Preparation method and application of three-dimensional core-shell hydrangea-shaped MnOX-coated Co3O4 catalyst
The synthesis of three-dimensional nano-hydrangea MnOX@Co3O4 catalyst by hydrothermal method solves the problems of small specific surface area and poor water resistance of existing catalysts, achieves efficient degradation and stability of VOCs, simplifies the preparation process, and has wide application prospects.
Patent Information
- Application Number
- CN202411327106.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2024-12-17
AI Technical Summary
When treating volatile organic exhaust gases (VOCs), existing catalysts have problems such as small specific surface area, poor water resistance and high commercial costs, which limits their wide application, especially under the demand for efficient degradation of VOCs at low temperatures.
The three-dimensional nano-hydrangea MnOX@Co3O4 catalyst was synthesized by hydrothermal method. By regulating the molar amount of metal salt, alkali release agent and potassium permanganate, two-stage calcination was achieved, and MnOX@Co3O4 with uniform size and high specific surface area was prepared. The catalyst exposes more active sites and enhances the catalytic oxidation capacity.
It achieves excellent catalytic degradation performance and good stability of VOCs, a simple and easy preparation process, does not require additional surfactants, has wide application prospects, and can produce high-efficiency catalysts on a large scale.
Smart Images
Figure CN119140113A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the fields of material chemistry, air pollution control technology, volatile organic waste gas (VOCs) catalytic oxidation technology, and preparation of catalysts in the field of environmental functional material technology, and particularly relates to a three-dimensional core-shell MnO X @Preparation method and application of Co3O4 catalyst. Background Art
[0002] In recent years, volatile organic compounds (VOCs) have been continuously emitted in large quantities. As an important precursor of O3 and PM2.5, VOCs not only have a huge impact on the natural environment, but also have a very serious impact on human health. Therefore, effective control of them is the key to further improving and improving air pollution. Among the many VOCs emissions, there are VOCs such as ethyl acetate, acetone, formaldehyde, and toluene. Among them, benzene series, represented by toluene and other benzene series, are widely used in many fields such as construction, packaging, hard brushes, and coatings, resulting in a high proportion of pollutants in typical pollution sources, and therefore have attracted widespread attention.
[0003] At present, there are a large number of relatively mature VOCs treatment technologies such as non-thermal plasma, biomass method, photocatalysis, direct combustion method and catalytic oxidation method. Among the many VOCs treatment technologies, catalytic oxidation method is considered to be one of the most widely used treatment technologies for effective terminal treatment of VOCs. This technology has the advantages of high treatment efficiency and no secondary pollution, so it is widely used. In this technology, the design and preparation of efficient catalysts is one of the key technical difficulties of this treatment method. It is generally believed that efficient catalysts often require the characteristics of large specific surface area, high thermal stability, low commercial cost of preparation, strong tolerance and repeatable regeneration. Based on this, in view of the shortcomings of currently commonly used industrial catalysts such as small specific surface area, poor water resistance and high commercial cost, it is urgent to develop a catalyst that is more low-temperature and efficient and can quickly achieve VOCs degradation. At present, a large number of catalysts have been prepared, among which the three-dimensional core-shell structure has relatively more exposed active sites, larger specific surface area, larger contact area and higher material transfer capacity, and is therefore widely used. However, the current core-shell structure has a relatively complex preparation process and often requires soft and hard template methods, which makes its synthesis cost relatively high, thus limiting its widespread application.
[0004] In view of this, the present invention adopts a hydrothermal method to synthesize a series of MnO X Coating the three-dimensional nano-hydrangea CoCO3 precursor, and then calcining in two stages to obtain MnO X@Co3O4 catalyst, and toluene was used as the target pollutant to evaluate the catalytic activity, which showed better catalytic activity than the single three-dimensional hydrangea-shaped Co3O4. This preparation scheme can not only prepare a large number of three-dimensional hydrangea-shaped core-shell structured MnO X @Co3O4, it will also have great promotion and applicability in industry and practical applications. Summary of the invention
[0005] The purpose of the present invention is to overcome the shortcomings of the existing high preparation cost and the need to add surfactants or soft and hard templates, and to provide a new and large-scale preparation of three-dimensional hydrangea-shaped core-shell structure MnO X @Co3O4, prepared MnO X @Co3O4 catalyst has good adsorption catalytic degradation performance for VOCs. The three-dimensional nano-hydrangea core-shell structure MnO X @Co3O4 has a more uniform size. With CoCO3 as the carbon source, KMnO4 can react with CoCO3 to generate MnO X , making MnO X It can be loaded more evenly on the surface of Co3O4, has a larger specific surface area, can expose more active sites, has strong water resistance, and exhibits better catalytic oxidation of VOCs and good stability. X The preparation process of @Co3O4 catalyst is simple and easy, no additional surfactant is required, the preparation conditions are mild, and large-scale preparation can be achieved. It is a method with broad application prospects for preparing MnO with high catalytic activity. X @Co3O4 catalyst.
[0006] To achieve the above-mentioned purpose, the present invention is realized by the following technical scheme: regulating the metal salt, alkali release agent, reaction temperature, potassium permanganate molar amount, etc. to synthesize a three-dimensional hydrangea-shaped MnO with uniform morphology and size. X @CoCO3, followed by two-stage calcination to obtain MnO X @Co3O4 catalyst.
[0007] The technical solution of the present invention is as follows:
[0008] A three-dimensional core-shell hydrangea-shaped MnO XThe preparation method of @Co3O4 catalyst comprises the following steps: dissolving cobalt salt and organic bridging ligand in organic solvent respectively, then mixing the two at room temperature, stirring evenly, ultrasonicating, centrifuging, and then washing with methanol and distilled water several times to remove unreacted metal salt and organic bridging ligand to obtain Co-MOFs-74 precursor for use; then dispersing and dissolving the precursor in deionized water, adding a certain mass of alkali release agent and mixing and stirring evenly, keeping warm for a certain time through hydrothermal reaction, cooling, then centrifuging and washing, and vacuum drying the product to obtain a specific three-dimensional hydrangea-shaped cobalt carbonate for use; dispersing the prepared specific three-dimensional hydrangea-shaped cobalt carbonate in a certain volume of distilled water, then weighing a certain volume of potassium permanganate (KMnO4) and dissolving it in a highly dispersed CoCO3 solution, stirring and dissolving, and then transferring it to a reactor and keeping warm for a certain time at a certain temperature, centrifuging, and washing with distilled water and anhydrous ethanol and vacuum drying the product at 80°C overnight to obtain MnO X @CoCO3 standby; the prepared MnO X @CoCO3 is calcined in two stages to obtain MnO X @Co3O4 catalyst.
[0009] The specific method is as follows:
[0010] (1) Preparation of Co-MOFs-74:
[0011] Take two 50mL centrifuge tubes, add a certain volume of organic solvent, then weigh the cobalt salt and the organic bridge partner and dissolve them in the above centrifuge tubes respectively to form solutions centrifuge tube A and centrifuge tube B; then slowly add solution A dropwise into the solution in centrifuge tube B and mix with stirring to obtain a mixed solution C. The obtained mixed solution C is ultrasonicated at room temperature for a period of time, then centrifuged and washed with methanol and distilled water several times to remove unreacted cobalt salt and organic ligand, then washed with deionized water and methanol several times to remove unreacted inorganic salt and organic ligand, to obtain one-dimensional Co-MOFs-74 for use.
[0012] (2) Preparation of three-dimensional hydrangea-like cobalt carbonate:
[0013] The Co-MOF-74 prepared in step (1) is dispersed in de-distilled water, and then a certain mass of alkali-release slow-release agent is weighed and mixed and stirred at room temperature, and then transferred to a certain volume of polytetrafluoroethylene reactor liner, and then the reactor is placed in a high-pressure reactor for hydrothermal reaction and kept warm for a certain time, and naturally cooled to room temperature, and the product is transferred to a centrifuge tube and centrifuged to obtain a precipitate, and then the precipitate is washed several times with deionized water and the pH is adjusted, and then centrifuged and washed with ethanol, and vacuum dried to obtain dark purple cobalt carbonate for use; the alkali-release slow-release agent is urea.
[0014] (3) Three-dimensional core-shell hydrangea-shaped MnO XPreparation of @CoCO3:
[0015] The dark red cobalt carbonate prepared in step (2) is dispersed in a certain volume of distilled water, and then a certain mass of potassium permanganate is weighed and mixed and stirred at room temperature, and then transferred to a polytetrafluoroethylene reactor liner, and then the reactor is placed in a high-pressure reactor for hydrothermal reaction and kept warm for a certain time, and naturally cooled to room temperature, and the product is transferred to a centrifuge tube and centrifuged to obtain a precipitate, and then the precipitate is washed several times with distilled water to remove unreacted potassium permanganate, and then centrifuged and washed with ethanol, and vacuum freeze-dried to obtain MnO X @CoCO3 spare.
[0016] (4) Three-dimensional core-shell hydrangea-shaped MnO X Preparation of @Co3O4:
[0017] The MnO prepared in step (3) X @CoCO3 In a tube furnace, three-dimensional core-shell MnO X @Co3O4 catalyst, and press it into tablets under the set pressure of the tablet press, and sieve it to obtain a catalyst with a mesh size of 40 to 60.
[0018] Compared with the conventional synthesis method, the three-dimensional nano-hydrangea-like core-shell structure MnO prepared by this preparation method X @Co3O4 has a more uniform size. With CoCO3 as the carbon source, KMnO4 can react with CoCO3 to generate MnO X , making MnO X It can be loaded more evenly on the surface of Co3O4, has a larger specific surface area, can expose more active sites, has strong water resistance, and exhibits better catalytic oxidation of VOCs and good stability. X The preparation process of @Co3O4 catalyst is simple and easy, no additional surfactant is required, the preparation conditions are mild, and large-scale preparation can be achieved. It is a method with broad application prospects for preparing MnO with high catalytic activity. X @Co3O4 catalyst.
[0019] In the above method, in step (1), the organic solvent is methanol with a total volume of 60 to 80 mL; the cobalt salt is cobalt acetate tetrahydrate with a mass of 4.40 to 1.32 g; and the organic bridging ligand is 2,5-dihydroxyterephthalic acid with a mass of 1.20 to 3.60 g.
[0020] In the above method, in step (2), the mass of Co-MOF-74 is 4.20-6.22 g; the volume of distilled water is 60-80 mL; the alkali release agent is urea, with a mass range of 1.00-3.00 g; the volume of the reactor is 100 mL; the reaction temperature is 120-140°C; the reaction time is 12-48h; the pH is adjusted to 6-7; the vacuum drying temperature is 80-100°C, and the drying time is 8-12h.
[0021] In the above method, in step (3), the mass of cobalt carbonate is 5.00-10.00 mmol; the volume of distilled water is 60-80 mL; the mass of potassium permanganate is 1.00-10.00 mmol; the hydrothermal insulation temperature is 80-120° C.; the insulation temperature is 8-12 h; the number of washing times is mainly washing until no light pink solution appears; the vacuum drying is freeze drying, and the drying time is 12-24 h.
[0022] In the above method, in step (4), first, under a nitrogen atmosphere, the temperature is raised from room temperature to 300-450°C at a rate of 1-5°C / min and kept at a constant temperature for 3-5 hours; then the nitrogen is turned off and switched to air, the temperature is lowered to 400°C and kept at a constant temperature for 3-5 hours, and finally lowered to room temperature at a rate of 5-10°C / min.
[0023] The MnO in the present invention X @Co3O4 catalyst is a three-dimensional core-shell hydrangea with uniform size. X The catalyst is uniformly loaded on the surface of Co3O4; the specific surface area of the catalyst is 22.7 to 58.6 m 3 / g, exposing more active sites, having stronger water resistance, showing better ability to catalyze and oxidize VOCs, and good stability.
[0024] Furthermore, the three-dimensional core-shell hydrangea-shaped MnOX@Co3O4 catalyst is used for catalytic oxidation of volatile organic waste gas VOCs. The volatile organic waste gas VOCs is toluene.
[0025] Compared with the prior art, the advantages of the present invention are:
[0026] 1. By adjusting the molar dosage of potassium permanganate and cobalt carbonate, three-dimensional hydrangea-shaped MnO with different loading amounts and different core-shell thicknesses can be prepared X @CoCO3 catalyst, followed by two-step calcination to prepare three-dimensional hydrangea-shaped MnO with different core-shell thicknesses X @Co3O4 catalyst increases the specific surface area of the catalyst material, can construct a Co-O-Mn interface, and enhances the migration and conversion of oxygen on the catalyst surface, thereby increasing the exposed active sites of the catalyst.
[0027] 2. The prepared MnO X @Co3O4 catalyst exhibits strong water resistance and strong VOCs adsorption capacity, as well as high catalytic oxidation activity. The preparation process is simple and easy, the preparation conditions are relatively mild and can be prepared on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 This is a scanning electron microscope image of the three-dimensional hydrangea-shaped Co3O4 prepared in the present invention.
[0029] Figure 2 The three-dimensional hydrangea-shaped core-shell MnO prepared by the present invention X @Co3O4 scanning electron microscope image (left) and its local enlarged surface image (right).
[0030] Figure 3 The three-dimensional hydrangea-shaped core-shell MnO prepared by the present invention X Activity evaluation diagram of @Co3O4 and single Co3O4 catalysts. DETAILED DESCRIPTION
[0031] The present invention will be further described in detail below in conjunction with specific embodiments, but the embodiments of the present invention are not limited thereto. For process parameters not particularly noted, conventional techniques may be used.
[0032] Example 1
[0033] 2.0 mmol of cobalt acetate and 1.00 mmol of 2,5-dihydroxyterephthalic acid were weighed and dispersed in 40 mL of methanol respectively to form 40 mL of solution A and 40 mL of solution B; then solution B was slowly added to solution A and mixed and stirred to obtain 80 mL of mixed solution C. The obtained mixed solution C was ultrasonicated for 30 minutes, then centrifuged at 400 r / min, and then washed with methanol several times to remove unreacted cobalt salt and ligand, and then washed with distilled water several times to remove residual methanol solution and washed to neutrality to obtain Co-MOF-74 for use.
[0034] Example 2
[0035] The Co-MOF-74 in Example 1 was transferred to a 100 mL polytetrafluoroethylene reactor, and 80 mL of distilled water was added to stir and disperse it evenly, and then 8 mmol of urea, an alkali-release slow-release agent, was added to stir and dissolve. It was then placed in a reactor and kept at 140°C for 1440 min, then cooled to room temperature, centrifuged, and the product was washed with distilled water several times until the pH was neutral; then washed twice with ethanol, and transferred to a freeze drying oven for drying to obtain dark red cobalt carbonate for use. The corresponding figure is attached. Figure 1 .
[0036] Example 3
[0037] The dark red cobalt carbonate in Example 2 was dispersed in a reactor filled with 80 mL of distilled water and stirred evenly. Then, 2.00 mmol of potassium permanganate was weighed and added to the above solution. The mixture was stirred at room temperature for 30 min, then placed in a reactor and kept at 80° C. for 720 min. The mixture was cooled to room temperature and centrifuged to obtain a dark brown precipitate. The precipitate was washed with clean water several times until no light pink color appeared. The precipitate was then washed with ethanol for 3 times and freeze-dried in a freeze drying oven overnight to obtain a dark brown three-dimensional nano-hydrangea-shaped MnO X @CoCO3 is precipitated for later use. The corresponding figure is attached Figure 2 (Upper Left and Upper Right).
[0038] Example 4
[0039] The dark red cobalt carbonate in Example 2 was dispersed in a reactor filled with 80 mL of distilled water and stirred evenly. Then, 2.00 mmol of potassium permanganate was weighed and added to the above solution. The mixture was stirred at room temperature for 30 min, then placed in a reactor and kept at 120° C. for 720 min. The mixture was cooled to room temperature and centrifuged to obtain a dark brown precipitate. The precipitate was washed with clean water several times until no light pink color appeared. The precipitate was then washed with ethanol for 3 times and freeze-dried in a freeze drying oven overnight to obtain a dark brown three-dimensional nano-hydrangea-shaped MnO X @CoCO3 is precipitated for later use. The corresponding figure is attached Figure 2 (Bottom left and bottom right).
[0040] Example 5
[0041] The dark brown MnO in Example 3 above X @CoCO3 was placed in a porcelain boat and calcined in two stages, i.e., the temperature was raised from room temperature to 450°C at a rate of 2°C / min under nitrogen conditions and kept at this temperature for 180 min; then the nitrogen was turned off and air was introduced to cool the temperature from 450°C to 400°C at a rate of 3°C / min, and the temperature was kept constant for 3.5 h, and finally the temperature was cooled to room temperature at a rate of 5°C / min, finally obtaining a three-dimensional nano-hydrangea-shaped MnO X @Co3O4 catalyst.
[0042] Example 6
[0043] The specific steps of Example 6 are as follows: the sample in Example 5 is granulated, and its activity is evaluated by testing the degradation rate of the sample to toluene. The reactor used is a (Φ6mm) quartz tube. Before the experiment, 0.1g of samples of different morphologies and 0.4g of quartz sand are weighed and mixed evenly and filled in a quartz tube for fixing. Then 1000ppm of toluene and 20% (O2 / N2) nitrogen are introduced as the balance gas, and the weight hourly space velocity is 60000mL g -1h -1 , the activity was evaluated at 180-280°C. The concentration change of toluene during the reaction was finally detected online by Foley gas chromatography (9790II) GC. The degradation rate of toluene was calculated as follows: Toluene degradation rate = [(toluene) inlet - (toluene) outlet] / (toluene) inlet. The results showed that after MnO X Modification of prepared MnO X @Co3O4 and hydrangea-shaped Co3O4 catalysts showed excellent catalytic performance for toluene degradation. Figure 3 It can be seen that the corresponding toluene conversion rate (T 90 ) at 248 and 237°C respectively.
[0044] The above embodiments are only used to illustrate the technical solutions of the present invention rather than strict conditional limitations. Those skilled in the art should understand that various changes may be made to the details or forms thereof without departing from the spirit and scope of the present invention as defined in the claims.
Claims
1. A three-dimensional core-shell hydrangea-shaped MnO X The preparation method of @Co3O4 catalyst is characterized in that: The cobalt salt and the organic bridging ligand are dissolved in an organic solvent respectively, and then the two are mixed and stirred at room temperature, ultrasonicated, and centrifuged, and then washed with methanol and distilled water several times to remove the unreacted metal salt and organic bridging ligand to obtain the Co-MOFs-74 precursor for use; then the Co-MOFs-74 precursor is dispersed and dissolved in deionized water, an alkali-releasing agent is added and mixed and stirred evenly, and the product is kept warm and cooled through a hydrothermal reaction, and then centrifuged and washed, and the product is vacuum dried to obtain a specific three-dimensional hydrangea-shaped cobalt carbonate for use; the prepared specific three-dimensional hydrangea-shaped cobalt carbonate is dispersed in distilled water, and then potassium permanganate is weighed and dissolved in a highly dispersed CoCO3 solution, stirred and dissolved, and then transferred to a reactor for heat preservation, centrifuged, and washed with distilled water and anhydrous ethanol, and the product is vacuum dried overnight to obtain MnO X @CoCO3 standby; the prepared MnO X @CoCO3 is calcined in two stages to obtain MnO X @Co3O4 catalyst.
2. The three-dimensional core-shell hydrangea-shaped MnO according to claim 1 X The preparation method of @Co3O4 catalyst is characterized in that: The cobalt salt is cobalt acetate; the organic bridging ligand is 2,5-dihydroxyterephthalic acid; and the alkali release agent is urea.
3. The method for preparing the three-dimensional core-shell hydrangea-shaped MnOX@Co3O4 catalyst according to claim 1, characterized in that: The preparation method comprises the following steps: (1) Preparation of Co-MOFs-74: Take an organic solvent, weigh the cobalt salt and the organic bridge partner respectively, and dissolve them in centrifuge tubes to form a solution centrifuge tube A liquid and a centrifuge tube B liquid; then add the A liquid dropwise to the centrifuge tube B solution and mix and stir to obtain a mixed solution C, ultrasonicate the obtained mixed solution C at room temperature, centrifuge and wash it with methanol and distilled water several times to remove the unreacted cobalt salt and organic ligand, wash it with deionized water and methanol several times to remove the unreacted inorganic salt and organic ligand, and obtain a one-dimensional Co-MOFs-74 for use; (2) Preparation of three-dimensional hydrangea-like cobalt carbonate: The one-dimensional Co-MOF-74 obtained in step (1) is dispersed in de-distilled water, and then an alkali-releasing agent is weighed and mixed and stirred at room temperature, and then transferred to a polytetrafluoroethylene reactor liner, and then the reactor is placed in a high-pressure reactor for hydrothermal reaction and insulation, and naturally cooled to room temperature, and the product is centrifuged to obtain a precipitate, and the precipitate is washed with deionized water, and the pH is adjusted, and then centrifuged and washed with ethanol, and vacuum dried to obtain a dark purple cobalt carbonate for use; (3) Three-dimensional core-shell hydrangea-shaped MnO X Preparation of @CoCO3: The dark red cobalt carbonate prepared in step (2) is dispersed in distilled water, potassium permanganate is weighed and mixed and stirred at room temperature, and then transferred to a polytetrafluoroethylene reactor liner, and then the reactor is placed in a high-pressure reactor for hydrothermal reaction and insulation, and naturally cooled to room temperature, and the product is centrifuged to obtain a precipitate, and the precipitate is washed several times with de-distilled water to remove unreacted potassium permanganate, and then centrifuged and washed with ethanol, and vacuum freeze-dried to obtain MnO X @CoCO3 spare; (4) Three-dimensional core-shell hydrangea-shaped MnO X Preparation of @Co3O4: The MnO prepared in step (3) X @CoCO3 In a tube furnace, three-dimensional core-shell MnO X @Co3O4 catalyst, and press it into tablets under the set pressure of the tablet press, and sieve it to obtain a catalyst with a mesh size of 40 to 60.
4. The three-dimensional core-shell hydrangea-shaped MnO according to claim 3 X The preparation method of @Co3O4 catalyst is characterized in that: In step (1), the organic solvent is methanol, with a total volume of 60 to 80 mL; the cobalt salt is cobalt acetate tetrahydrate, with a mass of 4.40 to 1.32 g; and the organic bridging ligand is 2,5-dihydroxyterephthalic acid, with a mass of 1.20 to 3.60 g.
5. The three-dimensional core-shell hydrangea-shaped MnO according to claim 3 X The preparation method of @Co3O4 catalyst is characterized in that: In step (2), the mass of the one-dimensional Co-MOF-74 is 4.20-6.22 g; the volume of the distilled water is 60-80 mL; the alkali release agent is urea, with a mass range of 1.00-3.00 g; the volume of the reactor is 100 mL; the reaction temperature is 120-140° C.; the reaction time is 12-48 h; the pH is adjusted to 6-7; the vacuum drying temperature is 80-100° C., and the drying time is 8-12 h.
6. The three-dimensional core-shell hydrangea-shaped MnO according to claim 3 X The preparation method of @Co3O4 catalyst is characterized in that: In step (3), the mass of cobalt carbonate is 5.00-10.00 mmol; the volume of distilled water is 60-80 mL; the mass of potassium permanganate is 1.00-10.00 mmol; the hydrothermal insulation temperature is 80-120° C.; the insulation temperature is 8-12 h; the number of washing times is mainly washing until no light pink solution appears; the vacuum drying is freeze drying, and the drying time is 12-24 h.
7. The three-dimensional core-shell hydrangea-shaped MnO according to claim 3 X The preparation method of @Co3O4 catalyst is characterized in that: In step (4), the two-stage calcination is specifically as follows: first, in a nitrogen atmosphere, the temperature is raised from room temperature to 300-450°C at a rate of 1-5°C / min, and the temperature is kept constant for 3-5 hours; then the nitrogen is turned off and switched to air, the temperature is lowered to 400°C and kept constant for 3-5 hours, and finally lowered to room temperature at a rate of 5-10°C / min.
8. The MnOX@Co3O4 catalyst prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The MnOX@Co3O4 catalyst is a three-dimensional core-shell hydrangea with uniform size. X The catalyst is uniformly loaded on the surface of Co3O4; the specific surface area of the catalyst is 22.7 to 58.6 m 3 / g, exposing more active sites, having stronger water resistance, showing better ability to catalyze and oxidize VOCs, and good stability.
9. The three-dimensional core-shell hydrangea-shaped MnOX@Co3O4 catalyst according to claim 8 is used for the catalytic oxidation of volatile organic waste gas (VOCs).
10. The use according to claim 9, characterized in that: The volatile organic waste gas VOCs is toluene.