.;Liu,H.S.;Shao,K.Z.;Su,Z.M.;Chem. Commun.,2015,51,9515.
Summary of the invention
The performance of aspect is separated to Dye Adsorption it is an object of the invention to explore ionic type metal-organic framework materials,
A kind of metal-organic framework materials are provided, while also providing a kind of preparation method of metal-organic framework materials.The frame
Frame material is the metal-organic framework of the poroid cationic of an example supermolecule, has biggish 1-dimention nano hole in a axis direction
Road, structure have relatively high chemical stability and thermal stability, have the function of selective absorption to anionic dye,
And show good separating effect, it has broad application prospects in materials science field.
Technical solution of the present invention:
It is a kind of with the metal-organic framework materials for being selectively adsorbing and separating anionic dye performance, chemical formula is
C60H39ClN14O10Zn4, with it is positively charged (1,3- bis- (4- carboxyl phenyl) imidazoles villaumite for main ligand, 1-H benzotriazole
For assistant ligand, solvent is n,N-Dimethylformamide, and benzotriazole and metal zinc ion form four core Zn clusters, then pass through two
Acid connects into hexagonal cavernous structure, passes through strong hydrogen bonding (C-HCl) between adjacent 2D layer and is linked to be three-dimensional oversubscription
Subframe, porosity 52.8%;The metal-organic framework materials crystal belongs to monoclinic system, P21/ m space group, structure cell ginseng
Number is respectively as follows: α=γ=
90 °, β=102.18 °;The decomposition temperature for being coordinated frame is 320 DEG C.
The preparation method of the metal-organic framework materials, comprising the following steps:
1) by organic ligand (1,3- bis- (4- carboxyl phenyl) imidazoles villaumite and benzotriazole and zinc nitrate hexahydrate
It is placed in 3mL n,N-Dimethylformamide solvent, this mixed solution is put into 10ml vial, ultrasonic 30min, mixing
Uniformly;
2) sealing of above-mentioned vial is placed in 85 DEG C of baking oven, carries out incubating solvent thermal response, reacted 72 hours
Afterwards, yellow bulk crystals can be obtained;
3) up to the metal-organic framework after above-mentioned yellow crystals being washed with N,N-dimethylformamide respectively, being dry
Material.
It is further, described that (1,3- bis- (4- carboxyl phenyl) imidazoles villaumite, benzotriazole and zinc nitrate hexahydrate rub
You are than being 1:1:2.
Further, (amount ratio of 1,3- bis- (4- carboxyl phenyl) imidazoles villaumite and solvent is 0.05 mM: 3 milli
It rises.
A kind of application of the cationic metal-organic framework materials, can be used as adsorbent, for anionic dye
Quick adsorption with separate, method be by the crystalline material by ethyl alcohol carry out exchange of solvent, be then separately immersed in six kinds of differences
It is real using liquid ultraviolet detection means in the ethanol solution of dye molecule (anionic dye, the dye of positive ion and neutral dye)
Test the result shows that: cationic MOF only has quick absorption property to anionic dye, and simultaneously to cation and neutral dye
Not similar absorption behavior.
The invention has the advantages that cationic metal-the organic frame is nontoxic and stable adsorbent material, for yin
Ionic dye has efficient absorption separating capacity.Provided by the invention preparation method is simple, short preparation period and easily recycling.
Ideal adsorption agent is provided for processing dye discoloration.
Detailed description of the invention
Fig. 1 is the poroid figure of metal-organic framework two dimension and three-dimensional perspective structure chart.
Fig. 2 is the powder diagram of the metal-organic framework.
Fig. 3 is absorption figure of the metal-organic framework to different dyes.
Fig. 4 is separation figure of the metal-organic framework to mixed dye.
Fig. 5 is that the dyestuff of the metal-organic framework discharges figure.
Specific embodiment
Example:
A kind of preparation method of the metal-organic framework materials, comprising the following steps:
1) (1,3- bis- (4- carboxyl phenyl) imidazoles villaumite (17.4mg), benzotriazole (5.9mg), zinc nitrate hexahydrate
(30mg) is added in the vial of 10ml, adds 3mLN, dinethylformamide solution.
2) sealing of above-mentioned vial is placed in 85 DEG C of baking oven, carries out incubating solvent thermal response, reacted 72 hours
Afterwards, strip light yellow crystal is obtained, yield is about 70%.
It 3) will be organic up to the metal-after above-mentioned light yellow crystal N,N-dimethylformamide and ethanol washing, drying
Frame material.
Gained metal-organic framework materials chemical formula is C60H39ClN14O10Zn4, with positive charge (1,3- bis- (4- carboxyl benzene
Base) imidazoles villaumite be main ligand, 1H- benzotriazole be assistant ligand, using solvent-thermal method, solvent N, N- dimethyl formyl
Amine aqueous solution synthesizes the metal-organic framework (NUM-4) of the poroid cationic of an example supermolecule.In NUM-4, zinc ion receives
Three nitrogen-atoms in benzotriazole form four core zinc clusters, pass through the carboxyl at diacid ligand both ends between four different core zinc clusters
Group, which is connected, becomes hexagonal cavernous structure.As shown in Fig. 1, which has biggish nano-pore in a axis direction
Road, hole size are about It is linked to be 3D by strong hydrogen bonding (C-HCl) between adjacent 2D layer to surpass
Molecular framework, porosity 52.8%.;Illustrate that obtained sample purity is very high in attached drawing 2, the decomposition temperature for being coordinated frame is 320
℃。
To the characterization of metal-organic framework materials obtained:
Crystal structure determination
The monocrystalline for choosing suitable size under the microscope, with the Mo-K through graphite monochromator monochromatization on single crystal diffractometer
Alpha ray, temperature 113K collect diffraction data in a manner of ω-φ.All diffraction datas carry out absorption school using SADABS program
Just.Cell parameter is determined with least square method.Data convert and structure elucidation use SAINT and SHELXTL program to complete respectively.
Whole non-hydrogen atom coordinates first are determined with difference function method and least square method, and obtain the hydrogen of main body frame with theoretical hydrogenation method
Then atom site carries out refine to crystal structure with least square method.Crystallography point diffraction data collection and structure refinement
Partial parameters see the table below 1.
Table 1: the crystal parameter table of the metal-organic framework
R1=Σ | | Fo|-|Fc||/Σ|Fo|;wR2=[Σ [w (Fo 2-Fc 2)2]/Σw(Fo 2)2]1/2.
Dye Adsorption, separation and release:
1) it is the frame material for exchanging 20mg ethyl alcohol first, is separately immersed in the different dyes molecule of 10ml 20ppm
Ethanol solution in.The ultraviolet test specification of liquid: the frame material, can be by 95% or more anionic dye within 720min
Absorption is complete, and to the dye of positive ion and neutral dye almost without absorption, (increase at any time, methyl as shown in Fig. 3
Orange, acid orange, methyl blue and Congo red absorbance are gradually reduced;The absorbance of methylene blue and Nile red remains unchanged).
2) secondly, the frame material that 20mg ethyl alcohol is exchanged, is separately immersed in isometric methyl orange/methylene blue,
In methyl orange/Nile red 10ml mixed solution.The ultraviolet test specification of liquid: frame material energy quick adsorption anion dye
Material stays cation and neutral dye in the solution, and (absorbance of increase at any time, methyl orange gradually drops as shown in Fig. 4
Low, the absorbance of methylene blue and Nile red is almost unchanged).
3) finally, the frame material for having adsorbed methyl orange and acid orange is immersed in 10ml saturation NH4The ethyl alcohol of Cl is molten
In liquid, over time, dyestuff can be released from frame quickly, and release rate is up to 99%, as shown in Fig. 5.
The Dye Adsorption experiment tested by TU-1950 ultraviolet-visible spectrometer, acquired results in the accompanying drawings,
Use Origin Software on Drawing.