Titanium dioxide supported ruthenium catalyst, preparation method and application in treating halogenated organic matter
By supporting ruthenium single atoms, nanoclusters and nanoparticles on the anatase phase titanium dioxide exposed on a high proportion of 201 crystal surface, an efficient titanium dioxide-supported ruthenium catalyst was prepared, which solved the problem that existing ruthenium catalysts are susceptible to moisture and by-product generation in the treatment of halogenated organic pollutants, and achieved efficient and stable catalytic degradation effect.
Patent Information
- Application Number
- CN202310932618.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-27
- Publication Date
- 2025-08-12
- Estimated Expiration
- 2043-07-27
AI Technical Summary
Existing ruthenium catalysts are easily affected by moisture when treating halogenated organic pollutants, have poor catalytic effects, and produce harmful by-products during the pyrolysis process, making it difficult to widely use in the treatment of halogenated organic pollutants.
A high proportion of the anatase phase titanium dioxide exposed on the crystal surface of 201 was used as a support, and the ruthenium single atoms, nanoclusters and nanoparticles were supported. The titanium dioxide supported ruthenium catalyst was prepared by stirring reaction of water-soluble ruthenium salt and sodium borohydride solution to improve the number of ruthenium active sites and catalyst stability.
It has achieved efficient and stable degradation of halogenated organic pollutants. The catalyst has good oxidation, chlorine resistance and water resistance, and has no harmful by-product generation, which significantly improves catalytic activity and stability.
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Figure CN116832807B_ABST
Abstract
Description
Technical Field
[0001] The present disclosure belongs to the technical field of organic pollutant treatment and nanomaterial preparation, and in particular relates to a titanium dioxide-supported ruthenium catalyst, a preparation method, and an application in the treatment of halogenated organic matter. Background Art
[0002] Organic pollutants refer to organic compounds that cause environmental pollution and have harmful effects on ecosystems. Halogenated organic compounds, as a highly toxic and difficult-to-degrade organic pollutant, are inevitably emitted by the pharmaceutical industry, secondary nonferrous metal smelting, and coking industry, becoming a major challenge in the control of organic pollutants. Most halogenated organic compounds have adverse effects on human health and even pose a carcinogenic risk. Therefore, the efficient disposal of halogenated organic compounds has become a major concern in the environmental field. Currently, the main disposal technologies for halogenated organic pollutants include incineration, condensation, photolysis, adsorption, and absorption. These technologies have many shortcomings, such as high cost, low removal efficiency, long reaction cycles, and inability to completely degrade halogenated organic pollutants. Catalytic degradation technology has attracted widespread attention in the disposal of halogenated organic pollutants due to its high catalytic activity, relatively simple catalyst preparation process, and low cost. However, catalytic degradation technology is also widely concerned because the catalyst is prone to halogen poisoning.
[0003] Ruthenium (Ru), a precious metal that is cheaper than gold, platinum, and palladium, can effectively convert chlorine species into chlorine gas through the Deacon reaction, thereby effectively removing chlorine species from the catalyst surface and avoiding catalyst deactivation due to chlorine poisoning. It is widely used in the catalytic degradation of halogenated organic pollutants. However, in the actual process of applying ruthenium catalysts to the treatment of industrial waste gas containing halogenated organic pollutants, the presence of moisture often causes the moisture to compete with the organic pollutants for active sites on titanium dioxide, resulting in a weak catalytic effect. In addition, existing ruthenium catalysts have problems such as incomplete degradation during the thermal decomposition and catalytic degradation of halogenated organic pollutants, resulting in the production of a large amount of highly toxic polyhalogenated benzene by-products. These problems have restricted the widespread application of ruthenium catalysts in the treatment of halogenated organic pollutants. Summary of the Invention
[0004] In response to the above technical problems, the present disclosure provides a titanium dioxide-supported ruthenium catalyst, a preparation method, and an application for the treatment of halogenated organic matter, in order to at least partially solve the above technical problems.
[0005] As a first aspect of the present disclosure, a titanium dioxide-supported ruthenium catalyst is provided, comprising:
[0006] Anatase titanium dioxide with a high proportion of 201 crystal planes exposed as a carrier, wherein the exposure rate of the 201 crystal planes of the anatase titanium dioxide is 60% to 100%; and
[0007] Ruthenium species supported on anatase phase titanium dioxide with a high proportion of 201 crystal planes exposed, including ruthenium single atoms, ruthenium nanoclusters and ruthenium nanoparticles.
[0008] As a second aspect of the present disclosure, a method for preparing a titanium dioxide-supported ruthenium catalyst is provided, comprising:
[0009] Under stirring, a water-soluble ruthenium salt is added to an aqueous solution of anatase-phase titanium dioxide with a high proportion of exposed 201 crystal faces to obtain a mixed solution;
[0010] Under stirring, sodium borohydride solution is injected into the mixed solution to react, thereby obtaining an anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 201 crystal faces.
[0011] As a second aspect of the present disclosure, an application in treating halogenated organic pollutants is provided, comprising: using the catalyst in the above embodiment, wherein the halogenated organic pollutant is selected from chlorobenzene.
[0012] Based on the above technical solution, the present disclosure provides a titanium dioxide-supported ruthenium catalyst, a preparation method, and an application for treating halogenated organic matter, which have at least one of the following beneficial effects:
[0013] (1) According to the embodiments of the present disclosure, anatase titanium dioxide with a high ratio of 201 crystal faces exposed is selected as a catalyst support. The high ratio of 201 crystal faces has a high surface energy, which can generate a stronger metal-support interaction with the metal, thereby enhancing the electron transfer and redox stability of the catalyst surface. In addition, the high ratio of 201 crystal faces has a unique surface morphology and some defect sites on the surface (such as oxygen vacancies, Ti 3+ defects), which enables the ruthenium species to be uniformly loaded on its surface and increases the number of ruthenium active sites; so that after ruthenium is loaded on its surface, the obtained titanium dioxide-loaded ruthenium catalyst has higher reaction activity and stability.
[0014] (2) According to the embodiments of the present disclosure, the preparation method of the titanium dioxide-supported ruthenium catalyst provided by the present disclosure is relatively simple, the ruthenium dispersion is high, and the ruthenium species can exist in multiple forms such as single atoms, nanoclusters and nanoparticles, thereby improving the catalytic activity of the ruthenium species.
[0015] (3) According to the embodiments of the present disclosure, the titanium dioxide-supported ruthenium catalyst provided by the present disclosure is used in the treatment of halogenated organic pollutants. The catalyst has good oxidizing properties, chlorine resistance, and water resistance, and does not produce harmful by-products. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1aThis is a scanning electron microscope image of anatase titanium dioxide with a high proportion of 201 crystal planes exposed in an embodiment of the present disclosure;
[0017] Figure 1b This is a high-angle annular dark-field scanning transmission electron microscopy image of an anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 201 crystal planes in an embodiment of the present disclosure, locally magnified at a scale of 20 nm;
[0018] Figure 1c This is a high-angle annular dark-field scanning transmission electron microscopy image of an anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 201 crystal planes in an embodiment of the present disclosure, locally magnified at a scale of 5 nm;
[0019] Figure 1d This is a high-angle annular dark-field scanning transmission electron microscope elemental mapping image of an anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 201 crystal planes in an embodiment of the present disclosure at a local magnified 20 nm scale;
[0020] Figure 2 This is a comparison chart of the thermal catalytic degradation efficiency of chlorobenzene by the catalysts in Example 1 and Comparative Example 1 of the present disclosure at different temperatures;
[0021] Figure 3 Graph showing the degradation efficiency stability test results of the catalysts of Example 1 and Comparative Example 1 at 300° C.;
[0022] Figure 4 Graph showing the stability test results of the degradation efficiency of chlorobenzene at 300° C. and 5 vol.% water vapor over anatase-phase titanium dioxide-supported ruthenium catalyst with different crystal facets exposed in the embodiments of the present disclosure;
[0023] Figure 5A This is a quantitative distribution diagram of degradation products during the degradation of chlorobenzene by the catalyst in Example 1 and Comparative Example 1 of the present disclosure;
[0024] Figure 5B This is a quantitative distribution diagram of degradation products during the degradation of chlorobenzene by the catalyst in Comparative Example 2 of the present disclosure. DETAILED DESCRIPTION
[0025] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments.
[0026] In view of the fact that the current halogenated organic pollutants usually contain moisture during the disposal process, which causes moisture to compete with organic pollutants for active sites on titanium dioxide, resulting in a weak catalytic effect of the catalyst, and the problem that ruthenium-loaded catalysts are not completely degraded during the thermal catalytic degradation of halogenated organic pollutants, and produce more toxic polyhalogenated benzene by-products, the present invention discloses a titanium dioxide-loaded ruthenium catalyst. Ruthenium as an active component is one aspect, and the selection of catalyst carrier is also crucial. Titanium dioxide (TiO2) is widely used as a catalyst carrier as a chemically stable, non-toxic and cheap and easily available material, and titanium dioxide itself has a variety of specific crystal planes, such as 201 crystal plane, 101 crystal plane, 001 crystal plane, etc. Titanium dioxide with specific crystal planes has different surface titanium atom density, Ti-O-Ti bond angle, surface energy, etc., and exhibits different chemical properties and reactivity. By loading the precious metal ruthenium on titanium dioxide with exposed specific crystal faces, it is expected to achieve stable and efficient degradation of halogenated organic pollutants. However, the preparation of ruthenium catalysts loaded on titanium dioxide with specific crystal faces still faces challenges, and there are few reports on their application in the treatment of halogenated organic pollutants.
[0027] In view of this, the present disclosure proposes to prepare anatase phase titanium dioxide with a high proportion of exposed 201 crystal faces, and load ruthenium on the prepared titanium dioxide carrier with exposed 201 crystal faces, and systematically explore its unique performance in the thermal catalytic degradation of difficult-to-degrade halogenated organic pollutants.
[0028] Specifically, as a first aspect of the present disclosure, a titanium dioxide-supported ruthenium catalyst is provided, comprising: anatase phase titanium dioxide with a high proportion of 201 crystal plane exposed as a carrier, wherein the 201 crystal plane exposure rate of the anatase phase titanium dioxide is 60%-100%; and ruthenium species supported on the anatase phase titanium dioxide with a high proportion of 201 crystal plane exposed, wherein the ruthenium species includes ruthenium single atoms, ruthenium nanoclusters and ruthenium nanoparticles.
[0029] In the embodiment of the present disclosure, anatase titanium dioxide with a high proportion of exposed 201 crystal faces is selected as the catalyst support. The high proportion of 201 crystal faces has a high surface energy, which can interact more strongly with the metal-support, thereby enhancing the electron transfer on the catalyst surface. In addition, the high proportion of 201 crystal faces has a unique surface morphology and some oxygen vacancies and Ti 3+ Defect sites can make ruthenium uniformly loaded on its surface and increase the number of ruthenium active sites; so that after ruthenium is loaded on its surface, the obtained titanium dioxide loaded ruthenium catalyst has higher reaction activity and stability.
[0030] According to the embodiments of the present disclosure, the ruthenium loading is 0.1-3 wt.%, for example, 0.1 wt.%, 0.5 wt.%, 1.0 wt.%, 2.0 wt.%, 3.0 wt.%, among which 1.0 wt.% is preferred in terms of economic cost and catalytic effect; the particle size of the ruthenium species is 0.1-20 nm, which can be 0.1 nm, 5 nm, 20 nm, etc., and the ruthenium species is mainly uniformly loaded in various forms such as single atoms, nanoclusters and nanoparticles on an anatase phase titanium dioxide carrier with a high proportion of 201 crystal planes exposed, so that the catalyst has the characteristics of high reaction activity of a small-size precious metal-supported catalyst and long-term stable operation.
[0031] According to the embodiments of the present disclosure, anatase titanium dioxide with a high proportion of exposed 201 crystal planes has a size of 0.5-3 μm, and anatase titanium dioxide with a high proportion of exposed 201 crystal planes has a unique dandelion-like morphology, which helps to further improve the catalytic activity of titanium dioxide-loaded ruthenium catalyst.
[0032] According to an embodiment of the present disclosure, the present disclosure also provides a method for preparing a titanium dioxide-supported ruthenium catalyst, comprising: adding a water-soluble ruthenium salt to an anatase phase titanium dioxide aqueous solution with a high proportion of 201 crystal faces exposed under stirring to obtain a mixed solution; injecting a sodium borohydride solution into the mixed solution to react under stirring to obtain an anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of 201 crystal faces exposed.
[0033] In an embodiment of the present disclosure, a ruthenium salt is added to an anatase-phase titanium dioxide solution with a high proportion of exposed 201 crystal faces. After uniform mixing, a sodium borohydride reducing agent is added to reduce the ruthenium salt to ruthenium active species such as ruthenium atoms, ruthenium nanoclusters, and ruthenium nanoparticles. These species are then loaded onto the anatase-phase titanium dioxide with a high proportion of exposed 201 crystal faces, thereby obtaining an anatase-phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 201 crystal faces. The preparation method provided by the present disclosure is simple and easy to implement. Furthermore, the addition of the ruthenium salt to the titanium dioxide solution by injection helps to improve the dispersion of the ruthenium, further increasing the number of ruthenium active sites and catalytic activity, and reducing the cost of the ruthenium-supported catalyst.
[0034] According to the embodiments of the present disclosure, the water-soluble ruthenium salt is selected from any one of RuCl3·xH2O, Ru(NO)(NO3)3, Ru(NO)(OOCCH3)3, and RuCl3NO·H2O, wherein RuCl3·xH2O may be RuCl3·3H2O. Other water-soluble ruthenium salts may also be used and are not further limited herein.
[0035] According to an embodiment of the present disclosure, the addition rate of the water-soluble ruthenium salt is 0.5-4mL / h, such as 0.5mL / h, 1.0mL / h, 2.0mL / h, 4mL / h, etc., wherein preferably 1.0mL / h, and the way of adding can be by dropwise injection. In the present embodiment, the ruthenium salt is added to the titanium dioxide solution at a dropping rate of 0.5-4mL / h, which helps the ruthenium salt to be uniformly loaded on the titanium dioxide. The injection rate of sodium borohydride (NaBH4) solution can be 0.5-3mL / h, such as 0.5mL / h, 1.0mL / h, 2.0mL / h, 3.0mL / h, etc., wherein the concentration of sodium borohydride can be 0.1-0.8mol / L, and the amount can be 1-3mL, and the way of adding can also be by dropwise injection. Sodium borohydride within this range of dropwise addition speed, dosage and concentration can effectively reduce ruthenium salts into ruthenium single atoms, ruthenium nanoclusters and ruthenium nanoparticles.
[0036] According to an embodiment of the present disclosure, a specific method for preparing a titanium dioxide-supported ruthenium catalyst can be as follows: a titanium dioxide support with a high proportion of 201 crystal faces exposed is taken, and the support is dissolved in an aqueous solution and ultrasonically stirred for 30-90 minutes. Under stirring, RuCl3 (3H2O) with a loading amount of 0.5-3wt.% is injected dropwise into the titanium dioxide solution with a high proportion of 201 crystal faces exposed through a syringe pump at a rate of 0.5-4mL / h (preferably 1mL / h), and the stirring state is maintained for 1-4h after addition to obtain a mixed solution. Then, 0.1-0.8mol / L freshly prepared NaBH4 is added dropwise to the mixed solution at a rate of 0.5-3mL / h through a syringe pump under stirring and the reaction is stirred at room temperature for 12h, wherein the amount of NaBH4 added is 1-3mL. Then, the stirring at room temperature was stopped, the ruthenium-loaded anatase phase titanium dioxide with a high proportion of 201 crystal planes exposed was centrifuged and washed with deionized water multiple times, and dried at 60-80°C overnight to obtain anatase phase titanium dioxide-loaded ruthenium catalyst material with highly dispersed ruthenium active components and a high proportion of 201 crystal planes exposed.
[0037] According to an embodiment of the present disclosure, preparing an anatase phase titanium dioxide support with a high proportion of exposed 201 crystal planes includes adding tetrabutyl titanate to a mixed solution of glacial acetic acid and dimethylformamide, stirring and mixing until uniform, and then maintaining the mixture at 180°C-220°C for 8-12 hours. The glacial acetic acid and dimethylformamide are mixed in a volume ratio of 1:1 to 2:3, and the amount of tetrabutyl titanate added is 1 / 10 to 1 / 20 of the volume of the glacial acetic acid, for example, 1 / 10, 1 / 12, 1 / 14, 1 / 16, 1 / 18, 1 / 20, etc., with 1 / 16 being preferred.
[0038] Specifically, a hydrothermal method is used to prepare anatase titanium dioxide carrier with a high proportion of 201 crystal planes exposed. The method can be as follows: glacial acetic acid and dimethylformamide are added to a beaker in a volume ratio of 2:3, and after magnetic stirring for 5-30 minutes, a tetrabutyl titanate solution with a volume ratio of one-sixteenth of glacial acetic acid is added dropwise. Stirring is continued for 2-30 minutes (preferably 5 minutes) to ensure that the solution is fully mixed. Then, the mixed suspension is transferred to a polytetrafluoroethylene-lined tube, the lined tube is placed in a stainless steel high-pressure reactor, placed in a blast drying oven, and maintained at 180°C-220°C for 8-12 hours. After cooling, the precipitate is collected, washed several times with deionized water and ethanol, and then dried in an oven at 60-80°C for 10-24 hours. After grinding, anatase titanium dioxide with a high proportion of 201 crystal planes exposed is obtained.
[0039] The exposure rate of the 201 crystal plane of the anatase phase titanium dioxide obtained by the above method is higher than 60%, and can even reach 100%.
[0040] As a third aspect of the present disclosure, there is provided an application of the titanium dioxide-supported ruthenium catalyst in the above embodiment in treating halogenated organic pollutants.
[0041] According to an embodiment of the present disclosure, the halogenated organic pollutant can be selected from any one of chlorobenzene, polychlorinated biphenyls, and polychlorinated naphthalenes.
[0042] According to an embodiment of the present disclosure, a method for treating halogenated organic pollutants with the titanium dioxide-loaded ruthenium catalyst in the above embodiment includes: placing the catalyst in the above embodiment in a reactor, introducing a mixed gas of N2, O2 and halogenated organic pollutants, and conducting a halogenated organic pollutant treatment reaction at 150-350°C; wherein the concentration of the halogenated organic pollutants is 50-600ppm, the volume content of O2 is 3%-20%, and the amount of the catalyst used is 50-300mg.
[0043] According to the embodiment of the present disclosure, the space velocity during the treatment of halogenated organic pollutants is 10000-60000h -1 In addition, the catalyst provided by the present disclosure can treat halogenated organic pollutants under water vapor conditions with a humidity of 2-20 vol.% without generating many harmful byproducts.
[0044] The following detailed examples and accompanying figures further illustrate the titanium dioxide-supported ruthenium catalyst, its preparation method, and its application. It should be noted that the following specific examples are provided for illustrative purposes only and are not intended to limit the scope of protection of this disclosure. It should be noted that the methods provided herein are conventional methods unless otherwise specified, and that reactants and reagents can be obtained from publicly available commercial sources unless otherwise specified.
[0045] Example 1
[0046] Anatase-phase titanium dioxide support (Ru / {201}-TiO2) with a high proportion of exposed 201 crystal faces was prepared by hydrothermal method. The specific preparation process is as follows:
[0047] Glacial acetic acid and dimethylformamide were added to a beaker in a volume ratio of 2:3. After magnetic stirring for 30 minutes, a solution of tetrabutyl titanate (1 / 16th the volume of glacial acetic acid) was added dropwise. Stirring was continued for 5 minutes to thoroughly mix the solution. The suspension was transferred to a polytetrafluoroethylene-lined tube, which was placed in a stainless steel autoclave and placed in a forced-air drying oven at 220°C for 8 hours. After cooling, the precipitate was collected, washed several times with deionized water and ethanol, and then dried in an oven at 80°C for 24 hours. After grinding, an anatase-phase titanium dioxide support with a high proportion of exposed 201 facets was obtained.
[0048] Ruthenium is loaded on the prepared anatase phase titanium dioxide support with a high proportion of 201 crystal planes exposed. The specific steps are as follows:
[0049] The prepared anatase titanium dioxide support with a high proportion of exposed 201 facets was dissolved in an aqueous solution, ultrasonically stirred, and stirred for 90 minutes. A 0.01 mol / L RuCl3·(3H2O) aqueous solution was prepared and added dropwise to the anatase titanium dioxide solution with a high proportion of exposed 201 facets via a syringe pump at a rate of 1 mL / h at a loading rate of 1 wt.%. The solution was stirred for 1-4 hours. While stirring, a freshly prepared 0.5 mol / L NaBH4 solution (1.979 mL) was added via a syringe pump at a rate of 0.5-3 mL / h. The reaction was stirred at room temperature for 12 hours. Then, the stirring at room temperature was stopped, the ruthenium-loaded anatase phase titanium dioxide catalytic material with a high proportion of 201 crystal faces exposed was centrifuged and washed multiple times with deionized water, and dried overnight at 60-80°C to obtain the anatase phase titanium dioxide catalytic material with a high proportion of 201 crystal faces exposed.
[0050] Figure 1a This is a scanning electron microscope image of anatase titanium dioxide with a high proportion of 201 crystal planes exposed in an embodiment of the present disclosure; Figure 1b This is a high-angle annular dark-field scanning transmission electron microscopy image of an anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 201 crystal planes in an embodiment of the present disclosure, locally magnified at a scale of 20 nm; Figure 1c This is a high-angle annular dark-field scanning transmission electron microscopy image of an anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 201 crystal planes in an embodiment of the present disclosure, locally magnified at a scale of 5 nm; Figure 1dThis is a high-angle annular dark-field scanning transmission electron microscope elemental mapping image of anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 201 crystal planes in the embodiment of the present disclosure, locally magnified at a scale of 20 nm.
[0051] from Figure 1a It can be seen that the exposure rate of the 201 crystal face of anatase phase titanium dioxide is close to 100%, and the morphology of titanium dioxide is dandelion-shaped. When the Ru loading is 1wt%, the ruthenium species in the catalyst mainly exist in the form of single atoms, nanoclusters and nanoparticles with a particle size of 0.1-5nm, and are uniformly loaded on the anatase phase titanium dioxide support with a high proportion of 201 crystal face exposure ( Figure 1b-Figure 1c ),from Figure 1d The element distribution diagram shows that ruthenium is evenly loaded on the titanium dioxide support.
[0052] Comparative Example 1
[0053] The method for preparing anatase phase titanium dioxide supported ruthenium catalyst (Ru / {101}-TiO2) with a high proportion of exposed 101 crystal faces by a hydrothermal method is as follows:
[0054] 1) First, a titanium dioxide support with a high proportion of 101 crystal face exposure was prepared by a hydrothermal method:
[0055] 3.6 mmol of disodium ethylenediaminetetraacetate and 3 mmol of titanium sulfate were added to 60 mL of deionized water and stirred for 6 hours. The suspension was transferred to a 100 mL polytetrafluoroethylene-lined tube, which was placed in a stainless steel autoclave and placed in a forced air drying oven at 180°C for 10 hours. After cooling, the precipitate was collected, washed several times with deionized water and ethanol, and dried in a 60°C oven for 12 hours to obtain a solid powder. The resulting solid powder was calcined at 400°C in air for 2 hours and ground to obtain anatase titanium dioxide with a high proportion of exposed 101 crystal faces.
[0056] 2) According to the ruthenium loading method in Example 1, anatase phase titanium dioxide with a high proportion of exposed 101 crystal faces is used as a carrier, and ruthenium is loaded on the anatase phase titanium dioxide carrier with a high proportion of exposed 101 crystal faces to obtain an anatase phase titanium dioxide with a high proportion of exposed 101 crystal faces loaded ruthenium catalyst.
[0057] The anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 201 crystal faces prepared in Example 1 and the anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 101 crystal faces prepared in Comparative Example 1 were compared and respectively applied in the chlorobenzene treatment process.
[0058] Specifically, 100 mg of each catalyst from Example 1 and Comparative Example 1 was placed in a glass tube, and a mixture of N2, O2, and chlorobenzene was introduced at a total flow rate of 80 mL / min, wherein the chlorobenzene concentration was 200 ppm and the O2 volume content was 5%. Chlorobenzene treatment experiments were conducted at a reaction temperature range of 150-350°C. The specific test results are shown in FIG. Figure 2 shown.
[0059] Figure 2 This is a comparison chart of the thermal catalytic degradation efficiency of chlorobenzene at different temperatures for the catalysts in Example 1 and Comparative Example 1 of the present disclosure.
[0060] from Figure 2 It can be seen that the degradation efficiency of chlorobenzene by the catalysts in Example 1 and Comparative Example 1 increases with increasing temperature. The catalyst in Comparative Example 1 can completely remove chlorobenzene at 325°C, while the catalyst in Example 1 can completely degrade chlorobenzene at 300°C, indicating that the activity of the catalyst in Example 1 is significantly higher than that of the catalyst in Comparative Example 1. Analysis shows that the catalyst in Example 1 contains more unsaturated coordinated Ti atoms on its surface, making it easier to generate oxygen vacancies and Ti atoms than the catalyst in Comparative Example 1. 3+ These defect sites can effectively promote the adsorption and activation of O2, thereby accelerating the Deacon reaction and deep oxidation of chlorobenzene, which are significantly affected by active oxygen species, so that the catalyst in Example 1 maintains a more excellent chlorobenzene oxidation ability during the thermal catalytic degradation of chlorobenzene.
[0061] Furthermore, the chlorine resistance and stability of the catalysts in Example 1 and Comparative Example 1 were tested, and the specific testing process is as follows:
[0062] 100 mg of the catalysts in Example 1 and Comparative Example 1 were placed in glass tubes, and a mixture of N2, O2, and chlorobenzene was introduced at a total flow rate of 80 mL / min, wherein the chlorobenzene concentration was 200 ppm and the O2 volume content was 5%. The reaction temperature of the heating furnace was slowly raised to 300°C, and a chlorobenzene treatment stability test was conducted. The specific test results are shown in FIG. Figure 3 shown.
[0063] Figure 3 Graph showing the degradation efficiency stability test results of the catalysts of Example 1 and Comparative Example 1 at 300°C.
[0064] from Figure 3It can be seen that under the test environment of 300°C, the chlorobenzene degradation efficiency of the catalyst in Comparative Example 1 shows a downward trend within 1000 minutes, while the degradation efficiency of the catalyst in Example 1 for chlorobenzene is always stably maintained at 100% within 1000 minutes, indicating that the catalyst in Example 1 has better chlorine resistance and stability. In-depth analysis shows that: compared with the anatase phase titanium dioxide-supported ruthenium catalyst with low-index 101 crystal plane exposed (Comparative Example 1), the anatase phase titanium dioxide-supported ruthenium catalyst with high-index 201 crystal plane exposed (Example 1) has a higher surface energy due to its surface, which can produce a stronger metal-support interaction with ruthenium, enhance the catalyst surface electron transfer and redox stability, further accelerate the activation of O2 and the deep oxidation of chlorobenzene, thereby ensuring that the catalyst in Example 1 has excellent chlorine resistance and stability.
[0065] Comparative Example 2
[0066] The hydrothermal method for preparing anatase phase titanium dioxide supported ruthenium catalyst (Ru / {001}-TiO2) with a high proportion of exposed 001 crystal faces is as follows:
[0067] 1) First, an anatase phase titanium dioxide support with a high proportion of exposed 001 crystal faces was prepared by a hydrothermal method:
[0068] 30 mL of tetrabutyl titanate was placed in a 100 mL polytetrafluoroethylene liner, and then 9 mL of 30% HF was added dropwise. After stirring for 30 minutes, it was transferred to a 100 mL reactor and placed in an oven at 180°C for 24 hours. It was cooled to room temperature, washed several times by centrifugation with deionized water and ethanol, and dried in an oven at 60°C overnight. Finally, it was ground to obtain anatase phase titanium dioxide with a high proportion of exposed 001 crystal planes.
[0069] 2) According to the ruthenium loading method in Example 1, anatase phase titanium dioxide with a high proportion of exposed 001 crystal faces is used as a carrier, and ruthenium is loaded on the anatase phase titanium dioxide carrier with a high proportion of exposed 001 crystal faces to obtain a titanium dioxide-loaded ruthenium catalyst with a high proportion of exposed 001 crystal faces.
[0070] Furthermore, the effect of anatase-phase titanium dioxide-supported ruthenium catalyst with different crystal face exposure on the degradation efficiency of chlorobenzene was investigated. The specific test process is as follows:
[0071] The catalysts in Example 1 and Comparative Examples 1 and 2 were compared. 100 mg of each catalyst in Example 1, Comparative Example 1, and Comparative Example 2 were placed in glass tubes and introduced with a mixture of N2, O2, and chlorobenzene at a total flow rate of 80 mL / min, wherein the chlorobenzene concentration was 200 ppm and the O2 volume content was 5%. The reaction temperature in the heating furnace was slowly raised to 300°C, and water was introduced into the reaction system using a constant flow rate of nitrogen as a carrier gas. The relative humidity of the entire gas flow was controlled to be 5 vol.% by varying the nitrogen flow rate to conduct a chlorobenzene treatment stability test. The specific test results are shown in FIG. Figure 4 shown.
[0072] Figure 4 Graph showing the stability test results of the degradation efficiency of chlorobenzene at 300° C. and 5 vol.% water vapor over anatase-phase titanium dioxide-supported ruthenium catalyst with different crystal planes exposed in the embodiments of the present disclosure.
[0073] like Figure 4 As shown, under the conditions of 300°C and a relative humidity of 5 vol.%, the degradation efficiency of the catalysts in Comparative Examples 2 and 1 for chlorobenzene fluctuated within 1000 min, while the degradation efficiency of the catalyst in Example 1 for chlorobenzene remained at 100% throughout 1000 min, indicating that the catalyst in Example 1 has excellent water resistance. After in-depth analysis, it was found that compared with the anatase-phase titanium dioxide-supported ruthenium catalysts with different crystal faces exposed in Comparative Examples 1 and 2, the anatase-phase titanium dioxide-supported ruthenium catalyst with the 201 crystal face exposed in Example 1 has more abundant defect sites, which allows the H2O adsorbed on the defect sites to dissociate and generate hydroxyl species, which can effectively promote the activation of O2, the removal of chlorine species and the deep oxidation of chlorobenzene, thereby making the catalyst in Example 1 have better water resistance. This shows that the catalyst provided by the present disclosure has oxidation, chlorine resistance and water resistance, and can efficiently treat chlorobenzene in halogenated organic pollutants.
[0074] Furthermore, the degradation products during the degradation of chlorobenzene by the catalyst in Example 1, Comparative Example 1 and Comparative Example 2 were quantitatively analyzed, and the specific process is as follows:
[0075] 100 mg of each catalyst from Example 1, Comparative Example 1, and Comparative Example 2 was placed in a glass bottle and introduced into each of the bottles at a total flow rate of 80 mL / min of a mixture of N₂, O₂, and chlorobenzene, wherein the chlorobenzene concentration was 200 ppm and the O₂ content was 5% by volume. The reaction temperature was raised to 300°C, and a chlorobenzene treatment experiment was conducted. The tail gas was collected using a 3 L Teflon FEP sampling bag, and 114 VOCs in the tail gas were detected by gas chromatography-mass spectrometry-flame ionization detector / mass spectrometry (GC-FID / MS).
[0076] Figure 5AQuantitative distribution diagram of degradation products during the degradation of chlorobenzene by the catalyst in Example 1 and Comparative Example 1 of the present disclosure.
[0077] like Figure 5A As shown, the catalysts in Comparative Example 1 and Example 1 did not produce polychlorobenzene by-products such as dichlorobenzene and trichlorobenzene during the catalytic degradation of chlorobenzene. Only about 22 VOCs were detected in the 114 VOCs in the exhaust gas. The catalyst in Example 1 produced fewer by-products than the catalyst in Comparative Example 1. This is mainly because the catalyst in Example 1 has a higher catalytic activity, which enables it to deeply oxidize most of the chlorobenzene into carbon dioxide and water, significantly reducing the generation of by-products.
[0078] Figure 5B This is a quantitative distribution diagram of degradation products during the degradation of chlorobenzene by the catalyst in Comparative Example 2 of the present disclosure.
[0079] like Figure 5B As shown, approximately 83 VOC byproducts were detected in the exhaust gas from the chlorobenzene degradation catalyzed by the catalyst in Comparative Example 2. Furthermore, polychlorinated benzene byproducts such as dichlorobenzene and trichlorobenzene were also detected in the product. This further confirms that the catalyst prepared in Example 1 of the present disclosure combines catalytic performance with oxidation, chlorine resistance, water resistance, and the absence of harmful byproducts, effectively treating chlorobenzene from halogenated organic pollutants without generating polychlorinated benzene byproducts in the product.
[0080] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.
Claims
1. Application of a titanium dioxide-supported ruthenium catalyst in treating halogenated organic pollutants, comprising: The titanium dioxide-supported ruthenium catalyst is placed in a reactor, and a mixed gas of N2, O2 and halogenated organic pollutants is introduced to carry out a halogenated organic pollutant treatment reaction at 150-350°C and a water vapor humidity of 2-20 vol.%; Wherein, the concentration of the halogenated organic pollutants is 50-600 ppm, the volume content of O2 is 3%-20%, and the amount of the catalyst is 50-300 mg; Wherein, the titanium dioxide supported ruthenium catalyst comprises: Anatase titanium dioxide with a high ratio of 201 crystal plane exposure as a carrier, wherein the 201 crystal plane exposure rate of the anatase titanium dioxide is 60% to 100%; and Ruthenium species supported on the anatase phase titanium dioxide with a high proportion of 201 crystal planes exposed, the ruthenium species including ruthenium single atoms, ruthenium nanoclusters and ruthenium nanoparticles; Wherein, the halogenated organic pollutant is selected from any one of chlorobenzene, polychlorinated biphenyls and polychlorinated naphthalenes.
2. The use according to claim 1, wherein The ruthenium loading is 0.1-3 wt %, and the particle size of the ruthenium species is 0.1-20 nm.
3. The use according to claim 1, wherein: The anatase titanium dioxide with a high ratio of exposed 201 crystal planes has a size of 0.5-3 μm.
4. The use according to claim 1, wherein The titanium dioxide-supported ruthenium catalyst is obtained by the following method: Under stirring, a water-soluble ruthenium salt is added to an aqueous solution of anatase-phase titanium dioxide with a high proportion of exposed 201 crystal faces to obtain a mixed solution; Under stirring, a sodium borohydride solution is injected into the mixed solution to react, thereby obtaining an anatase phase titanium dioxide-supported ruthenium catalyst with a high proportion of exposed 201 crystal faces.
5. The use according to claim 4, wherein: The water-soluble ruthenium salt is selected from any one of RuCl3·xH2O, Ru(NO)(NO3)3, Ru(NO)(OOCCH3)3, and RuCl3NO·H2O.
6. The use according to claim 4, wherein: The addition rate of the water-soluble ruthenium salt is 0.5-4 mL / h, and the injection rate of the sodium borohydride solution is 0.5-3 mL / h.
7. The use according to claim 4, wherein: The anatase phase titanium dioxide with a high proportion of exposed 201 crystal faces is prepared by adding tetrabutyl titanate to a mixed solution of glacial acetic acid and dimethylformamide, stirring and mixing the mixture uniformly, and then keeping the mixture at 180° C.-220° C. for 8-12 hours.
8. The use according to claim 7, wherein: The glacial acetic acid and dimethylformamide are mixed in a volume ratio of 1:1 to 2:3, and the amount of tetrabutyl titanate added is 1 / 10 to 1 / 20 of the volume of the glacial acetic acid.