CN116272954B - Catalyst based on MOFs metal framework oxide for VOCs treatment and preparation method thereof - Google Patents

Catalyst based on MOFs metal framework oxide for VOCs treatment and preparation method thereof Download PDF

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CN116272954B
CN116272954B CN202310564811.3A CN202310564811A CN116272954B CN 116272954 B CN116272954 B CN 116272954B CN 202310564811 A CN202310564811 A CN 202310564811A CN 116272954 B CN116272954 B CN 116272954B
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mofs
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CN116272954A (en
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刘珊珊
周忠雷
张豪
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Shandong Greider Environmental Protection Technology Co ltd
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Abstract

The invention discloses a catalyst based on MOFs metal skeleton oxide for VOCs treatment and a preparation method thereof, and belongs to the field of MOFs metal skeleton oxide catalysts. The technical proposal is as follows: zrCl is selected for use 4 、TiCl 4 And VCl 3 As the metal ion source, H is selected 2 DPA is used as an organic ligand, DMF is used as an organic solvent, catechol is adopted to introduce hydroxyl (-OH), zr-Ti-V MOFs catalyst, active carbon and diatomite are used as supporting materials for compounding, the advantages of the two supporting materials can be fully exerted, and the stability and the activity of the catalyst in the process of treating VOCs are improved, so that a more efficient and sustainable VOCs treatment process is realized.

Description

Catalyst based on MOFs metal framework oxide for VOCs treatment and preparation method thereof
Technical Field
The invention relates to the field of MOFs-based metal skeleton oxide catalysts and preparation methods thereof, in particular to a catalyst for VOCs treatment based on MOFs metal skeleton oxides and a preparation method thereof.
Background
VOCs (volatile organic compounds) are a class of volatile organic compounds that include a variety of substances such as benzene, formaldehyde, xylene, toluene, and the like. VOCs are widely found in human life and production. The volatility of VOCs makes them prone to entry into the atmosphere and poses environmental and health hazards. On the one hand, VOCs can generate photochemical reaction with substances such as nitrogen oxides in the atmosphere to form harmful substances such as ozone, thereby causing environmental problems such as photochemical smog, acid rain and the like; on the other hand, VOCs have serious effects on human health, including irritative respiratory symptoms, headache, nausea, eye and skin irritation, etc., and can even cause cancer when severe.
The catalyst plays a role in catalyzing oxidation reaction in VOCs treatment, and converts VOCs into harmless substances such as water, carbon dioxide and the like. The catalyst has the functions of improving the reaction rate, reducing the reaction temperature, improving the reaction selectivity, reducing the generation of reaction byproducts, and the like. During catalytic oxidation of VOCs, the catalyst provides active sites that allow the reactant molecules to adsorb onto the catalyst surface, followed by oxidation with oxygen molecules. Meanwhile, the specific surface area and the pore diameter structure of the catalyst also influence the reaction, so that reactant molecules are more easily adsorbed and reacted on the surface of the catalyst. Different catalysts have different catalytic activities and selectivities in the treatment of VOCs, such as metal oxide catalysts, nano-metal catalysts, MOFs catalysts and the like, and can effectively catalyze the oxidation reaction of VOCs. By adjusting factors such as active sites, structures and compositions of the catalyst, the catalytic performance of the catalyst can be further optimized, and the efficiency and selectivity of catalytic reaction can be improved.
When the MOFs metal skeleton oxide catalyst is used for treating VOCs, the VOCs are mainly converted into harmless substances such as water, carbon dioxide and the like through catalytic oxidation reaction. The high specific surface area and the regulated pore size structure of MOFs catalyst can improve the activity of catalytic reaction, and the surface active site can also improve the reaction rate and selectivity. Specifically, the pore channel structure and the pore size of the MOFs catalyst can contain VOCs molecules, so that the adsorption capacity of the VOCs molecules on the surface of the catalyst is improved. In the catalytic reaction process, VOCs molecules are firstly adsorbed on the surface of the catalyst and then undergo oxidation reaction with oxygen molecules to generate CO 2 、H 2 O, etc. Meanwhile, metal ions and organic ligands in the MOFs catalyst also participate in the reaction, so that the reaction is promoted, and the reaction rate and selectivity are improved.
However, the MOFs metal skeleton oxide catalyst has the problem of poor stability in the process of treating VOCs, and the MOFs metal skeleton oxide catalyst easily loses a crystal structure at high temperature, so that the active site of the catalyst is invalid; is sensitive to humidity, which can lead to destruction of the catalyst structure and failure of the active sites; the acid-base environment also affects the stability of MOFs metal framework oxide catalysts, particularly in acidic conditions, which tend to cause metal ion elution. Poor catalytic efficiency that can low catalyst of stability influences the effect that VOCs handled, influences the reusability and the life-span of catalyst, increases the use cost of catalyst, and the inefficacy of catalyst can lead to the reaction to produce the accessory substance, increases the risk of environmental and health problem. Therefore, improving the stability of MOFs metal framework oxide catalysts in the treatment of VOCs is of great importance for both environmental protection and health and safety.
Disclosure of Invention
In order to improve the stability of MOFs metal framework oxide catalysts in VOCs treatment, the invention provides a catalyst based on MOFs metal framework oxide for VOCs treatment, and the stability of the catalyst is improved.
In order to achieve the above object, the present invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, the preparation of the catalyst comprising the steps of:
a) ZrCl is selected for use 4 、TiCl 4 And VCl 3 As the metal ion source, H is selected 2 DPA is used as an organic ligand, and DMF is used as an organic solvent;
b) ZrCl is added to 4 、TiCl 4 、VCl 3 And H 2 DPA is respectively added into DMF, stirred and mixed, heated and reacted;
c) Drying and heat-treating the product obtained in the step b) to remove residual solvent and water;
d) Oxidizing the product obtained in the step c) in an oxygen stream until the color of the catalyst becomes dark red, thereby obtaining a Zr-Ti-V MOFs catalyst;
e) Adding Zr-Ti-V MOFs catalyst and catechol into dimethylformamide respectively, stirring and mixing, adjusting the PH value, and heating for reaction;
f) Washing the product of the step e) with a solvent to remove unreacted ligand and impurities, and then drying to obtain OH@Zr-Ti-V MOFs;
g) Respectively dissolving OH@Zr-Ti-V MOFs, active carbon and diatomite supporting material in a solvent DMFO, and stirring and cooling the solution to room temperature;
h) And c), centrifuging, filtering and drying the product obtained in the step g), and removing residual solvent and moisture to obtain the final catalyst.
ZrCl in the step a) 4 、TiCl 4 And VCl 3 The metal ion molar ratio of (1-2) is 1: (1-2).
ZrCl is added in the step b) 4 、TiCl 4 And VCl 3 And respectively addAdding into DMF, stirring and mixing until completely dissolved, and then adding H 2 DPA is stirred and mixed continuously to be dissolved completely, the mixed solution is heated to 160 ℃ under inert atmosphere and reacts for 24 hours, H 2 The molar ratio of DPA is 0.8-1.2 times of that of metal ions.
In the step c), the drying is carried out at 80 ℃ for 4 hours, the heat treatment temperature is 400 ℃, and the treatment is carried out for 5 hours.
The oxygen flow in step d) was 40mL/min and the treatment temperature was 400 ℃.
In the step e), the mass ratio of the Zr-Ti-V MOFs catalyst to the catechol is 1 (1-5), the PH value is regulated to 7 by NaOH, and the reaction is carried out for 5 hours at the temperature of 110 ℃.
And f) washing with ethanol, wherein the drying temperature is 80 ℃.
In the step g), the mass of OH@Zr-Ti-V MOFs is 40-90% of the total mass, and the mass ratio of the activated carbon to the diatomite is (5-9): 1, mass ratio of solid material to solvent 1: (10-20), stirring time was 1 hour, and heating temperature of the solvent was 60 ℃.
The drying temperature in the step h) is 80 ℃.
The invention also provides a preparation method of the catalyst for VOCs treatment based on MOFs metal skeleton oxide, which is characterized by comprising the following steps:
a) ZrCl is selected for use 4 、TiCl 4 And VCl 3 As the metal ion source, H is selected 2 DPA is used as an organic ligand, DMF is used as an organic solvent, and ZrCl is used as a catalyst 4 、TiCl 4 And VCl 3 The metal ion molar ratio of (1-2) is 1: (1-2);
b) ZrCl is added to 4 、TiCl 4 And VCl 3 And adding into DMF respectively, stirring and mixing until completely dissolved, and then adding H 2 DPA is stirred and mixed continuously to be dissolved completely, the mixed solution is heated to 160 ℃ under inert atmosphere and reacts for 24 hours, H 2 The mole ratio of DPA is 0.8-1.2 times of metal ion;
c) Drying the product obtained in the step b) at 80 ℃ for 4 hours, and performing heat treatment at 400 ℃ for 5 hours to remove residual solvent and moisture;
d) Oxidizing the product obtained in the step c) in an oxygen flow until the color of the catalyst becomes dark red to obtain a Zr-Ti-V MOFs catalyst, wherein the oxygen flow is 40mL/min, and the treatment temperature is 400 ℃;
e) Adding Zr-Ti-V MOFs catalyst and catechol into dimethylformamide respectively, stirring and mixing, adjusting the PH value to 7 by NaOH, and reacting for 5 hours at 110 ℃, wherein the mass ratio of the Zr-Ti-V MOFs catalyst to the catechol is 1 (1-5);
f) Washing the product of the step e) by ethanol to remove unreacted ligand and impurities, and then drying at 80 ℃ to obtain OH@Zr-Ti-V MOFs;
g) Respectively dissolving OH@Zr-Ti-V MOFs, active carbon and diatomite supporting materials in a solvent DMFO, stirring and cooling the solution to room temperature, wherein the mass of the OH@Zr-Ti-V MOFs is 40-90% of the total mass, and the mass ratio of the active carbon to the diatomite is (5-9): 1, mass ratio of solid material to solvent 1: (10-20), stirring for 1 hour, and heating the solvent at 60 ℃;
h) Centrifuging the product of the step g), filtering, and drying at 80 ℃ to remove residual solvent and water to obtain the final catalyst.
The beneficial effects of the invention are as follows:
1. zr, ti and V are metal elements with good catalytic performance, and can effectively catalyze the oxidation reaction of VOCs and convert the VOCs into harmless substances such as water, carbon dioxide and the like. The Zr, the Ti and the V have different chemical properties and oxidation-reduction capacities, and the three metal elements are selected to form the multi-metal MOFs catalyst, so that the interaction and the synergistic effect among the metal elements can be fully utilized, and the catalytic efficiency and the selectivity of the catalyst are improved. The structure and the property of the MOFs metal skeleton oxide catalyst can be realized by adjusting the proportion of metal elements and the coordination environment, the MOFs catalyst under different proportions and coordination environments can be obtained by selecting Zr, ti and V, the catalytic performance and the stability of the catalyst can be optimized, in the VOCs treatment, the coexistence of Zr, ti and V can improve the poisoning resistance of the catalyst, the dissolution of metal ions is reduced, and the service life and the reuse performance of the catalyst are improved.
2. Catechol is added into Zr-Ti-V MOFs catalysts to introduce hydroxyl (-OH), the hydroxyl (-OH) is introduced to improve the stability and catalytic activity of MOFs metal skeleton oxide catalysts when VOCs are treated, the hydroxyl (-OH) has good polarity and hydrophilicity, the interaction force between active sites on the surfaces of the catalysts and VOCs molecules can be enhanced, and the adsorption and reaction of reactant molecules are promoted, so that the catalytic activity and selectivity are improved; the hydroxyl (-OH) has better acid-base performance, and can neutralize acidic substances and adsorb acidic functional groups in VOCs molecules, so that the influence of the acidic substances on the surface of the catalyst is reduced, the stability and the reusability of the catalyst are improved, the surface oxidation performance of MOFs metal skeleton oxide catalysts can be improved by introducing the hydroxyl (-OH), the oxidation reaction activity of the MOFs metal skeleton oxide catalysts on the VOCs is enhanced, and the catalytic efficiency of the catalysts is improved; the hydroxyl (-OH) can also form coordination bond with metal ions, so that the metal ions are more stable, the metal ions are prevented from being dissolved out in the reaction process, and the service life and stability of the catalyst are improved.
3. The Zr-Ti-V MOFs catalyst and the supporting material are compounded, so that the stability, activity and selectivity of the catalyst can be improved, the catalytic performance and stability of the catalyst are optimized, and therefore, a more efficient and sustainable VOCs treatment process is realized, because the supporting material can provide physical support for the catalyst, the mechanical strength and stability of the catalyst are enhanced, the damage and dissolution of the catalyst in the reaction process are reduced, the service life and the reusability of the catalyst are improved, the supporting material has a larger specific surface area and a pore structure, the number of active sites and the contact area on the surface of the catalyst can be increased, the interaction between the VOCs and the catalyst is promoted, and the catalytic activity and selectivity are improved; by controlling the pore structure and the size of the support material, the catalyst can be uniformly dispersed on the support material, so that a highly stable catalyst/support material composite system is formed, the contact efficiency between the catalyst and VOCs is enhanced, and the reaction rate and conversion rate are improved; the supporting material can also adjust the surface acidity-alkalinity and oxidation-reduction properties of the catalyst, and optimize the catalytic performance and stability of the catalyst, thereby realizing a more efficient and sustainable VOCs treatment process.
4. The active carbon has a great specific surface area and a pore structure, can provide physical support for the catalyst, enhances the contact efficiency between the catalyst and VOCs, improves the catalytic activity and selectivity, the diatomite has excellent chemical stability and adsorption performance, can adjust the surface acidity and alkalinity and redox properties of the catalyst, improves the stability and reusability of the catalyst, the composite of the active carbon and the diatomite can form a multi-stage pore structure, so that the catalyst is easier to uniformly disperse on a supporting material, the number of active sites and the contact area on the surface of the catalyst are improved, the composite of the active carbon and the diatomite can reduce the dissolution and breakage of the catalyst, thereby improving the service life and reusability of the catalyst, combining the Zr-Ti-V MOFs catalyst with the active carbon and the diatomite by using the catalyst as the supporting material, fully playing the advantages of the two supporting materials, improving the stability, the activity and the selectivity of the catalyst when treating the VOCs, and realizing a more efficient and sustainable VOCs treatment process.
Detailed Description
In order to clearly illustrate the technical characteristics of the scheme, the scheme is explained below through a specific embodiment.
Example 1: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
a) ZrCl is selected for use 4 As the metal ion source, H is selected 2 DPA is used as an organic ligand, and DMF is used as an organic solvent;
b) ZrCl is added to 4 Respectively adding into DMF, stirring and mixing to dissolve completely, and adding appropriate amount of H 2 DPA is stirred and mixed continuously to be dissolved completely, the mixed solution is heated to 160 ℃ under inert atmosphere and reacts for 24 hours, H 2 The molar proportion of DPA is 0.8 times that of the metal ions.
c) Drying the product obtained in the step b) at 80 ℃ for 4 hours, and then performing heat treatment at 400 ℃ for 5 hours to remove residual solvent and moisture;
d) Oxidizing the product obtained in the step c) in 40mL/min oxygen flow at 400 ℃ until the color of the catalyst becomes dark red, thereby obtaining the Zr-Ti-V MOFs catalyst;
e) Adding a Zr-Ti-V MOFs catalyst and catechol into dimethylformamide respectively, stirring and mixing, adjusting the pH value to 7 by using NaOH, and reacting for 5 hours at 110 ℃;
f) Washing the product of the step e) by ethanol to remove unreacted ligand and impurities, and then drying at 80 ℃ to obtain OH@Zr-Ti-V MOFs;
g) Respectively dissolving OH@Zr-Ti-V MOFs, active carbon and diatomite supporting materials in a solvent DMFO, stirring and cooling the solution to room temperature, wherein the mass ratio of the OH@Zr-Ti-V MOFs to the active carbon is 5:1, mass ratio of solid material to solvent 1:10, stirring for 1 hour, and heating the solvent at 60 ℃;
h) Centrifuging and filtering the product of the step g), and drying at 80 ℃ to remove residual solvent and water to obtain the final catalyst.
Example 2: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is as in example 1, except that TiCl is chosen 4 Is a metal ion source.
Example 3: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is the same as in example 1, except that VCl is used 3 Is a metal ion source.
Example 4: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is the same as in example 1, except that ZrCl is used 4 、TiCl 4 Is metal ionThe molar ratio of the source and the metal ions is 1:1.
Example 5: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is the same as in example 1, except that ZrCl is used 4 、TiCl 4 And VCl 3 The metal ion source is a metal ion source, and the metal ion molar ratio is 1:1:1.
Example 6: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is the same as in example 5, except that ZrCl is used 4 、TiCl 4 And VCl 3 The metal ion source is a metal ion source, and the metal ion molar ratio is 2:1:1.
Example 7: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is the same as in example 5, except that ZrCl is used 4 、TiCl 4 And VCl 3 The metal ion source is a metal ion source, and the metal ion molar ratio is 1:1:2.
Example 8: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is the same as in example 5, except that H 2 The molar proportion of DPA is 1 times that of the metal ions.
Example 9: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is the same as in example 5, except that H 2 The molar proportion of DPA is 1.2 times that of the metal ions.
Example 10: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is as in example 8, except that the mass ratio of Zr-Ti-V MOFs catalyst to catechol is 1:2.
Example 11: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is as in example 10, except that the mass ratio of Zr-Ti-V MOFs catalyst to catechol is 1:5.
Example 12: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure was carried out as in example 10, except that catechol was not added.
Example 13: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is as in example 10, except that the mass of OH@Zr-Ti-V MOFs is 60% of the total mass, and the mass ratio of activated carbon to diatomaceous earth is 6:1, mass ratio of solid material to solvent 1:15.
example 14: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure was carried out as in example 13, except that the mass of OH@Zr-Ti-V MOFs was 80% of the total mass, and the mass ratio of activated carbon to diatomaceous earth was 6:1, mass ratio of solid material to solvent 1:15.
example 15: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is as in example 13, except that the mass of OH@Zr-Ti-V MOFs is 90% of the total mass, and the mass ratio of activated carbon to diatomaceous earth is 9:1, mass ratio of solid material to solvent 1:20.
example 16: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure is as in example 15, except that the OH@Zr-Ti-V MOFs mass is 50% of the total mass.
Example 17: the embodiment of the invention provides a catalyst for VOCs treatment based on MOFs metal skeleton oxide, and the preparation of the catalyst comprises the following steps:
the procedure was carried out as in example 14, except that no diatomaceous earth was added.
Catalyst stability test:
1. constant flow experiment:
the VOCs mixture comprises benzene, toluene and xylene, the ratio is 1:1:1, the mixture enters a reactor through a constant flow device, the catalyst is subjected to pre-activation treatment, the gas flow is started, the flow is 100 mL/min, the temperature of the reactor is 200 ℃, the sampling interval is 1 hour, and the reaction is carried out for 24 hours. Samples were taken and the catalyst deactivation rate was calculated by GC testing:
catalyst deactivation rate = (k 2-k 1)/k2×100%
Where k1 and k2 represent the values of the reaction rate constants at the beginning and end of the experiment, respectively.
2. Redox cycle test:
the catalyst sample was placed in a furnace and treated to steady state with a nitrogen stream. It was then heated to 300 ℃, oxidized in oxygen for about 30 minutes, then reduced in hydrogen for 30 minutes, oxygen and hydrogen were alternately introduced into the reactor, the redox cycle was periodically performed, samples were taken every one hour for analysis, and samples were tested by GC to calculate the catalyst deactivation rate:
catalyst deactivation rate = (k 2-k 1)/k2×100%
Where k1 and k2 represent the values of the reaction rate constants at the beginning and end of the experiment, respectively.
Catalyst deactivation rate
Examples Constant flow rate deactivation rate% Redox deactivation rate%
1 0.86 0.93
2 0.81 0.89
3 0.83 0.89
4 0.69 0.72
5 0.32 0.4
6 0.41 0.35
7 0.39 0.32
8 0.28 0.35
9 0.31 0.38
10 0.21 0.29
11 0.30 0.37
12 0.42 0.48
13 0.15 0.21
14 0.089 0.096
15 0.12 0.18
16 0.13 0.16
17 0.23 0.34
Conclusion:
the comparison of the deactivation rates of examples 1-5 shows that the three metal ions interact to form a more stable metal framework structure, and the dissolution and the loss of the metal ions in the catalyst can be effectively prevented, so that the stability of the catalyst is improved, and the catalyst has better stability in the long-term use process. The metal ions in the Zr-Ti-V MOFs can form more uniform and stable distribution, and the problem of instability of single metal ions or two metal ions in the VOCs treatment process is effectively avoided.
Comparison of examples 5-7 shows that equal levels of the three ions results in higher catalyst stability, and that imbalances reduce stability in handling VOCs, but increase their redox capacity.
Comparison of examples 5, 8, 9 shows that H is properly increased 2 DPA levels can increase the activity and stability of Zr-Ti-V MOFs catalysts in treating VOCs, but when H 2 When the DPA content is too high, the MOFs catalyst is unstable in crystal structure and is stuffed with pore diameters, so that the catalytic performance and stability of the MOFs catalyst are reduced.
Comparison of examples 8, 10, 11, 12 shows that the introduction of hydroxyl groups (-OH) in Zr-Ti-V MOFs catalysts can have an effect on stability. The introduction of hydroxyl (-OH) groups increases the acidic sites and redox properties of the catalyst surface, thereby increasing the reactivity of the catalyst. Meanwhile, hydroxyl (-OH) can also improve the stability of the catalyst and reduce the deactivation rate of the catalyst in a high humidity environment. However, if the hydroxyl (-OH) content is too high, lattice damage and reduction in catalytic activity of the MOFs catalyst are caused, thereby affecting the stability of the catalyst.
Examples 10 and 13-16 show that the composite of the Zr-Ti-V MOFs catalyst and the supporting structure effectively improves the stability, the supporting structure has larger specific surface area, the MOFs catalyst can be dispersed more uniformly, active sites of the catalyst are fully utilized, the reaction efficiency and the stability are improved, the MOFs catalyst has certain defects and sintering tendency, the supporting structure can effectively inhibit aggregation and sintering of the MOFs catalyst, the activity and the stability of the MOFs catalyst are maintained, the supporting structure can improve the mechanical strength of the catalyst, and the catalyst is more stable and is not easy to be deactivated by external factors.
In addition, the diatomite and the activated carbon have high specific surface area and good adsorption performance, so that the active site of the catalyst can be increased, the contact opportunity of the catalyst with organic substances in waste gas can be increased, in addition, the stability of the catalyst can be increased, the deactivation and falling-off of the catalyst are prevented, and the service life of the catalyst is prolonged. The combination of the diatomite and the activated carbon can also improve the water resistance and oxidation resistance of the catalyst and increase the adaptability of the catalyst under various working conditions, so that the catalyst is more stable and reliable. Therefore, diatomite and activated carbon are used as supporting materials to be compounded with the Zr-Ti-V MOFs catalyst, so that the stability of the catalyst in the process of treating VOCs can be improved.
Comparison of examples 14 and 17 shows that the addition of diatomaceous earth as a support material can improve the stability of the catalyst because diatomaceous earth has good stability and a high specific surface area, and can enhance the mechanical strength and thermal stability of the catalyst. Meanwhile, the addition of diatomite can also increase the porosity and dispersibility of the catalyst, and improve the diffusion rate and contact efficiency of reactants, so that the activity and stability of the catalyst are improved. Compared with the single use of the activated carbon, the diatomite can better support the catalyst, reduce the deactivation rate and prolong the service life of the catalyst.
The technical features of the present invention that are not described in the present invention may be implemented by or using the prior art, and are not described in detail herein, but the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, but is also intended to be within the scope of the present invention by those skilled in the art.

Claims (2)

1. A catalyst for treating VOCs based on MOFs metal skeleton oxide, which is characterized by comprising the following steps:
a) ZrCl is selected for use 4 、TiCl 4 And VCl 3 As the metal ion source, H is selected 2 DPA is used as an organic ligand, DMF is used as an organic solvent, and ZrCl is used as a catalyst 4 、TiCl 4 And VCl 3 The metal ion molar ratio of (1-2) is 1: (1-2);
b) ZrCl is added to 4 、TiCl 4 And VCl 3 And adding into DMF respectively, stirring and mixing until completely dissolved, and then adding H 2 DPA is stirred and mixed continuously to be dissolved completely, the mixed solution is heated to 160 ℃ under inert atmosphere and reacts for 24 hours, H 2 The mole ratio of DPA is 0.8-1.2 times of metal ion;
c) Drying the product obtained in the step b) at 80 ℃ for 4 hours, and performing heat treatment at 400 ℃ for 5 hours to remove residual solvent and moisture;
d) Oxidizing the product obtained in the step c) in an oxygen flow until the color of the catalyst becomes dark red to obtain a Zr-Ti-V MOFs catalyst, wherein the oxygen flow is 40mL/min, and the treatment temperature is 400 ℃;
e) Adding Zr-Ti-V MOFs catalyst and catechol into dimethylformamide respectively, stirring and mixing, adjusting the pH value to 7 by NaOH, and reacting for 5 hours at 110 ℃, wherein the mass ratio of the Zr-Ti-V MOFs catalyst to the catechol is 1 (1-5);
f) Washing the product of the step e) by ethanol to remove unreacted ligand and impurities, and then drying at 80 ℃ to obtain OH@Zr-Ti-V MOFs;
g) Respectively dissolving OH@Zr-Ti-V MOFs, active carbon and diatomite supporting materials in a solvent DMFO, stirring and cooling the solution to room temperature, wherein the mass of the OH@Zr-Ti-V MOFs is 40-90% of the total mass, and the mass ratio of the active carbon to the diatomite is (5-9): 1, mass ratio of solid material to solvent 1: (10-20), stirring for 1 hour, and heating the solvent at 60 ℃;
h) Centrifuging the product of the step g), filtering, and drying at 80 ℃ to remove residual solvent and water to obtain the final catalyst.
2. The preparation method of the catalyst for VOCs treatment based on MOFs metal skeleton oxide is characterized by comprising the following steps of:
a) ZrCl is selected for use 4 、TiCl 4 And VCl 3 As the metal ion source, H is selected 2 DPA is used as an organic ligand, DMF is used as an organic solvent, and ZrCl is used as a catalyst 4 、TiCl 4 And VCl 3 The metal ion molar ratio of (1-2) is 1: (1-2);
b) ZrCl is added to 4 、TiCl 4 And VCl 3 And adding into DMF respectively, stirring and mixing until completely dissolved, and then adding H 2 DPA is stirred and mixed continuously to be dissolved completely, the mixed solution is heated to 160 ℃ under inert atmosphere and reacts for 24 hours, H 2 The mole ratio of DPA is 0.8-1.2 times of metal ion;
c) Drying the product obtained in the step b) at 80 ℃ for 4 hours, and performing heat treatment at 400 ℃ for 5 hours to remove residual solvent and moisture;
d) Oxidizing the product obtained in the step c) in an oxygen flow until the color of the catalyst becomes dark red to obtain a Zr-Ti-V MOFs catalyst, wherein the oxygen flow is 40mL/min, and the treatment temperature is 400 ℃;
e) Adding Zr-Ti-V MOFs catalyst and catechol into dimethylformamide respectively, stirring and mixing, adjusting the pH value to 7 by NaOH, and reacting for 5 hours at 110 ℃, wherein the mass ratio of the Zr-Ti-V MOFs catalyst to the catechol is 1 (1-5);
f) Washing the product of the step e) by ethanol to remove unreacted ligand and impurities, and then drying at 80 ℃ to obtain OH@Zr-Ti-V MOFs;
g) Respectively dissolving OH@Zr-Ti-V MOFs, active carbon and diatomite supporting materials in a solvent DMFO, stirring and cooling the solution to room temperature, wherein the mass of the OH@Zr-Ti-V MOFs is 40-90% of the total mass, and the mass ratio of the active carbon to the diatomite is (5-9): 1, mass ratio of solid material to solvent 1: (10-20), stirring for 1 hour, and heating the solvent at 60 ℃;
h) Centrifuging the product of the step g), filtering, and drying at 80 ℃ to remove residual solvent and water to obtain the final catalyst.
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CN104370820A (en) * 2013-08-13 2015-02-25 中国科学院大连化学物理研究所 Preparation method and applications of porous metal organic skeleton material
CN109161029A (en) * 2018-08-21 2019-01-08 武汉绿帆世纪科技有限公司 A kind of ternary metal organic framework material and preparation method thereof
WO2019020086A1 (en) * 2017-07-28 2019-01-31 中国石油化工股份有限公司 Carbon-coated transition metal nanocomposite material, and preparation and use thereof
CN109316956A (en) * 2018-11-13 2019-02-12 南京师范大学 The reaction system and purification method of VOCs in a kind of purifying industrial waste gases

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104370820A (en) * 2013-08-13 2015-02-25 中国科学院大连化学物理研究所 Preparation method and applications of porous metal organic skeleton material
WO2019020086A1 (en) * 2017-07-28 2019-01-31 中国石油化工股份有限公司 Carbon-coated transition metal nanocomposite material, and preparation and use thereof
CN109161029A (en) * 2018-08-21 2019-01-08 武汉绿帆世纪科技有限公司 A kind of ternary metal organic framework material and preparation method thereof
CN109316956A (en) * 2018-11-13 2019-02-12 南京师范大学 The reaction system and purification method of VOCs in a kind of purifying industrial waste gases

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