High temperature resistant mercury adsorbent and method of making same

Abstract

The application provides a high-temperature-resistant mercury adsorbent and a preparation method thereof. The method for preparing the high-temperature-resistant mercury adsorbent is completed by a flame synthesis method, comprising the following steps: preparing a precursor solution, wherein the precursor solution comprises a precursor and a solvent, and the precursor comprises tetrabutyl titanate, cerium 2-ethylhexanoate, copper acetate and tungsten hexacarbonyl; introducing the precursor solution into a first communication hole of a flame spray pyrolysis burner at a predetermined rate, while introducing a dispersion gas into a second communication hole of the flame spray pyrolysis burner and introducing a fuel gas into a third communication hole of the flame spray pyrolysis burner; the dispersion gas disperses the precursor solution into dispersed droplets, and the dispersed droplets are sprayed into a flame combusted by the fuel gas; the dispersed droplets form precursor vapor in the flame, the precursor vapor forms nucleation particles, and the nucleation particles are condensed by cooling to obtain the high-temperature-resistant mercury adsorbent. Thus, the high-temperature-resistant mercury adsorbent prepared by the above method has excellent high-temperature resistance and excellent mercury adsorption performance.

Description

Technical Field

[0001] This invention relates to the field of adsorption, and more specifically, to a high-temperature resistant mercury adsorbent and its preparation method. Background Technology

[0002] Mercury emissions pose a significant threat to the ecological environment and human health. Therefore, developing efficient, high-temperature resistant mercury adsorbents is of great importance for mercury emission control across various industries. The cement industry, as a major sector within this industry, also faces the challenge of mercury emissions.

[0003] Besides the cement industry, other high-temperature industries, such as metallurgy and glass manufacturing, also face the problem of mercury emissions. Under these high-temperature conditions, traditional mercury adsorbents often lose their activity, limiting their application in these industries. Therefore, it is necessary to develop high-temperature resistant mercury adsorbents to address this issue. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one object of this invention is to provide a method for preparing a high-temperature resistant mercury adsorbent, wherein the high-temperature resistant mercury adsorbent prepared by this method can maintain its high adsorption performance for mercury even under high temperature conditions.

[0005] In one aspect of the present invention, a method for preparing a high-temperature resistant mercury adsorbent is provided. According to an embodiment of the present invention, the method is carried out by flame synthesis and includes the following steps: preparing a precursor solution comprising a precursor and a solvent, wherein the precursor comprises tetrabutyl titanate, cerium 2-ethylhexanoate, copper acetate, and tungsten hexacarbonyl; introducing the precursor solution into a first connecting hole of a flame spray pyrolysis burner (FSP) at a predetermined rate, simultaneously introducing a dispersion gas into a second connecting hole of the flame spray pyrolysis burner, and introducing fuel gas into a third connecting hole of the flame spray pyrolysis burner; the dispersion gas disperses the precursor solution into dispersed droplets, and sprays the dispersed droplets into a flame ignited by the fuel gas; the dispersed droplets form precursor vapor in the flame, the precursor vapor forms nucleating particles, and the nucleating particles condense upon cooling to obtain the high-temperature resistant mercury adsorbent. Therefore, this invention synthesizes a mercury adsorbent in a high-temperature flame using a flame synthesis method, resulting in a high-temperature resistant mercury adsorbent with excellent high-temperature resistance and superior mercury adsorption performance. The high-temperature resistant mercury adsorbent prepared by the above method can maintain its high adsorption performance even at temperatures up to 800°C, and can be widely used in various high-temperature industrial fields.

[0006] According to an embodiment of the present invention, the molar ratio of tetrabutyl titanate, cerium 2-ethylhexanoate, copper acetate and tungsten hexacarbonyl is (7-11):(0.5-1.5):(0.5-1.15):(1.5-3).

[0007] According to an embodiment of the present invention, the flame temperature is above 2800°C.

[0008] According to an embodiment of the present invention, the solvent comprises ethanol and n-hexane, wherein the volume ratio of ethanol to n-hexane is 1:(0.5 to 1.5).

[0009] According to an embodiment of the present invention, the predetermined rate is 700-900 mL / h.

[0010] According to an embodiment of the present invention, the pressure of the dispersed gas introduced is above 0.4 MPa, and the flow rate is 25 to 35 L / min.

[0011] In another aspect, the present invention provides a high-temperature resistant mercury adsorbent. According to an embodiment of the present invention, the high-temperature resistant mercury adsorbent is prepared by the aforementioned method. Therefore, the high-temperature resistant adsorbent possesses excellent high-temperature resistance and superior mercury adsorption performance, maintaining its high adsorption performance even at temperatures up to 800°C.

[0012] According to an embodiment of the present invention, the high-temperature resistant mercury adsorbent comprises a carrier and an active substance, wherein the carrier is titanium dioxide and the active substance comprises copper oxide, cerium dioxide and tungsten oxide.

[0013] According to an embodiment of the present invention, in the high-temperature mercury adsorbent, the tungsten oxide accounts for 7 to 11 wt% of the total mass of the high-temperature mercury adsorbent.

[0014] According to an embodiment of the present invention, the high-temperature resistant mercury adsorbent further satisfies at least one of the following conditions: the specific surface area of ​​the high-temperature resistant mercury adsorbent is 65-85 m². 2 / g; the pore size of the high-temperature resistant mercury adsorbent is 0.5–0.7 cm³. 3 / g.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0017] Figure 1 This is a flowchart of the method for preparing high-temperature resistant mercury adsorbent by flame synthesis in an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the preparation of high-temperature resistant mercury adsorbent by flame synthesis in an embodiment of the present invention.

[0019] Figure 3 This is a comparison chart of the adsorption effects of the high-temperature resistant mercury adsorbent prepared by flame synthesis in this embodiment of the invention with mercury adsorbents prepared by impregnation and McKenna flame synthesis.

[0020] Figure 4 This is a comparison chart of the adsorption effects of the high-temperature resistant mercury adsorbent prepared by flame synthesis in this embodiment of the invention under aerobic and anaerobic conditions.

[0021] Figure 5 This is a graph showing the test results of a temperature-programmed pyrolysis experiment of the high-temperature resistant mercury adsorbent prepared by flame synthesis in an embodiment of the present invention.

[0022] Figure 6 These are transmission electron microscope (TEM) and high-resolution TEM images of the high-temperature resistant mercury adsorbent prepared by flame synthesis in this embodiment of the invention.

[0023] Figure 7 This is a surface elemental scan image of the high-temperature resistant mercury adsorbent prepared by flame synthesis in an embodiment of the present invention.

[0024] Figure 8 This is a graph showing the changes in surface element content of the high-temperature resistant mercury adsorbent prepared by flame synthesis and the mercury adsorbent prepared by impregnation in embodiments of the present invention before and after mercury adsorption. Detailed Implementation

[0025] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0026] The present invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0027] In one aspect, the present invention provides a method for preparing a high-temperature resistant mercury adsorbent. According to an embodiment of the present invention, the method is carried out by flame synthesis, referring to… Figure 1 The method for preparing a high-temperature resistant mercury adsorbent includes the following steps:

[0028] S100: Prepare a precursor solution, which includes a precursor and a solvent. The precursor includes tetrabutyl titanate, cerium 2-ethylhexanoate, copper acetate, and tungsten hexacarbonyl.

[0029] According to an embodiment of the present invention, tetrabutyl titanate (C) is a precursor. 16 H 36 O4Ti), cerium 2-ethylhexanoate (C 24 H 45 The molar ratio of CeO6, copper acetate (Cu(CH3COO)2·H2O), and tungsten hexacarbonyl (W(CO)6) is (7–11):(0.5–1.5):(0.5–1.15):(1.5–3). In other words, the molar ratio of titanium, cerium, copper, and tungsten in the precursor satisfies (7–11):(0.5–1.5):(0.5–1.15):(1.5–3). For example, the molar ratios of titanium, cerium, copper, and tungsten are 9:1:1:2, 8:1:1:2, 9:1:1:3, 8:1:1:3, etc. Using the above-mentioned precursor components to prepare the precursor solution can highly disperse the titanium, cerium, copper, and tungsten elements in the prepared high-temperature mercury adsorbent, thereby giving the high-temperature mercury adsorbent better adsorption performance. The aforementioned copper to cerium ratio is beneficial for improving the adsorption efficiency and capacity of the high-temperature mercury adsorbent. However, excessive copper content can lead to the formation of copper oxide clusters within the adsorbent, resulting in a decrease in its adsorption capacity. Tungsten hexacarbonyl is reacted with a high-temperature flame to generate tungsten oxide (WO₂). x (Including trioxide and / or blue tungsten oxide) components, the above-mentioned hexacarbonyl tungsten content can achieve a suitable mass fraction of tungsten oxide WO3 in the high-temperature mercury adsorbent. x tungsten oxide (WO3) x It can increase the surface acidity of the high-temperature mercury adsorbent, thereby promoting adsorption. If the proportion of hexacarbonyl tungsten is too high, the mass fraction of tungsten oxide in the high-temperature mercury adsorbent will be too high, which will easily cover copper and cerium elements, thereby reducing the adsorption capacity of the high-temperature mercury adsorbent. If the proportion of hexacarbonyl tungsten is too low, the mass fraction of tungsten oxide in the high-temperature mercury adsorbent will be too low, which will also easily affect the adsorption capacity of the high-temperature mercury adsorbent.

[0030] In some embodiments, the tungsten oxide accounts for 7-11 wt% (e.g., 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%) of the total mass of the high-temperature mercury adsorbent. This tungsten oxide content provides a suitable acidity to the surface of the high-temperature mercury adsorbent, thereby promoting adsorption. However, if the tungsten oxide content is too high, it can easily cover copper and cerium elements, thus reducing the adsorption capacity. Conversely, if the tungsten oxide content is too low, it can also negatively impact the adsorption capacity.

[0031] In embodiments of the present invention, the solvent includes ethanol and n-hexane, with a volume ratio of ethanol to n-hexane of 1:(0.5-1.5), such as 1:0.5, 1:1, or 1:1.5. Solvents with these ratios can effectively dissolve the precursors. In some specific embodiments, the volume ratio of ethanol to n-hexane is 1:1. Cerium 2-ethylhexanoate is more soluble in n-hexane, and copper acetate is more soluble in ethanol. This 1:1 volume ratio allows for better dissolution of all components. In other words, the solvent components and their ratios can better dissolve the precursors, and also contribute to achieving higher flame temperatures. Furthermore, n-hexane has a higher calorific value; using 50% n-hexane can increase the subsequent flame temperature. When preparing the precursor solution, n-hexane can be added first, followed by ethanol, to prevent the cerium salt from undergoing a hydrolysis reaction with ethanol to form a precipitate.

[0032] S200: Reference Figure 2 The precursor solution is introduced into the first connecting hole 110 of the flame spray pyrolysis burner (FSP) 100 at a predetermined rate, while a dispersion gas is introduced into the second connecting hole 120 of the flame spray pyrolysis burner 100 and a fuel gas is introduced into the third connecting hole 130 of the flame spray pyrolysis burner 100. The dispersion gas disperses the precursor solution into dispersed droplets and sprays the dispersed droplets into the flame burned by the fuel gas.

[0033] In the embodiments of the present invention, the flame synthesis temperature is relatively high, reaching over 2800°C. This higher flame temperature is more conducive to the dispersion of oxides in the high-temperature mercury adsorbent. That is, in the obtained high-temperature mercury adsorbent, the oxides copper oxide, cerium dioxide, tungsten oxide, and titanium oxide have a higher degree of dispersion and are less prone to clustering, effectively improving the adsorption performance of the high-temperature mercury adsorbent. The aforementioned flame temperature of over 2800°C refers to the flame temperature when the dispersed droplets are injected into the flame.

[0034] In some embodiments, the dispersed droplets can be micron-sized, which is more conducive to the full oxidation of the precursor and improves the dispersibility of oxides in the high-temperature mercury adsorbent.

[0035] In some embodiments, the specific locations of the first connecting hole, the second connecting hole, and the third connecting hole in the flame spray pyrolysis burner are not particularly required, and those skilled in the art can design them flexibly according to actual needs. In some embodiments, the first connecting hole can be located in the middle of the flame spray pyrolysis burner, and a plurality of second connecting holes can be evenly arranged around the first connecting hole. In this way, the dispersing gas can better act on the precursor solution, uniformly disperse it, and obtain uniformly dispersed droplets. More preferably, the outlet of the second connecting hole can be inclined towards the direction of the first connecting hole, such as... Figure 2 As shown, this allows for better action on the precursor solution, ensuring thorough dispersion and improving yield. Multiple third connecting holes can be evenly distributed around the second connecting hole; more preferably, the outlet of the third connecting hole can be inclined towards the first connecting hole. Figure 2 As shown, this allows for better application of the high-temperature flame to the dispersed droplets, thereby improving the oxidation efficiency of the dispersed droplets.

[0036] According to some embodiments of the present invention, the predetermined rate is 700-900 mL / h, such as 700 mL / h, 800 mL / h, 900 mL / h, etc. The above-mentioned predetermined rate can ensure that the precursor solution is injected into the flame spray pyrolysis burner at an optimal rate, ensuring the formation of stable dispersed droplets, and also ensure that the formed dispersed droplets receive sufficient flame action.

[0037] According to some embodiments of the present invention, the pressure of the introduced dispersion gas is above 0.4 MPa, and the flow rate is 25–35 L / min (e.g., 25 L / min, 27 L / min, 29 L / min, 31 L / min, 33 L / min, 35 L / min, etc.). These conditions provide a stable dispersion gas acting on the precursor solution, ensuring the stable and orderly formation of dispersed droplets, thereby guaranteeing the stable and orderly progress of the overall reaction.

[0038] In some embodiments of the present invention, the fuel gas includes acetylene and air. This fuel gas not only burns to produce a high-temperature flame but also has low cost. During combustion, a premixed acetylene-air flame is used as an auxiliary flame to ignite and stabilize the main flame. The flame temperature of this main flame is the flame temperature described above in the present invention.

[0039] S300: Dispersed droplets form precursor vapor in a flame, the precursor vapor forms nucleating particles, and the nucleating particles condense upon cooling to obtain a high-temperature resistant mercury adsorbent. (Refer to...) Figure 2Dispersed droplets form precursor vapor in the flame, yielding an oxide precursor, which then forms nucleating particles. These nucleating particles are rapidly cooled in the rear flame zone, and can then be collected to obtain a high-temperature resistant mercury adsorbent. In some embodiments, the collection method may employ a stagnation plate circulated with cooling water. After rapid cooling in the rear flame zone, the nucleating particles deposit on the stagnation plate, where they cool and condense, thus obtaining the high-temperature resistant mercury adsorbent. The obtained high-temperature resistant mercury adsorbent is a grayish-white, loose granular substance.

[0040] In some embodiments of the present invention, the particle size of the nucleating particles can be 8 to 20 nm. Nucleating particles of this size have a larger specific surface area, which is more conducive to improving the adsorption performance of the high-temperature mercury adsorbent.

[0041] According to an embodiment of the present invention, the high-temperature resistant mercury adsorbent obtained by the above-described flame synthesis method is CuO-CeO2-TiO2-WO. x A mixed oxide mixture, wherein titanium dioxide (TiO2) is used as the support, and copper oxide (CuO), cerium dioxide (CeO2), and tungsten oxide (WO3) are used. x () is the active substance, which is loaded on the surface of the carrier.

[0042] According to embodiments of the present invention, a mercury adsorbent is synthesized in a high-temperature flame using the aforementioned flame synthesis method. This results in a high-temperature resistant mercury adsorbent with excellent high-temperature resistance and superior mercury adsorption performance. The high-temperature resistant mercury adsorbent prepared by this method can maintain its high adsorption performance even at temperatures up to 800°C, making it widely applicable in various high-temperature industrial fields. Furthermore, the flame synthesis temperature of the present invention is relatively high, exceeding 2800°C. This higher flame temperature is more conducive to the dispersion of oxides in the high-temperature resistant mercury adsorbent. That is, in the obtained high-temperature resistant mercury adsorbent, the oxides copper oxide, cerium dioxide, tungsten oxide, and titanium oxide have high dispersion and are less prone to clustering, effectively improving the adsorption performance of the high-temperature resistant mercury adsorbent.

[0043] In another aspect, the present invention provides a high-temperature resistant mercury adsorbent. According to an embodiment of the present invention, the high-temperature resistant mercury adsorbent is prepared by the aforementioned method. Therefore, the high-temperature resistant adsorbent possesses excellent high-temperature resistance and superior mercury adsorption performance, maintaining its high adsorption performance even at temperatures up to 800°C.

[0044] According to embodiments of the present invention, the high-temperature resistant mercury adsorbent comprises a carrier and an active substance. The carrier is titanium dioxide, and the active substance comprises copper oxide, cerium dioxide, and tungsten oxide, with the active substance loaded on the surface of the carrier. In the high-temperature resistant mercury adsorbent of the present invention, the active substance is highly uniformly dispersed, greatly improving the adsorption effect of the high-temperature resistant mercury adsorbent.

[0045] According to an embodiment of the present invention, in the high-temperature mercury adsorbent, tungsten oxide accounts for 7-11 wt% of the total mass of the high-temperature mercury adsorbent. This content of tungsten oxide allows the surface of the high-temperature mercury adsorbent to have a suitable acidity, thereby promoting adsorption. If the tungsten oxide mass fraction in the high-temperature mercury adsorbent is too high, it can easily cover copper and cerium elements, thus reducing the adsorption capacity of the high-temperature mercury adsorbent. Conversely, if the tungsten oxide mass fraction in the high-temperature mercury adsorbent is too low, it can also easily affect the adsorption capacity of the high-temperature mercury adsorbent.

[0046] According to some embodiments of the present invention, the specific surface area of ​​the high-temperature resistant mercury adsorbent is 65–85 m². 2 / g, for example, 65m 2 / g、68m 2 / g、70m 2 / g、72m 2 / g、75m 2 / g、78m 2 / g、80m 2 / g、84m 2 / g、85m 2 / g, thus, this high-temperature resistant mercury adsorbent has a high specific surface area, which helps to further improve the adsorption efficiency of the high-temperature resistant mercury adsorbent.

[0047] According to some embodiments of the present invention, the pore volume of the high-temperature resistant mercury adsorbent is 0.5–0.7 cm³. 3 / g, for example, 0.5cm 3 / g, 0.55cm 3 / g, 0.6cm 3 / g, 0.65cm 3 / g, 0.7cm 3 / g etc. Thus, the aforementioned pore capacity can further improve the adsorption efficiency of the high-temperature resistant mercury adsorbent.

[0048] Example

[0049] Example 1

[0050] A precursor solution was prepared, wherein the precursor included tetrabutyl titanate, cerium 2-ethylhexanoate (49% cerium 2-ethylhexanoate solution), copper acetate, and tungsten hexacarbonyl. The solvent was ethanol and n-hexane, with a volume ratio of ethanol to n-hexane of 1:1, and a molar ratio of titanium, cerium, and copper of 8:1:1. (Refer to...) Figure 2The precursor solution is introduced into the first connecting hole 110 of the flame spray pyrolysis burner 100 at a predetermined rate. At the same time, a dispersion gas is introduced into the second connecting hole 120 of the flame spray pyrolysis burner 100, and a fuel gas is introduced into the third connecting hole 130 of the flame spray pyrolysis burner 100. The dispersion gas disperses the precursor solution into dispersed droplets, and the dispersed droplets are sprayed into the flame burned by the fuel gas. The flame temperature is above 2800℃. During combustion, a small flame premixed with acetylene and air is used as an auxiliary flame to ignite and stabilize the main flame. The dispersed droplets form precursor vapor in the flame to obtain oxide precursor, which then becomes nucleating particles. The nucleating particles are rapidly cooled in the back flame zone and deposited on a stagnation plate with cooling water. On the stagnation plate, the nucleating particles cool and condense, thereby obtaining a high-temperature resistant mercury adsorbent (CuCeWTi-FSP).

[0051] Comparative Example 1

[0052] An adsorbent with the same composition and content (CuCeWTi-IM) was prepared using an impregnation method. The impregnation method used is the same as that employed in traditional adsorbent preparation.

[0053] Comparative Example 2

[0054] Adsorbents (CuCeWTi-McK) with the same composition and content were prepared using McKenna flame synthesis (i.e., using a McKenna burner). In McKenna flame synthesis, the precursor solution preparation method was the same as that in FSP flame synthesis in Example 1. Compared with FSP flame, this method uses an ultrasonic atomizer to atomize the precursor solution and introduce it into a McKenna premixed flame under the action of a carrier gas (N2). The flame temperature was 1600°C, and the solution was collected above the flame using the same method as FSP.

[0055] Analysis of the three adsorbents obtained in Example 1, Comparative Example 1, and Comparative Example 2 revealed that the FSP flame temperature was approximately 2800℃, while the McKenna flame temperature was 1600℃. Compared to CuCeWTi-McK, CuCeWTi-FSP exhibited better surface element dispersion, with highly dispersed copper and cerium components. In contrast, the CuCeWTi-IM adsorbent prepared by the impregnation method showed poor dispersion of copper and cerium components, which existed in cluster form.

[0056] Adsorption test:

[0057] The adsorbent CuCeWTi-FSP from Example 1 was exposed to 80 μg / m³. 3 At a mercury vapor concentration of 250 μg / m³, after one week of adsorption, it was found that the adsorption of the adsorbent CuCeWTi-FSP had not yet reached saturation. Subsequently, the mercury vapor concentration was increased to 250 μg / m³. 3The adsorption continued for one month. The adsorption experiment was repeated three times, and the experimental results showed good repeatability and consistent test results.

[0058] The adsorption performance of the three adsorbents obtained in Example 1, Comparative Example 1, and Comparative Example 2 was tested. The curves showing the change in adsorption capacity and efficiency over time can be found in the following figures. Figure 3 Experimental results show that the adsorbent CuCeWTi-IM prepared by impregnation method is saturated within 2 days, and the adsorbent CuCeWTi-McK prepared by McKenna burner is also saturated within about 15 days. The adsorption amount is much lower than that of the adsorbent CuCeWTi-FSP prepared by flame spray pyrolysis burner FSP used in this invention.

[0059] Test on the effect of oxygen on adsorption performance:

[0060] Adsorption tests were conducted under anaerobic conditions. For example... Figure 4 As shown, the adsorption efficiency of CuCeWTi-FSP initially exceeded 90%, then gradually decreased over time, reaching saturation after 450 minutes, with a MAC value (maximum adsorption capacity) of less than 700 μg / g. When oxygen was added again after 1000 minutes, the adsorption efficiency increased to 25% and remained relatively stable thereafter. This indicates that oxygen plays a crucial role in the mercury adsorption process of CuCeWTi-FSP. Experiments revealed that the active sites for mercury adsorption may be destroyed during anaerobic adsorption, with Hg atoms occupying the active sites for adsorbing O2 molecules, causing the adsorbent to lose its ability to utilize molecular O2. Even with the re-addition of oxygen, the adsorption capacity could not be restored. In other words, after mercury adsorption reached saturation under anaerobic conditions, the adsorbent lost its adsorption capacity upon the re-addition of oxygen, indicating that all adsorption sites were occupied. Tests revealed that the amount of mercury adsorbed under aerobic conditions was more than 200 times greater than under anaerobic conditions, suggesting that each site adsorbed more than one mercury atom under aerobic conditions.

[0061] Test on the effect of temperature on adsorption performance:

[0062] The adsorption efficiency of the adsorbent CuCeWTi-FSP for mercury was tested in the temperature range of 150℃ to 900℃. The results showed that the adsorbent CuCeWTi-FSP maintained a mercury adsorption efficiency of over 99% in the temperature range of 200~800℃.

[0063] Pyrolysis adsorption experiment test:

[0064] The pyrolytic adsorption behavior of mercury on the adsorbent CuCeWTi-FSP can be tested by temperature-programmed pyrolysis (TPD) experiments. Figure 5The results of the TPD experiments are presented. After 18 hours of adsorption, the adsorbent was heated from 450°C to 900°C under aerobic and anaerobic conditions using a temperature program. Below 800°C, only a small amount of mercury was released, less than 15 μg / m³. 3 This indicates that mercury adsorbed on the adsorbent is not easily desorbed below 800℃, and requires a temperature above 900℃ for complete desorption. This also proves that the adsorbent CuCeWTi-FSP of this invention can adsorb mercury in the temperature range of 20℃-800℃.

[0065] Physicochemical property characterization:

[0066] The specific surface area, pore structure, microstructure, surface active components, and crystal morphology of the adsorbent CuCeWTi-FSP obtained in Example 1 were tested as follows:

[0067] Specific surface area testing showed that the adsorbent CuCeWTi-FSP has a high specific surface area of ​​73 m². 2 / g.

[0068] Pore ​​structure analysis showed that the adsorbent has an appropriate pore capacity of 0.61 cm⁻¹. 3 / g, which is beneficial for the adsorption of mercury molecules.

[0069] Figure 6 For adsorbent TEM (transmission electron microscopy), Figure 6 (a and c) and HRTEM (high-resolution transmission electron microscopy) Figure 6 Images b and d) show that CuCeWTi-FSP exhibits a uniform particle morphology and good connectivity between particles.

[0070] Figure 7 The image shown is a surface scan image of the adsorbent CuCeWTi-FSP. Through the study of surface active components and crystal morphology, it can be found that the components on the surface of the adsorbent CuCeWTi-FSP are highly dispersed and doped, and there are active sites rich in Cu, Ce, W and Ti. These active sites play a key role in the adsorption of mercury molecules.

[0071] Figure 8 The changes in surface element content of flame-synthesized adsorbent CuCeWTi-FSP and impregnation-method adsorbent CuCeWTi-IM before and after mercury adsorption were studied (IM-fresh and FSP-fresh represent the surface element content of adsorbents CuCeWTi-IM and CuCeWTi-FSP before mercury adsorption, respectively; IM-used and FSP-used represent the surface element content of adsorbents CuCeWTi-IM and CuCeWTi-FSP after mercury adsorption, respectively). The results show that after mercury adsorption, CuCeWTi-FSP obtained by flame synthesis... 2+and Ce 4+ The content did not decrease significantly, while the CuCeWTi-IM impregnation adsorbent adsorbed mercury after adsorption of Cu 2+ The significant decrease in content indicates that the adsorption of mercury by the CuCeWTi-IM impregnation adsorbent consumes surface Cu. 2+ The composition, while the flame-synthesized adsorbent CuCeWTi-FSP does not consume surface-active components, directly using O2 from the air as an oxidant. On the surface of the adsorbent CuCeWTi-FSP, WO x It improves surface acidity and promotes adsorption. Cu and Ce elements do not provide oxidants, but act as catalysts. Through the transfer of electrons and O, they promote the adsorption and utilization of O2 in the air by the flame-synthesized adsorbent CuCeWTi-FSP.

[0072] The terms "first" and "second" used in this document are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature marked "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0073] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a high-temperature resistant mercury adsorbent, characterized in that, The method is accomplished by flame synthesis and includes the following steps: A precursor solution is prepared, the precursor solution comprising a precursor and a solvent, the precursor comprising tetrabutyl titanate, cerium 2-ethylhexanoate, copper acetate and tungsten hexacarbonyl; The precursor solution is introduced into the first connecting hole of the flame spray pyrolysis burner at a predetermined rate, while a dispersing gas is introduced into the second connecting hole of the flame spray pyrolysis burner and a fuel gas is introduced into the third connecting hole of the flame spray pyrolysis burner. The dispersing gas disperses the precursor solution into dispersed droplets and sprays the dispersed droplets into the flame burned by the fuel gas. The dispersed droplets form precursor vapor in the flame, the precursor vapor forms nucleating particles, and the nucleating particles condense upon cooling to obtain the high-temperature resistant mercury adsorbent. The molar ratio of tetrabutyl titanate, cerium 2-ethylhexanoate, copper acetate and tungsten hexacarbonyl is (7~11):(0.5~1.5):(0.5~1.15):(1.5~3). The flame temperature is above 2800℃.

2. The method according to claim 1, characterized in that, The solvent includes ethanol and n-hexane, wherein the volume ratio of ethanol to n-hexane is 1:(0.5~1.5).

3. The method according to any one of claims 1 to 2, characterized in that, The predetermined rate is 700~900 mL / h.

4. The method according to any one of claims 1 to 2, characterized in that, The pressure of the dispersed gas introduced is above 0.4 MPa, and the flow rate is 25~35 L / min.

5. A high-temperature resistant mercury adsorbent, characterized in that, It is prepared by the method according to any one of claims 1 to 4.

6. The high-temperature resistant mercury adsorbent according to claim 5, characterized in that, The high-temperature resistant mercury adsorbent comprises a carrier and an active substance, wherein the carrier is titanium dioxide and the active substance comprises copper oxide, cerium dioxide and tungsten oxide.

7. The high-temperature resistant mercury adsorbent according to claim 6, characterized in that, The tungsten oxide accounts for 7-11 wt% of the total mass of the high-temperature mercury adsorbent.

8. The high-temperature resistant mercury adsorbent according to any one of claims 5 to 7, characterized in that, The high-temperature resistant mercury adsorbent also meets at least one of the following conditions: The specific surface area of ​​the high-temperature resistant mercury adsorbent is 65~85m². 2 / g; The high-temperature resistant mercury adsorbent has a pore size of 0.5~0.7 cm³. 3 / g.

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