MOFS/MIPS CATALYST AND IN-SITU GROWTH PREPARATION METHOD THEREOF AND APPLICATION

Abstract

An MOFs/MIPs catalyst, an in situ growth preparation method for same, and applications thereof are provided. The method comprises: uniformly mixing template molecules, a functional monomer, and a pore-foaming agent and performing a prepolymerization to produce a prepolymerization reaction product; uniformly mixing a cross-linking agent, an initiator, and the prepolymerization reaction product, heating, eluting the template molecules via a Soxhlet extraction, and drying to produce an imprinted polymer; uniformly mixing dimethylformamide, 2,5-dihydroxyterephthalic acid, ferrous chloride, water, methanol, and the imprinted polymer, heating, washing, using methanol for immersion and washing, and drying to produce the MOFs/MIPs catalyst.

Claims

1. An in-situ growth preparation method of a MOFs/MIPs catalyst, comprising the following preparation steps: step (1) uniformly mixing template molecules, a functional monomer and a pore-foaming agent, performing a uniform ultrasonic dispersion, and performing a prepolymerization reaction to obtain a prepolymerization reaction product; step (2) uniformly mixing a crosslinking agent and an initiator with the prepolymerization reaction product in the step (1) to obtain a mixed solution, then performing a water bath heating to conduct a polymerization reaction to obtain a reaction product after the water bath heating, eluting the template molecules by Soxhlet extraction, and performing a drying to obtain an imprinted polymer; and step (3) uniformly mixing dimethyl formamide, 2,5-dyhydroxy terephthalic acid, ferrous chloride, water, methanol and the imprinted polymer in the step (2), performing a uniform ultrasonic dispersion, performing a heating treatment and a washing, then performing an immersion in methanol, performing a centrifugation to take a precipitate, washing and drying the precipitate to obtain the MOFs/MIPs catalyst.

2. The in-situ growth preparation method of an MOFs/MIPs catalyst according to claim 1, wherein the template molecules in the step (1) are dimethyl phthalate, the functional monomer is methacrylic acid, a volume ratio of the template molecules to the functional monomer is 2:1 to 4:1, the pore-forming agent is acetonitrile, a volume ratio of the template molecules to the pore-forming agent is 1:120 to 1:130, a time of the prepolymerization reaction ranges from 0.5 hour to 1.5 hours, and a temperature of the prepolymerization reaction ranges from 3° C. to 5° C.

3. The in-situ growth preparation method of an MOFs/MIPs catalyst according to claim 1, wherein the crosslinking agent in the step (2) is ethylene glycol dimethacrylate, a volume ratio of the crosslinking agent in the step (2) to the template modulates in the step (1) is 1:34 to 1:36, the initiator in the step (2) is azobisisobutyronitrile, and a mass volume ratio of the initiator in the step (2) to the pore-forming agent in the step (1) is (0.05-0.15): 1 g/mL.

4. The in-situ growth preparation method of an MOFs/MIPs catalyst according to claim 1, wherein a temperature of the water bath heating in the step (2) ranges from 55° C. to 65° C., and a time for the water bath heating ranges from 23 hours to 25 hours.

5. The in-situ growth preparation method of an MOFs/MIPs catalyst according to claim 1, wherein in the step (2), the reaction product after the water bath heating is subjected to Soxhlet extraction by using a mixed solution of methanol and acetic acid, so that the template molecules on the reaction product after the water bath heating are eluted, and specific recognition sites of the template molecules on the reaction product after the water bath heating are vacated, wherein a volume ratio of methanol to acetic acid is 8:1 to 10:1.

6. The in-situ growth preparation method of an MOFs/MIPs catalyst according to claim 1, wherein in the step (3), a volume ratio of 2,5-dyhydroxy terephthalic acid to dimethyl formamide is 1:175 to 1:185 g/mL, a mass volume ratio of ferrous chloride to dimethyl formamide is 1:87.5 to 1:92.5 g/mL, a volume ratio of dimethyl formamide to water is 17:1 to 19:1, a volume ratio of the dimethyl formamide to methanol is 17:1 to 19:1, and a mass volume ratio of the imprinted polymer to dimethyl formamide is 1:8 to 1:9 g/mL.

7. The in-situ growth preparation method of an MOFs/MIPs catalyst according to claim 1, wherein in the step (3), a temperature of the heating treatment ranges from 110° C. to 120° C., and a time for the heating treatment ranges from 23 hours to 25 hours.

8. The in-situ growth preparation method of an MOFs/MIPs catalyst according to claim 1, wherein in the step (3), the washing is washing with dimethyl formamide, and a time of the immersion in methanol ranges from 1 hour to 3 hours.

9. An MOFs/MIPs catalyst, prepared by the in-situ growth preparation method according to claim 1.

10. An application of the MOFs/MIPs catalyst according to claim 9 in degrading DMP in wastewater through targeted oxidation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Description of the Drawings

[0042] FIG. 1 is an X-ray diffraction (XRD) pattern of an MOFs/MIPs material.

[0043] FIG. 2 is a Fourier transform infrared (FTIR) pattern of an MOFs/MIPs material.

[0044] FIG. 3 is a targeted degradation curved graph of the MOFs/MIPs to DMP and structural analogues thereof.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the Present Invention

[0045] Further description of specific embodiments of the present invention in detail will be made below in combination with drawings and examples, but implementation and protection of the present invention are not limited thereto. It should be noted that processes that are not described in detail particularly below are realized or understood by those skilled in the field with reference to prior art. The used reagents or instruments not indicated by manufacturers are conventional products which can be purchased in the market.

Example 1

[0046] In the embodiment, influence on effect that MIPs adsorb DMP in different reaction conditions is compared.

[0047] A method for preparing MIPs includes the following steps.

[0048] (1) Template molecules (DMP), a functional monomer (MMA) and a pore-foaming agent (acetonitrile) were added into 50 mL centrifuge tube for uniform ultrasonic dispersion and then a prepolymerization reaction was performed.

[0049] The reaction conditions were controlled in the following six types (as shown in table 1 below).

TABLE-US-00001 TABLE 1 Reaction conditions Temperature of Time of Volume ratio of DMP to prepolymerization prepolymerization MAA to acetonitrile Reaction product reaction reaction (DMP:MAA:acetonitrile) Pre-MIPs-1 3° C. 0.5 h 2:1:120 Pre-MIPs-2 3° C.   1 h 3:1:125 Pre-MIPs-3 4° C.   1 h 3:1:125 Pre-MIPs-4 4° C. 1.5 h 4:1:130 Pre-MIPs-5 5° C. 0.5 h 2:1:120 Pre-MIPs-6 5° C.   1 h 4:1:130

[0050] Six prepolymerization reaction products were obtained, which were respectively named as Pre-MIPs-1, Pre-MIPs-2, Pre-MIPs-3, Pre-MIPs-4, Pre-MIPs-5 and Pre-MIPs-6;

[0051] (2) Hemispherical MIPs were prepared by means of the bulk polymerization method: a crosslinking agent EGDMA and an initiator AIBN were mixed with the prepolymerization reaction product (Pre-MIPs-3 herein) uniformly in the step (1), and water bath heating was performed to carry out the polymerization reaction.

[0052] The reaction conditions were controlled in the following six types (as shown in table 2 below);

TABLE-US-00002 TABLE 2 Reaction conditions Temperature of Time of Volume ratio Volume ratio polymerization polymerization of EGDMA of AIBN to Reaction product reaction reaction to DMP acetonitrile Water bath reaction 55° C. 23 h 1:34 0.05:1 g/mL product 1 Water bath reaction 60° C. 24 h 1:36  0.1:1 g/mL product 2 Water bath reaction 60° C. 24 h 1:35  0.1:1 g/mL product 3 Water bath reaction 65° C. 25 h 1:36 0.15:1 g/mL product 4 Water bath reaction 55° C. 23 h 1:34 0.05:1 g/mL product 5 Water bath reaction 65° C. 25 h 1:36 0.15:1 g/mL product 6

[0053] The volume ratio of EGDMA to DMP in the table 2 was the volume ratio of EDGMA in the step (2) to the DMP in the step (1), and the mass volume ratio of the AIBN to the acetonitrile in the table 2 was the mass volume ratio of the AIBN in the step (2) to the acetonitrile in the step (1).

[0054] The obtained six reaction products after water bath heating (corresponding water bath reaction products 1-6 in the table 2), were subjected to Soxhlet extraction by using a mixed solution of methanol (analytical pure, 99.5%) and acetic acid (analytical pure, 99.5%) respectively. In the mixed solution, the volume ratio of methanol to acetic acid was 9:1, and the template molecules were eluted and dried respectively to obtain six imprinted polymers which were respectively named as MIPs-1, MIPs-2, MIPs-3, MIPs-4, MIPs-5 and MIPs-6.

[0055] (3) 30 mg/L of a DMP solution was prepared as simulated wastewater containing DMP for later use.

[0056] (4) 100 mL 30 mg/L DMP solutions were added into 6 reactors respectively by taking conical flasks as the reactors, then the MIPs-1, MIPs-2, MIPs-3, MIPs-4, MIPs-5 and MIPs-6 were respectively added, the six conical flasks were respectively placed in a table at a rotating speed of 180 rpm, an adsorption reaction was performed at a constant temperature (25° C.), and sampling and analyzing were performed in 24 hours.

[0057] The adsorbing capacities of DMP under different MIPs are as shown in Table 3 below.

TABLE-US-00003 TABLE 3 MIP MIPs-1 MIPs-2 MIPs-3 MIPs-4 MIPs-5 MIPs-6 Adsorbing 7.3 10.4 11.3 8.1 7.9 10.1 capacity (mg/g)

[0058] It can be known from the table 3 that in different reaction conditions, the effects that the MIPs adsorb DMP are different, and with different reaction temperatures, reaction times and different inputting proportions of the reactants in the preparation process, the adsorbing capacities of DMP change obviously. It can be known from the above table that when the prepolymerization reaction condition is as follows: the temperature is 4° C., the time is 1 hour and the volume ratio of DMP to MMA to acetonitrile is 3:1:125, the effect that the prepared MIPs (MIPs-3) absorb DMP in the simulated wastewater is optimum under the condition that the polymerization reaction condition is as follows: the temperature is 60° C., the time is 24 hours, the volume ratio of EGDMA to DMP is 1:35 and the mass volume ratio of AIBN to acetonitrile is 0.1:1 g/mL.

Example 2

[0059] In the embodiment, influence on effect that MOFs/MIPs degrade DMP in a targeted manner in different reaction conditions is compared.

[0060] An in-situ growth preparation method of a MOFs/MIPs catalyst includes the following steps.

[0061] (1) MOFs/MIPs and MOFs/NIPs were prepared by means of in-situ growth method: DMF, 2,5-dihydroxyl terephthalic acid, ferrous chloride, water and methanol (analytical pure, 99.5%) were uniformly mixed with the imprinted polymer (MIPs-3 herein) prepared in the step (4) in Example 1 in a reaction kettle to obtain a mixed solution, ultrasonic dispersion was performed on the mixed solution, and heating treatment was performed in an oven.

[0062] The reaction conditions were controlled in the following six types (as shown in table 4 below);

TABLE-US-00004 TABLE 4 Reaction conditions Mass Mass volume volume Mass ratio ratio Volume ratio volume Temperature Time of (g/mL) of (g/mL) of of DMF to ratio of heating heating 2,5-dihydroxyl ferrous water to (g/mL) of Reaction treatment treatment terephthalic chloride methanol MIPs product (° C.) (h) acid to DMF to DMF (DMF:water:methanol) to DMF Heating 110 23 1:175 1:92.5 17:1:1 1:8 product-1 Heating 115 24 1:180 1:87.5 18:1:1 .sup. 1:8.5 product-2 Heating 110 24 1:180 1:87.5 18:1:1 .sup. 1:8.5 product-3 Heating 115 25 1:185 1:87.5 18:1:1 1:9 product-4 Heating 110 23 1:180 1:92.5 18:1:1 1:8 product-5 Heating 120 25 1:185 1:87.5 19:1:1 1:9 product-6

[0063] The obtained products (the heating product-1, the heating product-2, the heating product-3, the heating product-4, the heating product-5 and the heating product-6) were washed with DMF respectively and then immersed in methanol (analytical pure, 99.5%) respectively for 2 hours, centrifugation was performed respectively to take precipitates, and the precipitates were dried to obtain six reaction products (i.e., the MOFs/MIPs catalyst), and the six reaction products were respectively named as MOFs/MIPs-1, MOFs/MIPs-2, MOFs/MIPs-3, MOFs/MIPs-4, MOFs/MIPs-5 and MOFs/MIPs-6.

[0064] (2) A DMP solution (simulating wastewater containing DMP) with concentration of 30 mg/L was prepared for later use.

[0065] (3) 100 mL of DMP solutions with concentration of 30 mg/L and the MOFs/MIPs-1, MOFs/MIPs-2, MOFs/MIPs-3, MOFs/MIPs-4, MOFs/MIPs-5 and MOFs/MIPs-6 obtained in the step (2) were respectively added into the six reactors by taking conical flasks as the reactors, the six conical flasks were respectively placed in a table at a rotating speed of 180 rpm, an adsorption reaction was performed at a constant temperature (25° C.), in 24 hours (it was ensured that adsorption equilibrium was reached), the oxidizing agent PS (persulfate) was respectively added with the adding amount of 2.4 g/L, and sampling and analyzing at fixed points were performed.

[0066] The removal rates of DMP under different MOFs/MIPs catalysts are as shown in Table 5 below.

TABLE-US-00005 TABLE 5 Removal rate (%) Time MOFs/ MOFs/ MOFs/ MOFs/ MOFs/ MOFs/ (min) MIPs-1 MIPs-2 MIPs-3 MIPs-4 MIPs-5 MIPs-6 0 48.1 58.1 55.7 57.3 52.6 49.1 30 79.1 87.5 82.8 83.1 84.9 77.8 60 80.6 89.3 83.9 83.9 85.7 79.7 120 82.3 90.2 84.2 84.2 86.4 81.3 180 83.4 93.5 84.6 86.4 87.3 81.7 240 84 94.7 85.4 87.3 88 81.8 300 84.9 94 86.9 89.8 88.8 82.9 360 85.6 95.2 88.3 91.5 90.1 83.5 420 87.9 97.7 90.6 93.3 94.2 85.6 480 89.7 100 91.1 98.2 99.6 87.3

[0067] The removal rate when the time is 0 is the removal rate when the MOFs/MIPs adsorb DMP to reach adsorption equilibrium.

[0068] It can be known from table 5 that in different reaction conditions, the effects that the MOFs/MIPs catalysts remove DMP are different, and the removal rate of DMP changes obviously with different reaction times and proportions of inputting the reactants in the preparation process; when the reaction condition in the in-situ growth preparation method is as follows: the temperature is 115° C., the time is 24 hours, the mass volume ratio of 2,5-dihydroxyl terephthalic acid to DMF is 1:180 g/mL, the mass volume ratio of ferrous chloride to DMF is 1:87.5 g/mL, the volume ratio of DMF to water to methanol is 18:1:1, and the mass volume ratio of MIPs to DMF is 1:8 g/mL, and the effects of the prepared MOFs/MIPs (the XRD patterns and the FTIR patterns of MOFs/MIPs-2 are shown in FIG. 1 and FIG. 2) that remove DMP in the simulated wastewater are optimum.

Example 3

[0069] Targeted selectivity to DMP by the MOFs/MIPs catalyst is compared in the embodiment.

[0070] Analogues of three structures of DMP, which a diethyl phthalate (DEP) solution, a dibutyl phthalate (DBP) solution and di(2-ethylhexyl)phthalate (DEHP), were selected to perform targeted selectivity researches of the MOFs/MIPs catalysts to DMP, respectively. The DMP solution, the DEP solution, the DBP solution and the DEHP solution with initial concentrations of 30 mg/L were prepared respectively, the MOFs/MIPs catalysts (MOFs/MIPs-2) prepared in Example 2 were added respectively into the above-mentioned four solutions, the adding amount of the MOFs/MIPs catalyst prepared in Example 2 was 2.4 g/L (2.4 g of catalyst was input in solution per litre), in the 180 rpm table, an adsorption reaction was performed under the condition of constant temperature (25° C.), in 24 hours (it was ensured that absorption equilibrium was reached), the oxidizing agent PS (persulfate) was respectively added into the four solutions, and molar ratios of the adding amounts of the oxidizing agent PS to the adding amounts of the pollutants (DMP, DEP, DBP and DEHP) were 600:1; sampling and analyzing were performed at fixed points.

[0071] The degradation conditions of the four solutions are as shown in FIG. 3. FIG. 3 is a targeted degradation curved graph of the MOFs/MIPs to DMP and structural analogues thereof. A result of FIG. 3 shows that all the pollutants (DMP, DEP, DBP and DEHP) are quickly oxidized and degraded within the first hour (the degradation ratios of DMP, DEP, DBP and DEHP are respectively 90.0%, 66.5%, 57.6% and 58.8%), and then the degradation rate is slowed down. It illustrates that the MOFs/MIPs catalyst provided by the present invention and structural analogues thereof play removal roles, but are the best in targeted degradation effect on the template molecules DMP, which means that the MOFs/MIPs catalyst has good specific selectivity to the targeted pollutants and degrades the pollutants in a targeted manner.

[0072] The catalyst provided by the present invention is high in degrading efficiency, and can realize highly preferential adsorption and catalytic degradation of organic pollutants, so that it is good in stability. The catalyst provided by the present invention is a bulky catalyst, can avoid problems of difficulty in recovering a conventional water treatment catalyst and the like, and is easily applied accurately.

[0073] The above embodiments are merely preferred embodiments of the present invention and are merely used for explaining the present invention rather than limiting the present invention. Variations, substitutions and modifications made by those skilled in the field shall fall within the scope of protection of the present invention without departing from the spirit of the present invention.