Copper-based sulfide mercury removal agent and preparation method thereof

Abstract

The invention belongs to the technical field of mercury removal agents, and particularly discloses a copper-based sulfide mercury removal agent and a preparation method thereof. The copper-based sulfide mercury removal agent comprises the following raw materials in percentage by mass: 15-18% of copper sulfide powder, 2-3% of MnO2, 60-65% of an activated carbon carrier and 12-20% of a pretreated attapulgite binder. Various raw materials are mixed, the specific surface area is high, the catalytic performance is good, the contact area with mercury is increased, and the mercury removal efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mercury removal agents, and in particular to a copper-based sulfide mercury removal agent and a preparation method thereof. BACKGROUND

[0002] Mercury is one of the most toxic heavy metals in the environment, has persistence, long-distance migration and biological enrichment, and can be converted into methyl mercury in nature, which is highly toxic to the environment and process equipment, and therefore needs to be removed.

[0003] Traditional mercury removal agents such as activated carbon, calcium adsorbents and zeolite materials have low utilization rate, high cost, and adsorption efficiency limited by contact area and contact efficiency. Copper-based sulfides (such as copper sulfide, CuS) can combine with mercury through chemical bonding, have higher mercury removal efficiency, and gradually replace traditional mercury removal agents.

[0004] In the prior art, a copper-based sulfide mercury removal agent is prepared by impregnation method. Specifically, a soluble copper salt solution is mixed with an ethylenediamine solution, ammonia water is added to form a premixed solution, a thiourea solution is added to obtain an impregnation solution, a carrier is immersed in the impregnation solution, and after activation and drying, a copper sulfide mercury removal agent is obtained. Through the impregnation method, the copper salt and the sulfur source can be uniformly dispersed on the surface and in the pores of the carrier, ensuring uniform distribution of the active components and improving the overall performance of the mercury removal agent.

[0005] However, the pore structure and specific surface area of the carrier limit the loading amount of the active components, which may result in insufficient loading amount of the active components and affect the performance of the mercury removal agent. SUMMARY

[0006] In order to improve the poor performance of the mercury removal agent, the present application provides a copper-based sulfide mercury removal agent and a preparation method thereof.

[0007] The present application provides a copper-based sulfide mercury removal agent, which adopts the following technical solution: A copper-based sulfide mercury removal agent comprises the following raw materials: copper sulfide powder 15-18%, MnO2 2-3%, activated carbon carrier 60-65%, and pretreated attapulgite binder 12-20% by mass percentage.

[0008] By adopting the above technical solution, the copper sulfide powder as the main active component can react with mercury to generate stable mercury sulfide, achieving efficient mercury removal. The manganese dioxide can promote the oxidation of mercury, enhance the capture ability of copper sulfide for mercury, and also improve the activity of the mercury removal agent in low-temperature or high-humidity environments. The activated carbon carrier has high specific surface area and rich pore structure, which can effectively disperse the active components (copper sulfide and manganese dioxide), increase the contact area with mercury, and improve the mercury removal efficiency. At the same time, the activated carbon can also adsorb part of the mercury, further improving the mercury removal effect.

[0009] The pretreated attapulgite binder enhances the binding force between particles in the molding process, prevents the mercury removal agent from pulverizing or structural collapse during use, and ensures the mechanical strength and wear resistance of the mercury removal agent. The synergistic effect of copper sulfide and manganese dioxide significantly improves the mercury removal efficiency. The use of activated carbon carrier and pretreated attapulgite binder ensures the stability and mechanical strength of the mercury removal agent in high temperature or high humidity environment.

[0010] Preferably, the preparation method of the activated carbon carrier comprises the following steps: (1) Mix coconut shell, tree bark and grapefruit peel, crush, carbonize at a temperature of 550-600℃ for 1-2h, then raise the temperature to 650-700℃ for carbonization for 2-3h, obtain carbonized material, then soak in potassium hydroxide solution for 3-4h for activation, obtain activated activated carbon; (2) Disperse modified graphene in ethanol solution, add activated activated carbon of step (1), ultrasonic for 2-3h, dry, obtain mixture, disperse the mixture in polyvinyl alcohol solution, spray dry, steam activation at 650-700℃ for 1-1.5h, dry, obtain activated carbon carrier; The polyvinyl alcohol solution comprises polyvinyl alcohol, deionized water and starch.

[0011] By adopting the above technical scheme, coconut shell, tree bark and grapefruit peel are mixed, coconut shell contains high lignin, tree bark contains cellulose, and grapefruit peel is rich in volatile matter, and the porosity of the carbonized material is improved by complementary components. Carbonize at 550-600℃ first to remove volatile components in the raw materials and form a preliminary carbon skeleton. Carbonize at 650-700℃ again to promote graphitization of the carbon skeleton, increase the proportion of aromatic structure, and improve the mechanical strength and thermal stability of the carbonized material. Activation with potassium hydroxide solution generates a large number of micropores on the carbon skeleton, increases the porosity and specific surface area of the activated carbon, and improves the adsorption performance.

[0012] Modified graphene has excellent mechanical properties and can coat the surface of activated carbon to improve the mechanical properties of activated carbon. Polyvinyl alcohol has good adhesion and forms a colloidal protective film during spray drying to prevent activated carbon from agglomerating with modified graphene, enhance the binding force between activated carbon and modified graphene, and improve the electrical conductivity and mechanical strength of the activated carbon carrier.

[0013] Water vapor secondary activation, H2O reacts with carbon at 650-700℃ to expand the original pore and generate new mesopores, increase the porosity and specific surface area of the activated carbon, and improve the adsorption performance. The obtained activated carbon carrier has more pores, and the micropores and mesopores cooperate to load CuS for flue gas mercury removal, greatly improving the mechanical strength.

[0014] The polyvinyl alcohol solution has good adhesion and molding properties, and enhances the mechanical strength of the material. The starch enhances the molding properties and thermal stability, and provides additional adhesion. The starch enhances the binding force between the activated carbon particles, prevents pulverization during molding and use, provides good molding performance, ensures the formation of uniform particles during spray drying, and improves the mechanical strength and thermal stability of the activated carbon carrier, so that it maintains its performance in high-temperature or high-humidity environments. Moreover, the subsequent starch decomposes into CO2 when activated by water vapor at 650-700℃, which has a pore-forming effect and produces mesopores, optimizing the pore hierarchy structure.

[0015] Preferably, the mass ratio of the coconut shell, modified graphene and polyvinyl alcohol solution is 1:0.2-0.3:6-7.

[0016] By using the above technical solution, the mass ratio of the coconut shell, modified graphene and polyvinyl alcohol solution is further limited within a certain range, and the activated carbon carrier obtained has excellent mechanical strength, adsorption and large specific surface area. The carbonization of the coconut shell has a developed microporous and mesoporous structure and a large specific surface area, which provides a large number of loading sites for copper-based sulfides, enabling them to be highly dispersed and thus exposing more active sites to participate in the mercury removal reaction. The modified graphene has excellent electrical conductivity, which promotes the transfer of electrons from the Hg 0 adsorption sites to the CuS or other active sites, accelerating the oxidation process. The modified graphene surface contains a large number of oxygen-, nitrogen-, and sulfur-containing functional groups or defect sites, which act as anchor points to improve the dispersion and loading stability of copper-based sulfide particles on its surface, prevent agglomeration, and expose more active sites.

[0017] The polyvinyl alcohol solution binds the coconut activated carbon powder, modified graphene powder and copper-based sulfide precursor together, and has sufficient mechanical strength for molding. After drying and curing, the polyvinyl alcohol forms a polymer network, firmly binding the components together and improving the mechanical strength and wear resistance of the final molded mercury removal agent.

[0018] Preferably, the method for preparing the modified graphene comprises the following steps: adding graphite oxide to distilled water and ultrasonically treating for 115-120 min to obtain a graphene oxide dispersion, adding polydiallyldimethylammonium chloride and heating in a water bath at 80-85℃ for 3-4 h to obtain a modified graphene dispersion, filtering, then dispersing in deionized water, adding nano-ZnS and sodium alginate, stirring at a temperature of 60-65℃ for 1-2 h, and drying to obtain modified graphene.

[0019] By adopting the above technical scheme, the graphite oxide is exfoliated into single-layer or multi-layer graphene oxide through cavitation effect of ultrasonic waves, and the dispersibility is improved. The polydiallyldimethylammonium chloride is a cationic polymer, which can be adsorbed on the surface of graphene oxide through electrostatic effect to form a stable dispersion liquid, and at the same time, the graphene oxide is endowed with positive charge to enhance the dispersibility of graphene oxide in water, prevent graphene from re-agglomeration, and form stable modified graphene.

[0020] The nano ZnS has good photocatalytic and adsorption performance, which can further improve the adsorption capacity and catalytic performance of the modified graphene. The nano ZnS is fixed on the surface of the graphene through the bridging effect or electrostatic adsorption of the polydiallyldimethylammonium chloride, and provides active sites for subsequent mercury removal. The sodium alginate is combined with the hydroxyl groups on the surface of the graphene through hydrogen bonds, and at the same time, the nano ZnS particles are wrapped, which prevents agglomeration, increases the adhesion between the nano ZnS and the graphene, and enhances the mechanical properties and stability of the modified graphene, which is helpful for improving the mercury removal efficiency.

[0021] Preferably, the preparation method of the pretreated attapulgite binder comprises the following steps: (1) grinding and crushing attapulgite, dispersing it in hydrochloric acid, stirring for 1-2 h, washing with water, and heating at 250-260℃ for 2-3 h to obtain attapulgite powder; (2) dispersing modified nano titanium dioxide in deionized water, adding the attapulgite powder of step (1) and carboxymethyl cellulose, wet ball milling to obtain a mixture, drying, grinding to obtain a pretreated attapulgite binder.

[0022] By adopting the above technical scheme, the attapulgite is ground to increase the specific surface area and improve the subsequent acid activation efficiency. The hydrochloric acid treatment removes carbonates, iron and aluminum oxides and other impurities in the attapulgite, purifies the clay, and increases the porosity and surface acid sites. The attapulgite loses part of the structural water at 250-260℃, making the pore channel more unobstructed.

[0023] The modified nano titanium dioxide improves its dispersibility in water and the bonding force with the attapulgite. The modified nano titanium dioxide can be adsorbed on the surface of the attapulgite powder, improving the mechanical strength of the attapulgite and the subsequent photocatalytic activity. The hydroxyl groups / carboxyl groups of the carboxymethyl cellulose form hydrogen bonds with the attapulgite and the modified nano titanium dioxide, enhancing the inter-particle bonding force and improving the mechanical strength of the composite material. Wet ball milling realizes uniform loading of the modified nano titanium dioxide on the surface of the attapulgite, promotes the coating of the carboxymethyl cellulose on the surface of the particles, forms a stable composite structure, and improves the bonding performance and mechanical strength of the pretreated attapulgite binder, which in turn improves the adsorption performance and mechanical stability of the mercury removal agent.

[0024] Preferably, the mass ratio of the attapulgite, the modified nano titanium dioxide and the carboxymethyl cellulose is 1:0.4-0.5:0.1-0.2.

[0025] By adopting the technical scheme, the mass ratio of the attapulgite, the modified nano-titanium dioxide and the carboxymethyl cellulose is limited in a certain range, the pretreated attapulgite binder has good cohesiveness, mechanical strength and photocatalytic performance. The attapulgite after acid activation and heat activation has a developed mesoporous structure, provides a high dispersion loading platform for the copper-based sulfide, increases the contact area of the copper-based sulfide and Hg 0 The high compressive strength of the composite material prevents the mercury removal agent from being pulverized under the impact of the gas flow. The modified nano-titanium dioxide generates active oxygen to oxidize the difficult-to-adsorb Hg 0 Into the easy-to-capture Hg 2+ , improves the removal efficiency of the copper-based sulfide on Hg 0 , improves the porosity of the attapulgite, promotes the transfer of electrons from Hg 0 to the copper-based sulfide, and accelerates the conversion process of Hg 0 to HgS.

[0026] The long-chain molecules of the carboxymethyl cellulose form hydrogen bonds with the attapulgite, the modified nano-titanium dioxide and the copper-based sulfide through the hydroxyl groups / carboxyl groups, improve the inter-particle bonding force, and prevent the mercury removal agent from being broken in use. The mixed use of the attapulgite, the modified nano-titanium dioxide and the carboxymethyl cellulose can significantly improve the adsorption performance and catalytic performance of the mercury removal agent, thereby improving the mercury removal efficiency.

[0027] Preferably, the preparation method of the modified nano-titanium dioxide comprises the following steps: dispersing nano-titanium dioxide in a cerium nitrate solution, adding citric acid, adjusting the pH to 7-7.5, calcining at 450-460℃ to obtain a mixture; dispersing the mixture in deionized water, adding sodium tripolyphosphate and maltodextrin, stirring at a temperature of 60-65℃ for 1-2h, and drying to obtain the modified nano-titanium dioxide.

[0028] By adopting the technical scheme, the cerium nitrate provides cerium ions (Ce 3+ ), the Ce 3+ is adsorbed on the surface of TiO2 through ion exchange, the citric acid prevents the hydrolysis and precipitation of Ce 3+ , promotes uniform doping, and is beneficial to Ce 3+ adsorption. The calcination promotes the formation of the oxide of cerium (CeO2) and the nano-titanium dioxide, enhances the catalytic performance and thermal stability of the material.

[0029] The PO4 3-The TiO2 surface is bonded with Ti-OH to form a Ti-O-P bond, which improves hydrophilicity and anti-aggregation, and can further improve the dispersibility of nano-titanium dioxide, preventing particle aggregation.

[0030] The composite of nano-titanium dioxide and cerium oxide (CeO2) significantly improves the catalytic performance of the material. Through high-temperature calcination and dispersion treatment, the modified nano-titanium dioxide has good thermal stability and mechanical strength. Subsequently, as a reinforcing material, it improves the adsorption performance and catalytic performance of the mercury removal agent.

[0031] Preferably, the preparation method of the copper sulfide powder comprises the following steps: dissolving basic copper carbonate in ammonia water to obtain a copper ammonia solution, drying to obtain copper diammonium carbonate, and then calcining at 210-220°C to obtain nano-copper oxide. The nano-copper oxide is immersed in an ammonium sulfide solution, taken out and drained, and then dried to obtain nano-copper sulfide.

[0032] By adopting the above technical solution, calcination decomposes the copper diammonium carbonate to generate nano-copper oxide, and the nano structure helps to improve the specific surface area and reactivity of the material. The nano structure of the nano-copper sulfide provides a large number of active sites, improves the mercury removal efficiency, and helps to uniformly distribute in the mercury removal agent, improving the overall performance and catalytic performance.

[0033] Preferably, the grain size of the copper sulfide powder is 80-90nm, and the particle size is greater than 100 mesh.

[0034] By adopting the above technical solution, the nano-level grain size makes the copper sulfide powder have a very high specific surface area, and the nano structure provides more active sites, thereby significantly improving the catalytic performance of the copper sulfide. The particle size of the copper sulfide powder is relatively large, but still maintains the nano-level grain size, achieving better handling and use performance in actual application.

[0035] In a second aspect, the application also provides a preparation method of a copper-based sulfide mercury removal agent, comprising the following steps: mixing copper sulfide powder, MnO2, activated carbon carrier, pretreated attapulgite binder, and deionized water, stirring uniformly, rolling into a ball, and drying to obtain a copper-based sulfide mercury removal agent.

[0036] By adopting the above technical solution, the application is simple to operate, the prepared copper sulfide mercury removal agent has high activity and uniform distribution, ensures the high efficiency of the mercury removal agent, and improves the mechanical strength of the particles, so that they are not easy to break during use.

[0037] In summary, the application has the following beneficial effects: 1. The manganese oxide in the present application can promote the oxidation of mercury, enhance the capture ability of copper sulfide to mercury, and also improve the activity of the mercury removal agent in a low-temperature or high-humidity environment.

[0038] 2. The activated carbon carrier in the present application has a high specific surface area and a rich pore structure, which can effectively disperse the active components, increase the contact area with mercury, improve the mercury removal efficiency, and further improve the mercury removal effect by adsorbing part of the mercury.

[0039] 3. The pretreated attapulgite binder in the present application enhances the binding force between particles during the molding process, prevents the mercury removal agent from pulverizing or structural collapse during use, and ensures the mechanical strength and wear resistance of the mercury removal agent. DETAILED DESCRIPTION

[0040] The present application is further described in detail below in conjunction with examples.

[0041] The raw materials used in the examples and comparative examples can be obtained by market purchase.

[0042] Preparation Example of Activated Carbon Carrier Preparation Example 1 The preparation method of the activated carbon carrier comprises the following steps: (1) Mix 110 g of coconut shell, 70 g of tree bark, and 90 g of pomelo peel, crush them, carbonize at a temperature of 580℃ for 1.5 h, then increase the temperature to 680℃ and carbonize for 2.5 h to obtain carbonized material, then soak the carbonized material in 200 mL of a 50% potassium hydroxide solution for 3.5 h for activation to obtain activated carbon after activation; (2) Disperse the modified graphene in 160 mL of an ethanol solution, add the activated carbon after step (1), ultrasonic for 2.8 h, dry to obtain a mixture, disperse the mixture in a polyvinyl alcohol solution, spray dry, steam activate at 700℃ for 1 h, and dry to obtain an activated carbon carrier; The polyvinyl alcohol solution comprises 20 g of polyvinyl alcohol, 200 mL of deionized water, and 10 g of starch mixed uniformly.

[0043] Spray drying process: inlet air temperature 120℃, feed amount 10 mL / min, inlet air pressure 0.15 MPa, at this time the outlet air temperature is 95℃.

[0044] The mass ratio of coconut shell, modified graphene, and polyvinyl alcohol solution is 1:0.3:6.

[0045] A method for preparing modified graphene includes the following steps: 30 mg of graphite oxide is added to 120 mL of distilled water, ultrasonic treatment is performed for 120 min to obtain a graphene oxide dispersion, 3 mL of polydiallyldimethylammonium chloride with a concentration of 0.3 ‰ is added, water bath heating is performed at 80 ℃ for 4 h to obtain a modified graphene dispersion, filtration is performed, and then the modified graphene dispersion is dispersed in 200 mL of deionized water, 6 g of nano-ZnS and 3 g of sodium alginate are added, stirring is performed at a temperature of 62 ℃ for 1.5 h, and drying is performed to obtain modified graphene.

[0046] Preparation Example 2 The difference from Preparation Example 1 is that, in step (2), no modified graphene is added.

[0047] Preparation Example 3 The difference from Preparation Example 1 is that, in step (2), no polyvinyl alcohol solution is added.

[0048] Preparation Example 4 The difference from Preparation Example 1 is that the mass ratio of coconut shell, modified graphene and polyvinyl alcohol solution is 1:0.2:7.

[0049] Preparation Example 5 The difference from Preparation Example 1 is that the mass ratio of coconut shell, modified graphene and polyvinyl alcohol solution is 1:0.1:12.

[0050] Preparation Example 6 The difference from Preparation Example 1 is that, in the method for preparing modified graphene, no nano-ZnS is added.

[0051] Preparation Example 7 The difference from Preparation Example 1 is that, in the method for preparing modified graphene, no sodium alginate is added.

[0052] Preparation Example of pretreated attapulgite binder Preparation Example 8 A method for preparing a pretreated attapulgite binder includes the following steps: (1) 30 g of attapulgite is ground, crushed and sieved to 2 mm, dispersed in 100 mL of hydrochloric acid, stirred for 1.5 h, washed with water, and heated at 255 ℃ for 2.6 h to obtain attapulgite powder; (2) The modified nano-titanium dioxide is dispersed in 180 L of deionized water, the attapulgite powder of step (1) and carboxymethyl cellulose are added, wet ball milling is performed to obtain a mixture, drying is performed, and grinding is performed to obtain a pretreated attapulgite binder.

[0053] The mass ratio of attapulgite, modified nano-titanium dioxide and carboxymethyl cellulose is 1:0.4:0.2.

[0054] A method for preparing modified nano-titanium dioxide includes the following steps: dispersing 20 g of nano-titanium dioxide in 60 mL of a 10% cerium nitrate solution, adding citric acid, adjusting the pH to 7, calcining at 450°C for 1 h to obtain a mixture; dispersing the mixture in 100 mL of deionized water, adding 3 g of sodium tripolyphosphate and 5 g of maltodextrin, stirring at 65°C for 2 h, and drying to obtain modified nano-titanium dioxide.

[0055] Preparation Example 9 The difference from Preparation Example 8 is that in step (2), no modified nano-titanium dioxide is added.

[0056] Preparation Example 10 The difference from Preparation Example 8 is that in step (2), no carboxymethyl cellulose is added.

[0057] Preparation Example 11 The difference from Preparation Example 8 is that the mass ratio of attapulgite, modified nano-titanium dioxide, and carboxymethyl cellulose is 1:0.5:0.1.

[0058] Preparation Example 12 The difference from Preparation Example 8 is that the mass ratio of attapulgite, modified nano-titanium dioxide, and carboxymethyl cellulose is 1:0.05:0.5.

[0059] Preparation Example 13 The difference from Preparation Example 8 is that in the preparation method of modified nano-titanium dioxide, no cerium nitrate is added.

[0060] Preparation Example 14 The difference from Preparation Example 8 is that in the preparation method of modified nano-titanium dioxide, no maltodextrin is added. Example

[0061] Example 1 A copper-based sulfide demercuration agent includes the following raw materials: 18% copper sulfide powder, 22% MnO2, 60% activated carbon carrier, and 20% pretreated attapulgite binder, with a total of 100 g by mass.

[0062] A method for preparing copper sulfide powder includes the following steps: dissolving 50 g of basic copper carbonate in 120 mL of 22% ammonia water to obtain a copper ammonia solution, drying at 100°C to obtain copper diammonium carbonate, calcining at 220°C to obtain nano-copper oxide, immersing the nano-copper oxide in 120 mL of a 12 wt% sulfur-containing ammonium sulfide solution, taking it out and draining after 2 h, and drying to obtain nano-copper sulfide.

[0063] The copper sulfide powder has a grain size of 80 nm and a particle size of 120 mesh.

[0064] The preparation method of the copper-based sulfide demercuration agent comprises the following steps: mixing copper sulfide powder, MnO2, an activated carbon carrier, a pretreated attapulgite binder, and 150 mL of deionized water, uniformly stirring, rolling into a ball, drying at 80 DEG C for 0.5 h, and obtaining the copper-based sulfide demercuration agent.

[0065] The activated carbon carrier is prepared according to Preparation Example 1, and the pretreated attapulgite binder is prepared according to Preparation Example 8.

[0066] Example 2 A copper-based sulfide demercuration agent, which is different from Example 1 in that the following raw materials are included: 17% of copper sulfide powder, 3% of MnO2, 65% of an activated carbon carrier, and 15% of a pretreated attapulgite binder by mass.

[0067] Example 3 A copper-based sulfide demercuration agent, which is different from Example 1 in that the activated carbon carrier is prepared according to Preparation Example 2.

[0068] Example 4 A copper-based sulfide demercuration agent, which is different from Example 1 in that the activated carbon carrier is prepared according to Preparation Example 3.

[0069] Example 5 A copper-based sulfide demercuration agent, which is different from Example 1 in that the activated carbon carrier is prepared according to Preparation Example 4.

[0070] Example 6 A copper-based sulfide demercuration agent, which is different from Example 1 in that the activated carbon carrier is prepared according to Preparation Example 5.

[0071] Example 7 A copper-based sulfide demercuration agent, which is different from Example 1 in that the activated carbon carrier is prepared according to Preparation Example 6.

[0072] Example 8 A copper-based sulfide demercuration agent, which is different from Example 1 in that the activated carbon carrier is prepared according to Preparation Example 7.

[0073] Example 9 A copper-based sulfide demercuration agent, which is different from Example 1 in that the pretreated attapulgite binder is prepared according to Preparation Example 9.

[0074] Example 10 A copper-based sulfide demercuration agent, which is different from Example 9 in that the pretreated attapulgite binder is prepared according to Preparation Example 10.

[0075] Example 11 A copper-based sulfide demercuration agent, which is different from Example 9 in that the pretreated attapulgite binder is prepared according to Preparation Example 11.

[0076] Example 12 A copper-based sulfide demercuration agent, which is different from Example 9 in that the pretreated attapulgite binder is prepared by Preparation Example 12.

[0077] Example 13 A copper-based sulfide demercuration agent, which is different from Example 9 in that the pretreated attapulgite binder is prepared by Preparation Example 13.

[0078] Example 14 A copper-based sulfide demercuration agent, which is different from Example 9 in that the pretreated attapulgite binder is prepared by Preparation Example 14.

[0079] Example 15 A copper-based sulfide demercuration agent, which is different from Example 9 in that the activated carbon carrier is purchased from,,, and.

[0080] Comparative Example Comparative Example 1 A copper-based sulfide demercuration agent, which is different from Example 1 in that the pretreated attapulgite binder is replaced by attapulgite.

[0081] Performance detection test The copper-based sulfide demercuration agents prepared by Examples 1-15 and Comparative Example 1 are subjected to performance test; The pore volume is determined by the method of “RIPP 151-90 Nitrogen adsorption capacity method for determining the pore volume and pore size distribution of catalysts”; and the specific surface area is determined according to “GB-T 19587-2004 Gas adsorption BET method for determining the specific surface area of solid materials”.

[0082] The tail gas can be determined by “GBT 16781.2-1997 Determination of mercury content in natural gas by cold atomic fluorescence spectrophotometry”, and when the mercury content of the outlet gas exceeds 10 μg / m 3 for three times in succession, it is considered to be penetrated. The waste mercury of the penetrated is taken out and mixed evenly, and the mercury content is determined by “GBT 17136-1997 Determination of total mercury in soil quality by cold atomic absorption spectrophotometry”, and the test results are shown in Table 1.

[0083] Table 1 Test data of examples and comparative examples As can be seen from Table 1, the copper-based sulfide demercuration agent prepared in Examples 1-2 has good demercuration efficiency and specific surface area, wherein the specific surface area of Example 1 is 850 m2 / g, the pore volume is 0.48 mL / g, and the mercury capacity is 7.9%. It can be seen that the copper-based sulfide demercuration agent prepared in the present application has a large specific surface area, increases the contact area with mercury, and improves the demercuration efficiency.

[0084] In the preparation methods of the active carbon carriers in Examples 3-4, no modified graphene and polyvinyl alcohol solution is added respectively, and the mass ratio of coconut shell, modified graphene and polyvinyl alcohol solution is changed in Examples 5-6. As can be seen from Table 1, the test effects of the specific surface area, pore volume and mercury capacity of Examples 3-4 are obviously poorer than those of Examples 1-2 and Example 5, and the test effects of the corresponding properties of Example 6 are better than those of Examples 3-4 but poorer than those of Examples 1-2 and Example 5. It is shown that the carbonization of coconut shell has developed microporous and mesoporous structures and a large specific surface area, which provides a large number of loading sites for copper-based sulfides, the surface of modified graphene contains a large number of oxygen-containing, nitrogen-containing and sulfur-containing functional groups or defect sites, which improves the dispersion degree and loading stability of copper-based sulfide particles on its surface, and the polyvinyl alcohol solution binds the coconut shell active carbon powder, modified graphene powder and copper-based sulfide precursor together, has sufficient mechanical strength for molding, and will decompose, volatilize or carbonize in the subsequent drying and calcination process, leaving additional pores in the composite material, which helps to increase the specific surface area and pore volume of the material and expose more active sites.

[0085] In the preparation methods of modified graphene in Examples 7-8, no nano-ZnS and sodium alginate is added respectively. As can be seen from Table 1, the test effects of the specific surface area, pore volume and mercury capacity of Examples 7-8 are obviously poorer than those of Examples 1-2 but better than those of Example 3. It is shown that nano-ZnS has good photocatalytic and adsorption properties, which can further improve the adsorption capacity and catalytic performance of modified graphene, sodium alginate is combined with the hydroxyl groups on the surface of graphene through hydrogen bonds, and at the same time, it wraps the nano-ZnS particles, increases the adhesion between nano-ZnS and graphene, enhances the mechanical properties and stability of modified graphene, and is helpful to improve the demercuration efficiency in the subsequent process.

[0086] In Examples 9 and 10, the preparation methods for the pretreated attapulgite binder omitted modified nano-titanium dioxide and carboxymethyl cellulose, respectively. In Examples 11 and 12, the mass ratios of attapulgite, modified nano-titanium dioxide, and carboxymethyl cellulose were varied. As shown in Table 1, the specific surface area, pore volume, and mercury capacity of Examples 9 and 10 were significantly lower than those of Examples 1-2 and 11, while the corresponding performance of Example 12 was better than that of Examples 9 and 10, but lower than that of Examples 1-2 and 11. This indicates that the long-chain carboxymethyl cellulose molecules form hydrogen bonds with the attapulgite, modified nano-titanium dioxide, and copper-based sulfide through hydroxyl and carboxyl groups, enhancing interparticle bonding. During drying or calcination, the carboxymethyl cellulose decomposes and volatilizes, leaving additional mesopores and macropores, which optimize mass transfer pathways. The combined use of attapulgite, modified nano-titanium dioxide, and carboxymethyl cellulose significantly improves the adsorption and catalytic properties of the mercury removal agent, thereby increasing mercury removal efficiency.

[0087] In the preparation methods of modified nano-titanium dioxide in Examples 13-14, cerium nitrate and maltodextrin were not added. As can be seen from Table 1, the specific surface area, pore volume and mercury capacity of Examples 13-14 were significantly worse than those of Examples 1-2, but better than those of Example 9. This shows that cerium nitrate provides cerium ions (Ce 3+ ), Ce 3+ By adsorbing on the TiO2 surface through ion exchange, the catalytic performance and thermal stability of the material are enhanced. The composite of nano-titanium dioxide and cerium oxide (CeO2) significantly improves the catalytic performance of the material. Through high-temperature calcination and dispersion treatment, the modified nano-titanium dioxide has good thermal stability and mechanical strength. It is subsequently used as a reinforcing material to improve the adsorption and catalytic performance of the demercuration agent.

[0088] In Comparative Example 1, the pretreated attapulgite binder was replaced with attapulgite. As shown in Table 1, the specific surface area, pore volume, and mercury capacity test results for Comparative Example 1 were significantly inferior to those for Examples 1-2. This indicates that the pretreated attapulgite binder in this application enhances the bonding force between particles during the molding process, preventing the mercury removal agent from pulverizing or structural collapse during use, ensuring its mechanical strength and wear resistance, facilitating the subsequent bonding of copper sulfide and manganese dioxide, and improving mercury removal efficiency.

[0089] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A copper-based sulfide mercury removal agent, characterized in that: The invention comprises the following raw materials: calculated by mass percentage, 15-18% of copper sulfide powder, 2-3% of MnO2, 60-65% of activated carbon carrier, and 12-20% of pretreated attapulgite binder.

2. A copper-based sulfide mercury removal agent according to claim 1, characterized in that: The preparation method of the activated carbon carrier comprises the following steps: (1) Coconut shell, bark and grapefruit peel are mixed and crushed, first carbonized at a temperature of 550-600℃ for 1-2 hours, then heated to 650-700℃ for 2-3 hours to obtain carbonized material, which is then dispersed in potassium hydroxide solution and soaked for 3-4 hours for activation to obtain activated carbon; (2) dispersing the modified graphene in an ethanol solution, adding the activated carbon activated in step (1), ultrasonicating for 2-3 hours, drying to obtain a mixture, dispersing the mixture in a polyvinyl alcohol solution, spray drying, steam activation at 650-700°C for 1-1.5 hours, and drying to obtain an activated carbon carrier; The polyvinyl alcohol solution comprises polyvinyl alcohol, deionized water and starch.

3. A copper-based sulfide mercury removal agent according to claim 2, characterized in that: The mass ratio of the coconut shell, modified graphene and polyvinyl alcohol solution is 1:0.2-0.3:6-7.

4. A copper-based sulfide mercury removal agent according to claim 2, characterized in that: The modified graphene preparation method comprises the following steps: adding graphite oxide to distilled water, ultrasonicating for 115-120 minutes to obtain a graphene oxide dispersion, adding polydiallyldimethylammonium chloride, heating in a water bath at 80-85°C for 3-4 hours to obtain a modified graphene dispersion, filtering, then dispersing in deionized water, adding nano-ZnS and sodium alginate, stirring at 60-65°C for 1-2 hours, and drying to obtain the modified graphene.

5. The copper-based sulfide mercury removal agent according to claim 1, characterized in that: The preparation method of the pretreated attapulgite binder comprises the following steps: (1) Grind and crush the attapulgite, sieve it, disperse it in hydrochloric acid, stir it for 1-2 hours, wash it with water, and heat it at 250-260°C for 2-3 hours to obtain attapulgite powder; (2) Dispersing the modified nano-titanium dioxide in deionized water, adding the attapulgite powder and carboxymethyl cellulose of step (1), wet ball milling to obtain a mixture, drying, and grinding to obtain a pretreated attapulgite binder.

6. A copper-based sulfide mercury removal agent according to claim 5, characterized in that: The mass ratio of the attapulgite, modified nano titanium dioxide and carboxymethyl cellulose is 1:0.4-0.5:0.1-0.

2.

7. The copper-based sulfide mercury removal agent according to claim 5, characterized in that: The preparation method of the modified nano-titanium dioxide comprises the following steps: dispersing the nano-titanium dioxide in a cerium nitrate solution, adding citric acid, adjusting the pH to 7-7.5, and calcining at 450-460° C. to obtain a mixture; The mixture is dispersed in deionized water, sodium tripolyphosphate and maltodextrin are added, stirred at a temperature of 60-65° C. for 1-2 hours, and dried to obtain modified nano-titanium dioxide.

8. The copper-based sulfide mercury removal agent according to claim 1, characterized in that: The preparation method of the copper sulfide powder comprises the following steps: dissolving basic copper carbonate in ammonia water to obtain a copper ammonia solution, drying to obtain diammine copper carbonate, calcining at 210-220° C. to obtain nano copper oxide, immersing the nano copper oxide in the ammonium sulfide solution, taking out, draining, and drying to obtain nano copper sulfide.

9. The copper-based sulfide mercury removal agent according to claim 1, characterized in that: The copper sulfide powder has a grain size of 80-90 nm and a particle size greater than 100 mesh.

10. The method for preparing a copper-based sulfide mercury removal agent according to claim 1, characterized in that: The method comprises the following steps: mixing copper sulfide powder, MnO2, an activated carbon carrier, a pretreated attapulgite binder and deionized water, stirring evenly, rolling into balls, and drying to obtain a copper-based sulfide mercury removal agent.

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