CN103337327B - Heterogeneous Fe3O4/ Co metal-organic framework materials and its preparation method and application - Google Patents

Abstract

The present invention relates to Material Field, be specifically related to a kind of heterogeneous Fe₃O₄The preparation method of/Co-MOF and application thereof, a kind of heterogeneous Fe₃O₄/ Co metal-organic framework materials, with metal organic framework compound Co-MOF for carrier, is attached with Fe in its surface and hole₃O₄Nanoparticle.Preparation method is by Fe₃O₄Nano material and soluble cobalt, trimesic acid are dissolved in deionized water, are placed in closed reactor, and heating, to 135～150 DEG C, keeps 20～28 hours；Then cool the temperature to 118～122 DEG C, keep 4.5～6 hours；It is cooled to 98～105 DEG C afterwards again and is incubated 4.5～6 hours, finally make it naturally be down to room temperature and stand 11～14h；Take precipitation point washing, then carry out sucking filtration, natural air drying, finally give Fe₃O₄/ Co-MOF composite.Resulting materials has good heat stability and chemical stability.

Description

Heterogeneous Fe3O4/ Co metal-organic framework materials and its preparation method and application

Technical field

The present invention relates to a kind of composite synthesis field, be specifically related to a kind of heterogeneous Fe₃O₄The preparation method of/Co-MOF and application thereof.

Background technology

Metal-organic framework materials (Metal-Organic-Framework, MOF) it is that a class is new, the microporous materials of flexible design, it is crystalline material (the J.RowsellandO.M.Yaghi.Metal-organicframeworks:anewclasso fporousmaterials.MicroporousMesoporousMater. being made up of transition metal ions and organic bridge ligand, 2004,73 (1): 3-14.).It combines the feature of inorganic compound and organic compound, becomes one of class system most with potential application foreground in materials chemistry research due to the multiformity of the complexity of its composition, metal and ligand species, the adjustability of coordination environment.Owing to there is good physicochemical characteristics, extraordinary biocompatibility, good electric conductivity and being prone to functionalization, therefore favor (the 2.G.F é rey.Hybridporoussolids:past of researcher especially it is subject to, present, future.Chem.Soc.Rev, 2008,37 (1), 191-215.3.Dybtsev, DanilN;Chun, Hyungphil;Kim, Kimoon.RigidandFlexible.AngewandteChemieInternationalEdi tion, 2004,43 (38): 5033-5035.4.XiZhu, abHanyeZheng, aXiaofengWei, aZhenyuLin, aLonghuaGuo, aBinQiuaandGuonanChen.Chem.Commun, 2013,49 (13): 1276-1278.

5.TuerkC, GoldbergL.Science, 1990,249 (4968): 505-510.).MOF material has the topological geometry that can control and adjustable space function, and its cellular structure is the absorption of molecule, enrichment, detection provides possibility, owing to the micro structure that MOF is special makes it in absorption, gas stores, and the application of catalysis aspect receives the concern of researcheres gradually.

Magnetic material has many unique effect being different from conventional material, such as quantum size effect, skin effect, small-size effect and macro quanta tunnel effect etc., also there is good magnetic conductance tropism, good biocompatibility, due to magnetic-particle stable performance, it is easier to preparation, particle surface functionalization can be made with different kinds of molecules compound, magnetic material is as a kind of novel affinity solid phase carrier function nano material, it has also become study hotspot.But magnetic nano-particle ubiquity bad dispersibility, it is easy to the shortcomings such as reunion.

At present, become the focus of scientific research about the preparation of compound MOF material, but relevant composition metal organic frame (MOF) material few.This material is advantageous in that, one of which metal ion, as the node of MOF network, builds stable MOF framework, and another kind of metal ion is as the center of active sites.Researches about magnetic MOF material.Magnetic MOF material is advantageous in that, combines the performance of MOF material on the one hand to build stable MOF framework, its loose structure, provides possibility for micromolecular absorption；Still further aspect is the magnetic of ferroso-ferric oxide, it is to avoid the feature that conventional magnetic nanoparticle is easily reunited, separation and enrichment for molecule provide possibility, and can separate from reactant and product easily, recycle and reuse.

Summary of the invention

The deficiencies in the prior art that present invention aims to, it is proposed to the Fe of a kind of simple synthetic method and a kind of compound of water heat transfer₃O₄/ Co-MOF material and preparation method thereof, and utilize this heterogeneous material to carry out dye adsorption experiment with water for medium.

The purpose of the present invention is achieved through the following technical solutions:

A kind of heterogeneous Fe₃O₄/ Co-MOF material, with metal organic framework compound Co-MOF for carrier, is attached with ferriferrous oxide nano-particle in its surface and hole.Preferably, Fe₃O₄The diameter of nanoparticle is 10～40nm, described heterogeneous Fe₃O₄The specific surface area of/Co metal-organic framework materials is 6～10m²/g。

Above-mentioned heterogeneous Fe₃O₄The preparation method of/Co-MOF material is:

(1) nanometer Fe₃O₄Prepared by material

Solubility trivalent iron salt (such as ferric chloride hexahydrate) is completely dissolved in ethylene glycol, is slowly added to anhydrous sodium acetate and Polyethylene Glycol, is sufficiently stirred for 30min, pour in reactor, seal.It is warming up to 200 DEG C and keeps 12h, being down to thereafter room temperature, pouring into and beaker takes precipitation washing three times, alcohol wash three times, dry 6 hours of 60 DEG C of baking oven, gained Fe₃O₄The particle diameter of nanoparticle is 10～40nm；

(2) Fe₃O₄The synthesis of/Co-MOF

Weigh the nanometer Fe that soluble cobalt (such as cobaltous acetate hydrate), trimesic acid and step (1) synthesize respectively₃O₄, it is placed in closed reactor, adding deionized water, being sufficiently stirred for until being completely dissolved.Heating, to 135～150 DEG C, keeps 20～28 hours；Then cool the temperature to 118～122 DEG C, keep 4.5～6 hours；It is cooled to 98～105 DEG C afterwards and is incubated 4.5～6 hours, finally make it naturally be down to room temperature and stand 11～14h.Take precipitation respectively by deionized water and washing with alcohol, then carry out sucking filtration, natural air drying, finally give Fe₃O₄/ Co-MOF composite.

The ferrum element of step (1) trivalent iron salt and sodium acetate mol ratio are 1:8～1:10；The amount ratio of ferrum element and Polyethylene Glycol and ethylene glycol is 1mmol:150～240mg:30～50ml.In step (2), cobalt element is 2:1～1:1 with the mol ratio of trimesic acid.

Cobalt element and Fe in step (2)₃O₄The amount ratio of nanoparticle is 1mol:10g～1mol:20g.

The Fe of above-mentioned synthesis₃O₄/ Co-MOF composite can be used for absorption and the separation of dyestuff, and after adsorption reaction completes, this composite can repeatedly use.

The present invention utilizes hydro-thermal method to be prepared for the metal Co metal organic framework compound (MOF) being carrier, and nano ferriferrous oxide is loaded in Co-MOF, Co-MOF has significantly high specific surface area and pore volume, it is ensured that dispersed, the substrate of active adsorption sites and being fully contacted of active center；The method utilizing reduction of ethylene glycol obtains being loaded with the Co-MOF material of magnetic ferroferric oxide, the magnetic of material can realize the enrichment to reacting substance and separation, this material heat stability and chemical stability are all fine, and chemical stability shows and structure can be kept not change in aqueous solution or other organic solvent；This material can effectively prevent the reunion of magnetic material, and therefore, when the adsorption reaction carrying out dyestuff with water for medium, this heterogeneous composite material exhibits goes out significantly high activity.

Accompanying drawing explanation

Fig. 1 is magnetic Fe prepared by the embodiment of the present invention 1₃O₄The SEM figure of nanoparticle

Fig. 2 is Fe in the embodiment of the present invention₃O₄The SEM figure of/Co-MOF material.

Fig. 3 is Co-MOF material, magnetic Fe in the embodiment of the present invention₃O₄Nanoparticle, Fe₃O₄The XRD figure of/Co-MOF composite, wherein (a) MOF material；(b) nanometer Fe₃O₄Material；(c) MOF-Fe₃O₄Composite.

Fig. 4 is the Fe in the embodiment of the present invention₃O₄The thermal weight loss TGA figure of/Co-MOF material.

Fig. 5 is the Fe in the embodiment of the present invention₃O₄The BET figure of/Co-MOF material.

Fig. 6 is the Fe in the embodiment of the present invention₃O₄/ Co-MOF is for dye adsorption lab diagram.

Detailed description of the invention

Co (Ac) used in the present embodiment₂·4H₂O, 1,3,5-trimesic acid, ethylene glycol, anhydrous sodium acetate, Polyethylene Glycol, FeCl₃·6H₂O etc. are analytical pure, and water used is all deionized water.

Embodiment 1

By ferric chloride hexahydrate 0.14g(0.518mmol) it is completely dissolved in 20ml ethylene glycol, it is slowly added to 0.36g(4.4mmol) anhydrous sodium acetate and 0.10g Polyethylene Glycol, it is sufficiently stirred for 30min, pours in reactor, seal.It is warming up to 200 DEG C and keeps 12h, being down to thereafter room temperature, going precipitation to pour in beaker and wash three times, alcohol wash three times, put into 60 DEG C of baking oven dry 6 hours, sucking filtration or centrifuging and taking precipitation obtain nanometer Fe₃O₄, its particle diameter is that 10～40nm, SEM scheme as shown in Figure 1.

Embodiment 2

The Co(Ac weighed respectively)₂·4H₂O0.41g(1.65mmol), 1,3,5-trimesic acid 0.20g(0.95mmol), the nanometer Fe of embodiment 1₃O₄0.02g, is placed in closed reactor, adds 15ml deionized water, is sufficiently stirred for until Co(Ac)₂·4H₂O and 1,3,5-trimesic acids are completely dissolved, and make Fe₃O₄It is uniformly dispersed.

Being placed in baking oven by reactor, heating, to 140 DEG C, keeps this temperature 24 hours；Then cool the temperature to 120 DEG C, keep 5 hours；Afterwards to be cooled to 100 DEG C, then keep 5 hours, finally make it naturally be down to room temperature, stand 12h.Respectively with 10mL deionized water and ethanol wash 3 times, then carry out sucking filtration, natural air drying, finally give Fe₃O₄/ Co-MOF composite.

Fig. 2 is Fe₃O₄The SEM figure of/Co-MOF material, it can be seen that Fe₃O₄The crystal structure of/Co-MOF material.

Fig. 3 is Co-MOF material, magnetic Fe₃O₄, Fe₃O₄The XRD figure of/Co-MOF material, Fe₃O₄XRD peak both corresponds to cubic system inverse spinel Fe₃O₄Standard diffraction spectrum (JCPDS card, No119-0629), it can be seen that contrast Co-MOF material (curve a), by Fe prepared by hydro-thermal method₃O₄/ Co-MOF composite (curve c), the two principal character peak is consistent；Contrast Fe₃O₄Material (curve b), the characteristic peak having about 35 ° is consistent with it, it was shown that be successfully prepared Fe by hydro-thermal method₃O₄/ Co-MOF composite.

As shown in Figure 4, the Fe of the present invention₃O₄/ Co-MOF there occurs twice thermogravimetric weight loss in whole temperature range, occurs thermogravimetric weight loss to lose the water of crystallization in complex and water of coordination molecule between 100 DEG C to 175 DEG C；Second time thermogravimetric weight loss, from 385 DEG C, is complex coordination bond fission at 385 DEG C-550 DEG C, structure collapse, the process of organic backbone combustion decomposition.Being basically completed to 550 DEG C, thermogravimetric weight loss is about 63%.

Fig. 5 is Fe₃O₄The BET figure of/Co-MOF material, is analyzed as follows.

Table 1BET map analysis

Specific surface area refers to the gross area that unit mass material has, and solid has certain geometric shape, by means of common Instrument measuring numerical value, adopts BET method to calculate its specific surface area.

BET equation at constant temperature is:

$\frac{1}{Q(\frac{p_0}{p}-1)}=\frac{1}{V_{m}C}+\frac{C-1}{V_{m}C}\×\frac{p}{P_0}$

In formula:

P adsorbate dividing potential drop/Pa；

p₀Adsorbate saturated vapor pressure/Pa；

Q adsorbance/(cm²/ g)；

V_mSingle molecular layer saturated absorption/(cm²/ g)；

C BET equation constant；

C, V can be calculated by slope_mAnd by the A of Instrument measuring_mBET specific surface area can be calculated

$\mathrm{Sg}=A_m\×\mathrm{NA}\×\frac{V_m}{22414}\×{10}^{-18}$

In formula:

A_m—0.1620nm²

NA Avogadro constant number (6.02 × 10²³)

By calculating above it can be seen that MOF-Fe₃O₄Material BET specific surface area is 7.7548m²/g。

Embodiment 3

Fe₃O₄Dye adsorption experiment is carried out by/Co-MOF material according to the following step: takes 4mg/L rhodamine, isatin and the biological stain each 5mL of element respectively, adds composite 0.8g, at room temperature stir.After 300min, above-mentioned solution is centrifuged and passes through the content of ultraviolet method detection reactant.

Fig. 6 is the adsorption rate figure of dyestuff, is respectively as follows: 16.8%, 19.3%, 15.3%；Curve above is the absorbance before absorption, and curve below is the absorbance after absorption.Remaining heterogeneous composite can use deionized water wash 3 times, and vacuum drying at 80 DEG C is reused next time, and adsorption effect is constant.

The above is presently preferred embodiments of the present invention, but the present invention should not be limited to this embodiment disclosure of that.So every without departing from the equivalence completed under spirit disclosed in this invention or amendment, both fall within the scope of protection of the invention.

Claims (4)

1. a heterogeneous Fe₃O₄The preparation method of/Co metal-organic framework materials, it is characterised in that described heterogeneous Fe₃O₄/ Co metal-organic framework materials specific surface area is 6～10m²/ g, with metal organic framework compound Co-MOF for carrier, is attached with the Fe that diameter is 10～40nm in its surface and hole₃O₄Nanoparticle, its preparation process includes:

(1)Fe₃O₄Prepared by nanoparticle: be completely dissolved in ethylene glycol by solubility trivalent iron salt, is slowly added to anhydrous sodium acetate and Polyethylene Glycol, pours in reactor after being sufficiently stirred for, and is warming up to 195～205 DEG C and keeps 10～15h under sealing state；It is down to room temperature again to take washing of precipitate and dry, washes three times, alcohol wash three times, dry 6 hours of 60 DEG C of baking oven, gained Fe₃O₄The particle diameter of nanoparticle is 10～40nm；The ferrum element of trivalent iron salt and sodium acetate mol ratio are 1:8～1:10；The amount ratio of the ferrum element of trivalent iron salt and Polyethylene Glycol and ethylene glycol is 1mmol:150～240mg:30～50ml；

(2)Fe₃O₄The synthesis of/Co-MOF: the Fe that soluble cobalt, trimesic acid and step (1) are synthesized₃O₄Nanoparticle, is placed in closed reactor, adds deionized water, is sufficiently stirred for until soluble cobalt and trimesic acid are completely dissolved, makes Fe₃O₄Nanoparticle is uniformly dispersed；The mol ratio of cobalt element and trimesic acid is 2:1～1:1, with Fe₃O₄The amount ratio of nanoparticle is 1mol:10g～1mol:20g；

Heating, to 135～150 DEG C, keeps 20～28 hours；Then cool the temperature to 118～122 DEG C, keep 4.5～6 hours；It is cooled to 98～105 DEG C afterwards again and is incubated 4.5～6 hours, finally make it naturally be down to room temperature and stand 11～14h；Take precipitation point washing, then carry out sucking filtration, natural air drying, finally give Fe₃O₄/ Co-MOF composite.

2. heterogeneous Fe described in claim 1₃O₄The preparation method of/Co metal-organic framework materials, it is characterised in that in step (2), described soluble cobalt is cobaltous acetate.

3. the heterogeneous Fe that preparation method described in claim 1 or 2 is obtained₃O₄/ Co metal-organic framework materials is used for preparing adsorbent.

4. the heterogeneous Fe that preparation method described in claim 1 or 2 is obtained₃O₄/ Co metal-organic framework materials is for preparing the adsorbent of absorbing dye.