A sulfur-resistant mercury removal material, and a preparation method and application thereof

Abstract

The application discloses an anti-sulfur mercury-removing material and a preparation method and application thereof, and comprises the following steps: S1, dissolving a proper amount of a copper source in deionized water; then dissolving a proper amount of 1, 3, 5-benzene tricarboxylic acid in a mixed solution of N, N-dimethylformamide, anhydrous ethanol and deionized water; after mixing and stirring the two solutions, the mixed solution is transferred into an autoclave for heating reaction, and an intermediate is obtained after drying; S2, adding a sulfur source into the obtained intermediate for solid-phase grinding to obtain a CuS-BTC material; the CuS-BTC-10 composite adsorbent prepared by the application has the advantages of good mercury adsorption performance, high-temperature resistance and anti-sulfur performance, and can be widely applied to the purification of mercury-containing flue gas in the fields of smelting, coal burning, steel, waste incineration and the like.

Description

Technical Field

[0001] This invention relates to the preparation field of sulfur-resistant mercury removal materials in the field of energy conservation and environmental protection, and particularly to a sulfur-resistant mercury removal material, its preparation method, and its application. Background Technology

[0002] Mercury (Hg) pollution poses a serious threat to humans and the environment due to its high toxicity, persistence, high volatility, and bioaccumulation in the environment. Non-ferrous metal smelting is one of the most significant sources of mercury emissions, with mercury in smelting flue gas primarily in the form of elemental mercury (Hg). 0 ), oxidized mercury (Hg) 2+ ) and particulate bound mercury (Hg p It exists in three forms. Hg 2+ and Hg p Hg can be effectively removed using wet desulfurization equipment and electrostatic precipitators, but... 0 It is almost insoluble in water, making it difficult to collect and remove using flue gas removal equipment. Furthermore, sulfur (S) associated with non-ferrous metals is converted to SO2 during combustion, resulting in flue gas rich in SO2. Meanwhile, Hg... 0 It is difficult to oxidize in a reducing gas like SO2, and high concentrations of SO2 easily lead to catalyst deactivation, causing Hg to... 0 Removal is even more difficult.

[0003] In existing technologies, gaseous Hg in flue gas... 0 Mercury can be adsorbed by activated carbon (AC), but its adsorption capacity for mercury is low and its high-temperature adsorption activity is poor, which cannot meet the needs of non-ferrous metal smelting. Transition metal oxides, such as Mn, Cu, and Fe oxides, are low in cost, have high oxidation performance, and exhibit superior mercury adsorption performance. However, SO2 in the flue gas components of non-ferrous metal smelting easily sulfates the active sites of transition metal oxides, thereby reducing the adsorption capacity for mercury. Metal-modified sulfides, such as Cu and Zn, not only have high mercury adsorption capacity but also exhibit good sulfur resistance. Test results show that CuS exhibits high mercury adsorption capacity under low-temperature, high-SO2 atmospheres. Divalent copper ions are 3d... 9 The valence electron configuration of CuS readily yields a stable, fully filled state with a single electron, which is conducive to defect formation. The undercoordinated characteristics of CuS favor Hg formation. 0 The oxidation and fixation of Hg were also observed. Furthermore, CuS was found to be superior to ZnS and FeS, and CuS microspheres exhibited better oxidation and fixation of Hg within the temperature range of 25-100℃. 0 The removal rate remains almost 100%. Cu in CuS can directly react with mercury to form a mercury alloy, which is also superior to other reactive metals. However, the inherently dense structure of CuS is not conducive to the removal of Hg. 0 Mass transfer, active sulfur sites cannot be fully utilized, for Hg 0The adsorption capacity still needs improvement. A good support can expose more active sites on the surface of sulfur-based materials. In the existing technology, some studies have found that Cu-BTC has good mercury removal performance, but it is also susceptible to SO2, which leads to a significant decrease in performance.

[0004] Due to the aforementioned problems, developing a material with good sulfur resistance and high mercury removal rate is crucial for the effective removal of Hg from non-ferrous metal smelting flue gas. 0 It is of great significance. Summary of the Invention

[0005] Therefore, there is a need for a mercury removal material that exhibits good sulfur resistance at high SO2 concentrations, good mercury adsorption capacity, and strong high-temperature adaptability.

[0006] To achieve the above objectives, the inventors provide a method for preparing a sulfur-resistant mercury-removing material, comprising the following steps:

[0007] S1, dissolve an appropriate amount of copper source in deionized water; then dissolve an appropriate amount of 1,3,5-benzenetricarboxylic acid in a mixed solution of N,N-dimethylformamide, anhydrous ethanol and deionized water; after mixing and stirring the two solutions, transfer the mixed solution to an autoclave for heating and reaction, and dry to obtain an intermediate;

[0008] S2, a sulfur source is added to the obtained intermediate and solid-phase grinding is performed to obtain CuS-BTC material.

[0009] In a preferred embodiment of the present invention, in steps S1-S2, the copper source is Cu(NO3)2·3H2O, the sulfur source is sublimed sulfur, the molar ratio of copper nitrate to 1,3,5-benzenetricarboxylic acid is 1.7:1, and the ratio of N,N-dimethylformamide, anhydrous ethanol and water is 1:1:1.

[0010] In a preferred embodiment of the present invention, in step S1, the mixed solution is transferred to an autoclave, the temperature of which is set to 90-110°C and the heating time is set to 10-72 hours.

[0011] In a preferred embodiment of the present invention, in step S1, the intermediate obtained after heating and reacting in a high-pressure reactor is washed several times with N,N-dimethylformamide and anhydrous ethanol, and then dried under vacuum to obtain the dried intermediate.

[0012] As a preferred embodiment of the present invention, the temperature is set to 80-110°C during vacuum drying.

[0013] To achieve the above objectives, the inventors also provide a sulfur-resistant mercury removal material, including the CuS-BTC material prepared by the preparation method described in any one of claims 1-5.

[0014] In a preferred embodiment of the present invention, the molar ratio of Cu:S is 1:10.

[0015] To achieve the above objectives, the inventors also provide an application of a sulfur-resistant mercury removal material, comprising a CuS-BTC-10 material prepared by the method described in any one of claims 1-5, wherein the CuS-BTC-10 material is used to remove Hg from flue gas in non-ferrous metal smelting. 0 The removal of.

[0016] As a preferred embodiment of the present invention, it is applicable to Hg in non-ferrous metal smelting flue gas at temperatures between 100℃ and 150℃. 0 The removal of.

[0017] The beneficial effects achieved by the above technical solution, which differ from existing technologies, are as follows:

[0018] CuS-BTC-10 composite materials were prepared by hydrothermal and solid-state grinding methods. The CuS-BTC-10 synthesized from S-modified Cu-BTC exhibited good trapping and SO2 resistance properties. The high surface area and porous structure of MOFs are beneficial to Cu… 2+ Dispersion of Cu on the surface 2+ It appears as an electron acceptor to oxidize Hg. 0 And oxidized Hg 2+ Further with S 2- This binds to form HgS on the adsorbent surface. S2 2- and S x 2- With Hg adsorbed on the material surface 0 The reaction produces HgS. The removal performance of porous materials for elemental mercury was systematically investigated under different simulated flue gas atmospheres. The results showed that the synthesized CuS-BTC-10 effectively removed HgS. 0 It has high removal efficiency, with an average removal rate of over 90%. Attached Figure Description

[0019] Figure 1 The different proportions of CuS-BTC material and the Hg of CuS described in the specific embodiments 0 Removal efficiency graph;

[0020] Figure 2 The mercury adsorption performance curves of CuS-BTC-10 under different temperature conditions are shown in the specific embodiments.

[0021] Figure 3 The mercury adsorption performance curves of CuS-BTC-10 under different SO2 concentrations are shown in the specific embodiments.

[0022] Figure 4XRD patterns of CuS, Cu-BTC, CuS-BTC-10, CuS-BTC-5, and CuS-BTC-1 materials described in the specific embodiments;

[0023] Figure 5 SEM images of CuS-BTC-1, CuS-BTC-5, and CuS-BTC-10 materials described in the specific embodiments;

[0024] Figure 6 XPS images of CuS-BTC-10 material before and after mercury adsorption in the specific embodiment (a. Cu 2p, b. S 2p, c. Hg 4f). Detailed Implementation

[0025] To explain in detail the technical content, structural features, objectives, and effects of the technical solution, the following description is provided in conjunction with specific embodiments and accompanying drawings.

[0026] Example 1: Preparation of CuS-BTC adsorbent.

[0027] like Figures 1 to 6 As shown, this embodiment provides a method for preparing a sulfur-resistant mercury removal material, including the following steps:

[0028] S1. First, dissolve an appropriate amount of Cu(NO3)2·3H2O in deionized water to obtain solution A. Then, dissolve an appropriate amount (molar ratio with copper nitrate 1:1.7) of 1,3,5-benzenetricarboxylic acid (H3BTC) in a mixed solution of N,N-dimethylformamide (DMF), anhydrous ethanol, and L of deionized water. Stir both solutions thoroughly for 30 min. The volume ratio of water, N,N-dimethylformamide, and anhydrous ethanol required in the preparation is 1:1:1. Transfer the mixed solution to an autoclave, set the autoclave temperature to 90-110℃, and the heating time to 10-72 hours. Wash the intermediate obtained after the autoclave reaction and the recovered blue crystals several times with N,N-dimethylformamide and anhydrous ethanol, and dry under vacuum at 110℃ overnight to obtain the dried intermediate. The intermediate solid was transferred to a mortar, and sublimed sulfur was added in appropriate proportions for solid-phase grinding to obtain CuS-BTC materials, wherein the molar ratio of Cu:S was 1:1, 1:5, 1:10, and 1:20. Four different CuS-BTC mercury adsorbent materials were obtained.

[0029] An appropriate amount of Cu(NO3)2·3H2O was dissolved in a dimethyl sulfoxide solution, and the solution was magnetically stirred until completely mixed. An equimolar amount of sulfur powder was added to the above-prepared solution and sonicated until completely dispersed. The resulting solution was then placed in a high-pressure reactor lined with polytetrafluoroethylene and reacted in an oven at 120°C for 12 hours. After the reaction was complete, the product was washed several times by centrifugation with a mixture of ethanol and distilled water, and dried overnight in a drying oven to obtain CuS material.

[0030] The materials obtained above were subjected to performance tests, and the results are as follows:

[0031] like Figure 1 As shown, tests at different scales were conducted to evaluate the mercury removal performance of the adsorbent using a catalytic reaction system comprising a fixed-bed quartz reactor, a gas simulation pipeline, a mercury permeation unit, a mercury analyzer, and a tail gas control system. Hg was generated by purging the mercury permeation tube with pure nitrogen. 0 SO2 is supplied by an external generator, with the total gas flow rate controlled at 300 ml / min. -1 In the fixed-bed reaction unit, the reaction temperature was set within the range of 50-200℃ using a temperature controller. 30 mg of material was placed in a quartz tube with an inner diameter of 7 mm. Mercury signal data were recorded online using a cold atomic absorption spectrometer (CVASS) calibrated with a Lumex RA 915+.

[0032] The effects of CuS and CuS-BTC materials with different proportions on Hg were tested at 100℃. 0 Removal efficiency. Experimental results show that CuS-BTC has better mercury removal performance than CuS material. Comparative evaluation of materials with different ratios of 1:1, 1:5, 1:10, and 1:20 revealed that the CuS-BTC-10 composite material with a ratio of 1:10 has the best mercury removal efficiency. 0 The highest removal rate was observed. After 120 minutes of continuous reaction, the mercury removal rate showed a slow decreasing trend, but still remained above 90%. However, the 1:1 CuS-BTC-1 material showed a significant decrease in mercury removal rate after 25 minutes of reaction. The 1:5 and 1:20 CuS-BTC-5 materials also showed a decreasing trend in mercury removal rate, reaching only 70% and 80% respectively after 120 minutes of reaction.

[0033] like Figure 2As shown, the mercury removal performance of CuS-BTC-10 was tested under different temperature conditions. The results showed that the mercury adsorption performance increased with increasing temperature, and the best effect was observed at 100℃. The effect decreased at 150℃, and further at 200℃, the mercury adsorption performance declined to near the level at 50℃. This indicates that this material still exhibits good mercury adsorption performance under high temperature conditions (100-150℃).

[0034] Example 2:

[0035] like Figure 3 As shown, the CuS-BTC-10 adsorbent sample described in Example 1 was used to test the effect of different concentrations of SO2 on Hg under simulated flue gas conditions. 0 The effect of SO2 on removal efficiency. Experiments showed that with N2 as the carrier gas, an O2 concentration of 5%, and an SO2 concentration of 500 ppm, the mercury removal rate remained around 93%. At SO2 concentrations of 1000 ppm and 1500 ppm, the removal rate showed a slight decreasing trend, but remained around 90%. This indicates that SO2 significantly affects the removal efficiency of Hg. 0 The adsorption efficiency is somewhat affected, but it is better than the sulfur resistance of most adsorbents.

[0036] Example 3: The powder sample described in Example 1 was subjected to BET characterization. The results showed that the specific surface area of ​​the prepared CuS-BTC materials with different doping ratios increased with the increase of the S doping ratio, and was higher than that of CuS except for CuS-BTC-1. Table 1 shows the test results of specific surface area and pore volume of CuS-BTC-1, CuS-BTC-5, CuS-BTC-10, and CuS:

[0037] Table 1. Specific surface area, pore volume, and pore size of the adsorbent

[0038]

[0039] like Figure 4 As shown, X-ray diffraction (XRD) scans of CuS, Cu-BTC, CuS-BTC-10, CuS-BTC-5, and CuS-BTC-1 revealed CuS diffraction peaks in CuS-BTC-10, CuS-BTC-5, and CuS-BTC-1, indicating that CuS was produced in all three ratios. The peak intensity of CuS decreased with increasing S ratio, suggesting that increasing S introduction leads to more defect sites in Cu-BTC-S, thereby promoting mercury adsorption.

[0040] The morphological characteristics of CuS-BTC-1, CuS-BTC-5, and CuS-BTC-10 were analyzed using field emission scanning electron microscopy. Figure 5It can be seen that as the proportion of S increases, the range of layered CuS formation also increases. At a Cu-S ratio of 1:1, almost no layered CuS is formed. However, when the Cu-S ratio increases to 1:5, the morphology of the particles changes noticeably in some areas, but the range is small, and layered formation appears. When the Cu-S ratio increases to 1:10, even more layered CuS is formed. Therefore, CuS-BTC-10 is the optimal ratio, at which Cu and S are highly combined to form more layered CuS, thereby increasing the adsorption capacity of mercury.

[0041] XPS was used to determine the chemical state and relative proportion of major elements on the surface of CuS-BTC-10 before and after the reaction. Figure 6 The splitting of Cu 2p, S 2p, and Hg 4f peaks before and after the CuS-BTC-10 reaction is shown. Before the reaction, the Cu 2p peaks in the 2p region of the CuS-BTC-10 material... 3 / 2 and Cu 2p 1 / 2 The binding energies were 931.33 eV, 932.06 eV, 951.21 eV, and 951.24 eV, respectively. Figure 6 a) where the peak position of the lower binding energy in each orbital is Cu + Adsorption of Hg 0 Subsequently, the peak position shifted to the left, and the binding energy increased, indicating the presence of electron transfer; Table 2 shows the relative changes in the valence states of Cu in the CuS-BTC-10 adsorbent before and after the reaction. This indicates that Cu... 2+ Participated in Hg 0 The removal of adsorbed Hg 0 Oxidized to Hg 2+ Promote Hg 0 Chemisorption on CuS-BTC-10 adsorbent. Hg 0 After the reaction, the peak position increased to the left, but the sulfur species it represented remained unchanged. Figure 6 b). The relative contents of different valence states of S on the surface of the sample are shown in Table 3. After mercury adsorption, S... x 2- The relative content of S decreased. 2- S2 2- The increase in the relative content of S indicates that x 2- It participated in the adsorption reaction of mercury. And SO4 2- The presence of this may be due to the partial oxidation of element S during synthesis. (Similar to Hg) 0 The binding energies of CuS-BTC after the reaction were 103.8 eV and 99.8 eV, respectively. Figure 6 c) This is attributed to Hg adsorbed on CuS-BTC. 0 Oxidized to Hg 2+The phenomenon observed was observed. Based on the above results, a possible mechanism of CuS-BTC-10 in the mercury removal reaction was speculated. Hg 0 The adsorption on CuS-BTC-10 follows the Mars-Maessen mechanism, where Hg 0 First, it adsorbs onto the CuS-BTC-10 surface to form Hg(ad). The Cu in the adsorbent... 2+ and S2 2- It reacts with Hg(ad) to produce HgS. The reaction process is as follows:

[0042] Hg 0 (g) → Hg 0 (ads) (1);

[0043] Hg 0 (ads) + Cu 2+ → HgS + Cu (2);

[0044] Hg 0 (ads) + S2 2- → HgS + S 2- (3);

[0045] Hg 0 (ads) + S x 2- → HgS(ads) + S x-1 2- (4).

[0046] Table 2. Changes in the relative valence states of Cu in the CuS-BTC-10 adsorbent before and after the reaction.

[0047]

[0048] Table 3. Changes in the relative valence states of sulfur in the CuS-BTC-10 adsorbent before and after the reaction.

[0049]

[0050] Example 3

[0051] The CuS-BTC-10 powder prepared above was ground and sieved to 100-200 mesh particles. Testing was conducted in actual smelting flue gas. 1000 m³ of the raw smelting flue gas (after electrostatic precipitator) was extracted. 3 The flue gas, after being treated by a jet adsorption + bag filter system, returns to the original flue gas at a temperature of 175℃ and a mercury concentration of 10mg / m³. 3 SO2 volume concentration 0.5%, adsorbent injection rate 50 g / m³ 3The mercury concentration in the treated flue gas was reduced to below 2 mg / m3, with a purification efficiency exceeding 80%. This demonstrates the promising industrial application potential of this material.

[0052] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection of the present invention. Therefore, any changes and modifications made to the embodiments described herein based on the innovative concept of the present invention, or equivalent structural or procedural transformations made using the content of the present invention's specification and drawings, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of patent protection of the present invention.

Claims

1. A method for preparing a sulfur-resistant mercury-removing material, characterized in that, Includes the following steps: S1, dissolve an appropriate amount of copper source in deionized water; then dissolve an appropriate amount of 1,3,5-benzenetricarboxylic acid in a mixed solution of N,N-dimethylformamide, anhydrous ethanol and deionized water; after mixing and stirring the two solutions, transfer the mixed solution to an autoclave for heating and reaction, and dry to obtain an intermediate; S2, add a sulfur source to the obtained intermediate and perform solid-phase grinding to obtain CuS-BTC material; In steps S1-S2, the copper source is Cu(NO3)2·3H2O, the sulfur source is sublimed sulfur, the molar ratio of copper nitrate to 1,3,5-benzenetricarboxylic acid is 1.7:1, and the ratio of N,N-dimethylformamide, anhydrous ethanol and water is 1:1:

1.

2. The method for preparing the sulfur-resistant mercury-removing material according to claim 1, characterized in that: In step S1, the mixed solution is transferred to an autoclave, the autoclave temperature is set to 90-110℃, and the heating time is set to 10-72 hours.

3. The method for preparing the sulfur-resistant mercury-removing material according to claim 1, characterized in that: In step S1, the intermediate obtained after heating and reacting in the autoclave is washed several times with N,N-dimethylformamide and anhydrous ethanol, and then dried under vacuum to obtain the dried intermediate.

4. The method for preparing the sulfur-resistant mercury-removing material according to claim 3, characterized in that: Set the temperature to 80-110℃ during vacuum drying.

5. A sulfur-resistant mercury removal material, characterized in that: Including CuS-BTC material prepared by the preparation method described in any one of claims 1-4.

6. The sulfur-resistant mercury-removing material according to claim 5, characterized in that: The molar ratio of Cu to S is 1:

10.

7. The application of a sulfur-resistant mercury removal material, characterized in that: CuS-BTC material produced by the preparation method of any one of claims 1-4 for removal of Hg 0 from non-ferrous smelting flue gas.

8. The application of the sulfur-resistant mercury-removing material according to claim 7, characterized in that: Suitable for Hg in non-ferrous metal smelting flue gas at temperatures of 100℃~150℃ 0 The removal of.

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