CN110170302A - Preparation method, material and application of in-situ nano-selenium carbon-based mercury removal adsorption material - Google Patents

Abstract

The invention discloses a preparation method, material and application of an in-situ nano-selenium carbon-based adsorption material for mercury removal. The invention is to pass sulfur dioxide gas into the carbon-based adsorption material loaded with selenium, and use the gas phase in-situ reduction method to prepare In-situ carbon-based nano-selenium adsorption material for mercury removal. The preparation method of the present invention is simple, and the preparation cost is low. The prepared in-situ grade nano-selenium carbon-based mercury removal adsorption material has the advantages of strong selenium crystal adhesion, not easy to fall off, and good dispersibility. There are many centers, strong mercury adsorption capacity, and long service life, which can meet the requirements of complex mercury-containing flue gas tail gas treatment in mercury-related industries, natural gas mercury removal, non-ferrous metal smelters, and coal-fired power plants.

Description

Preparation method, material and application of in-situ nano-selenium carbon-based mercury removal adsorption material

technical field

The invention relates to atmospheric mercury pollution control technology, in particular to a preparation method, material and application of an in-situ nanometer selenium carbon-based mercury removal adsorption material.

Background technique

Mercury (Hg) is one of the most toxic heavy metal elements in the natural environment. Mercury is very volatile at room temperature, and the generated mercury vapor exists in a single molecular state, and the saturation concentration of mercury in the air is relatively high. At 5-30°C, the partial pressure of mercury vapor is 0.04-0.37Pa, while the saturation concentration is 3.52-29.5mg/m ³ , and the heat of vaporization of mercury is 271.7J/g.

At present, industries involved in atmospheric mercury pollution include PVC industry, anthraquinone compound production industry, coal-fired power plants and their coal-fired boilers, petroleum refinery industry, chemical industry, steel and non-ferrous metal smelting industry, mercury-containing waste disposal and recycling industry, Cement industry, waste incineration power generation, soil heavy metal mercury pollution control projects, energy-related industries such as coke oven gas, water gas, natural gas and shale gas, batteries, electric light sources and medical equipment industries.

Among them, coal-fired power plants emit the most metallic mercury, with an annual emission of about 800-1200t/a, which is the main source of mercury pollution. With the increase in emissions, mercury pollution space in the country continues to expand. Under this pressure, the Mercury Convention came into effect for my country on August 16, 2017, with the goal of protecting human health and the environment from the hazards of man-made emissions and releases of mercury and its compounds.

In view of the fact that atmospheric mercury pollution is increasing nationwide and globally, mercury emission reduction standards are formulated by industry across the country. The mercury pollution emission standards of various industries are not consistent. The limit of mercury emission standards for flue gas from coal-fired power plants is 0.03mg/m ³ , the standard limit for flue gas mercury emission in tin, antimony, mercury industry and inorganic chemical industry is 0.01mg/m ³ , and the limit value for lead and zinc industry flue gas mercury emission standard is 0.05mg/m ³ .

It can be seen that the most stringent mercury emission standard limits for mercury-related pollution source gases are: mercury and its compounds≦0.01mg/m ³ .

There are many researches on air mercury pollution control at home and abroad, and they mainly focus on chemical reaction washing, reaction adsorption and physical adsorption. In summary, the main mercury removal methods are as follows:

(1) Mercury removal from coal-fired power plant fly ash, North China Electric Power University pioneered online halogen modification adsorption mercury removal technology for coal-fired power plant fly ash described in the invention patent [CN106732331A] and developed related equipment, with a comprehensive mercury removal rate of 90%, but If the mercury content in the import is too high, its use effect is not stable, and there is no corresponding mercury discharge standard for the mercury discharge in the export, and the elements iodine and bromine used are rare non-metallic elements, the price is high and it is not easy to recycle (in a certain Under medium and high temperature conditions, bromine and iodine elements are easily oxidized into Br ₂ , I ₂ , HBr, HI and other toxic vapors that are discharged into the atmosphere, causing secondary pollution and seriously damaging the ecological balance of the air and human health), comprehensive high cost. The invention patent [CN103495322A] described "an integrated device and method for dust removal and mercury removal", although the method is good, it does not mention the problem of mercury emission compliance, and the process is relatively complicated, so it cannot be really used in industrial production.

(2) Activated carbon demercuration, the adsorbent for flue gas demercuration and its preparation method described in the invention patent [CN101497029] uses low-cost sulfur and activated carbon to make sulfur-loaded activated carbon, but does not specify the mercury removal efficiency and The standard emission limits that can be achieved after mercury removal cannot really prove the adsorption effect of sulfur-loaded activity on mercury. The flue activated carbon injection method (ACI) described in the document "Activated Carbon Injection Technology for Controlling Mercury Emissions in Coal-fired Power Plants" by Zhou Qiang and others is the most mature and feasible technology for reducing mercury emissions in coal-fired power plants. It has been widely used in coal-fired power plants in the United States. The development of ACI technology in the United States has gone through laboratory tests, pilot tests, and field tests. At present, there are still problems such as high cost, large concentration range of acid gases in flue gas, and short residence time of adsorbents.

Plasma mercury removal, a flue gas dedusting and mercury removal device with a plasma reactor combined with a film-coated filter bag described in the invention patent [CN105709597A] and its treatment method, the oxidation rate of plasma to elemental mercury is only 70%, which cannot reach To 100% oxidation efficiency, the Mn-Ce/TiO ₂ catalyst polytetrafluoroethylene layer filled at the rear end has a thin film thickness (if the thickness is thicker, the space resistance will increase, and the exhaust gas will hardly pass through the system normally, and the system will paralysis), mercury vapor easily penetrates the catalyst layer, and it is difficult to ensure that the remaining 30% of elemental mercury is catalyzed and adsorbed for a long time, and the total mercury removal efficiency is between 65% and 92%, and the mercury removal efficiency is not stable . The double-tower plasma-coupled sodium-based absorption flue gas deep purification device and method described in the patent [CN105056723A] does not mention the removal rate of mercury, and whether elemental mercury can meet the requirements of the national emission limit standard for mercury It has not been explained, and it cannot be proved that it can be normally applied to the industrial production process, and this technology is not yet mature.

(4) Amalgam-type mercury removal agent, a preparation method of a silver-based mercury removal agent described in the invention patent [CN104645927A], which does not explain the mercury removal effect that this type of mercury removal agent can achieve, and the mercury removal of mercury-containing gas The mercury content of the final tail gas is uncertain, and the mercury emission limit of the national standard that can be achieved is uncertain. This kind of mercury removal technology is immature. Honeywell produces UOP HgSIVTM molecular sieve renewable adsorbent, which can be used for the adsorption of mercury in natural gas, but this kind of adsorbent can only be used for mercury removal of natural gas in small quantities. It is suitable for non-ferrous metal smelting, coal-fired power plants, and mercury recovery industries. The use cost of this kind of adsorbent is bound to be high. Amalgam-based adsorbents will be expensive to use under large-scale flue gas conditions, and are not really used under ultra-large flue gas flow conditions.

(5) Selenium-loaded adsorbent, a nano-selenium-loaded activated carbon and its chemical preparation and application described in the invention patent [CN106582517A] mentioned that sodium selenite is dispersed in polyvinyl alcohol aqueous solution, and activated carbon is added, Reduction with ascorbic acid, drying to obtain activated carbon loaded with nano-selenium, the mercury removal efficiency is between 94% and 99%, but according to the content of [0007] in this patent, this type of selenium-loaded activated carbon is mainly used in new research and development Masks cannot be used in the treatment of large-scale mercury-containing flue gas and mercury-containing tail gas from other important mercury-related industries. Invention patents [CN107051045A] and [CN106902776A] provide sponges loaded with nano-selenium and their chemical preparation and application, and the preparation method of mercury-removing wallpaper. In this method, the sponge is placed in a polydopamine solution, and sodium selenite is adsorbed. Reduction to obtain sponges loaded with nano-selenium. The production process is prone to waste water. The mercury-containing sponge after mercury-containing gas demercuration cannot be treated. The mercury emission limit that can be achieved by the demercury gas has not been defined.

The mercury adsorbents prepared in the above 3 patents [CN106582517A], [CN107051045A] and [CN106902776A] mainly have the following defects:

①Reduction is carried out in aqueous solution. The reducing agent ascorbic acid (VC) is a strong organic reducing agent. When PH≦4, its redox potential is 0.166V, while E _Se ⁺⁴ _/Se ⁰ =0.74V, high The nano-selenium particles generated under the reduction potential are easy to agglomerate, and finally sponge-type selenium particles are formed on the activated carbon. The surface is spherical and smooth, with fewer active sites, resulting in a decrease in the adsorption activity of the material for mercury;

② Elemental selenium is insoluble in water. Due to the influence of water molecules on the weak wettability of selenium particles, the reduced selenium is easily eluted by aqueous solution, and the spherical selenium particles float in the solution, resulting in a large amount of active selenium on the carbon-based material. Adhering to activated carbon or sponge, the adsorption activity of mercury is low.

③After treating mercury-containing gas with this material, the mercury-containing waste generated at the end is likely to cause secondary mercury pollution.

④In the above three patents, there is no mention of the state’s limit value for the emission of mercury and its compounds in mercury-containing tail gas from various mercury-related industries, nor does it explain the industrialization of the sponges loaded with nano-selenium and activated carbon loaded with nano-selenium. Whether the mercury content in the tail gas after mercury-containing flue gas can meet the mercury emission limit stipulated by the Ministry of Environmental Protection of the People's Republic of China, therefore, it cannot really be applied to complex containing large amounts of water, sulfur dioxide, nitrogen oxides, particulate matter, carbon monoxide, carbon dioxide and other heavy metals. Mercury fume treatment.

The present invention aims to overcome the above-mentioned technical defects. The purpose of the present invention is to use the in-situ reduction characteristics of the gaseous reducing agent sulfur dioxide to reduce the selenide adsorbed on the carbon-based material in-situ to generate nano-selenium, which is coated on the outer surface and inner surface of the carbon-based material. On the surface, in large, medium and small pores, the carbon-based selenium-loaded mercury removal material is used for deep purification and removal of mercury in tail gas containing mercury through fixed bed adsorption, powder spraying, fluidized adsorption, etc., and a truly mercury removal process has been found. Short, low-cost, high-efficiency, and easy-to-recycle adsorbents are green, environmentally friendly, and high-efficiency gas-standard mercury removal methods, so that various types of mercury-containing flue gas can be discharged up to standard. Activated carbon loaded with nano-selenium can be used in the industries mentioned above, especially coal-fired power plants, steel and non-ferrous smelting industries, PVC production industries, mercury chemical product processing industries, mercury-containing waste comprehensive recycling industries, natural gas industries, petrochemical industries , waste incineration and other important mercury-related industries in-depth purification and standard discharge process.

Contents of the invention

The object of the present invention is to provide an in-situ grade nano selenium carbon-based mercury removal adsorption material, its preparation method and application. The preparation method of the present invention is simple, and the preparation cost is low. The prepared in-situ grade nano-selenium carbon-based mercury removal adsorption material has the advantages of strong selenium crystal adhesion, not easy to fall off, and good dispersibility. There are many centers, strong mercury adsorption capacity, and long service life, which can meet the requirements of complex mercury-containing flue gas tail gas treatment in mercury-related industries.

The technical solution of the present invention: the preparation method of the in-situ nano-selenium carbon-based adsorption material for mercury removal, by passing sulfur dioxide gas into the carbon-based adsorption material loaded with selenium, and using the gas phase in-situ reduction method to prepare the in-situ nano-selenium carbon based mercury removal adsorbents.

In the above-mentioned preparation method of in-situ nanometer selenium ^- carbon-based mercury removal adsorption material, the mass concentration of the sulfur dioxide gas is greater than 1 ppm; 24h.

In the aforementioned preparation method of in-situ carbon-based nanometer selenium-based mercury-removing adsorbent, the mass concentration of the sulfur dioxide gas is greater than ¹ ppm; 18h.

In the aforementioned method for preparing the in-situ carbon-based nano-selenium-based adsorbent for mercury removal, the selenium-loaded carbon-based adsorbent is prepared by immersing the carbon-based adsorbent in a selenium-containing solution.

In the above-mentioned preparation method of in-situ carbon-based nano selenium-based adsorbent for mercury removal, the carbon-based adsorbent material includes biomass charcoal, graphene or silicon carbide.

In the aforementioned method for preparing the in-situ carbon-based nano-selenium-based mercury-removing adsorbent, the biochar includes activated carbon and microcrystalline carbon.

In the above-mentioned preparation method of in-situ carbon-based nano selenium-based mercury removal adsorption material, the concentration of selenium in the selenium-containing solution is 0.1-600 g/L.

In the above-mentioned preparation method of in-situ carbon-based nano selenium-based mercury removal adsorption material, the concentration of selenium in the selenium-containing solution is 5-100 g/L.

In the above-mentioned preparation method of in-situ carbon-based nanometer selenium-based mercury removal adsorption material, the selenium-containing solution is a solution of a +4-valent or +6-valent selenium compound.

In the preparation method of the aforementioned in-situ nanometer selenium-based carbon-based mercury removal adsorption material, the selenium-containing solution includes the selenium-containing solution obtained after processing selenium-containing mud, selenium-containing waste residue or selenium-containing smoke, or acid and alkali will A selenium-containing solution obtained by dissolving a selenium compound, or a solution of selenium dioxide, sodium selenite, sodium selenate or potassium selenite.

In the aforementioned method for preparing the in-situ nano-selenium carbon-based mercury removal adsorption material, the in-situ nano-selenium carbon-based mercury removal adsorption material is prepared according to the following steps:

(a) Selection and screening of carbon-based adsorption materials;

(b) dissolving the selenium compound in water to obtain a selenium-containing solution;

(c) adding the carbon-based adsorption material into the selenium-containing solution to impregnate the selenide in the adsorption solution, the impregnation and adsorption temperature is 25-99°C, and the adsorption time is 0.01-24h;

(d) Liquid-solid separation to obtain a carbon-based adsorption material loaded with selenium;

(e) drying the carbon-based adsorption material loaded with selenium at 80-150°C for 1-24 hours;

(f) The carbon-based adsorption material loaded with selenium is loaded into the reactor, and the gas containing sulfur dioxide is introduced to perform in-situ generation of nano-selenium, and the in-situ nano-selenium carbon-based adsorption material for mercury removal is obtained.

In the above-mentioned preparation method of in-situ carbon-based nano selenium-based mercury removal adsorption material, in the step (b), 0.01% sodium dodecylsulfonate containing selenium solution is added as a dispersant.

In the above-mentioned preparation method of in-situ carbon-based nanometer selenium-based mercury removal adsorption material, the adsorption time in the step (c) is 8-20 hours.

The adsorption material prepared by the aforementioned in-situ-level nano-selenium carbon-based mercury removal adsorption material preparation method, the adsorption material includes carbon-based adsorption materials and nano-selenium attached to the outer surface, inner surface or pores of the carbon-based adsorption material , the nano-selenium is obtained by reduction of sulfur dioxide gas.

In the aforementioned adsorbent material, the amount of selenium in the adsorbent material is 0.001%-90%.

In the aforementioned adsorbent material, the amount of selenium in the adsorbent material is 0.5%-35%.

The application of the aforementioned adsorbent material in the treatment of mercury-containing flue gas tail gas in natural gas plants, non-ferrous metal smelters, coal-fired power plants or mercury recovery industries.

Compared with the prior art, the present invention has the following advantages:

①Compared with the use of ascorbic acid reduction in aqueous solution to generate nano-selenium, the reduction condition of the present invention is gas-solid phase contact reduction, the reduction condition is milder, and the reduced selenium nucleates and grows up on activated carbon with nano-sized selenium crystals, It has strong adhesion and is not easy to fall off; it solves the defects that the nano-selenium particles are easy to fall off in the aqueous solution and the selenium nanoparticles are easy to agglomerate when the nano-selenium is prepared by reduction in the aqueous solution.

②Compared with the reduction of ascorbic acid in aqueous solution to generate nano-selenium, the present invention uses gas-phase in-situ reduction, and there are in-situ uniform growth of nano-sized selenium crystals in all tiny directions of the carbon-based adsorption material, and the dispersion is relatively high. Well, the number of active centers of selenium on the carbon-based adsorption material is increased, and the reactivity of nano-selenium particles on the carbon-based adsorption material is improved.

The inventors have shown through experimental analysis that in the process of ascorbic acid reducing nano-selenium, the reaction is carried out in the solution. Due to the collision of liquid molecules, there is migration and aggregation of nano-selenium active sites. The particle size of selenium is between 120-150nm, and the The invention adopts sulfur dioxide to be reduced in the gas phase, and the nano-selenium particle size is between 80-100nm. Under the same selenium loading condition, the active sites are smaller and the distribution is more uniform.

③The in-situ nano-selenium carbon-based adsorption material prepared by the present invention has stronger affinity and adsorption capacity for mercury, and can be applied to coal-fired power plants, steel and non-ferrous smelting industries, PVC production industries, and mercury chemical product processing industries , mercury-containing waste comprehensive recycling industry, natural gas industry, petrochemical industry, waste incineration and other important mercury-related industries for deep purification of mercury-containing flue gas. Compound≦0.01mg/m ³ , reaching the national emission standard limits for various types of mercury and its compounds.

The inventor obtained through experimental analysis:: using conventional adsorption materials with the same selenium load to remove mercury-containing tail gas, the mercury removal efficiency of nano-selenium obtained by reducing ascorbic acid is 93%, and the mercury removal efficiency of the adsorption material of the present invention is 99%. %. Activated carbon loaded with in-situ nano-selenium can deeply purify mercury-containing flue gas through fixed-bed adsorption, spraying, and fluidization.

The carbon-based adsorption material loaded with in-situ nano-selenium has good selenium dispersibility, has more active sites and active centers for mercury adsorption, and has a long service life. The carbon-based adsorbent material loaded with in-situ nano-selenium The service life of mercury-containing tail gas can reach 8000 hours, but the service life of the adsorbent with the same selenium loading obtained by using ascorbic acid reduction can only reach 6000 hours

In summary, the preparation method of the present invention is simple and the preparation cost is low. The prepared in-situ nano-selenium carbon-based mercury removal adsorption material has the advantages of strong selenium crystal adhesion, not easy to fall off, and good dispersibility. There are many active sites and active centers, strong mercury adsorption capacity, and long service life, which can meet the requirements of complex mercury-containing flue gas tail gas treatment in mercury-related industries.

Detailed ways

The following examples further illustrate the present invention, but are not as the basis for limiting the present invention.

Example 1. A method for preparing an in-situ carbon-based nanometer selenium-based mercury removal adsorption material. The carbon-based adsorption material loaded with selenium is prepared by impregnating the activated carbon of the carbon-based adsorption material in a selenium-containing solution. In situ carbon-based nano-selenium-based adsorbents for mercury removal, the gas-phase in-situ reduction method is used to prepare in-situ carbon-based adsorbents for mercury removal;

The above-mentioned in-situ nano-selenium carbon-based mercury removal adsorption material is prepared according to the following steps:

(a) Select activated carbon, sieve to remove impurities, and the particle size is 3mm;

(b) Dissolve selenium dioxide in an aqueous solution, add 0.01% sodium dodecylsulfonate as a dispersant, and prepare an aqueous solution containing 200 g/L of selenium, product A;

(c) Pour activated carbon into product A for full impregnation, impregnating selenium dioxide in the adsorption solution, the impregnation adsorption temperature is 85°C, and the time is 6h;

(d) filtering and separating to obtain activated carbon loaded with selenium dioxide;

(e) Dry the activated carbon loaded with selenium dioxide at 120°C for 12 hours;

(f) Put the activated carbon loaded with selenium dioxide obtained by drying into the in-situ generator, continuously feed the gas with a sulfur dioxide concentration of 10%, and control the gas flow rate to 3000m ³ /h, and generate the selenium dioxide on the activated carbon. At this time, the selenium is attached to the outer surface and inner surface of the activated carbon and the pores of the activated carbon. The reduction time is controlled to 4 hours, and the in-situ nano-selenium activated carbon is obtained. The selenium content 10%.

Through the above steps, the prepared in-situ nano-selenium activated carbon adsorption material is loaded into a fixed adsorption bed, which can adsorb mercury in various mercury-containing flue gases. After the mercury-containing flue gas is treated, the mercury and its compounds in the flue gas are 0.0029mg/m ³ , lower than the mercury emission limit of 0.01mg/m ³ , reaching the most stringent national mercury emission standard limit for mercury-containing flue gas.

Example 2. A method for preparing an in-situ carbon-based nanometer selenium-based mercury removal adsorption material. The carbon-based adsorption material loaded with selenium is prepared by impregnating the activated carbon of the carbon-based adsorption material in a selenium-containing solution. In situ carbon-based nano-selenium-based adsorbents for mercury removal, the gas-phase in-situ reduction method is used to prepare in-situ carbon-based adsorbents for mercury removal;

The above-mentioned in-situ nano-selenium carbon-based mercury removal adsorption material is prepared according to the following steps:

(a) Select activated carbon, sieve to remove impurities, and the particle size is 0.1mm;

(b) Dissolve selenium dioxide in an aqueous solution, add 0.01% of the dispersant sodium dodecylsulfonate, and prepare an aqueous solution containing 600g/L of selenium, product A;

(c) Pour activated carbon into product A for full impregnation, impregnation with selenium dioxide in the adsorption solution, the impregnation adsorption temperature is 40°C, and the time is 24h;

(d) filtering and separating to obtain activated carbon loaded with selenium dioxide;

(e) Dry the activated carbon loaded with selenium dioxide at 120°C for 12 hours;

(f) Put the activated carbon loaded with selenium dioxide obtained by drying into the in-situ generator, continuously feed the gas with a sulfur dioxide concentration of 30%, and control the gas flow rate to 100,000m ³ /h, and process the selenium dioxide on the activated carbon At this time, the selenium is attached to the outer surface and inner surface of the activated carbon and the pores of the activated carbon. The reduction time is controlled to 24 hours, and the in-situ nano-selenium activated carbon is obtained. The selenium content 30%.

Through the above steps, the in-situ nano-selenium activated carbon adsorption material prepared can absorb mercury in various types of mercury-containing flue gas by means of activated carbon injection in coal-fired power plants. After the mercury-containing flue gas is treated, the mercury and its compounds in the flue gas It is 0.0005mg/m ³ , which is lower than the strictest national mercury emission standard limit for mercury-containing flue gas—mercury and its compounds≦0.01mg/m ³ .

Example 3. A method for preparing an in-situ carbon-based nanometer selenium-based mercury removal adsorption material. The carbon-based adsorption material loaded with selenium is prepared by impregnating the activated carbon of the carbon-based adsorption material in a selenium-containing solution. In situ carbon-based nano-selenium-based adsorbents for mercury removal, the gas-phase in-situ reduction method is used to prepare in-situ carbon-based adsorbents for mercury removal;

The above-mentioned in-situ nano-selenium carbon-based mercury removal adsorption material is prepared according to the following steps:

(a) Select activated carbon, sieve to remove impurities, and the particle size is 0.1mm;

(b) Dissolve selenium dioxide in an aqueous solution, add 0.01% sodium dodecylsulfonate as a dispersant, and prepare an aqueous solution containing 50 g/L of selenium, product A;

(c) Pour activated carbon into product A for full impregnation, impregnation with selenium dioxide in the adsorption solution, the impregnation adsorption temperature is 25°C, and the time is 1h;

(d) filtering and separating to obtain activated carbon loaded with selenium dioxide;

(e) Dry the activated carbon loaded with selenium dioxide at 120°C for 12 hours;

(f) Put the activated carbon loaded with selenium dioxide obtained by drying into the in-situ generator, continuously feed the gas with a sulfur dioxide concentration of 100ppm, and control the gas flow rate to 100m ³ /h, and in-situ generate the selenium dioxide on the activated carbon. Reduction, generate nano-selenium on the activated carbon, the selenium at this time is attached to the outer surface of the activated carbon, the inner surface and the large and small pores of the activated carbon, the reduction time is controlled for 12 hours, and the in-situ grade nano-selenium activated carbon is obtained, and its selenium content is 5%.

Through the above steps, the in-situ nano-selenium activated carbon adsorption material prepared can absorb mercury in various types of mercury-containing flue gas by means of activated carbon injection in coal-fired power plants. After the mercury-containing flue gas is treated, the mercury and its compounds in the flue gas It is 0.0001mg/m ³ , which is lower than the strictest national mercury emission standard limit for mercury-containing flue gas—mercury and its compounds≦0.01mg/m ³ .

Example 4. An in-situ nano-selenium carbon-based mercury removal adsorption material is prepared by selecting the carbon-based adsorption material graphene, and taking the selenium-containing solution obtained after treating the selenium-containing mud by hydrometallurgy, and the remaining steps are the same as those in 2. .

Example 5. An in-situ nano-selenium carbon-based mercury removal adsorption material is prepared by selecting carbonized silicon carbide as the carbon-based adsorption material, taking 300g/L sodium selenite solution, and carrying out the rest of the steps as in step 1.

Example 6. An in-situ nano-selenium non-carbon-based mercury removal adsorption material is prepared by selecting carbon-based adsorption material activated carbon, taking 200g/L sodium selenate solution, and performing the remaining steps in the same manner as in step 3.

Example 7. An in-situ nano-selenium non-carbon-based mercury removal adsorption material is prepared by selecting carbon-based adsorption material microcrystalline carbon, taking 400g/L potassium selenite solution, and performing the remaining steps in the same manner as in step 3.

Example 8. An in-situ nano-selenium non-carbon-based mercury removal adsorption material. The carbon-based adsorption material microcrystalline carbon is selected, and the selenium-containing solution obtained after treating the selenium-containing waste residue by hydrometallurgy is taken. The remaining steps are the same as the steps in 1. prepared.

Example 9. An in-situ nano-selenium non-carbon-based mercury removal adsorption material, select carbon-based adsorption material graphene, and take the selenium-containing solution obtained after treating selenium-containing fumes through hydrometallurgical methods, and the remaining steps are the same as those in step 3. Preparation get.

Example 10. An in-situ nano-selenium non-carbon-based mercury removal adsorption material is prepared by selecting carbonized silicon carbide as the carbon-based adsorption material, taking 400g/L sodium selenite solution, and performing the remaining steps in the same manner as in step 3.

Example 11. An in-situ nano-selenium non-carbon-based mercury-removing adsorption material is selected from the carbon-based adsorption material silicon carbide, and the selenium-containing solution obtained after the selenium-containing mud is treated by a hydrometallurgical method, and the remaining steps are the same as the steps in 1. prepared.

Example 12. An in-situ nano-selenium non-carbon-based mercury removal adsorption material is prepared by selecting activated carbon as a carbon-based adsorption material, and taking a selenium-containing solution obtained after treating selenium-containing waste residue by hydrometallurgical methods, and the remaining steps are the same as those in step 1. .

Example 13. An in-situ-level nano-selenium non-carbon-based mercury removal adsorption material is prepared by selecting carbon-based adsorption material mesoporous activated carbon, taking 350g/L potassium selenite solution, and performing the remaining steps in the same manner as in step 2.

Claims (17)

1. The preparation method of the in-situ nano-selenium carbon-based adsorption material for mercury removal is characterized in that: the in-situ nano-selenium carbon is prepared by gas-phase in-situ reduction by passing sulfur dioxide gas into the carbon-based adsorption material loaded with selenium based mercury removal adsorbents. 2. The preparation method of in-situ grade nano selenium carbon-based mercury removal adsorption material according to claim 1, characterized in that: in the method, the mass concentration of sulfur dioxide gas is greater than 1 ppm; the flow rate of sulfur dioxide gas is 0.1 to 10 million m ³ /h, the time of introducing sulfur dioxide gas is 0.01~24h. 3. The method for preparing in-situ carbon-based nano-selenium-based mercury removal adsorption material according to claim 2, characterized in that: the mass concentration of the sulfur dioxide gas is greater than 1 ppm; the flow rate of the sulfur dioxide gas is 1 to 1 million m ³ / h, the time for introducing sulfur dioxide gas is 5 to 18 hours. 4. The preparation method of the in-situ grade nano selenium carbon-based adsorbent material for mercury removal according to claim 1, characterized in that: the carbon-based adsorbent material loaded with selenium is obtained by immersing the carbon-based adsorbent material in a selenium-containing solution prepared. 5. The method for preparing in-situ nano-selenium carbon-based mercury removal adsorption material according to claim 4, characterized in that: the carbon-based adsorption material comprises biomass charcoal, graphene or silicon carbide. 6 . The preparation method of in-situ nano selenium carbon-based mercury removal adsorption material according to claim 5 , characterized in that: the biochar includes activated carbon and microcrystalline carbon. 7 . The method for preparing in-situ nano selenium carbon-based mercury removal adsorption material according to claim 4 , wherein the concentration of selenium in the selenium-containing solution is 0.1-600 g/L. 8 . The method for preparing in-situ nano selenium carbon-based mercury removal adsorption material according to claim 7 , wherein the concentration of selenium in the selenium-containing solution is 5-100 g/L. 9 . The preparation method of in-situ nano selenium carbon-based mercury removal adsorption material according to claim 4 , characterized in that: the selenium-containing solution is a solution of +4-valent or +6-valent selenium compounds. 10. The preparation method of in-situ nanometer carbon-based selenium-based mercury removal adsorption material according to claim 9, characterized in that: the selenium-containing solution comprises selenium-containing mud, selenium-containing waste residue or selenium-containing smoke obtained after processing A selenium-containing solution, or a selenium-containing solution obtained by dissolving a selenium compound with an acid or an alkali, or a solution of selenium dioxide, sodium selenite, sodium selenate or potassium selenite. 11. The preparation method of the in-situ nano-selenium carbon-based mercury removal adsorption material according to claim 1, characterized in that: the in-situ nano-selenium carbon-based mercury removal adsorption material is prepared according to the following steps: (a) Selection and screening of carbon-based adsorption materials; (b) dissolving the selenium compound in water to obtain a selenium-containing solution; (d) Liquid-solid separation to obtain a carbon-based adsorption material loaded with selenium; (e) drying the carbon-based adsorption material loaded with selenium at 80-150°C for 1-24 hours; (f) The carbon-based adsorption material loaded with selenium is loaded into the reactor, and the gas containing sulfur dioxide is introduced to perform in-situ generation of nano-selenium, and the in-situ nano-selenium carbon-based adsorption material for mercury removal is obtained. 12. The method for preparing in-situ carbon-based nano-selenium-based mercury removal adsorption material according to claim 13, characterized in that: in the step (b), 0.01% sodium dodecylsulfonate containing selenium solution is added to make as a dispersant. 13. The method for preparing in-situ nano-selenium carbon-based mercury removal adsorption material according to claim 13, characterized in that: the adsorption time in the step (c) is 8-20 hours. 14. The adsorption material prepared by the method for preparing the in-situ nano-selenium carbon-based mercury removal adsorption material according to any one of claims 1-13, characterized in that: the adsorption material includes carbon-based adsorption materials and carbon-based adsorption materials attached to carbon Nano-selenium on the outer surface, inner surface or pores of the base adsorption material, the nano-selenium is obtained by reducing sulfur dioxide gas. 15. The adsorption material according to claim 14, characterized in that: the selenium content of the adsorption material is 0.001%-90%. 16. The adsorption material according to claim 15, characterized in that: the selenium content of the adsorption material is 0.5%-35%. 17. The application of the adsorption material according to any one of claims 14-16 in the treatment of mercury-containing flue gas tail gas in natural gas plants, non-ferrous metal smelters, coal-fired power plants or mercury recovery industries.