PREPARATION METHOD AND USE OF NOVEL COPPER-METAL ORGANIC FRAMEWORK (CU-MOF)-DERIVED MAGNETIC Fe3O4@Cu/C COMPOSITE FOR ANTIBIOTIC DEGRADATION

Abstract

Provided are a preparation method and use of a novel copper-metal organic framework (Cu-MOF)-derived magnetic Fe.sub.3O.sub.4@Cu/C composite for antibiotic degradation. The preparation method of the composite includes: compounding a novel Cu-MOF material obtained in a high-pressure reactor with Fe.sub.2O.sub.3, and then conducting calcination under an inert gas atmosphere to obtain the magnetic Fe.sub.3O.sub.4@Cu/C composite.

Claims

1. A copper-metal organic framework (Cu-MOF) material, wherein the Cu-MOF material has unit cell parameters comprising: a=8.7292 , b=20.4196 , c=34.3986 , ===90, and V=6131.42 .sup.3, and belongs to an orthorhombic crystal system and a Pbca space group.

2. A method for preparing the Cu-MOF material of claim 1, comprising the following steps: mixing tris(4-(4H-1,2,4-triazol-4-yl)phenyl)amine, copper acetate, 1,3,5-benzenetricarboxylic acid, water and alcohol at a temperature of 120 C. to 170 C. to obtain a system; adjusting a pH value of the system to 5 to 7 to obtain a solution; subjecting the solution to reaction in a reactor for 72 h to 96 h to obtain a reaction product; and subjecting the reaction product to gradient cooling to a temperature of 70 C. to 90 C. and natural cooling to room temperature in sequence to obtain the Cu-MOF material; wherein a molar ratio of the tris(4-(4H-1,2,4-triazol-4-yl)phenyl)amine, the copper acetate, and the 1,3,5-benzenetricarboxylic acid is in a range of 1:(1-5):(1-5).

3. The method of claim 2, wherein the reaction is conducted at a temperature of 145 C. to 165 C.; the gradient cooling is conducted at a speed of 5 C./h to 10 C./h; and the alcohol is selected from the group consisting of methanol and ethanol.

4. A method for preparing a magnetic Fe.sub.3O.sub.4@Cu/C composite, comprising the following steps: mixing the Cu-MOF material of claim 1 with Fe.sub.2O.sub.3 in a hexagonal structure and grinding evenly to obtain a mixture, then transferring the mixture to a tubular furnace, and conducting calcination under an inert gas atmosphere to obtain the magnetic Fe.sub.3O.sub.4@Cu/C composite.

5. The method of claim 4, wherein a molar ratio of the Cu-MOF material to the Fe.sub.2O.sub.3 in the hexagonal structure is in a range of 1:(1-1.5), and the grinding is conducted for 2 h to 4 h; and the calcination is conducted by programmed heating at a heating rate of 2 C./min to 3 C./min to a calcination temperature of 600 C. to 650 C. and holding at the calcination temperature for 2 h to 4 h, and then subjecting an obtained calcination product to natural cooling to room temperature.

6. A Fe.sub.3O.sub.4@Cu/C composite, which is prepared by the method of claim 4.

7. A method of using the magnetic Fe.sub.3O.sub.4@Cu/C composite prepared by the method of claim 4, comprising using the magnetic Fe.sub.3O.sub.4@Cu/C composite in antibiotic degradation.

8. The method of claim 7, wherein the magnetic Fe.sub.3O.sub.4@Cu/C composite cooperates with a persulfate as a catalyst for efficient degradation of an antibiotic pollutant in water.

9. The method of claim 8, wherein the persulfate is sodium peroxymonosulfate (PMS), and the PMS is added in an amount of 0.5 mmol/L to 1.5 mmol/L.

10. The method of claim 7, wherein an antibiotic is oxytetracycline (OTC), and the antibiotic degradation is conducted under a pH value of 3 to 11 at a temperature of 25 C. to 45 C. for 50 min to 60 min.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 shows a coordination environment diagram of the novel Cu-MOF material in Example 1 of the present disclosure (where H atoms are omitted);

[0026] FIG. 2 shows a scanning electron microscopy (SEM) image of the hexagonal appearance of the magnetic Fe.sub.3O.sub.4@Cu/C composite in Example 1 of the present disclosure;

[0027] FIG. 3 shows a degradation rate of OTC catalytically degraded by the Fe.sub.3O.sub.4@Cu/C composite in Example 1 of the present disclosure;

[0028] FIG. 4 shows an anti-interference test when the Fe.sub.3O.sub.4@Cu/C composite degrades OTC in Example 1 of the present disclosure;

[0029] FIG. 5 shows a degradation rate of OTC catalytically degraded by the Fe.sub.3O.sub.4@Cu/C composite at different pH values in Example 1 of the present disclosure;

[0030] FIG. 6 shows a magnetic hysteresis loop of the magnetic Fe.sub.3O.sub.4@Cu/C composite in Example 1 of the present disclosure; and

[0031] FIG. 7 shows a recyclable test of the magnetic Fe.sub.3O.sub.4@Cu/C composite in Example 1 of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The present disclosure will be further described below in conjunction with examples, but the scope of the present disclosure is not limited thereto.

[0033] A method for preparing hexagonal Fe.sub.2O.sub.3 was performed by the following procedures:

[0034] 1.0 mmol of FeCl.sub.3.Math.6H.sub.2O was dissolved in 30 mL of ethanol, and 1 mL of water was added thereto; after complete dissolution, 0.8 g of sodium acetate was added, and then stirred vigorously for 1 h to obtain a solution. The solution was transferred to a polytetrafluoroethylene (PTFE) liner, heated to 180 C. for 12 h, and then cooled to room temperature to obtain a suspension. The suspension was centrifuged at a rotating speed of 10,000 rpm, and a resulting product was then washed repeatedly with water and ethanol, and dried in an oven at a temperature of 60 C. to obtain the hexagonal Fe.sub.2O.sub.3.

Example 1

[0035] A magnetic Fe.sub.3O.sub.4@Cu/C composite was synthesized in two steps as follows:

(1) Synthesis of Novel Cu-MOF Material

[0036] 45.0 g (0.1 mol) of tris(4-(4H-1,2,4-triazol-4-yl)phenyl)amine, 42.1 g (0.2 mol) of 1,3,5-benzenetricarboxylic acid, and 57.5 g (0.3 mol) of copper acetate were added into a mixture of water and ethanol to obtain a reaction solution, where a mass of the water was 75 g (4.1 mol) and a mass of the methanol was 50 g (1.6 mol). A pH value of the reaction solution was adjusted to 6.5. A resulting solution was stirred for 15 min to obtain a mixed solution of reactants. The mixed solution was feed into a reactor, and crystallized at a temperature of 150 C. for 72 h to obtain a reaction product. After the reaction, the reaction product was subjected to gradient cooling at a speed of 10 C./h to a temperature of 80 C., then natural cooling to room temperature, and a resulting cooled product was filtered to obtain a blue transparent crystal, namely the novel Cu-MOF material. The blue transparent crystal was washed with a methanol solution until the surface of the crystal was free of impurities, and dried to obtain a compound with a novel structure. The obtained Cu-MOF material has a purity of 95% and a yield of 88%. According to results of the X-ray single crystal diffraction test, the crystal structure parameters of the Cu-MOF material show that its crystal system belongs to an orthorhombic crystal system and a Pbca space group. Specific unit cell parameters are: a=8.7292 , b=20.4196 , c=34.3986 , ===90, and V=6131.42 .sup.3. There are two-dimensional layered structural features in the crystal structure.

(2) Synthesis of Magnetic Fe.sub.3O.sub.4@Cu/C Composite

[0037] 7.4 g (0.01 mol) of the Cu-MOF prepared in step (1) and 1.9 g (0.012 mol) of the hexagonal Fe.sub.2O.sub.3 were mixed, and ground for 2.5 h until the materials were evenly composited to obtain a composite Cu-MOF@Fe.sub.2O.sub.3. The composite Cu-MOF@Fe.sub.2O.sub.3 was transferred to a tubular furnace, and subjected to programmed calcination (the temperature was set to 600 C., and the heating rate was controlled to 2 C./h) under a nitrogen atmosphere for 3 h and then natural cooling to room temperature to obtain the novel magnetic Fe.sub.3O.sub.4@Cu/C composite. This composite could still maintain a hexagonal lamellar appearance and a large specific surface area, which are conducive to the dispersion of active sites during catalytic reactions (FIG. 2).

(3) Performance Test of Antibiotic Degradation by Magnetic Fe.sub.3O.sub.4@Cu/C Composite

1) Degradation Performance

[0038] The magnetic Fe.sub.3O.sub.4@Cu/C composite prepared in Example 1 was used to cooperatively excite PMS to degrade OTC, as follows:

[0039] 5 mg of Fe.sub.3O.sub.4@Cu/C composite was weighed and placed in a 100 mL glass bottle, 50 mL of OTC (initial concentration was 20 mg/L) solution was added thereto, and the PMS was added thereto in an amount of 1 mmol/L. The degradation test was conducted in a constant-temperature water bath shaker at 180 rpm/min. At regular intervals, 2 mL of a reaction solution was taken and filtered with a 0.45 m filter membrane, and quenched by 20 mM Na.sub.2S.sub.2O.sub.3, where the test was conducted for 50 min. A concentration change of the reaction solution was measured with a UV-visible spectrophotometer. A degradation rate was calculated according to a formula c.sub.0c/c.sub.0100%, where c.sub.0 and c are mass concentrations of the solution before and after degradation, respectively, in mg/L.

[0040] Under the condition that the composite prepared in Example 1 was used to degrade OTC, the degradation rate could reach 95% within 50 min (FIG. 3).

2) Anti-Interference Performance of the Composite

[0041] During the degradation performance test in 1), 50 mmol/L of interfering ions (H.sub.2PO.sub.4.sup., NO.sub.3.sup., Cl.sup., HCO.sub.3.sup.; and SO.sub.4.sup.2) or 50 mg/L of humic acid were added. For OTC, the degradation efficiency only dropped by about 10%, proving that the composite has strong anti-interference ability (FIG. 4).

3) Applicable pH Range of the Composite

[0042] In the example of degrading OTC in 1), the pH value of the reaction system solution was adjusted to 3 to 11, and the Fe.sub.3O.sub.4@Cu/C composite could still exert a desirable catalytic degradation effect (FIG. 5).

4) Recovery and Recycling Performance of the Composite

[0043] After each test run was completed, the Fe.sub.3O.sub.4@Cu/C composite was separated from the reaction solution using an external magnetic field (FIG. 6).

5) The composite recovered in 4) was cleaned and dried for 12 h for a recyclable test.

[0044] The composite was recycled 5 times, and its degradation rate of OTC could still reach 82% (FIG. 7).