Method for preparing renewable demercuration adsorbent by using industrial waste acid modified waste mercury catalyst and application of renewable demercuration adsorbent

Abstract

The invention discloses a method for preparing a renewable demercuration adsorbent from an industrial waste acid modified waste mercury catalyst and application of the renewable demercuration adsorbent, and belongs to the related technical field of industrial waste resource utilization and fixed source tail gas mercury pollution control. According to the renewable demercuration adsorbent prepared through the method, the demercuration efficiency can be kept at 99.15% after 22 min in the pure N2 atmosphere, the demercuration efficiency is 96.41% after ten times of circulation, cooperative treatment and resource utilization of the waste mercury catalyst and the waste acid are achieved, and the method is suitable for industrial waste acid treatment. And the method can effectively control the mercury pollution of the tail gas of the fixed source, and is a recyclable, environment-friendly and low-cost renewable demercuration adsorbent preparation technology.

Description

Technical Field

[0001] The present invention belongs to the technical fields related to the resource utilization of industrial waste and the control of mercury pollution in fixed-source tail gas. More specifically, it relates to a method for preparing a renewable mercury-removing adsorbent by modifying waste mercury catalyst with industrial waste acid and its application. Background Art

[0002] Mercury (Hg) in fixed-source waste gas, as a typical persistent pollutant, its environmental risk mainly comes from the special physical and chemical properties of elemental mercury (Hg 0 ). Compared with the oxidized state (Hg 2+ ) and particulate state (Hg p ), Hg 0 has characteristics such as high volatility (saturated vapor pressure 0.25 Pa / 25 °C), high toxicity, strong chemical stability, and poor solubility in water, resulting in low capture efficiency of conventional flue gas purification equipment for it and accelerating the equipment corrosion process. The mercury emitted in fixed-source tail gas also has long-range migration and bioaccumulation, seriously threatening the safety of the ecosystem.

[0003] In the process of preparing vinyl chloride monomer by the calcium carbide method, a mercury catalyst prepared by loading 10%-12% mercury chloride (HgCl 2 ) on activated carbon is usually used as a catalyst. After the mercury catalyst is deactivated, it still contains about 2% HgCl 2 . Existing processes mostly use methods such as distillation and thermal desorption to recover mercury from waste mercury catalysts, but there is no systematic solution for the recycling of the activated carbon carrier in waste mercury catalysts, which not only causes waste of carbon-based resources but also has potential environmental risks.

[0004] Industrial waste acid, as a typical hazardous waste, is produced in large quantities in industrial processes such as the process of removing metal surface oxide layers in the metal production industry, the process of dissolving precious metals in the metal recycling industry, the pickling process in the electroplating industry pretreatment, and the circuit etching process in the printed circuit board industry. When the acidity of the acid solution decreases or the impurities exceed the standard, it loses its use value. Improper disposal of industrial waste acid not only causes the risk of environmental acidification but also leads to an increase in the treatment cost of enterprises. The waste acid generated in the metal processing industrial chain has the characteristics of high heavy metal concentration and high salt content. Its complex components result in a large amount of sludge being generated by traditional neutralization processes, and the effective components in the waste acid lack resource utilization, so a more environmentally friendly and efficient waste acid treatment process flow needs to be provided.

[0005] As an efficient mercury pollution control technology, the activated carbon injection technology (ACI) in flue gas has been widely used in urban solid waste incineration plants. However, activated carbon itself adsorbs Hg 0The method is physical adsorption, and the adsorption effect is poor, so the activated carbon needs to be modified. In order to improve the mercury removal performance of activated carbon adsorbents, on the one hand, the pore structure can be improved by physical modification such as mechanical ball milling, steam activation, freeze-drying pore formation, and acid etching to increase the number of micropores and pore volume, thereby improving the mass transfer effect of gaseous mercury on the surface of activated carbon; on the other hand, specific adsorption sites such as Fe-C, Cu-C, and Cl-C can be constructed by chemical modification to achieve the transformation from physical adsorption to chemical adsorption, greatly improving the capture performance of activated carbon for gaseous mercury. Traditional activated carbon modification methods have high energy consumption, high cost, and chemical modification is prone to causing environmental pollution, so a recyclable, low-cost, and environmentally friendly modification method needs to be developed.

[0006] Activated carbon has a large number of micropores and pore volume, and is often used as a carrier for mercury catalysts to uniformly load HgCl 2 , and it is also an ideal material for preparing mercury removal adsorbents. Therefore, the activated carbon after thermal desorption and mercury recovery from waste mercury catalysts, that is, mercury-free waste mercury catalysts, can be used to prepare mercury removal adsorbents. However, the pore structure of mercury-free waste mercury catalysts will be damaged to a certain extent during the thermal desorption process, and the mercury adsorption method of unmodified activated carbon is physical adsorption with low adsorption efficiency. Waste acid can be used to carry out physical and chemical synergistic modification of activated carbon. The acidic environment has a pore-expanding effect on activated carbon, and H + in the waste acid can dissolve some surface impurities, which can further improve the pore structure of activated carbon. At the same time, metal cations such as Fe 2+ , Fe 3+ , Cu 2+ , and Cu + and halogen anions such as Cl - , Br - , and I - in the waste acid can provide active sites for activated carbon to achieve efficient chemical adsorption of Hg 0 . However, there are few reports on how to combine the characteristics of waste mercury catalysts and waste acid to achieve the collaborative treatment and resource utilization of hazardous wastes. Summary of the Invention

[0007] The present invention provides a method and application for preparing a renewable mercury removal adsorbent by modifying waste mercury catalysts with industrial waste acid. The present invention solves the problem of resource utilization of waste mercury catalysts and waste acid, and realizes the collaborative treatment of hazardous wastes, the low-cost preparation of mercury removal adsorbents, and the efficient control of mercury pollution in the tail gas of fixed sources.

[0008] The present invention provides a method for preparing a renewable mercury removal adsorbent by modifying waste mercury catalyst with industrial waste acid. In the present invention, the waste mercury catalyst generated in the PVC industry is thermally desorbed to recover mercury, and the mercury-free waste mercury catalyst is obtained after the residual solid is cooled. The mercury-free waste mercury catalyst is modified by physical and chemical synergy with industrial waste acid to obtain an industrial waste acid-modified waste mercury catalyst. The etching effect of the acidic environment of the industrial waste acid can effectively improve the surface structure of the mercury-free waste mercury, and the metal cations and anions in the industrial waste acid provide chemical active sites for the mercury-free waste mercury. After the obtained industrial waste acid-modified waste mercury catalyst is used for mercury removal from flue gas, the mercury removal performance can be recycled again by using the same modification steps and raw materials as above. The industrial waste acid-modified waste mercury catalyst renewable mercury removal adsorbent has high mercury removal performance, recycling performance, multi-scenario applicability and recycling performance, and at the same time realizes the co-treatment of hazardous waste and resource utilization, as well as the efficient control of mercury pollution in the tail gas of fixed sources. The specific steps are as follows:

[0009] Step 1: After crushing and grinding the waste mercury catalyst, transfer it to a tubular furnace, and thermally desorb the mercury remaining on the surface of the waste mercury catalyst under the protection of an inert gas. The desorbed gas is condensed to recover liquid mercury metal, and the residual solid is cooled to obtain a mercury-free waste mercury catalyst;

[0010] Step 2: Dilute the waste acid with deionized water to obtain a waste acid dilution solution. Immerse the mercury-free waste mercury catalyst obtained in Step 1 in the waste acid dilution solution, and continuously stir and disperse it magnetically under a constant temperature water bath for acid etching and surface active site modification. Then, perform solid-liquid separation, and dry the separated solid to obtain a renewable mercury removal adsorbent.

[0011] Preferably, the waste mercury catalyst is derived from the process of preparing vinyl chloride monomer by the calcium carbide method in the PVC industry, and the particle size of the waste mercury catalyst after crushing and grinding is 80 mesh.

[0012] Preferably, the waste acid is derived from industries that generate a large amount of waste acid, such as the process of removing metal surface oxide layers in the metal production industry, the process of dissolving precious metals in the metal recycling industry, the pre-treatment pickling process in the electroplating industry, and the circuit etching process in the printed circuit board industry.

[0013] Preferably, the concentration of H + in the waste acid is 1-3 mol / L, the metal cations contain one or any combination of Fe 2+ 、Fe 3+ 、Cu 2+ and Cu + , and the anions contain one or any combination of Cl - 、Br - and I - .

[0014] Preferably, in step 2, when diluting the waste acid with deionized water, the volume ratio of the waste acid to deionized water is (5 - 30):100; the solid-liquid ratio of the mercury-free spent mercury catalyst to the waste acid diluent is 1.0 g:50 mL.

[0015] Preferably, in step 1, the thermal desorption inert gas is N 2 , the gas flow rate is 0.5 L / min, the temperature is 500 °C, and the time is 4 h.

[0016] Preferably, in step 2, the conditions of magnetic stirring and constant temperature water bath are: the time is 2 h, the stirring speed is 200 r / min, and the water bath temperature is 40 °C; the solid-liquid separation method is vacuum filtration separation; the drying method is drying at 60 °C for 2 h.

[0017] The regenerated mercury removal adsorbent prepared by the method of preparing a regenerated mercury removal adsorbent by modifying a spent mercury catalyst with industrial waste acid according to the present invention can be used to remove gaseous mercury in the tail gas of fixed sources. Specifically, the regenerated mercury removal adsorbent is placed in a fixed bed device to capture gaseous mercury in the tail gas of fixed sources. In the fixed bed device, the reaction temperature is set to 40 - 120 °C, and the gas flow rate (including the tail gas of fixed sources and auxiliary gas) is 1.0 L / min. The tail gas of fixed sources includes coal combustion flue gas, synthesis gas, and non-ferrous metal smelting flue gas. After the regenerated mercury removal adsorbent is used, the method of the present invention can be used to regenerate it again.

[0018] Beneficial effects:

[0019] (1) The method for recycling the spent mercury catalyst and waste acid provided by the present invention, on the one hand, uses thermal desorption to recover the mercury and activated carbon remaining on the surface of the spent mercury catalyst, realizing the harmless treatment of hazardous solid waste; on the other hand, uses industrial waste acid to modify the mercury-free spent mercury catalyst to prepare a regenerated mercury removal adsorbent, realizing the resource utilization of the main component activated carbon of waste acid and spent mercury catalyst. Therefore, the present invention is beneficial to promoting circular economy and can reduce the economic cost of mercury removal adsorbents.

[0020] (2) The waste acid modification method provided by the present invention utilizes the etching effect of the acidic environment on the thermally desorbed spent mercury catalyst to increase the number of micropores and pore volume of the mercury-free spent mercury catalyst, and can improve the surface structure of the mercury removal adsorbent. At the same time, using anions such as Cl - , Br - and I - and metal cations such as Fe 3+ , Cu 2+ and Cr 3+ etc., load active sites on the surface of the mercury removal adsorbent, and improve the ability of the mercury removal adsorbent to catalytically oxidize Hg 0 .

[0021] (3) After the renewable mercury removal adsorbent provided by the present invention is applied, it can be regenerated by the preparation method of the renewable mercury removal adsorbent of the present invention. Due to the abundant cations and anions in the waste acid liquid phase system, new mercury oxidation sites are provided, which can restore the activity of the adsorbent and maintain good mercury removal performance, thus realizing the effective regeneration of the mercury removal adsorbent, saving equipment costs, reducing operation complexity, improving process utilization rate, providing a new sustainable green regeneration method, and conforming to the concept of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the technical flow chart of the method of the present invention.

[0023] Figure 2 are the XRD diagrams of the waste mercury catalyst, mercury-free waste mercury catalyst, commercial activated carbon, and waste acid-modified waste mercury catalysts with different dilution ratios in Example 1.

[0024] Figure 3 are the SEM diagrams of the waste mercury catalyst, mercury-free waste mercury catalyst, waste mercury catalyst modified with 5% waste acid diluent, and waste mercury catalyst modified with 30% waste acid diluent in Example 1.

[0025] Figure 4 are the BET diagrams of the waste mercury catalyst, mercury-free waste mercury catalyst, commercial activated carbon, and waste acid-modified waste mercury catalysts with different dilution ratios in Example 1.

[0026] Figure 5 are the mercury removal efficiency curves of the mercury removal adsorbents in Examples 3 to 5 respectively.

[0027] Figure 6 are the mercury removal efficiency diagrams of the renewable mercury removal adsorbents with different regeneration times in Example 6 respectively. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The present invention provides a method and application for preparing a renewable mercury removal adsorbent by modifying waste mercury catalyst with industrial waste acid, and its flow chart is as shown in Figure 1. The technical solution of the present invention will be described in detail below through examples, but the protection scope of the present invention is not limited to the described examples.

[0029] Example 1

[0030] This example provides a method for preparing a renewable mercury removal adsorbent by modifying waste mercury catalyst with industrial waste acid. The waste acid solution used in this example is from the process of removing the metal surface oxide layer in the metal production industry. After testing, the main components of the waste acid in this example are: 2.00 mol / L of H + , 0.72 mol / L of Fe 2+ , 0.18 mol / L of Fe 3+ and 3.97 mol / L of Cl -。In this embodiment, the waste mercury catalyst used is sourced from the process of preparing vinyl chloride monomer by the calcium carbide method in the PVC industry. Its main component is activated carbon, which is loaded with 1 - 2% of HgCl 2 。

[0031] This embodiment provides a method for preparing a renewable mercury removal adsorbent by modifying waste mercury catalyst with industrial waste acid, including the following steps: Take 6.0 g of waste mercury catalyst, crush and grind it, sieve out 80 - mesh particles with a standard sieve, transfer them to a tubular furnace, and under an N 2 atmosphere with a gas flow rate of 0.5 L, conduct thermal desorption at 500 °C for 4 h. Condense and recover the mercury remaining on the surface of the desorbed gas, and cool the remaining solid to obtain mercury - free waste mercury catalyst (unmodified mercury - free waste mercury catalyst mercury removal adsorbent). Gradiently dilute the waste acid with deionized water. Take five portions of 1.0 g of mercury - free waste mercury catalyst, and respectively add waste acid solutions with a volume of 50 mL and dilution ratios of 5%, 10%, 15%, 20%, and 30% (solid - liquid ratio is 1.0 g:50 mL). Continuously stir magnetically for 2 h under the condition of a 40 °C constant - temperature water bath, with a stirring speed of 200 r / min, for acid etching and surface active site modification. After the modification step, perform solid - liquid separation by vacuum filtration, transfer the collected solid to an oven at 60 °C and dry it for 2 h to obtain a renewable mercury removal adsorbent of waste acid - modified waste mercury catalyst.

[0032] Take 1.0 g of commercial activated carbon, crush and grind it, and sieve out 80 - mesh particles to obtain commercial activated carbon for mercury removal experiments.

[0033] Perform X - ray diffraction tests (crystal structure tests), BET tests (specific surface area and pore size distribution tests), and SEM tests (morphology tests) on the waste mercury catalyst, the treated commercial activated carbon, the obtained mercury - free waste mercury catalyst, and the waste acid - modified waste mercury catalyst with different dilution ratios. The results are as Figures 2 to 4 shown.

[0034] Figure 2 In (a), it is the XRD pattern of the waste mercury catalyst, mercury - free waste mercury catalyst, and commercial activated carbon. Figure 2 In (b), it is the XRD pattern of the waste acid - modified waste mercury catalyst with different dilution ratios (b).

[0035] Figure 3 In (a), it is the SEM image of the waste mercury catalyst. Figure 3 In (b), it is the SEM image of the mercury - free waste mercury catalyst. Figure 3 In (c), it is the SEM image of the waste mercury catalyst modified with 5% waste acid dilution solution. Figure 3 In (d), it is the SEM image of the waste mercury catalyst modified with 30% waste acid dilution solution. From Figure 3 it can be seen that after thermal desorption to recover mercury, Figure 3 as shown in (a), the massive dense structure of the waste mercury catalyst is partially cracked and transformed intoFigure 3 The small lamellar disordered stacking structure shown in (b) of []. This structural change is beneficial to the subsequent waste acid modification treatment. Further analysis Figure 3 As can be seen from (c) and (d) of [], the surface of the mercury-free waste mercury catalyst after etching with 5% waste acid is slightly etched to form a porous structure; while etching with 30% waste acid results in deep etching of the surface of the mercury-free waste mercury catalyst, and partial areas collapse, presenting a sponge-like porous structure. This phenomenon confirms the effectiveness of the acid environment in the pore expansion of materials.

[0036] Figure 4 Figure (a) of [] is the BET diagram of waste mercury catalyst, mercury-free waste mercury catalyst and commercial activated carbon, Figure 4 Figure (b) of [] is the BET diagram of waste mercury catalyst modified by waste acid with different dilution ratios. As Figure 4 shown in (a) of [], the physical adsorption capacity of the waste mercury catalyst is small, while the adsorption capacities of the mercury-free waste mercury catalyst and commercial activated carbon are close, indicating that the process of thermal desorption and mercury recovery improves the pore structure of the mercury-free waste mercury catalyst by cracking the dense stacking structure of the waste mercury catalyst, providing physical conditions for waste acid modification. As Figure 4 shown in (b) of [], with the increase of the concentration of waste acid, the physical adsorption capacity of the waste mercury catalyst modified by waste acid first increases and then decreases, which indicates that on the one hand, the etching of the acid solution will increase the number of surface pores and improve the pore structure; on the other hand, the etching of the acid solution with too high concentration will cause partial structure collapse and damage the pore structure.

[0037] Example 2

[0038] The waste acid solution used in this example is from the circuit etching process in the printed circuit board industry, and its main components are: 2.18 mol / L of H + , 1.74 mol / L of Cu 2+ , 1.93 mol / L of Na + and 7.65 mol / L of Cl - . The waste mercury catalyst used in this example is from the process of preparing vinyl chloride monomer by calcium carbide method in the PVC industry, and its main component is activated carbon, loaded with 2% of HgCl 2 .

[0039] A method for preparing a renewable mercury removal adsorbent by modifying waste mercury catalyst with industrial waste acid provided in this example includes the following steps: Take 6.0 g of waste mercury catalyst, crush and grind it, sieve out 80-mesh particles with a standard sieve, transfer them to a tubular furnace, and under a gas flow rate of 0.5 L of N 2Under an inert atmosphere, thermal desorption was carried out at 500 °C for 4 h. The desorbed gas was condensed to recover the mercury remaining on the surface, and the residual solid was cooled to obtain mercury-free waste mercury catalysts. The waste acid was gradually diluted with deionized water. Five portions of 1.0 g of mercury-free waste mercury catalysts were taken and added to waste acid solutions with a volume of 50 mL and dilution ratios of 5%, 10%, 15%, 20%, and 30% (solid-liquid ratio of 1.0 g:50 mL), respectively. Under the condition of a constant temperature water bath at 40 °C, continuous magnetic stirring was carried out for 2 h at a stirring speed of 200 r / min for acid etching and surface active site modification. After the modification step, solid-liquid separation was carried out by vacuum filtration, and the collected solid was transferred to an oven at 60 °C for drying for 2 h to obtain a renewable mercury-removing adsorbent of waste acid-modified waste mercury catalysts.

[0040] Example 3

[0041] This example is about the mercury-removing application of the renewable mercury-removing adsorbent prepared by modifying waste mercury catalysts with industrial waste acid, including the following steps: The commercial activated carbon, the unmodified mercury-free waste mercury catalyst mercury-removing adsorbent obtained in Example 1, and the renewable adsorbents prepared by modifying waste mercury catalysts with waste acid at different dilution ratios were applied to the fixed-bed mercury-removing performance test. The mercury-removing performance of the samples was evaluated by the mercury removal efficiency (the ratio of the difference in mercury concentration at the inlet and outlet of the fixed bed to the inlet mercury concentration). In the fixed-bed device, the reaction temperature was set at 80 °C, and the total gas flow rate was 1.0 L / min, specifically including 200 mL / min of mercury-carrying N 2 and 800 mL / min of N 2 as the balance gas. The mercury concentration at the inlet of the fixed bed was 72 μg / m 3 , the dosage of the mercury-removing adsorbent was 10 mg, and the reaction time was 60 min. The mercury removal efficiency curves of the mercury-removing adsorbents modified with waste acid at different dilution ratios are as shown in Figure 5 (a). The mercury adsorption efficiency of the commercial activated carbon was 4.14%, and the mercury adsorption efficiency of the unmodified mercury-free waste mercury catalyst mercury-removing adsorbent was 11.96%. The mercury adsorption efficiencies of the five renewable mercury-removing adsorbents prepared by modifying waste mercury catalysts with waste acid at dilution ratios of 5%, 10%, 15%, 20%, and 30% were 79.54%, 84.45%, 91.10%, 93.14%, and 97.32%, respectively. It can be seen that by using the method of the present invention to prepare a renewable mercury-removing adsorbent by modifying waste mercury catalysts with waste acid, compared with the unmodified mercury-free waste mercury catalyst mercury-removing adsorbent, the Hg 0 adsorption performance was significantly improved, and it had good application prospects in the control of mercury pollution in the tail gas of fixed sources.

[0042] Example 4

[0043] This example is about the mercury-removing application at different temperatures after preparing a renewable mercury-removing adsorbent by modifying waste mercury catalysts with industrial waste acid, including the following steps:

[0044] The renewable adsorbent obtained from the waste mercury catalyst modified with waste acid at a dilution ratio of 20% obtained in Example 1 was applied to the fixed-bed mercury removal performance test, and the mercury removal performance of the sample was evaluated by the mercury removal efficiency (the ratio of the difference in mercury concentration at the inlet and outlet of the fixed bed to the inlet mercury concentration). In the fixed-bed device, the total gas flow rate was 1.0 L / min, specifically including 200 mL / min of mercury-laden N 2 and 800 mL / min of N 2 as the balance gas. The mercury concentration at the inlet of the fixed bed was 72 μg / m 3 , the dosage of the mercury removal adsorbent was 10 mg, the reaction time was 60 min, and the reaction temperatures were set at 40°C, 60°C, 80°C, 100°C, 120°C, and 140°C respectively. The mercury removal efficiency curves of the mercury removal adsorbent under different temperature conditions are as shown in Figure 5 (b). Under the six temperature conditions, the mercury removal efficiencies of the renewable mercury removal adsorbent were 82.06%, 89.09%, 93.14%, 75.54%, 49.01%, and 30.98% respectively. It can be seen that the renewable mercury removal adsorbent prepared by modifying the waste mercury catalyst with waste acid has strong mercury removal activity, has a wide operating temperature window, the optimal mercury removal temperature is 80°C, and it is suitable for injection downstream of the wet flue gas desulfurization device WFGD.

[0045] Example 5

[0046] This example is about the mercury removal application of the renewable mercury removal adsorbent prepared by modifying the waste mercury catalyst with industrial waste acid under simulated coal gas atmosphere, including the following steps:

[0047] The renewable adsorbent obtained from the waste mercury catalyst modified with waste acid at a dilution ratio of 20% obtained in Example 1 was applied to the fixed-bed mercury removal performance test, and the mercury removal performance of the sample was evaluated by the mercury removal efficiency (the ratio of the difference in mercury concentration at the inlet and outlet of the fixed bed to the inlet mercury concentration). In the fixed-bed device, the reaction temperature was set at 80°C, the total gas flow rate was 1.0 L / min, the mercury-laden N 2 flow rate was 200 mL / min, the mercury concentration at the inlet of the fixed bed was 72 μg / m 3 , the dosage of the mercury removal adsorbent was 10 mg, the reaction time was 22 min, and it was respectively in pure N 2 , N 2 +480 ppm H 2 S, 80% N 2 +20% CO 2 , 60% N 2 +40% CO, 80% N 2 +20% H 2 and 20% N 2 +20% CO 2 +40% CO + 20% H 2+480ppm H 2 Experiments were carried out under S atmosphere. The mercury removal efficiency curves of the mercury removal adsorbent under different atmosphere conditions are as shown in Figure 5 (c). Under six atmosphere conditions, the mercury removal efficiencies of the renewable mercury removal adsorbent are 99.15%, 37.60%, 63.24%, 26.04%, 91.28% and 49.39% respectively. It can be seen that the renewable mercury removal adsorbent prepared by modifying waste mercury catalyst with waste acid shows high anti-interference ability in reducing atmosphere, has high mercury removal efficiency in simulated coal gas atmosphere, and can be applied to the control of mercury pollution in tail gas of different fixed sources.

[0048] Example 6

[0049] This example is a regeneration method and mercury removal performance test after mercury removal of a renewable mercury removal adsorbent prepared by modifying waste mercury catalyst with industrial waste acid, including the following steps:

[0050] Example 5 was carried out multiple times, and fixed-bed mercury removal experiments were carried out under pure N 2 atmosphere respectively, and 100 mg of the renewable adsorbent after mercury removal was collected. The obtained renewable adsorbent after mercury removal was transferred to a tubular furnace, and thermally desorbed at 500 °C for 4 h under N 2 atmosphere with a gas flow rate of 0.5 L. The desorbed gas was condensed to recover the mercury remaining on the surface, and the residual solid was cooled to obtain mercury-free waste mercury catalyst. Deionized water was used to dilute the waste acid. 1.0 g of mercury-free waste mercury catalyst was taken and added to 50 mL of waste acid solution with a dilution ratio of 30% (solid-liquid ratio of 1.0 g:50 mL). Under the condition of constant temperature water bath at 40 °C, continuous magnetic stirring was carried out for 2 h, and the stirring speed was 200 r / min for acid etching and surface active site modification. After the modification step, solid-liquid separation was carried out by vacuum filtration, and the collected solid was transferred to an oven at 60 °C and dried for 2 h to obtain the regenerated waste acid-modified waste mercury catalyst renewable mercury removal adsorbent. The obtained regenerated renewable mercury removal adsorbent was applied to the fixed-bed mercury removal performance cyclic test, which was recorded as 1 adsorption agent cyclic regeneration process. The results are as Figure 6 shown. After ten cyclic regeneration processes, the mercury removal efficiency of the regenerated mercury removal adsorbent still remains as high as 89.24%. It can be seen that the renewable mercury removal adsorbent prepared by modifying waste mercury catalyst with waste acid can be successfully regenerated through the same process as the preparation process and has good cyclic regeneration performance.

[0051] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as a limitation of the present invention itself. Various changes can be made to it in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A method for preparing a regenerable mercury removal adsorbent by modifying waste mercury catalyst with industrial waste acid, characterized in that: The method comprises: Step 1: After the waste mercury catalyst is crushed and ground, it is transferred to a tube furnace, and the mercury remaining on the surface is thermally desorbed under the protection of an inert gas, and the liquid metal mercury is recovered after the desorbed gas is condensed, and the residual solid is cooled to obtain a mercury-free waste mercury catalyst; Step 2: diluting the waste acid with deionized water to obtain a waste acid dilution solution, immersing the obtained mercury-free waste mercury catalyst in the waste acid dilution solution, and continuously performing magnetic stirring and dispersion in a constant temperature water bath to perform acid etching and surface active site modification, then performing solid-liquid separation, and drying the separated solid to obtain a regenerable demercuration adsorbent.

2. The method according to claim 1, characterized in that The waste mercury catalyst is the waste mercury catalyst generated when preparing vinyl chloride monomer by calcium carbide process in PVC industry; The waste acid is industrial waste acid generated during the process of removing oxide layers from metal surfaces in the metal production industry, the process of dissolving precious metals in the metal recycling industry, the pre-treatment pickling process in the electroplating industry, or the circuit etching process in the printed circuit board industry.

3. The method according to claim 1, characterized in that In step 1, the waste mercury catalyst is crushed and ground to obtain a particle size of 80 meshes.

4. The method according to claim 1, characterized in that: In step 1, The waste acid contains H + The concentration is 1-3 mol / L, and the metal cation contains Fe 2+ , Fe 3+ , Cu 2+ and Cu + One or more of the following, the anion contains Cl - Br - and I - One or any combination of these.

5. The method according to claim 1, characterized in that In step 2, when the waste acid is diluted with deionized water, the volume ratio of the waste acid to the deionized water is (5-30):100; the solid-liquid ratio of the mercury-free waste mercury catalyst to the waste acid dilution liquid is 1.0 g:50 mL.

6. The method according to claim 1, characterized in that In step 1, the thermal desorption inert gas is N2, the gas flow rate is 0.5 L / min, the temperature is 500°C, and the time is 4 h.

7. The method according to claim 1, characterized in that In step 2, the conditions of magnetic stirring and constant temperature water bath are: time is 2h, stirring speed is 200r / min, water bath temperature is 40°C; solid-liquid separation method is vacuum filtration separation; drying method is drying at 60°C for 2h.

8. Use of the regenerable mercury removal adsorbent prepared by the method of claim 1, characterized in that: It can be used to remove gas-phase mercury from tail gas of stationary sources.

9. The use of the regenerable mercury removal adsorbent prepared by the method according to claim 8, characterized in that: The regenerable demercuration adsorbent was placed in a fixed bed device, the reaction temperature was set to 40-120°C, and the gas flow rate was 1.0 L / min.

10. Use of the regenerable mercury removal adsorbent prepared by the method according to claim 8, characterized in that: The fixed source tail gas includes coal combustion flue gas, synthesis gas, and non-ferrous metal smelting flue gas.

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