High-capacity stable ammonia gas adsorbent and preparation method thereof

Abstract

The invention relates to the technical field of environment purification, in particular to a high-capacity stable ammonia gas adsorbent and a preparation method thereof.The high-capacity stable ammonia gas adsorbent is prepared from, by mass, 68-74 parts of an active component and 30-40 parts of a carrier and further comprises a drying agent and an anti-caking agent, the mass ratio of the active component to the drying agent to the anti-caking agent is 1: (0.1-0.3): (0.06-0.08), and the particle sizes of the active component, the carrier, the drying agent and the anti-caking agent are all less than or equal to 200 meshes. According to the high-capacity stable ammonia gas adsorbent, the adsorption capacity of the adsorbent is increased by utilizing the characteristics of physical adsorption heat release and chemical adsorption heat absorption in cooperation with the modified silicon dioxide, meanwhile, the influence of water molecules on the adsorbent can be reduced by adopting the drying agent and the anti-caking agent, the stability of the adsorbent is improved, and the service life of the adsorbent is prolonged; in addition, the preparation process of the high-capacity stable ammonia gas adsorbent is simple, water is not introduced in the whole process, and the preparation cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental purification, and particularly relates to a high-capacity and stable ammonia adsorbent and a preparation method thereof. Background Art

[0002] Ammonia is an inorganic substance and a colorless gas with a pungent odor. Ammonia is one of the most important compounds on Earth and plays a crucial role in many biological processes and industrial applications. However, due to its high solubility and polarity, ammonia is also highly toxic and poses a potential hazard to both humans and the environment. Ammonia can easily combine with water molecules to form hydrogen bonds, so it can dissolve rapidly in the air. When the human body is exposed to high concentrations of ammonia, the ammonia will quickly penetrate into the eyes, nose, and respiratory mucosa, causing pain, burns, and severe respiratory irritation. If a large amount of ammonia is inhaled, it may lead to asphyxiation and death. With the rapid development of the semiconductor industry, the number of semiconductors produced each year is increasing, and the production process of solar wafers is the main source of ammonia-containing waste gas. Due to the polarity of ammonia, it can interact with many metal surfaces, resulting in corrosion and damage to equipment. In addition, if the ammonia content in industrial wastewater or agricultural wastewater is too high, it may pose a serious threat to aquatic organisms and human health. Another potential hazard of ammonia is its impact on the environment. Although ammonia is essential for plant growth, excessive ammonia can damage plants and even cause plant death. In addition, if a large amount of ammonia is emitted into the air, it may form acid rain, causing further damage to the environment. Therefore, it is necessary to develop methods to significantly reduce the emission and treatment of ammonia-containing gases.

[0003] Currently, there are many methods for treating ammonia-containing gases, such as ion exchange method, electrochemical oxidation method, breakpoint chlorination method, magnesium ammonium phosphate crystallization method, and adsorption method, etc. Among them, the adsorption method has become a research hotspot due to its high selectivity and high adsorption efficiency. For example, in CN202111226455 "An Adsorbent and Its Preparation Method and Application", a magnesium source is first mixed and granulated, and then a phosphorus source solution is atomized and sprayed onto the surface of the magnesium source particles. Stirring is carried out during the reaction, and the reaction temperature is controlled; after the reaction is completed, it is cooled to room temperature, then washed, filtered, dried, and classified to obtain the target product. The ammonia adsorbent obtained by this method can not only dissolve slowly in wastewater, leaving no residue and no regeneration pollution, but also has simple operation and can efficiently remove ammonia nitrogen in wastewater without adjusting the pH value of the solution. However, this method introduces a large amount of phosphate ions, resulting in new pollution problems during the later treatment process. At the same time, its use is restricted by the alkaline environment, and the adsorption system used in this method is relatively single, with a small adsorption capacity.

[0004] For another example, "An ammonia adsorbent and its preparation method" with the patent number CN202110583646 is prepared by the following steps: Dissolve metal chloride in a solvent to obtain a metal chloride solution; Mix molecular sieve with the metal chloride solution and dry to obtain an active component; Prepare a slurry from the active component, water and a binder, and coat it on cordierite honeycomb ceramics to obtain an ammonia adsorbent. The ammonia adsorbent obtained by this method increases the ammonia adsorption capacity, and at the same time avoids the problems of adsorbent accumulation, caking, powdering and falling. However, this method has a high cost and is not suitable for industrial production. Moreover, if the water used in the preparation process is not dried sufficiently, it will affect the adsorption capacity of the ammonia adsorbent.

[0005] Therefore, it is urgent to develop an ammonia gas adsorbent with less environmental factor constraints, large adsorption capacity, low cost and stability. Summary of the Invention

[0006] In view of the above-mentioned problems in the prior art, the present invention combines active components with various different adsorption principles and specific modified silica, thereby increasing the adsorption capacity of the ammonia adsorbent. By combining a desiccant, an anti-caking agent and an active component, the present invention can reduce the influence of moisture on the adsorbent, improve the durability of the adsorbent, and is less restricted by environmental factors.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] On the one hand, the present invention provides a high-capacity and stable ammonia adsorbent. The preparation of the ammonia adsorbent comprises the following components in parts by mass: 68-74 parts of an active component and 30-40 parts of a carrier;

[0009] The ammonia adsorbent further comprises a desiccant and an anti-caking agent;

[0010] The mass ratio of the active component, the desiccant and the anti-caking agent is 1:(0.1-0.3):(0.06-0.08);

[0011] The particle sizes of the active component, the carrier, the desiccant and the anti-caking agent are all ≤200 mesh.

[0012] Preferably, the mass ratio of the active component, the desiccant and the anti-caking agent is 1:0.2:0.07.

[0013] The applicant has found that adding appropriate proportions of the active component, the desiccant and the anti-caking agent can make the adsorbent have better performance. However, adding excessive amounts of the desiccant and the anti-caking agent will cause the adsorbent to reach saturation faster during use and have a shorter service life. The reason is that the desiccant and the anti-caking agent will occupy the pore positions of the carrier, preventing some of the active components from effectively occupying the carrier, thus reducing the performance of the active components and affecting the adsorption performance of the adsorbent.

[0014] In some embodiments, the active component contains at least cuprous oxide, ferric oxide and activated carbon, and the mass ratio of the three is 1:(0.8-1.2):(3-5).

[0015] Preferably, the active components contain at least cuprous oxide, ferric oxide and activated carbon, and the mass ratio of the three is 1:1:4.

[0016] The applicant found that the adsorption rate of a single active component is unstable and the adsorption amount is low. Once the component is deactivated, the entire adsorbent will lose its effect. The present application solves the above problem by combining iron oxide, cuprous oxide and activated carbon, and adsorbing ammonia by combining physical and chemical methods. The reason is that on the one hand, the added iron oxide has a porous structure and a large specific surface area, and can adsorb ammonia molecules through van der Waals forces and hydrogen bonds to form an ammonia complex, which can achieve physical adsorption of ammonia; at the same time, iron oxide can undergo an oxidation-reduction reaction with ammonia, converting ammonia into harmless substances, such as nitrogen and water vapor, to achieve chemical adsorption of ammonia. On the other hand, cuprous oxide can promote the oxidation reaction of ammonia, thereby improving the adsorption effect and service life of the ammonia adsorbent, because cuprous oxide catalyzes the oxidation-reduction reaction in the ammonia adsorbent to oxidize and reduce ammonia into nitrogen and water vapor. More specifically, when ammonia passes through the surface of cuprous oxide, cuprous oxide will undergo a redox reaction with ammonia, taking away hydrogen atoms in ammonia to generate nitrogen and water vapor; at the same time, a layer of copper nitride film will form on the surface of cuprous oxide, which can effectively prevent nitrogen from further oxidation to generate nitrogen oxides; plus the addition of activated carbon can make ammonia molecules form ammonia complexes on its surface, and will release a certain amount of heat, so that the iron oxide is activated by heat, increasing the specific surface area and surface chemical activity of the iron oxide, improving the ability of chemical adsorption, and greatly improving the adsorption efficiency and capacity of the adsorbent. This application combines three active components with different adsorption principles in a specific ratio to improve the adsorption capacity of the adsorbent.

[0017] In some embodiments, the support is one or more of alumina, molecular sieves, and modified silica.

[0018] Silica as a carrier provides a porous, high specific surface area structure. It can provide a large amount of surface area and space, allowing the adsorbent to interact with ammonia molecules, providing a larger attachment space, making the adsorbent more evenly distributed, and accommodating more adsorbents without blocking the pores, allowing the adsorbent to expose more active sites. However, silica itself has a weak ability to adsorb ammonia. Therefore, in order to further improve the capacity and adsorption capacity of the adsorbent, this application uses sulfonic acid modified silica as a carrier, which can significantly improve the adsorption capacity and selectivity of the ammonia adsorbent. The reason is that these functional groups can interact with ammonia molecules to form chemical bonds or ion exchanges, thereby adsorbing ammonia molecules on the surface of the adsorbent.

[0019] In some embodiments, the modified silica is sulfonic acid group modified silica, and its preparation method includes the following steps: First, mix tetraethyl orthosilicate with a solvent and stir evenly to obtain solution A; add the block copolymer microemulsion to solution A and stir to obtain solution B; while stirring solution B, adjust the pH value of the solution to less than 4 with dilute sulfuric acid, control the temperature at 60 - 70 °C and continue stirring to obtain material C; wash and centrifuge material C and then dry it to obtain sulfonic acid group modified silica.

[0020] Preferably, the preparation method of the sulfonic acid group modified silica includes the following steps: First, mix tetraethyl orthosilicate with toluene and stir for 1 - 3 hours to obtain solution A; add the block copolymer microemulsion to solution A and stir for 2 - 4 hours to obtain solution B; while stirring solution B, adjust the pH value of the solution to less than 4 with 7 mol / L dilute sulfuric acid, control the temperature at 65 °C and continue stirring for 12 - 24 hours to obtain material C; wash and centrifuge material C 6 - 8 times, and then dry it at 100 - 120 °C for 6 - 7 hours to obtain sulfonic acid group modified silica.

[0021] On the one hand, this application introduces a block copolymer microemulsion, which provides hydrophilic and hydrophilic-hydrophobic segments, helping to stabilize the hydrated silicic acid gel precursor, namely solution A. Through this method, the formation of silicic acid groups can be better controlled, preventing agglomeration. On the other hand, tetraethyl orthosilicate hydrolyzes into hydroxy-silicides and alcohols in an ethanol aqueous solution, and the hydroxy-silicides react with sulfuric acid at high temperature to form sulfonic acid group modified silica gel. This process relies on the hydrolysis of esters in an alcohol solution, and more hydroxy-site silicides can be obtained, increasing the modification sites of sulfonic acid groups, which is beneficial to improving the ammonia adsorption capacity of the adsorbent. Compared with the method of preparing sulfonic acid group modified silica by the traditional sol-gel method, this modification method shortens the process flow and saves the preparation cost.

[0022] In some embodiments, the mass ratio of tetraethyl orthosilicate to the block copolymer microemulsion is 1:(69 - 75).

[0023] Preferably, the mass ratio of tetraethyl orthosilicate to the block copolymer microemulsion is 1:72.

[0024] In some embodiments, the preparation method of the block copolymer microemulsion is: dissolve polymethyl methacrylate and polyethylene oxide in an ethanol solution, and form a block copolymer microemulsion through ultrasonic oscillation.

[0025] Preferably, the preparation method of the block copolymer microemulsion is: dissolve polymethyl methacrylate and polyethylene oxide in an ethanol solution with a concentration of 45 - 55%, and form a block copolymer microemulsion through ultrasonic oscillation at a frequency of 35 - 39 kHz for 30 - 50 minutes.

[0026] More preferably, preferably, the method for preparing the block copolymer microemulsion is as follows: Dissolve polymethyl methacrylate and polyethylene oxide in an ethanol solution with a concentration of 50%, and form a block copolymer microemulsion by ultrasonic oscillation at a frequency of 37 kHz for 40 minutes.

[0027] In some embodiments, the mass ratio of polymethyl methacrylate, polyethylene oxide and ethanol is 1:(0.4 - 0.6):(2 - 4).

[0028] Preferably, the mass ratio of polymethyl methacrylate, polyethylene oxide and ethanol is 1:0.5:3.

[0029] In some embodiments, the anti-caking agent is calcium sulfate or sodium aluminosilicate, and the desiccant is magnesium oxide or phosphorus pentoxide.

[0030] Preferably, the anti-caking agent is calcium sulfate and the desiccant is magnesium oxide.

[0031] The applicant has found that ammonia generated during the semiconductor manufacturing process often contains a large amount of water vapor. The presence of moisture will competitively adsorb the adsorption sites between the adsorbent and ammonia, thereby reducing the adsorption effect of the adsorbent. At the same time, an excessively humid environment may also cause a decrease in the mechanical strength of the adsorbent. In this application, magnesium oxide is used as the desiccant, which can not only remove the moisture brought by ammonia itself, but also remove the moisture generated when the active component adsorbs ammonia, stabilizing the adsorption effect of the adsorbent. However, the adsorbent after moisture absorption is prone to caking, resulting in an increase in specific surface area and a decrease in adsorption efficiency. In this application, a specific ratio of calcium sulfate and magnesium oxide is introduced and used in combination to solve the above problems and make the adsorption effect of the adsorbent more stable. The reason is that calcium sulfate can dissociate into calcium ions and sulfate ions, and these ions can interact with water molecules to form hydrogen bonds, thereby generating an association effect, causing a repulsive force between solid particles, thus playing a role in preventing caking.

[0032] On the other hand, the present invention provides a method for preparing a high-capacity stable ammonia adsorbent, which is characterized by including the following steps:

[0033] Step 1: Mix the active component, carrier, desiccant and anti-caking agent, and then pour them into a ball mill to ball mill and mix evenly to obtain material A;

[0034] Step 2: Add material A to anhydrous ethanol with a mass 2 - 4 times that of material A, heat and stir, then perform solid-liquid separation, and dry the solid to obtain material B;

[0035] Step 3: Calcinate material B in an inert gas atmosphere to obtain a high-capacity stable ammonia adsorbent.

[0036] Preferably, it includes the following steps:

[0037] Step 1, the active component, carrier, desiccant and anti-caking agent are mixed and poured into a ball mill for ball milling and mixing to obtain material A;

[0038] Step 2, adding material A to anhydrous ethanol with a mass three times that of material A, heating and stirring to separate the solid and liquid, and drying the solid to obtain material B;

[0039] Step 3: calcining material B under an inert gas atmosphere to obtain a high-capacity stable ammonia adsorbent.

[0040] In some embodiments, in the step 1, the ball mill speed is 100-300 rpm, the time is 2-4 hours, and the ball mill particle size is 200-300 mesh; in the step 2, the heating temperature is 40-70°C, the stirring time is 8-10 hours, the drying temperature is 80-100°C, and the drying time is 2-4 hours; in the step 3, the calcination temperature is 550-650°C, the calcination time is 3-4 hours, and the gas flow rate in the inert gas atmosphere is 30-50sccm.

[0041] Preferably, in the step 1, the ball mill speed is 200 rpm, the time is 3 hours, and the ball mill particle size is 250 mesh; in the step 2, the heating temperature is 55°C, the stirring time is 9 hours, the drying temperature is 90°C, and the drying time is 3 hours; in the step 3, the calcination temperature is 600°C, the calcination time is 3.5 hours, and the gas flow rate in the inert gas atmosphere is 40sccm.

[0042] The applicant found that the particle size of the adsorbent affects the adsorption performance of the adsorbent, and the ball milling speed and time will affect the uniformity of the adsorbent particle size; the temperature and stirring time of heating anhydrous ethanol will affect the degree of bulk reaction between the active component and the carrier, thereby affecting the adsorption amount of the adsorbent; the appropriate calcination temperature and time can make the adsorbent reach the optimal activation state. When the adsorbent is calcined at high temperature, the bound water in its components will continue to evaporate. At this time, the flow rate of the inert gas is too low to effectively take away the volatile steam in time, consuming part of the desiccant and reducing the stability of the adsorbent. An excessively fast inert gas flow rate will blow the adsorbent away and take it out of the furnace. The present application is conducive to improving the adsorption effect of the adsorbent on ammonia by controlling the conditions of each step.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The present invention adopts a specific ratio of active components, desiccants and anti-caking agents, which can prevent the influence of water vapor on the adsorption sites of the adsorbent, and at the same time avoid the problem of reduced adsorption capacity of the adsorbent caused by agglomeration of the adsorbent after moisture absorption.

[0045] (2) The active component of the present invention is composed of iron oxide, cuprous oxide and activated carbon in a specific ratio, making use of the characteristics of physical adsorption with heat release and chemical adsorption with heat absorption. After the physical adsorption releases heat, the components of the chemical adsorption are heated and activated, increasing the specific surface area and surface chemical activity, and improving the adsorption capacity of the adsorbent.

[0046] (3) The present invention uses sulfonic acid group-modified silica as the carrier, which can significantly improve the adsorption capacity and selectivity of the ammonia adsorbent.

[0047] (4) During the preparation of the sulfonic acid group-modified silica in the present invention, the introduction of block copolymer microemulsion can better control the formation of silicic acid groups and prevent agglomeration; in addition, the method of hydrolyzing tetraethyl orthosilicate and then sulfonating is used to prepare sulfonic acid group-modified silica gel, and more sulfonic acid group-modified sites of modified silica are obtained in the subsequent preparation process, improving the ammonia adsorption amount of the adsorbent, shortening the process flow and saving costs at the same time.

[0048] (5) In the whole preparation process of the present invention, ball milling is used for mixing, and the particle size of the obtained adsorbent is controllable, increasing the specific surface area and improving the adsorption efficiency of the adsorbent; in addition, anhydrous ethanol is used as the solvent to cause the active component and the carrier to undergo a bulk phase reaction, avoiding the problem that the adsorption effect is reduced due to incomplete drying after mixing with an aqueous solution. Specific embodiments

[0049] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0050] Example 1

[0051] A high-capacity and stable ammonia adsorbent comprises the following components in parts by mass: 71 parts of active component and 35 parts of carrier, and the mass ratio of the active component to the desiccant and the anti-caking agent is 1:0.2:0.07.

[0052] The active component is composed of cuprous oxide, iron oxide and activated carbon, and the mass ratio of the three is 1:1:4.

[0053] The carrier is sulfonic acid group modified silica, and the preparation method includes the following steps: First, mix tetraethyl orthosilicate and toluene and stir for 2 hours to obtain solution A; add the block copolymer microemulsion to solution A and stir for 3 hours to obtain solution B; adjust the pH value of solution B to 2 with 7 mol / L dilute sulfuric acid and stir at 65 °C for 18 hours to obtain material C; after washing and centrifuging material C 7 times, dry it at 110 °C for 6.5 hours to obtain sulfonic acid group modified silica.

[0054] The mass ratio of tetraethyl orthosilicate to the block copolymer microemulsion is 1:72;

[0055] The preparation method of the block copolymer microemulsion includes the following steps: Dissolve polymethyl methacrylate and polyethylene oxide in an ethanol solution with a volume fraction of 50%, and form a stable block copolymer microemulsion by ultrasonic oscillation at 37 kHz for 40 minutes.

[0056] The mass ratio of polymethyl methacrylate, polyethylene oxide and ethanol is 1:0.5:3.

[0057] The desiccant is magnesium oxide.

[0058] The anti-caking agent is calcium sulfate.

[0059] Cuprous oxide is purchased from Jiangsu Taihe Metal Industry Co., Ltd., with a particle size of 150 mesh; iron oxide is purchased from Pengyu Building Materials Factory in Lingshou County, with a particle size of 130 mesh; activated carbon is purchased from Henan Shuifang Water Purification Materials Co., Ltd., with a particle size of 10 mesh; magnesium oxide is purchased from Shouguang Luheng Chemical Co., Ltd., with a particle size of 180 mesh; calcium sulfate is purchased from Shandong Longbang Gypsum Products Co., Ltd., with a particle size of 200 mesh; tetraethyl orthosilicate is purchased from Jinan Shanhaiguan Chemical Technology Co., Ltd.; polymethyl methacrylate is purchased from Jinan Xinfei Yuxiang Trading Co., Ltd.; polyethylene oxide is purchased from Pande (Shanghai) International Trading Co., Ltd.

[0060] The preparation method of the high-capacity stable ammonia adsorbent in this example includes the following steps:

[0061] (1) Mix the active component, carrier, desiccant and anti-caking agent and pour them into a ball mill. The ball milling speed is 200 revolutions per minute, the time is 3 hours, and the ball milling particle size is 250 mesh. Mix evenly to obtain material A.

[0062] (2) Add material A to anhydrous ethanol with a mass 3 times that of material A, heat and stir, then perform solid-liquid separation, and dry the solid to obtain material B;

[0063] (3) Calcinate material B in a nitrogen atmosphere with a flow rate of 40 sccm at 600 °C for 3.5 hours to obtain the high-capacity stable ammonia adsorbent.

[0064] Example 2

[0065] A high-capacity and stable ammonia adsorbent, comprising the following components in parts by mass: 68 parts of an active component and 30 parts of a carrier, and the mass ratio of the active component to the desiccant and the anti-caking agent is 1:0.15:0.06.

[0066] The active component consists of cuprous oxide, iron oxide and activated carbon, and the mass ratio of the three is 1:1.2:3.5.

[0067] The carrier is sulfonic acid group-modified silica, and the preparation method comprises the following steps: First, tetraethyl orthosilicate and toluene are mixed and stirred for 1 hour to obtain solution A; the block copolymer microemulsion is added to solution A and stirred for 2 hours to obtain solution B; the pH value of solution B is adjusted to 1 with 7 mol / L dilute sulfuric acid and stirred at 60 °C for 12 hours to obtain material C; after material C is washed with water and centrifuged 6 times, it is dried at 100 °C for 6 hours to obtain sulfonic acid group-modified silica.

[0068] The mass ratio of tetraethyl orthosilicate to the block copolymer microemulsion is 1:69.

[0069] The preparation method of the block copolymer microemulsion comprises the following steps: polymethyl methacrylate and polyethylene oxide are dissolved in an ethanol solution with a volume fraction of 50%, and are subjected to ultrasonic oscillation at 37 kHz for 30 minutes to form a stable block copolymer microemulsion.

[0070] The mass ratio of methyl methacrylate, polyethylene oxide and ethanol is 1:0.4:2.

[0071] The desiccant is magnesium oxide.

[0072] The anti-caking agent is calcium sulfate.

[0073] The cuprous oxide is purchased from Jiangsu Taihe Metal Industry Co., Ltd., and the particle size is 150 mesh; the iron oxide is purchased from Pengyu Building Materials Factory, Lingshou County, and the particle size is 130 mesh; the activated carbon is purchased from Henan Shuifangcheng Water Purification Materials Co., Ltd., and the particle size is 10 mesh; the magnesium oxide is purchased from Shouguang Luheng Chemical Co., Ltd., and the particle size is 180 mesh; the calcium sulfate is purchased from Shandong Longbang Gypsum Products Co., Ltd., and the particle size is 200 mesh; the tetraethyl orthosilicate is purchased from Jinan Shanhaiguan Chemical Technology Co., Ltd.; the polymethyl methacrylate is purchased from Jinan Xinfei Yuxiang Trading Co., Ltd.; the polyethylene oxide is purchased from Pande (Shanghai) International Trading Co., Ltd.

[0074] The preparation method of the high-capacity and stable ammonia adsorbent of this example comprises the following steps:

[0075] (1) The active component, the carrier, the desiccant and the anti-caking agent are mixed and then poured into a ball mill, the ball milling speed is 100 revolutions per minute, the time is 2 hours, the ball milling particle size is 200 mesh, and they are mixed evenly to obtain material A.

[0076] (2) Add Material A to absolute ethanol with a mass twice that of Material A. After heating and stirring, perform solid-liquid separation. Dry the solid to obtain Material B.

[0077] (3) Calcinate Material B at 550 °C for 3 hours under a nitrogen atmosphere with a flow rate of 30 sccm to prepare a high-capacity and stable ammonia adsorbent.

[0078] Example 3

[0079] A high-capacity and stable ammonia adsorbent includes the following components in parts by mass: 74 parts of active components and 30 parts of a carrier. The mass ratio of the active components to the desiccant and the anti-caking agent is 1:0.25:0.07.

[0080] The active components are composed of cuprous oxide, iron oxide, and activated carbon, and their mass ratio is 1:0.8:4.5.

[0081] The carrier is sulfonic acid group-modified silica, and its preparation method includes the following steps: First, mix tetraethyl orthosilicate and toluene and stir for 1 hour to obtain Solution A; add the block copolymer microemulsion to Solution A and stir for 2.5 hours to obtain Solution B; adjust the pH value of Solution B to 1 with 7 mol / L dilute sulfuric acid and stir at 63 °C for 15 hours to obtain Material C; after washing and centrifuging Material C 6 times, dry it at 100 °C for 6 hours to obtain sulfonic acid group-modified silica.

[0082] The mass ratio of tetraethyl orthosilicate to the block copolymer microemulsion is 1:71.

[0083] The preparation method of the block copolymer microemulsion includes the following steps: Dissolve polymethyl methacrylate and polyethylene oxide in an ethanol solution with a volume fraction of 50%, and use 37 kHz ultrasonic oscillation for 30 minutes to form a stable block copolymer microemulsion.

[0084] The mass ratio of methyl methacrylate, polyethylene oxide, and ethanol is 1:0.4:2.5.

[0085] The desiccant is magnesium oxide.

[0086] The anti-caking agent is calcium sulfate.

[0087] Cuprous oxide is purchased from Jiangsu Taihe Metal Industry Co., Ltd., with a particle size of 150 mesh; iron oxide is purchased from Pengyu Building Materials Factory in Lingshou County, with a particle size of 130 mesh; activated carbon is purchased from Henan Shuifang Water Purification Materials Co., Ltd., with a particle size of 10 mesh; magnesium oxide is purchased from Shouguang Luheng Chemical Co., Ltd., with a particle size of 180 mesh; calcium sulfate is purchased from Shandong Longbang Gypsum Products Co., Ltd., with a particle size of 200 mesh; tetraethyl orthosilicate is purchased from Jinan Shanhaiguan Chemical Technology Co., Ltd.; polymethyl methacrylate is purchased from Jinan Xinfei Yuxiang Trading Co., Ltd.; polyethylene oxide is purchased from Pande (Shanghai) International Trading Co., Ltd.

[0088] The preparation method of the high-capacity and stable ammonia adsorbent in this embodiment includes the following steps:

[0089] (1) Mix the active component, carrier, desiccant, and anti-caking agent, then pour them into a ball mill. The ball mill speed is 100 revolutions per minute, the time is 2 hours, and the ball mill particle size is 200 mesh. Mix evenly to obtain material A.

[0090] (2) Add material A to absolute ethanol with a mass 2 times that of material A. After heating and stirring, perform solid-liquid separation. Dry the solid to obtain material B;

[0091] (3) Calcinate material B at 550 °C for 3 hours in a nitrogen atmosphere with a flow rate of 30 sccm to obtain the high-capacity and stable ammonia adsorbent.

[0092] Example 4

[0093] A high-capacity and stable ammonia adsorbent includes the following components in parts by mass: 70 parts of active component, 40 parts of carrier, and the mass ratio of the active component to the desiccant and anti-caking agent is 1:0.3:0.08.

[0094] The active component is composed of cuprous oxide, iron oxide, and activated carbon, and the mass ratio of the three is 1:0.9:3.

[0095] The carrier is sulfonic acid group-modified silica, and its preparation method includes the following steps: First, mix tetraethyl orthosilicate and toluene and stir for 3 hours to obtain solution A; add the block copolymer microemulsion to solution A and stir for 4 hours to obtain solution B; adjust the pH value of solution B to 4 with 7 mol / L dilute sulfuric acid and stir at 70 °C for 24 hours to obtain material C; after washing and centrifuging material C 8 times, dry it at 120 °C for 7 hours to obtain sulfonic acid group-modified silica.

[0096] The mass ratio of tetraethyl orthosilicate to the block copolymer microemulsion is 1:75.

[0097] The preparation method of the block copolymer microemulsion includes the following steps: Dissolve polymethyl methacrylate and polyethylene oxide in an ethanol solution with a volume fraction of 50%, and use 37 kHz ultrasonic oscillation for 50 minutes to form a stable block copolymer microemulsion.

[0098] The mass ratio of methyl methacrylate, polyethylene oxide, and ethanol is 1:0.6:4.

[0099] The desiccant is magnesium oxide.

[0100] The anti-caking agent is calcium sulfate.

[0101] Cuprous oxide was purchased from Jiangsu Taihe Metal Industry Co., Ltd. with a particle size of 150 mesh; iron oxide was purchased from Pengyu Building Materials Factory, Lingshou County with a particle size of 130 mesh; activated carbon was purchased from Henan Shuifangcheng Water Purification Materials Co., Ltd. with a particle size of 10 mesh; magnesium oxide was purchased from Shouguang Luheng Chemical Co., Ltd. with a particle size of 180 mesh; calcium sulfate was purchased from Shandong Longbang Gypsum Products Co., Ltd. with a particle size of 200 mesh; ethyl silicate was purchased from Jinan Shanha Chemical Technology Co., Ltd.; polymethyl methacrylate was purchased from Jinan Xinfei Yuxiang Trading Co., Ltd.; polyethylene oxide was purchased from Pande (Shanghai) International Trading Co., Ltd.

[0102] The preparation method of the high-capacity stable ammonia adsorbent in this example includes the following steps:

[0103] (1) Mix the active components, carrier, desiccant and anti-caking agent and pour them into a ball mill. The ball mill speed is 300 revolutions per minute, the time is 4 hours, and the ball mill particle size is 300 mesh. Mix evenly to obtain material A.

[0104] (2) Add material A to anhydrous ethanol with a mass 4 times that of material A. After heating and stirring, perform solid-liquid separation. Dry the solid to obtain material B;

[0105] (3) Calcinate material B at 650 °C for 4 hours under a nitrogen atmosphere with a flow rate of 50 sccm to obtain the high-capacity stable ammonia adsorbent.

[0106] Example 5

[0107] A high-capacity stable ammonia adsorbent includes the following components in parts by mass: 72 parts of active components and 40 parts of carrier. The mass ratio of the active components to the desiccant and anti-caking agent is 1:0.1:0.06.

[0108] The active components are composed of cuprous oxide, iron oxide and activated carbon, and the mass ratio of the three is 1:1.1:5.

[0109] The carrier is sulfonic acid group-modified silica. The preparation method includes the following steps: First, mix and stir ethyl silicate and toluene for 3 hours to obtain solution A; add the block copolymer microemulsion to solution A and stir for 6 hours to obtain solution B; adjust the pH value of solution B to 1 with 7 mol / L dilute sulfuric acid and stir at 68 °C for 20 hours to obtain material C; wash and centrifuge material C 8 times, and then dry at 120 °C for 7 hours to obtain sulfonic acid group-modified silica.

[0110] The mass ratio of ethyl silicate to the block copolymer microemulsion is 1:73.

[0111] The preparation method of the block copolymer microemulsion includes the following steps: Dissolve polymethyl methacrylate and polyethylene oxide in an ethanol solution with a volume fraction of 50%, and use ultrasonic oscillation at 37 kHz for 50 minutes to form a stable block copolymer microemulsion.

[0112] The mass ratio of methyl methacrylate, polyethylene oxide and ethanol is 1:0.6:3.5.

[0113] The desiccant is magnesium oxide.

[0114] The anti-caking agent is calcium sulfate.

[0115] Cuprous oxide was purchased from Jiangsu Taihe Metal Industry Co., Ltd. with a particle size of 150 mesh; iron oxide was purchased from Pengyu Building Materials Factory, Lingshou County with a particle size of 130 mesh; activated carbon was purchased from Henan Shuifang Water Purification Materials Co., Ltd. with a particle size of 10 mesh; magnesium oxide was purchased from Shouguang Luheng Chemical Co., Ltd. with a particle size of 180 mesh; calcium sulfate was purchased from Shandong Longbang Gypsum Products Co., Ltd. with a particle size of 200 mesh; ethyl silicate was purchased from Jinan Shanha Chemical Technology Co., Ltd.; polymethyl methacrylate was purchased from Jinan Xinfei Yuxiang Trading Co., Ltd.; polyethylene oxide was purchased from Pande (Shanghai) International Trading Co., Ltd.

[0116] The preparation method of the high-capacity stable ammonia adsorbent in this example includes the following steps:

[0117] (1) Mix the active components, carrier, desiccant and anti-caking agent and pour them into a ball mill. The ball milling speed is 300 revolutions per minute, the time is 4 hours, and the ball milling particle size is 300 mesh. Mix evenly to obtain material A.

[0118] (2) Add material A to anhydrous ethanol with a mass 4 times that of material A. After heating and stirring, perform solid-liquid separation. Dry the solid to obtain material B;

[0119] (3) Calcinate material B at 650 °C for 4 hours in a nitrogen atmosphere with a flow rate of 50 sccm to obtain the high-capacity stable ammonia adsorbent.

[0120] Example 6

[0121] This example provides a preparation method of an ammonia adsorbent. The specific implementation method is the same as that of Example 1, except that the mass ratio of cuprous oxide, iron oxide and activated carbon in step (1) is 1:1:1.

[0122] Example 7

[0123] This example provides a preparation method of an ammonia adsorbent. The specific implementation method is the same as that of Example 1, except that the mass ratio of cuprous oxide, iron oxide and activated carbon in step (1) is 1:1:7.

[0124] Example 8

[0125] This embodiment provides a preparation method of an ammonia adsorbent. The specific implementation manner is the same as that of Embodiment 1, except that in the step (1), the active components include 14.2 parts of cuprous oxide and 56.8 parts of activated carbon.

[0126] Example 9

[0127] This embodiment provides a preparation method of an ammonia adsorbent. The specific implementation manner is the same as that of Embodiment 1, except that in the step (1), the sulfonic acid group-modified silica is replaced by silica of equal mass.

[0128] The silica was purchased from Shanghai Yuanye Bio-Technology Co., Ltd. and had a particle size of 100 mesh.

[0129] Example 10

[0130] This embodiment provides a preparation method of an ammonia adsorbent. The specific implementation manner is the same as that of Embodiment 1, except that the mass ratio of the tetraethyl orthosilicate to the block copolymer microemulsion is 1:60.

[0131] Comparative Example 1

[0132] This embodiment provides a preparation method of an ammonia adsorbent. The specific implementation manner is the same as that of Embodiment 1, except that in the step (1), the mass ratio of the active components to the desiccant and the anti-caking agent is 1:0.05:0.03.

[0133] Comparative Example 2

[0134] This embodiment provides a preparation method of an ammonia adsorbent. The specific implementation manner is the same as that of Embodiment 1, except that in the step (1), the mass ratio of the active components to the desiccant and the anti-caking agent is 1:0.5:0.1.

[0135] Performance Test

[0136] 1. Ammonia Adsorption Test:

[0137] Take 0.1 g of the adsorbents of the above-mentioned Embodiments 1-9 and the adsorbents of Comparative Examples 1-7, and place them in a 10-cubic centimeter sealed container respectively. Fill the container with ammonia at a concentration of 10 ppm, control the temperature at 25 °C, and after the internal circulation is started in the container, pass the ammonia through the adsorbent at a wind speed of 2 m / s. Calculate the ammonia removal rate according to the ammonia concentration at the inlet / outlet; Take another 0.1 g of the adsorbent and load it into a micro fixed-bed reactor, and use a nitrogen stream with an ammonia concentration of 500 ppm at a flow rate of 100 mL / min for testing, and control the gas flow rate to be 3 m 3 / min to pass through the adsorbent to test the ammonia adsorption capacity.

[0138] 2. Adsorbent Stability Test

[0139] After the adsorbent adsorption test is completed, slowly pour out the adsorbent in the container and spread it out flat, and observe whether there is caking. The adsorption performance and stability test results of the adsorbent are shown in Table 1.

[0140] Table 1

[0141]

[0142]

[0143] It can be seen from Table 1 that the ammonia adsorbents prepared in Examples 1-5 have good ammonia adsorption capacity and ammonia removal rate, and there is no caking phenomenon after testing, and the stability is good. In Examples 6 and 7, due to the change of the ratio between cuprous oxide, iron oxide and activated carbon, the performance of the adsorbent decreased. The reason is that the proportion of activated carbon decreased, the temperature of the adsorbent did not increase significantly, and the heat absorbed by chemical adsorption was insufficient, resulting in a decrease in the performance of the adsorbent. Although a large amount of activated carbon can significantly increase the temperature of the adsorbent, the component that plays a role in chemical adsorption decreases, resulting in a decrease in the performance of the adsorbent; in Example 8, due to the lack of introduction of iron oxide, the chemical adsorption component in the adsorbent decreased, resulting in a decrease in the performance of the adsorbent; in Example 9, due to the introduction of unmodified silica as a carrier, its ammonia adsorption ability is poor, resulting in poor adsorption performance of the adsorbent; in Example 10, due to the change of the mass ratio of tetraethyl orthosilicate and block copolymer microemulsion, the number of sulfonic acid groups in the modified silica decreased, resulting in a decrease in the adsorption capacity of the adsorbent; in Comparative Example 1, due to the change of the mass ratio of the active component to the desiccant and anti-caking agent, during the ammonia adsorption process of the adsorbent, the water vapor carried by ammonia and the water generated by the adsorbent itself could not be absorbed in time, and the water competed for the adsorption sites between the adsorbent and ammonia, resulting in a decrease in the performance of the adsorbent, and there was a slight caking phenomenon after the adsorbent was used for a period of time; in Comparative Example 2, due to the change of the mass ratio of the active component to the desiccant and anti-caking agent, a large amount of desiccant and anti-caking agent occupied the limited pore positions on the carrier, and the active component could not occupy the carrier to exert its maximum performance, resulting in a decrease in the performance of the adsorbent. The test results show that the high-capacity and stable ammonia adsorbent prepared by the present invention not only has good adsorption performance, but also is more stable during the adsorption process and has lower cost.

[0144] The above examples are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A high-capacity and stable ammonia adsorbent, characterized in that, Preparing the ammonia adsorbent includes the following components in parts by mass: 68 - 74 parts of active components and 30 - 40 parts of carriers; The ammonia adsorbent further includes a desiccant and an anti-caking agent; The mass ratio of the active components, the desiccant and the anti-caking agent is 1:(0.1 - 0.3):(0.06 - 0.08); The particle sizes of the active components, the carriers, the desiccant and the anti-caking agent are all ≤ 200 mesh.

2. The high-capacity and stable ammonia adsorbent according to claim 1, characterized in that, The active components at least contain cuprous oxide, iron oxide and activated carbon, and the mass ratio of the three is 1:(0.8 - 1.2):(3 - 5).

3. The high-capacity and stable ammonia adsorbent according to claim 1, wherein, The carrier is one or more of alumina, molecular sieve and modified silica.

4. The high-capacity and stable ammonia adsorbent according to claim 3, wherein The modified silica is sulfonic acid group modified silica, and its preparation method includes the following steps: First, mix tetraethyl orthosilicate with a solvent and stir evenly to obtain solution A; add the block copolymer microemulsion to solution A and stir to obtain solution B; while stirring solution B, adjust the pH value of the solution to be less than 4 with dilute sulfuric acid, control the temperature at 60 - 70 °C and continue stirring to obtain material C; wash and centrifuge material C and then dry it to obtain sulfonic acid group modified silica.

5. The high-capacity and stable ammonia adsorbent according to claim 4, characterized in that, The mass ratio of the tetraethyl orthosilicate and the block copolymer microemulsion is 1:(69 - 75).

6. The high-capacity and stable ammonia adsorbent according to claim 5, wherein The preparation method of the block copolymer microemulsion is: dissolve polymethyl methacrylate and polyethylene oxide in an ethanol solution and form a block copolymer microemulsion through ultrasonic oscillation.

7. The high-capacity and stable ammonia adsorbent according to claim 6, characterized in that The mass ratio of the polymethyl methacrylate, the polyethylene oxide and the ethanol is 1:(0.4 - 0.6):(2 - 4).

8. The high-capacity and stable ammonia adsorbent according to claim 1, wherein The anti-caking agent is calcium sulfate or sodium aluminosilicate, and the desiccant is magnesium oxide or phosphorus pentoxide.

9. A preparation method of a high-capacity and stable ammonia adsorbent according to any one of claims 1-8, characterized in that, It includes the following steps: Step 1, mix the active components, the carriers, the desiccant and the anti-caking agent and pour them into a ball mill to ball mill and mix evenly to obtain material A; Step 2, add material A into absolute ethanol with a mass 2 - 4 times that of material A, heat and stir, then carry out solid-liquid separation, and dry the solid to obtain material B; Step 3, calcine material B under an inert gas atmosphere to obtain a high-capacity and stable ammonia adsorbent.

10. The preparation method of a high-capacity and stable ammonia adsorbent according to claim 9, characterized in that, In step 1, the rotation speed of the ball mill is 100 - 300 revolutions per minute, the time is 2 - 4 hours, and the ball milling particle size is 200 - 300 mesh; In step 2, the heating temperature is 40 - 70 °C, the stirring time is 8 - 10 hours, the drying temperature is 80 - 100 °C, and the drying time is 2 - 4 hours; In step 3, the calcination temperature is 550 - 650 °C, the calcination time is 3 - 4 hours, and the gas flow rate in the inert gas atmosphere is 30 - 50 sccm.

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