CN107159088B

CN107159088B - Mercury-containing material with lasting adsorption performance

Info

Publication number: CN107159088B
Application number: CN201710334404.8A
Authority: CN
Inventors: 张正洁; 陈扬; 冯钦忠
Original assignee: Zhongke Jingtou Environmental Science And Technology Jiangsu Co ltd
Current assignee: XUZHOU ZHENFENG NEW WALL MATERIAL Co.,Ltd.
Priority date: 2017-05-12
Filing date: 2017-05-12
Publication date: 2020-04-14
Anticipated expiration: 2037-05-12
Also published as: CN107159088A

Abstract

The invention relates to the field of environmental purification and protection, and discloses a mercury-containing material with lasting adsorption performance. Firstly, preparing a composite alumina ceramic material as a carrier by adopting an organic foam impregnation process, and then loading an active agent on the surface of the carrier and in micropores thereof by adopting an impregnation method, wherein the coverage area of the active agent is required to reach more than 85%. The elemental mercury is fixed by utilizing the oxidation effect of chloride ions, sulfate radicals and nitrate ions in the active agent on the mercury, the silver and the mercury are utilized to form amalgam reaction to dissolve the elemental mercury, and the great surface area of the porous ceramic is utilized to adsorb the valence-state mercury. And finally, recovering mercury by a low-temperature thermal desorption method, and realizing cyclic utilization of the carrier. The material has the advantages of large surface area, strong permeability, high compression strength, impact resistance, high temperature resistance, environmental friendliness, high chemical stability and the like, the carrier can be recycled, the mercury recovery is simple and feasible, and secondary pollution is avoided. In addition, the preparation process of the material is simple and the cost is low. Has good application potential and good social and economic benefits.

Description

Mercury-containing material with lasting adsorption performance

Technical Field

The invention relates to the field of environmental purification and protection, in particular to a durable nano-mercury material applied to treatment of mercury-containing waste gas in the processes of non-ferrous metal smelting, PVC chemical industry, waste incineration waste gas and coal emission.

Background

Mercury is one of heavy metal elements which are relatively strong in toxicity when being discharged into the atmosphere, and has great harm to human health and atmospheric quality. It is also a globally migrating pollutant and the problem of mercury pollution has become a global concern.

In order to reasonably control the mercury content in waste gas and flue gas discharged outwards in the production or working process of industries or departments such as chemical industry, mining, smelting, coal burning, hospitals, factories and the like, a large amount of research on the aspect of mercury removal technology is carried out abroadAnd (6) working. The mercury discharged in industrial production mainly comprises gaseous elementary mercury Hg and gaseous oxide mercury Hg²⁺And solid particulate mercury Hg. The mercury in coal-fired flue gas is removed by adopting activated carbon injection technology (ACI) in the United states, and activated carbon particles after absorbing the mercury are captured by a dust remover. Since mercury on the surface of the activated carbon is easy to evaporate and escape, and the mercury removal efficiency is reduced, the activated carbon is modified by halogen, sulfur, metal oxide and the like. Not only prevents mercury desorption, but also provides more mercury binding sites on the surface of the activated carbon, thereby improving the mercury removal capability. However, the adsorption capacity of activated carbon per unit volume is limited, which results in huge consumption of activated carbon and high operating investment cost of ACI technology. For this reason, some power plants utilize fly ash or other combustion byproducts to adsorb a portion of the gaseous mercury from the combustion of bituminous coals and begin to consider re-injecting the collected fly ash into the flue gas for mercury removal purposes. For example, sub-fugton corporation uses certain emissions from combustion units to remove mercury-containing materials, general-purpose companies use partially gasified coal for mercury removal, and the university of michigan regulatory commission uses unburned carbon from combustion byproducts to control mercury emissions. In general, the carbon-based adsorbent has low mercury removal efficiency and can adversely affect the comprehensive utilization of the fly ash of the coal-fired power station boiler. The calcium-based substances are easy to obtain and low in price, and can remove SO in the flue gas₂The effective desulfurizing agent of (1). The U.S. PSI agency discovered that zeolite materials have the ability to adsorb mercury and have been used as sorbents for industrial boilers to control mercury emissions. However, since zeolite itself has weak adsorption ability to mercury, in order to improve the mercury removal effect per unit volume of zeolite, zeolite can be treated with an additive to greatly improve the adsorption ability to mercury. However, calcium-based substances are easy to absorb moisture and fall off, are still in the laboratory research stage at present, and do not enter the industrial application stage. Selective Catalytic Reduction (SCR) denitration catalyst is used by Nippon Hitachi to remove mercury in tail gas of coal-fired power plants, and the SCR denitration catalyst is found to have oxidizing capability on mercury in flue gas of the power plants and can oxidize Hg⁰Oxidation to Hg²⁺And the mercury removal rate reaches over 75 percent. Meanwhile, the SCR catalyst is improved, and the mercury removal rate is over 85 percent. After the catalyst is used for 9500h, the oxidation activity of mercury is still above 0.85.

In recent years, China pays attention to the problems of mercury pollution and control, and researches on mercury control are carried out. The Shanghai university of transportation studies manganese-based composite oxides and their adsorption properties to zero-valent mercury. The manganese oxides prepared from different manganese sources have different adsorption properties on zero-valent mercury, wherein the manganese oxide prepared from manganese nitrate as the manganese source has higher adsorption property (the adsorption capacity of about 2.1mg/g at 100 ℃ for 10 h), and the adsorption property is related to the structure of the adsorbent and the valence state of manganese, and the high-valence manganese is more favorable for adsorption and oxidation of mercury. But with the disadvantage that in SO₂The desorption performance after adsorbing mercury under existing conditions is poor. Loading NaI, CuCl has been proposed₂、CuBr₂、FeCl₃The zeolite, calcium silicate and neutral alumina have high mercury removal efficiency. Some students use calcium-based adsorbents (CaO, Ca (OH)₂、CaCO₃、CaSO₄·2H₂O) to remove mercury, it was found that the calcium-based sorbent had a stronger adsorption capacity for combined mercury than activated carbon, but a weaker adsorption capacity for elemental mercury than activated carbon. SO (SO)₂And high temperature favors the adsorption of elemental mercury by the calcium-based adsorbent, but for HgCl₂The opposite is true for adsorption. Calcium-based sorbent to Hg²⁺The adsorption efficiency of (2) is high, but the removal efficiency of HgO is low, and the adsorption can be cooperatively removed by combining with an oxidation catalyst, but the problem of mercury reduction cannot be solved. One method of oxidizing and absorbing mercury with chlorine oxide is adopted, but chlorine ions are liable to corrode metal devices. The multi-stage combined desulfurization and denitration process of limestone, gypsum and an oxidant is adopted to remove mercury, but secondary pollution and mercury re-release problems are caused.

The coal gangue is solid waste discharged in the coal mining process and the coal washing process, and is a black and gray rock which has lower carbon content and is harder than coal and is associated with a coal bed in the coal forming process. The main component of which is Al₂O₃、SiO₂And in addition, Fe in different quantities₂O₃、CaO、MgO、Na₂O、K₂O、P₂O₅、SO₃And trace amount of rare earth elementsAnd (4) element. However, at present, the utilization rate of the coal gangue is extremely low due to the incomplete technology and unbalanced regional development. The open stacking of the coal gangue can generate a large amount of dust, and the coal gangue absorbs water and is easy to disintegrate, thereby generating a large amount of dust. The quality of the atmosphere in the mine will be deteriorated by the wind. The coal gangue contains combustible substances such as residual coal, carbonaceous mudstone, waste wood and the like, and is easy to self-ignite when being stacked in the open air, so that toxic gas is generated to pollute the environment.

Disclosure of Invention

Based on the problems, the invention provides a composite alumina ceramic porous material with a honeycomb structure or a net structure as a carrier, and a strong acid silver-containing solution is adopted to carry out activation treatment on the surface of the carrier, so that a mercury containing material with lasting adsorption performance on mercury in atmosphere, industrial waste gas and coal-fired flue gas is developed. The material has the advantages of large surface area, strong permeability, high compression strength, impact resistance, high temperature resistance, environmental friendliness, high chemical stability and the like, the carrier can be recycled, the mercury recovery is simple and feasible, and secondary pollution is avoided. Waste coal gangue is used as a raw material, waste is changed into valuable, the adsorbent beneficial to the environment can be prepared, and the accumulation amount of the coal gangue can be reduced. Because the coal gangue used as the waste is adopted, the waste is turned into treasure, and the production cost can be further reduced. In addition, the preparation process is simple, the cost is low, and the method has good application potential and good social and economic benefits.

In order to achieve the purpose, the invention provides the following technical scheme:

the technical key points of the material with lasting absorption performance are as follows: the composite ceramic material is prepared from 92-98 wt% of a composite ceramic carrier and 2-10 wt% of an active agent.

Further, the composite ceramic carrier is prepared by mixing the following components in a weight ratio of 1:3, and silica sol, wherein the main raw material comprises 30-35 wt% of Al₂O₃55-60 wt% of coal gangue and 5-10 wt% of charcoal powder or starch.

Further, the coal gangue comprises SiO₂52~55wt%、Al₂O₃16 to 36wt% and Fe₂O₃2~14wt%。

Further, the pH value of the mercury adsorbent solution is 1-5, and the concentration is 0.1-0.5 mol/L (by Ag)⁺Ion meter), silver sulfate, silver chloride or silver nitrate. The pH can be adjusted by hydrochloric acid or nitric acid. Preferably, the temperature of the mercury adsorbent solution is 20-35 ℃.

Further, the solvent of the mercury sorbent is tap water.

Furthermore, the compression strength of the composite ceramic carrier is 3.0-5.0 Mpa, and the surface roughness is 0.3-0.8 mm.

The preparation method of the nano-mercury material with lasting adsorption performance comprises the following steps:

step 1) adding 30-35 wt% of Al₂O₃The coal gangue powder is prepared by uniformly mixing main raw materials of 55-60 wt% of coal gangue and 5-10 wt% of charcoal powder or starch, and stirring the mixture in a weight ratio of 1:3, putting the mixture into silica sol, and continuously and uniformly stirring the mixture to obtain slurry for later use;

step 2) soaking the polyurethane foam with the porous structure into the slurry, taking out and drying;

step 3) repeating the step 2) until the pores of the polyurethane foam are filled with the slurry to obtain a ceramic blank;

step 4) roasting the ceramic blank at 1280-1390 ℃ for 4h, taking out, and naturally cooling to room temperature to obtain a composite ceramic carrier with a porous structure;

step 5) washing attachments on the surface of the composite ceramic carrier with water, and naturally drying for 2-4 h;

step 6) immersing the composite ceramic carrier into a mercury adsorbent solution with the concentration of 0.1-0.5 mol/L for 2-8 hours until gaps are filled with the mercury adsorbent, taking out the composite ceramic carrier, and naturally drying for 2-6 hours;

step 7) repeating the step 6) for 1-5 times;

step 8) drying the composite ceramic carrier for 2-6 h at 80 ℃; or dipping the carrier into a mercury adsorbent solution with the concentration of 0.1-0.5 mol/L, and evaporating the mercury adsorbent solution at 80 ℃ to obtain a finished product.

Further, the mercury adsorbent solution is an aqueous solution of more than one of silver sulfate, silver chloride or silver nitrate, wherein the pH value of the mercury adsorbent is 1-5, and the concentration of the mercury adsorbent is 0.1-0.5 mol/L.

Further, the polyurethane foam is net-shaped or honeycomb-shaped.

The invention has the advantages and beneficial effects that: the method crystallizes silver ions, chloride ions, sulfate ions and nitrate ions on the surface and in pores of the composite ceramic carrier with a mesh structure or a honeycomb structure, and can ensure that the coverage area of the adsorbent reaches over 85 percent only by a plurality of simple cyclic processes of soaking, drying by distillation, re-soaking and re-drying by distillation. On one hand, the ceramic body is made into a porous structure, so that the flue gas carrying mercury can pass through conveniently; on the other hand, the ceramic has a microporous structure, can contain adsorbent crystals (silver sulfate, silver chloride and silver nitrate) capable of absorbing mercury to the maximum extent, and can be locked in micropores or pores after absorbing mercury, so that toxic substances are prevented from flowing out. The concentration of the activating agent is preferably 0.1-0.5 mol/L, so that the cost can be saved on the premise of ensuring the coverage rate and the adsorption effect of the activating agent. Although, in general, it is understood that within this concentration range, the activator coverage is linear with concentration, i.e., the coverage is higher at higher concentrations. At the lowest critical concentration, i.e. 0.1mol/L, a coverage of 85% on the surface of the ceramic channels is already achieved (which already gives good adsorption in normal use, but depending on the mercury content, there is a further need for an adsorption capacity per unit volume for a prolonged replacement frequency), and if sufficient time is available, complete coverage is achieved. And when the concentration is lower than 0.1mol/L, the active agent solution and the ceramic carrier mutually rob active groups in the active agent, so that the coverage rate of 85 percent cannot be always achieved, and the adsorption effect of the ceramic in unit volume is obviously reduced.

And from metallographic observation, when the concentration is at the highest critical concentration, namely 0.5mol/L, even if the coverage area reaches 100%, the crystallized active agent still continuously adsorbs active groups in the active agent due to the action of intermolecular force, so that the ceramic carrier is in a supersaturated state, the capacity of the active groups is further improved, and the ion exchange balance between the ceramic carrier and the active agent solution is realized. In this case, even if the concentration of the active agent is increased, the excess active groups are present in the solution only in a free state, and do not form a bond with the ceramic support, and the metallographic state does not change significantly.

In actual production, it is difficult to maintain the concentration at a value between the upper and lower critical values by technical means, and usually a concentration range is preset, the sampling frequency is determined according to the yield, and when the concentration is lower than the lower limit of the set concentration, the pH is adjusted and the concentration of the active agent is adjusted to the upper limit.

Mercury exists in exhaust gas mainly in three forms, namely mercury simple substance vapor, mercury simple substance particles and valence state mercury. And taking the crystallized silver sulfate, silver chloride and silver nitrate attached to micropores of the composite ceramic carrier as adsorbents, reacting with mercury simple substance vapor, and fixing in the microporous structure of the carrier. On one hand, the silver elementary substance generated after roasting can form amalgam with mercury elementary substance steam, and the amalgam is dispersed and adhered in the microporous structure of the ceramic carrier, so that accumulation cannot occur and leakage cannot occur from the microporous structure; on the other hand, the valence state mercury and the particle state mercury are paved and adsorbed in the micropores by utilizing the good adsorbability of the micropore surface area of the porous ceramic, and finally, the mercury vapor, the mercury simple substance particles and the valence state mercury are completely adsorbed and removed. The main reaction principle is as follows: 2Ag⁺+Hg→2Ag+Hg²⁺The main reaction involved is ① Hg +2AgNO₃→Hg(NO₃)₂+2Ag；②Hg+Ag₂SO₄→2Ag+ HgSO₄；③Hg+2AgCl→2Ag+HgCl₂；④xHg+yAg→Hg_xAgy。

The preparation raw materials are easy to obtain, and particularly, the ceramic main material is coal gangue which is often used as waste, so that the aims of utilizing waste and treating pollution can be fulfilled; tap water is selected as the solvent of the active agent without considering the concentration of free chlorine in the tap water; the driving body is made of the honeycomb polyurethane foam which is easy to prepare, so that the production cost is greatly reduced; the viscosity agent adopts silica sol with high stability, so that the product quality of the composite ceramic carrier is ensured. The drying, roasting and activating of the ceramic body can be carried out under normal pressure, the requirement on the sealing property is low, and the preparation cost can be reduced. The prepared composite ceramic body is a macroporous ceramic, and the aperture is 500 nm-800 nm.

Although the preparation method of the invention has the similar advantages in the process of preparing the porous ceramic by the wet foaming method in the prior art, the surface activation of the porous ceramic in the prior art is mostly to improve the inherent characteristics of the porous ceramic, for example, CMC, lignin and PEI with different concentrations are adopted to improve the properties of the ceramic body such as compressive strength, porosity and the like. The compression resistance and the seismic resistance of the ceramic material can be improved by adding trace (0-3 wt%) rare earth elements (such as Ga, V, Ti and Co), and the rare earth elements can be directly obtained from coal gangue without additional addition, so that preparation components are reduced, and the production cost is indirectly reduced.

The thermal decomposition of polyurethane foam known in the prior art mainly occurs between 240 ℃ and 440 ℃, and the polyurethane foam is slightly weightless between 440 ℃ and 500 ℃ and 600 ℃, and the weightlessness is caused by the gas components such as carbon dioxide, carbon monoxide, hydrogen cyanide, formaldehyde and the like overflowing due to the combustion or thermal decomposition of the polyurethane. When the temperature exceeded 700 c, the weight hardly changed. And the gas generates stress to the ceramic body in the overflowing process, so that the body is easy to damage and even collapse. Therefore, the temperature is slowly raised in the temperature range of 240-600 ℃, and the temperature is preserved at the sintering point, so that the blank is prevented from being damaged.

In the preparation process, a certain amount of charcoal powder or starch is added into the slurry, and the dried polyurethane foam with the pores filled with the slurry is immediately and directly put into the temperature of 1280-1390 ℃ for roasting, so that the stability of the blank can be still ensured even though the temperature is not slowly raised. The slow heating or heat preservation process is not needed, the preparation time is naturally shortened, the energy is saved, and the process flow is simplified, so that the production cost is greatly reduced, and the production efficiency is improved. After the charcoal powder or starch uniformly dispersed in the slurry is heated to expand or burn, the roughness of the ceramic can be increased, and further the surface area is increased, so that the effective volume of the active agent is increased.

And the material after absorbing mercury can recover mercury by a high-temperature (400-600 ℃) low-temperature thermal desorption method and enable the carrier to be regenerated and recycled, so that the use cost is reduced, and the purposes of energy conservation and environmental protection are realized. The accumulated quantity of the adsorbed mercury in the porous ceramic is large, so that the mercury can be conveniently recovered in a centralized way, and the mercury recovered by a low-temperature thermal desorption method can be recycled. Not only is the manufacturing and use costs reduced, but also the absorbed mercury can be reused, which is not common in the prior art.

In addition, when the ceramic body is used, the whole ceramic in the mercury absorption process has an obvious weight increasing process, when the ceramic body reaches a saturated state, the weight basically cannot be changed, and the mercury containing material can be matched with a gravity sensor to be used by utilizing the phenomenon so as to detect the saturated state of the mercury containing material, so that the mercury containing material can be replaced timely. Avoid the problem that the adsorption activity of the material cannot be controlled when the use state of the material cannot be observed. Obviously, this usage is not applicable to non-solid materials.

In conclusion, the invention has the characteristics of simple preparation process, low cost, capability of recycling the carrier, capability of realizing continuous adsorption and no environmental pollution, and has good application potential and good social and economic benefits.

Drawings

FIG. 1 is a microstructure of the pore structure of a ceramic support;

FIG. 2 is a microscopic topography of the surface of the ceramic support after activation;

FIG. 3 is a microscopic topography of the surface activation region topography of the ceramic carrier after activation;

FIG. 4 is a microscopic topography of a cross-section of a hole beam in a ceramic carrier after activation;

FIG. 5 is a graph showing the average concentration of mercury at the inlet and outlet of mercury per day versus time in a test atmosphere in which a ceramic support is impregnated with 0.15mol/L silver nitrate aqueous solution;

FIG. 6 is a graph of the average mercury adsorption efficiency per day versus time for a 0.15mol/L silver nitrate aqueous solution impregnated ceramic support;

FIG. 7 is a graph of the average mercury capacity per day versus time for a 0.15mol/L aqueous silver nitrate impregnated ceramic support.

Detailed Description

The following describes the present invention in detail with reference to the embodiments with reference to fig. 1 to 7. The nano-mercury material with the lasting adsorption performance is prepared from 90-98 wt% of a composite ceramic carrier and 2-10 wt% of a mercury adsorbent. The composite ceramic carrier is prepared by mixing the following components in percentage by weight of 1:3 as the main raw material and as the adhesiveThe main raw material of the silicon sol as a binder comprises 30-35 wt% of Al₂O₃55-60 wt% of coal gangue and 5-10 wt% of charcoal powder or starch. Because of the high viscosity of silica sol, continuous stirring is required during compounding. In general, the coal gangue components mined in the same region are relatively fixed, but the invention still preferably adopts the coal gangue components containing SiO₂52~55wt%、Al₂O₃16~36wt%、Fe₂O₃2-14 wt% and the balance of coal gangue of rare earth elements. The mercury adsorbent solution is an aqueous solution of more than one of silver sulfate, silver chloride or silver nitrate with pH of 1-5 and concentration of 0.1-0.5 mol/L (calculated by Ag + ions). The solvent can be tap water, distilled water or purified water, and tap water is preferred because tap water is convenient to obtain and contains chloride ions required by preparation. The composite ceramic carrier with the porous structure, which has the compression strength of 3.0-5.0 Mpa, the surface roughness of 0.3-0.8 mm and the mercury adsorbent coverage area of more than 85%, can be prepared by the above proportioning.

The preparation method comprises the following steps:

example 1

In this example, the composite ceramic carrier prepared according to the method described in the present invention will include 33wt% of Al₂O₃60wt% of coal gangue, 7wt% of charcoal powder and silica sol, wherein the weight ratio of the main raw materials to the silica sol is 1:3 mixing into slurry, then immersing the polyurethane organic foam with the three-dimensional reticular framework structure or the honeycomb structure into the slurry, evaporating to dryness, and repeating for several times until the pores in the reticular framework foam are full. And finally, roasting for 4 hours at 1300-1390 ℃, and air-cooling to room temperature to prepare the reticular or honeycomb composite ceramic carrier. The carrier samples were assembled and placed at an average concentration of 0.1mg/m³The sample continuously absorbs mercury for 10 hours, and the average mercury concentration at the outlet is 0.08mg/m³About, the adsorption rate was about 20%. The pore structure of the ceramic support is shown in fig. 1.

Example 2

In this example, the composite ceramic support was first prepared according to the method described in the present invention, and would include 35wt% Al₂O₃60wt% of coal gangue5wt% of starch and silica sol in a weight ratio of 1:3 mixing into slurry, then immersing the polyurethane organic foam with the three-dimensional reticular framework structure or the honeycomb structure into the slurry, drying, and repeating for a plurality of times until the pores in the reticular framework foam are full. And finally, roasting for 4 hours at 1280-1390 ℃, and air-cooling to room temperature to prepare the reticular or honeycomb composite ceramic carrier. And (3) cleaning and drying the carrier, soaking the carrier in 0.1mol/L silver sulfate aqueous solution for 1-2 h, and then drying the carrier in an oven at 80 ℃. The sample is assembled and placed at the mercury content of 0.1mg/m³The test is carried out in the atmosphere, the continuous mercury absorption time of the sample is 240 hours, and the mercury concentration at the outlet is 0.015-0.05 mg/m³Meanwhile, the adsorption rate is 50-85%. The microstructure of the surface of the ceramic carrier after activation is shown in figure 2, the morphology of the active region is shown in figure 3, and the microstructure of the cross section is shown in figure 4.

Example 3

In this example, the composite ceramic support was first prepared according to the method described in the present invention, and would include 30wt% Al₂O₃60wt% of coal gangue, 10wt% of charcoal powder and silica sol, wherein the weight ratio of the main raw materials to the silica sol is 1:3 mixing into slurry, then immersing the polyurethane organic foam with the three-dimensional reticular framework structure or the honeycomb structure into the slurry, drying, and repeating for a plurality of times until the pores in the reticular framework foam are full. And finally, roasting for 4 hours at 1280-1390 ℃, and air-cooling to room temperature to prepare the reticular or honeycomb composite ceramic carrier. And (3) cleaning and drying the carrier, soaking the carrier in 0.2mol/L silver chloride aqueous solution for 1-2 h, and then drying the carrier in an oven at 80 ℃. The sample is assembled and placed at the mercury content of 0.1mg/m³The test is carried out in the atmosphere, the time of continuously absorbing the mercury of the sample reaches 280 hours, and the mercury concentration at the outlet is 0.01-0.04 mg/m³The adsorption rate is 60-90%.

Example 4

In this example, the composite ceramic support was first prepared according to the method described in the present invention, and would include 35wt% Al₂O₃55wt% of coal gangue, 10wt% of starch and silica sol in a weight ratio of 1:3 mixing into slurry, immersing the polyurethane organic foam with three-dimensional network skeleton structure or honeycomb structure into the slurry, drying, repeating for several times until the network structure is formedThe skeleton foam is filled with pores. And finally, roasting for 4 hours at 1280-1390 ℃, and air-cooling to room temperature to prepare the reticular or honeycomb composite ceramic carrier. And (3) cleaning and drying the carrier, soaking the carrier in 0.1mol/L silver nitrate aqueous solution for 1-2 h, and then drying the carrier in an oven at 80 ℃. The sample is assembled and placed at the mercury content of 0.1mg/m³The mercury concentration at the outlet was 0.001mg/m for 24h³About 99% adsorption rate.

Example 5

In this example, the composite ceramic support was first prepared according to the method described in the present invention, and would include 32wt% Al₂O₃Mixing 58wt% of coal gangue, 10wt% of starch and silica sol in a weight ratio of 1:3 to form slurry, then immersing the polyurethane organic foam with a three-dimensional reticular skeleton structure or a honeycomb structure into the slurry, drying, and repeating for several times until the pores in the reticular skeleton foam are full. And finally, roasting for 4 hours at 1280-1390 ℃, and air-cooling to room temperature to prepare the reticular or honeycomb composite ceramic carrier. And (3) cleaning and drying the carrier, soaking the carrier in 0.3mol/L sodium sulfide aqueous solution for 1-2 h, and then drying the carrier in an oven at 80 ℃. The sample is assembled and placed at the mercury content of 0.1mg/m³In an atmosphere of about 0.05mg/m mercury concentration at the outlet for 24h³About 50% adsorption rate.

Example 6

In this example, the composite ceramic support was first prepared according to the method described in the present embodiment, and would include 34wt% Al₂O₃58wt% of coal gangue, 8wt% of starch and silica sol in a weight ratio of 1:3 mixing into slurry, then immersing the polyurethane organic foam with the three-dimensional reticular framework structure or the honeycomb structure into the slurry, drying, and repeating for a plurality of times until the pores in the reticular framework foam are full. And finally, roasting for 4 hours at 1280-1390 ℃, and air-cooling to room temperature to prepare the reticular or honeycomb composite ceramic carrier. And (3) cleaning and drying the carrier, soaking the carrier in 0.15mol/L silver nitrate water solution for 1-2 h, and then drying the carrier in an oven at 80 ℃. The sample is assembled and placed at the mercury content of 0.01-0.311 mg/m³The test is carried out in the atmosphere, the sample continuously absorbs mercury for 336 hours, and the mercury concentration at an outlet is 0-0.018 mg/m³Left and rightThe time-dependent change of the concentration of mercury at the inlet and outlet is shown in FIG. 5, the time-dependent change of the adsorption rate is shown in FIG. 6, and the time-dependent change of the adsorption amount is shown in FIG. 7.

The results of the examples show that the invention develops a porous ceramic active substance-loaded nano-mercury material with durable adsorption performance.

Claims

1. The preparation method of the nano-mercury material with the lasting adsorption performance is characterized by comprising the following steps of:

step 6) immersing the composite ceramic carrier into a mercury adsorbent solution with the concentration of 0.1-0.5 mol/L, pH 1-5 for 2-8 h until the gap is filled with the mercury adsorbent, taking out the composite ceramic carrier, and naturally drying for 2-6 h;

step 7) repeating the step 6) for 1-5 times;

step 8) drying the composite ceramic carrier for 2-6 h at 80 ℃; or dipping the carrier into a mercury adsorbent solution with the concentration of 0.1-0.5 mol/L, and evaporating the mercury adsorbent solution at 80 ℃ to obtain a finished product;

the mercury adsorbent solution in the step 6) is more than one aqueous solution of silver sulfate, silver chloride or silver nitrate;

the polyurethane foam in the step 2) is net-shaped or honeycomb-shaped.