Double-defect moisture-resistant sulfur-resistant mercury removal adsorbing material as well as preparation method and application thereof

Abstract

The invention discloses a double-defect moisture-resistant sulfur-resistant mercury removal adsorption material and a preparation method and application thereof, the preparation method of the adsorption material comprises the following steps: adding a sulfur source into a solution dissolved with a copper source, CTAB (cetyltrimethylammonium bromide) and PVP (polyvinylpyrrolidone), heating, washing and drying; the mass ratio of the sulfur source to the copper source to the CTAB to the PVP is (1-1.2): 1: (2-5): (2-5). The adsorbing material is relatively low in crystallinity, can provide more active sites and defect sites for reaction, has double defects, can effectively improve the mercury removal efficiency, and also has excellent low-temperature mercury removal performance, moisture resistance and sulfur resistance.

Description

Technical Field

[0001] The invention relates to a double-defect moisture-resistant and sulfur-resistant mercury removal adsorption material and a preparation method and application thereof, belonging to the technical field of mercury removal. Background Art

[0002] Mercury is a highly toxic and volatile heavy metal pollutant. Due to its persistence, bioaccumulation and long-range migration, it seriously harms the environment and human health, so its pollution problem has attracted widespread attention. Fossil fuel combustion and non-ferrous metal smelting are the main sources of anthropogenic mercury emissions, and non-ferrous metal smelting is one of the main sources of mercury pollution in China, accounting for 20%-40% of anthropogenic mercury pollution.

[0003] There are three main forms of mercury in non-ferrous smelting waste gas: elemental mercury (Hg 0 ), mercuric oxide (Hg 2+ ) and particulate mercury (Hg p ), where oxidized mercury and particulate mercury can be removed by existing flue gas dust removal equipment, such as electrostatic precipitator, wet scrubbing equipment, etc. However, the capture efficiency of zero-valent mercury by the above equipment is poor, resulting in a large amount of mercury being transferred to the polluted acid during the scrubbing and demisting process. The presence of mercury exacerbates the difficulty of treating the polluted acid.

[0004] CuS material is an adsorbent material, but its mercury removal efficiency is limited. Surface defects can serve as active sites to increase the adsorption capacity of gaseous mercury and resist SO 2 The increased defect sites effectively increase the mobility of electrons, enhance the chemical adsorption of mercury, further enable the electrons to be captured and transported to the adsorbed mercury, and ultimately increase the activation degree of mercury. Based on this, CuS with sulfur vacancies is used 1-x The material is used for mercury removal, but its mercury removal efficiency, low-temperature mercury removal performance, and moisture and sulfur resistance need to be improved. Summary of the invention

[0005] The object of the present invention is to provide a double-defect moisture-resistant and sulfur-resistant mercury removal adsorbent material and a preparation method and application thereof. The adsorbent material has low crystallinity and double defects, can effectively improve the mercury removal efficiency, and has excellent low-temperature mercury removal performance as well as moisture and sulfur resistance.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A preparation method of a double-defect moisture-resistant and sulfur-resistant mercury removal adsorption material comprises adding a sulfur source to a solution containing a copper source, CTAB (cetyltrimethylammonium bromide) and PVP (polyvinylpyrrolidone), heating, washing and drying.

[0008] Among them, the mass ratio of sulfur source, copper source, CTAB and PVP is (1-1.2):1:(2-5):(2-5).

[0009] Preferably, the copper source is at least one of copper sulfate, copper chloride and copper nitrate.

[0010] Preferably, the sulfur source is at least one of thiourea, thioacetamide and sodium sulfide nonahydrate.

[0011] Preferably, the heating conditions are: 100-200° C., 2-12 h.

[0012] Preferably, the drying temperature is 60-100°C.

[0013] A double-defect moisture-resistant and sulfur-resistant mercury-removing adsorption material is prepared by any of the above methods.

[0014] Application of the double-defect moisture-resistant and sulfur-resistant mercury removal adsorbent material prepared by any of the above methods in the adsorption and desorption of gaseous mercury.

[0015] Preferably, the adsorption and desorption are carried out at 20-200°C.

[0016] The beneficial effects of the present invention are:

[0017] The double-defect adsorption material has a low degree of crystallinity and can provide more active sites and defect sites for the reaction, thereby further improving the mercury removal efficiency of the catalyst. The double-defect adsorption material has a greatly improved mercury removal efficiency compared to defect-free and single-defect copper sulfide.

[0018] Among them, the role and advantages of PVP in coordinating with CTAB to regulate copper defects are as follows:

[0019] Function: Adsorption and dispersion: The long chain structure of PVP can wrap metal particles through physical adsorption or chemical bonding, inhibit particle agglomeration, and ensure the uniform distribution of copper defects; Regulate the direction of crystal growth: PVP and CTAB synergistically change the surface energy of the crystal, preferentially expose specific crystal faces, thereby affecting the generation site and density of copper defects; Stabilize the reaction environment: PVP, as a non-ionic surfactant, can reduce the interfacial tension of the reaction system and maintain the thermodynamic stability of copper defect generation during the synthesis process.

[0020] Advantages: Enhanced material uniformity: By inhibiting particle aggregation, PVP helps to form a copper defect structure of uniform size and improve the performance of the material; Temperature adaptability: PVP can effectively regulate the crystal morphology at different temperatures and can still maintain the directional growth of copper defects at high temperatures.

[0021] At a temperature of 50-100°C, the mercury removal efficiency of the material is close to 100%, and at a temperature of 150°C, the mercury removal efficiency of the material is as high as 90%. At the same time, the material's anti-humidity and anti-sulfur properties were tested. The material can still maintain a mercury removal efficiency of more than 90% under high sulfur dioxide, water, and gas components. At the same time, the preparation process is simple and has the advantages of magnetic recyclability, environmental friendliness, and economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 (a, b) SEM images of different materials, (c, d) Cu 1-y S 1-x -1 elemental mapping and (e)Cu 1-y S 1-x -1 EDS spectrum;

[0023] Figure 2 A) XRD and b) EPR comparison diagrams of different materials;

[0024] Figure 3 Raman graphs of different materials;

[0025] Figure 4 (ac) Mercury removal performance curves of different materials at different temperatures; (d) Cu 1-y S 1-x -1 Mercury removal performance curve of materials at different temperatures;

[0026] Figure 5 is the different contents of O at 100℃ 2 , SO 2 and H 2 O to Cu 1-y S 1-x -1 Removal of Hg 0 Effect diagram of efficiency;

[0027] Figure 6 (ad) Hg-programmed temperature desorption curves of different materials. DETAILED DESCRIPTION

[0028] Example 1

[0029] 0.1 g Cu(NO 3 ) 2 ·3H 2 O, 300 mg CTAB and 300 mg PVP were dissolved in 15 ml ethylene glycol, stirred for 0.5 h, and then 0.1 g CH 3 CSNH 2Stir for another 0.5 h, put the solution into a 50 ml polytetrafluoroethylene-lined stainless steel autoclave, heat at 150 ° C for 3 h, wash several times with deionized water and ethylene glycol by centrifugation, and dry the resulting precipitate in a 60 ° C drying oven overnight to obtain Cu 1-y S 1-x Material, named Cu 1-y S 1-x -1.

[0030] Comparative Example 1

[0031] 0.1 g Cu(NO 3 ) 2 ·3H 2 O and 0.1 g Na 2 S were dissolved in 60 ml of deionized water and stirred, and then Na 2 S solution was dropped into Cu(NO 3 ) 2 ·3H 2 O solution, and then put it into a 50 ml polytetrafluoroethylene-lined stainless steel high-pressure reactor, heated at 150 ° C for 3 h, and washed several times by centrifugation with deionized water. The obtained precipitate was placed in a 60 ° C drying oven and dried overnight to obtain CuS material.

[0032] Comparative Example 2

[0033] 0.1 g Cu(NO 3 ) 2 ·3H 2 O was dissolved in 15 ml of ethylene glycol, stirred for 0.5 h, and then 0.1 g of CH 3 CSNH 2 Stir for another 0.5 h, put the solution into a 50 ml polytetrafluoroethylene-lined stainless steel autoclave, heat at 150 ° C for 3 h, wash several times with deionized water and ethylene glycol by centrifugation, and dry the resulting precipitate in a 60 ° C drying oven overnight to obtain CuS 1-x Material.

[0034] Comparative Example 3

[0035] 0.1 g Cu(NO 3 ) 2 ·3H 2 O, 300 mg CTAB was dissolved in 15 ml ethylene glycol, stirred for 0.5 h, and then 0.1 g CH 3 CSNH 2 Stir for another 0.5 h, put the solution into a 50 ml polytetrafluoroethylene-lined stainless steel autoclave, heat at 150 ° C for 3 h, wash several times with deionized water and ethylene glycol by centrifugation, and dry the resulting precipitate in a 60 ° C drying oven overnight to obtain Cu 1-y S1-x Material, named Cu 1-y S 1-x -2.

[0036] Figure 1 The a and b regions are CuS and Cu 1-y S 1-x -1 SEM image, it can be seen that CuS has a lamellar structure and good crystallinity. 1-y S 1-x -1 presents a small block structure with defects and large gaps between materials. 1-y S 1-x -1 has poor crystallinity, which is conducive to the exposure of surface active sites and the generation of defect sites. Figure 1 In the c and d areas, the presence of Cu and S elements can be observed and they are evenly distributed. Figure 1 The middle e region reflects the Cu 1-y S 1-x -1 EDS energy spectrum, the Cu and S elements in the material can be clearly seen.

[0037] Figure 2 Area a in the figure is the XRD diagram of different materials, and area b is the EPR diagram. Figure 2 It can be seen from the middle a area that the diffraction peak intensity of CuS is significantly higher than that of CuS 1-x and Cu 1-y S 1-x -1, this is due to CuS 1-x and Cu 1-y S 1-x -1 is due to the abundance of inherent defects. Figure 2 In the b region, when g = 2.002, CuS 1-x and Cu 1-y S 1-x -1 all show obvious electron paramagnetic resonance (EPR) signals, which is closely related to the existence of sulfur defects as typical anion defects. 1-y S 1-x -1 shows obvious electron paramagnetic resonance (EPR) signals, which is closely related to the existence of copper defects as typical cation defects. 1-y S 1-x -1 has both copper defects and sulfur defects.

[0038] Figure 3 is the Raman diagram of different materials. Figure 3 It can be seen that the diffraction peak of CuS material is sharp, high-intensity, and narrow in width, indicating a high degree of crystallinity. 1-x and Cu1-y S 1-x The diffraction peak of -1 is weak and wide, indicating that the material has low crystallinity and a relatively rough surface texture. The rough surface will bring specific defect sites, which can promote Hg 0 adsorption.

[0039] Mercury vapor is generated by purging the mercury permeation tube with pure nitrogen. SO 2 、N 2 and O 2 Both are connected to external generators, N 2 Gas flow rate 220ml·min -1 , O 2 Gas flow rate 71.5ml·min -1 , Hg 0 Gas flow rate 8.5ml·min -1 , control the total gas flow rate to 300ml min -1 . In the fixed bed reaction unit, the reaction temperature was set in the range of 50-150°C using a temperature controller. 30 mg of the prepared adsorbent was placed in a quartz tube with an inner diameter of 4 mm. The mercury signal data was recorded online using a cold atomic absorption spectrometer (CVASS) calibrated with LumexRA915+. The waste gas that was not completely treated by the reactor device was adsorbed with potassium permanganate solution before being discharged.

[0040] Hg 0 The removal efficiency was calculated according to the equation:

[0041]

[0042] in and Hg 0 The concentration before and after the reaction.

[0043] Figure 4 The ac area in the middle is the mercury removal performance curve of different materials at different temperatures, and the d area is the Cu 1-y S 1-x -1 Mercury removal performance curve of material at different temperatures. Figure 4 It can be seen that Cu 1-y S 1-x -1 at 50℃ and 100℃ for Hg 0 The removal rate is close to 100%, compared with CuS, CuS 1-x and Cu 1-y S 1-x -2,Cu 1-y S 1-x -1 material showed better activity. When the temperature was raised to 150℃, Cu 1-y S1-x The mercury removal capacity of -1 began to decrease slightly, indicating that the material can maintain a high activity at medium and low temperatures.

[0044] Figure 5 The results showed that the temperature of O 2 The content of Cu 1-y S 1-x -1 Removal of Hg 0 The effect of efficiency, where the total gas flow rate is 300 ml min -1 , Hg 0 Gas flow rate 8.5ml·min -1 , N 2 As supplemental gas; 5% O 2 For example, the total gas flow rate is 300 ml min -1 , Hg 0 Gas flow rate 8.5ml·min -1 Next, O 2 The gas flow rate is 300*0.05ml·min -1 , the remainder is N 2 .Depend on Figure 5 It can be seen that this material has a 2 The mercury removal efficiency is best.

[0045] Then we studied the effect of 100℃, 5%O 2 Under different SO 2 Cu content 1-y S 1-x -1 Removal of Hg 0 The effect of efficiency, where the total gas flow rate is 300 ml min -1 , Hg 0 Gas flow rate 8.5ml·min -1 , O 2 The gas flow rate is 300*0.05ml·min -1 , N 2 As supplementary gas, SO 2 The contents are 2000, 4000, 7000ppm (SO 2 Content ppm = sulfur dioxide gas flow ml / min divided by the total flow 300 ml / min multiplied by the SO in the sulfur dioxide cylinder 2 Content 10000ppm, the same below). Figure 5 It can be seen that under anhydrous conditions, as SO 2 With the increase of concentration, Cu 1-y S 1-x -1 Removal of Hg 0 The efficiency was only slightly reduced, indicating that Cu 1-yS 1-x -1 material has strong anti-sulfur performance.

[0046] At the same time, the results of the study were also conducted at 100°C and 5% O 2 , 5% H 2 O content, different SO 2 Cu content 1-y S 1-x -1 Removal of Hg 0 The effect of efficiency, where the total gas flow rate is 300 ml min -1 , Hg 0 Gas flow rate 8.5ml·min -1 , O 2 The gas flow rate is 300*0.05ml·min -1 , H 2 The gas flow rate of O is 300*0.05ml·min -1 , N 2 As supplementary gas, SO 2 The contents are 1000, 2000, and 4000 ppm respectively. Figure 5 It can be seen that at 5% H 2 O conditions, with SO 2 With the increase of concentration, Cu 1-y S 1-x -1 Removal of Hg 0 The efficiency was only slightly reduced, indicating that Cu 1-y S 1-x -1The material has strong moisture resistance.

[0047] Mercury vapor is generated by purging the mercury permeation tube with pure nitrogen. 2 and O 2 Both are connected to external generators, N 2 Gas flow rate 220ml·min -1 , O 2 Gas flow rate 71.5ml·min -1 , Hg 0 Gas flow rate 8.5ml·min -1 , control the total gas flow rate to 300ml min -1 . In the fixed bed reaction unit, the reaction temperature was set in the range of 100-700°C using a temperature controller. 30 mg of the prepared adsorbent was placed in a quartz tube with an inner diameter of 4 mm. The mercury signal data was recorded online using a cold atomic absorption spectrometer (CVASS) calibrated with LumexRA915+. The waste gas that was not completely treated by the reactor device was adsorbed with potassium permanganate solution before being discharged.

[0048] CuS, CuS 1-x , Cu1-y S 1-x -1 and Cu 1-y S 1-x -2 First react at 100℃ for 20min, then stop Hg 0 and O 2 By using N 2 Purge to remove residual Hg in the pipeline 0 After purging for 20 min, Hg-TPD was performed at 5 °C min -1 The temperature was raised from 100°C to 700°C at a heating rate of , and the corresponding mercury signal curve was recorded.

[0049] In the temperature range of 200-400℃, a large amount of mercury is released. Figure 6 It can be seen from the a region that CuS has an adsorbent desorption peak at 269.5°C, which corresponds to the characteristic peak of HgS, indicating that the product is mainly HgS and mercury is mainly adsorbed on the surface of the material in the form of HgS. Figure 6 In the middle bd region, it can be seen that CuS 1-x , Cu 1-y S 1-x -1.Cu 1-y S 1-x -2 exhibits a significant adsorption-desorption peak at 300.3℃, 323℃, and 306℃, which is consistent with the characteristic peak of HgS. 1-x , Cu 1-y S 1-x -1 and Cu 1-y S 1-x -2 Hg-TPD curves all show a main peak, indicating that HgS is CuS, CuS 1-x , Cu 1-y S 1-x -1 and Cu 1-y S 1-x -2The main adsorbed species on the surface.

[0050] And Cu 1-y S 1-x The adsorption and desorption peak temperature of -1 is higher than that of CuS and CuS 1-x and Cu 1-y S 1-x -2 adsorption-desorption peak temperature, indicating that Cu 1-y S 1-x -1 and Hg 0 The ability to combine is better than CuS and CuS 1-x and Cu 1-y S 1-x-2, which is attributed to the dual existence of copper defects and sulfur defects on the one hand, and the positive effect of the synergistic effect of PVP and CTAB on copper defects on the other hand, making it have better performance than the product obtained by single CTAB regulation.

[0051] The above is only a preferred implementation of the patent of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the patent of the present invention. These improvements and modifications should also be regarded as the scope of protection of the patent of the present invention.

Claims

1. A method for preparing a double-defect moisture-resistant and sulfur-resistant mercury removal adsorbent material, characterized in that: The sulfur source is added into the solution containing the copper source, CTAB and PVP, and then heated, washed and dried. Among them, the mass ratio of sulfur source, copper source, CTAB and PVP is (1-1.2):1:(2-5):(2-5).

2. The method for preparing the double-defect moisture-resistant and sulfur-resistant mercury-removing adsorbent material according to claim 1, characterized in that: The copper source is at least one of copper sulfate, copper chloride and copper nitrate.

3. The method for preparing the double-defect moisture-resistant and sulfur-resistant mercury-removing adsorbent material according to claim 1, characterized in that: The sulfur source is at least one of thiourea, thioacetamide and sodium sulfide nonahydrate.

4. The method for preparing the double-defect moisture-resistant and sulfur-resistant mercury-removing adsorbent material according to claim 1, characterized in that: The heating conditions are: 100-200°C, 2-12h.

5. The method for preparing the double-defect moisture-resistant and sulfur-resistant mercury-removing adsorbent material according to claim 1, characterized in that: The drying temperature is 60-100°C.

6. A double-defect moisture-resistant and sulfur-resistant mercury removal adsorption material, characterized in that: The method is prepared by any one of claims 1 to 5.

7. Use of the double-defect moisture-resistant and sulfur-resistant mercury removal adsorbent material prepared by the method according to any one of claims 1 to 5 in the adsorption and desorption of gaseous mercury.

8. The use according to claim 7, characterized in that: The adsorption and desorption were carried out at 20-200°C.

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