Sulfuric acid removal adsorbent, preparation method thereof and method for removing trace sulfuric acid in chlorine

Abstract

The invention discloses an adsorbent for removing sulfuric acid, a preparation method of the adsorbent and a method for removing trace sulfuric acid in chlorine. By preparing the efficient adsorbent, the removal of the sulfuric acid fog drops in the crude chlorine is realized. The process for removing the sulfuric acid fog drops by the dry method is simple in flow, the chlorine resistance of the adsorbent is relatively excellent, the operation stability of a reaction unit Ru-based catalyst is greatly improved after the adsorbent is put into use, the service life of the catalyst is prolonged, and the production cost of liquid chlorine is reduced.

Description

Technical Field

[0001] The present invention relates to an adsorbent, in particular to an adsorbent in the field of chlorine cycle, and more particularly to an adsorbent for removing sulfuric acid. Background Art

[0002] Chlorine (Cl2), as an important basic chemical, is widely used in the production of chemical raw materials, agrochemicals, building materials, and pharmaceutical preparations. However, in most chlorine-related reactions, the utilization rate of chlorine resources is very low. Chloride mainly exists as a reaction intermediate and does not enter the final target product. Currently, the most effective way to treat the by-product hydrogen chloride in industry is to directly convert it into chlorine for recycling. Catalytic oxidation has many advantages such as simple operation, low energy consumption, no other side reactions, and high efficiency. It is an efficient and energy-saving way to achieve the recycling of chlorine resources.

[0003] At the end of the last century, Sumitomo Chemical developed a Ru-based industrial catalyst with strong low-temperature catalytic activity and stability, which has been successfully applied industrially. However, due to the sulfur-loving nature of Ru-based catalysts, they react with sulfides to form stable ruthenium sulfate salts that cover the active sites of ruthenium oxide microcrystals, affecting the catalyst's reaction activity. In the current industrial process, after the crude chlorine gas is dried with sulfuric acid and compressed and deep-chilled, most of the non-condensable gas at the top of the tower is returned to the reaction system. The current industrial design of the sulfuric acid drying tower adds a sulfuric acid demister. During actual operation, trace sulfuric acid droplets ≤10 microns will still penetrate the demister, which not only creates a corrosion risk in the subsequent system due to contact between sulfuric acid droplets and equipment such as the chlorine compressor, but will also eventually enter the reactor, affecting the operating life of the catalyst. Due to the high price of ruthenium, the cost of catalyst replacement is high, which greatly increases the production cost of industrial liquid chlorine. For this reason, it is necessary to control the index of sulfuric acid droplet content in the system raw materials.

[0004] CN110404343A discloses a system and method for removing SO3 aerosol from coal-fired flue gas. The device is designed to use a centrifugal removal tower to make the flue gas rotate at high speed and centrifuge so that SO3 droplets and aerosols are adsorbed on the wall of the centrifugal removal tower. The adsorbed aerosols and droplets are washed with cleaning water through a cleaning water spray device, and the SO3 and aerosols that are difficult to remove from the flue gas are dissolved in water and sent to the desulfurization system for further treatment. The treatment effect of this solution can reach 95%, PM 2.5 Aerosols were reduced by 83.4%. However, this process can cause water mist to be entrained in the gas phase, the system contains a Cl2 atmosphere, and the system is made of carbon steel, which has corrosion and leakage problems.

[0005] CN102989259A discloses a method for eliminating sulfuric acid mist. This method uses solid waste alumina red mud as an adsorbent to eliminate sulfuric acid mist. Additives are added to the alumina red mud and calcined at high temperature to improve the adsorption properties of the alumina red mud. The additives involved in this invention mainly include components such as Fe2O3, Al2O3, CaO, MgO, and Na2O in the red mud, as well as partially soluble alkalis that react chemically with sulfuric acid mist, exhibiting strong adsorption capacity and reactivity. Adsorption can reach over 90% within 2 hours, followed by a continuous decrease in adsorption capacity, reaching saturation within 6 hours. Because the current HCl oxidation process system contains Cl2, the use of alkaline adsorbents will quickly lead to saturation, making it unsuitable for long-term operation.

[0006] CN109701381A discloses a system and process for removing SO3 from coal-fired flue gas. The invention uses MgO powder as a reducing agent. After mixing the MgO powder with compressed air, the powder is sprayed into the flue through a powder spray nozzle located after the economizer or before the air preheater. When the powder spray nozzle is located after the economizer, SO3 can be removed from the flue gas, preventing SO3 from reacting with ammonia in the SCR denitrification device to form NH4HSO4. When the powder spray nozzle is located before the air preheater, SO3 and NH4HSO4 can be removed from the flue gas simultaneously. The invention is used to address the treatment of coal-fired flue gas pollutants, ensuring that SO3 emissions meet standards, while also addressing the corrosion of flues and equipment in low-temperature areas and the blockage of air preheaters. However, the main principle of this method is also based on the acid-base neutralization chemical reaction between MgO and SO3, making it unsuitable for crude Cl2 systems. Furthermore, the actual removal efficiency has not been evaluated in terms of sulfuric acid droplets, and thus cannot meet operational requirements.

[0007] CN117225369B discloses a preparation method of modified desulfurized activated carbon fiber and modified desulfurized activated carbon fiber. The fiber is modified by a nitrogen-containing organic base, not only so that the obtained activated carbon fiber has one or more nitrogen-containing groups, the nitrogen-containing groups are mainly basic groups such as amino groups, amine groups, amide groups, and nitrogen heterocyclic groups. These basic groups can chemically adsorb acidic gases and significantly increase the acidic gas adsorption rate. At the same time, the nitrogen-containing organic base etches pores on the surface of the fiber, significantly increasing the micropore volume of the obtained activated carbon fiber, thereby increasing the number of adsorption sites for acidic gases, thereby increasing the acidic gas adsorption rate. The nitrogen content of the modified desulfurized activated carbon fiber is 2.51% to 3.32%, the micropore volume is 0.81 to 0.85 mL / g, and the micropore ratio is 0.78 to 0.81. After 800 minutes of use, the saturated adsorption efficiency is only 33%, which does not meet the target of industrial removal efficiency. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention provides an adsorbent for removing sulfuric acid and its preparation method, thereby removing trace amounts of sulfuric acid from chlorine gas. By modifying the adsorbent to alter its surface functional group composition and pore structure, the adsorption capacity and efficiency of commercial molecular sieves are enhanced, enabling efficient adsorption and removal of sulfuric acid droplets from crude chlorine gas, reducing system corrosion.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] An adsorbent for removing sulfuric acid is an SBA-15 molecular sieve modified with a cerium-zirconium solid solution, comprising an SBA-15 molecular sieve, a zirconium component and a cerium component.

[0011] As a preferred solution, the adsorbent comprises the following components:

[0012] The content of SBA-15 molecular sieve is 65-80wt%;

[0013] The zirconium component is calculated as ZrO2, and the content of ZrO2 is 15-25wt%,

[0014] The cerium component is calculated as CeO2, and the content of CeO2 is 5-10 wt%.

[0015] As a preferred solution, the SBA-15 molecular sieve described in the present invention has a pore size of about 1 to 5 nm, a skeleton mainly composed of amorphous SiO2, and the molecular sieve surface contains silanol groups. The SBA-15 molecular sieve also contains 30 to 50% micropores, which can effectively capture sulfuric acid droplets ≤10 microns and meet the demand for high adsorption capacity.

[0016] The preparation method of the adsorbent of the present invention comprises the following steps:

[0017] S1. After the template, salt source, water and acid are uniformly mixed to obtain solution a, a silicon source is added for activation, the solution is filtered, washed and dried to obtain x-CN / SBA-15, which is added to an acid solution for treatment, stirred at a constant temperature, filtered, washed with water and dried to obtain x-COOH / SBA-15;

[0018] S2. Disperse the zirconium source, cerium source and x-COOH / SBA-15 in alcohol, stir evenly, remove the solvent, separate, wash, dry and calcine.

[0019] As a preferred solution, the template of the present invention includes P123 (EO 20 -PO 70 -EO 20 )、F127(EO 106 -PO 70 -EO 106 )、Brij56(C16 H 33 (OCH2CH2) 10 OH) in one or more.

[0020] As a preferred solution, the salt source of the present invention is one or more of KCl, NH4Cl, and NaCl.

[0021] As a preferred embodiment, the acid of the present invention is one or more of hydrochloric acid, sulfuric acid and nitric acid.

[0022] As a preferred solution, the silicon source of the present invention is one or both of cyanoethyltriethoxysilane (CETES) and tetraethyl orthosilicate (TEOS).

[0023] As a preferred solution, the silicon source of the present invention is cyanoethyltriethoxysilane (CETES) and tetraethyl orthosilicate (TEOS) in a mass ratio of 1:0-1.

[0024] As a preferred solution, the zirconium source of the present invention is one or more of zirconium nitrate, zirconyl oxalate, and zirconium hydroxide.

[0025] As a preferred solution, the cerium source of the present invention is one or more of cerium nitrate, cerium chloride, and cerium sulfate.

[0026] As a preferred solution, the mass ratio of the template to the salt source in the present invention is 1:1-3.

[0027] As a preferred solution, the mass ratio of the template agent to the acid and water of the present invention is 1:40-60.

[0028] As a preferred solution, the acid of the present invention accounts for 16 to 32 wt % of the total weight of the acid and water.

[0029] As a preferred solution, in S1 of the present invention, the mixing temperature is 40-80°C.

[0030] As a preferred solution, in S2 of the present invention, the mass ratio of the cerium source, the zirconium source and x-COOH / SBA-15 is 1:(2.6-2.8):(6.7-14.6).

[0031] As a preferred embodiment, in S2 of the present invention, the alcohol is ethanol.

[0032] As a preferred embodiment, the method for preparing the adsorbent of the present invention comprises the following steps:

[0033] S1. Add the template and salt source to the acid aqueous solution, mix well to obtain solution a, slowly add the silicon source, stir for 4-8 hours, transfer to a Teflon-lined reactor, place the reactor in an oven at 100-120°C, and activate for 24-36 hours;

[0034] The obtained product is filtered, washed with distilled water and then with anhydrous ethanol, and then dried in an oven at 60-120° C. to obtain cyano-functionalized x-CN / SBA-15; x-CN / SBA-15 is added to a 6-18.0 wt% acid solution at a mass ratio of 1:50-70, stirred at a constant temperature of 65-85° C. for 12-24 hours, filtered, washed with water, and dried at 80-120° C. to obtain x-COOH / SBA-15;

[0035] S2. Mix the cerium source, the zirconium source and x-COOH / SBA-15 to obtain a mixture b, disperse it in ethanol, stir it for 30 to 60 minutes, remove the solvent, filter it, wash it, dry it, and calcine it.

[0036] x represents the molar ratio of CN / SiO2.

[0037] As a preferred solution, in S1 of the present invention, the mass ratio of the acid aqueous solution to the template is 40-60:1.

[0038] As a preferred solution, in S1 of the present invention, the mass ratio of the silicon source to the solution a is 1:8.4-13.

[0039] As a preferred solution, in S2 of the present invention, the mass ratio of mixture b to ethanol is 1:9-11.

[0040] As a preferred solution, in S3 of the present invention, the temperature for removing the solvent is 160 to 220° C. and the time is 12 to 18 hours.

[0041] As a preferred solution, in S3 of the present invention, ethanol is used for washing.

[0042] As a preferred solution, in S3 of the present invention, the drying is vacuum drying at 60-90°C.

[0043] As a preferred solution, in S3 of the present invention, the calcination is performed at 400-600° C. for 2-6 hours.

[0044] A method for removing trace sulfuric acid from chlorine gas comprises the following steps: using a tubular adsorption tank filled with the adsorbent of the present invention, with an adsorption temperature of 15-30°C, an adsorption pressure of 0.2-0.4 MPag, and a residence time of 6-10 seconds.

[0045] By doping the SBA molecular sieve with cerium-zirconium solid solution, the molecular sieve is modified to have stronger chlorine resistance to meet the needs of long-term stable operation.

[0046] The present invention adopts cerium zirconium solid solution to modify molecular sieve to prepare sulfuric acid adsorbent, and the main effects of doping with cerium and zirconium are: (1) CeO2 and ZrO2 doped in a certain proportion have strong chlorine resistance in a chlorine-containing system, and the cerium zirconium-molecular sieve obtained by the impregnation method can solve the problem of rapid deactivation of the adsorbent caused by the destruction and collapse of the skeleton of ordinary molecular sieves in a chlorine atmosphere, thereby meeting the requirements of long-term stable operation; (2) After the cerium zirconium is mixed and calcined, an appropriate amount of ZrO2 is doped on the surface of Ce. 4+ The interaction between cerium and zirconium can be enhanced to form microcrystalline Ce-Zr mixed oxides that are highly dispersed in the molecular sieve, thereby increasing the pore size and micropore ratio of the molecular sieve to enhance the adsorption and removal effect of micron-sized sulfuric acid droplets. DETAILED DESCRIPTION

[0047] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0048] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0049] The sources of the raw materials used in the following examples of the present invention are shown in Table 1 below:

[0050] Table 1

[0051]

[0052] The following detection methods are used in the following examples:

[0053] (1) Specific surface area and pore structure determination (BET). Using a 3H-2000 specific surface area and pore size analyzer from Bester Technology Instrument Co., Ltd., the samples were pre-degassed at 200°C for 3 h under vacuum conditions. The N2 adsorption-desorption of the samples was measured at 77.3 K (liquid nitrogen temperature). The specific surface area of ​​the samples was calculated according to the BET equation, and the pore size distribution was calculated according to the BJH method.

[0054] (2) Particle strength tester: Use the particle strength tester from Taizhou Jiangyan Analytical Instrument Factory. Place a single particle sample in the middle of the sample tray, press the start button, and stop the test after the display shows real-time data output.

[0055] (3) Analysis of sulfuric acid droplet content: After the gas phase is absorbed by an alkaline solution prepared with deionized water, it is analyzed by ion chromatography.

[0056] Example 1

[0057] S1. Add 300 g of template P123 (EO20-PO70-EO20) and 300 g of salt source KCl to 12 kg of 16% hydrochloric acid solution, mix well to obtain solution a, slowly add 1500 g of cyanoethyltriethoxysilane as silicon source, stir for 4 h, and transfer to Teflon-lined reactor.

[0058] The reactor was placed in an oven at 100°C for activation for 24 hours. The resulting product was filtered, washed with distilled water and then with anhydrous ethanol, and then dried in an oven at 60°C to obtain cyano-functionalized x-CN / SBA-15, where x = 1.

[0059] Weigh 200 g of x-CN / SBA-15 and add it to 10 kg of 6 wt% hydrochloric acid solution in a mass ratio of 1:50. Stir at 65°C for 12 h. Filter, wash with water, and dry at 80°C to obtain x-COOH / SBA-15.

[0060] S2. Mix 140 g of cerium sulfate, 220 g of zirconium oxynitrate, and 500 g of COOH / SBA-15 in a mass ratio of 1:1.6:3.6 to obtain a mixture b, disperse the mixture in 8000 g of ethanol, and stir the mixture in a Teflon reactor for 30 min.

[0061] The solvent was removed by heating in a muffle furnace at 160°C and filtered after 12 hours. The product was washed with anhydrous ethanol, dried in a 60°C oven under vacuum, and calcined in a muffle furnace at 400°C for 2 hours to obtain Zr-Ce / SBA-15. BET characterization of the adsorbent revealed a pore size primarily of 4 nm, with micropores comprising 32%.

[0062] The adsorbent for removing sulfuric acid has an SBA-15 molecular sieve content of 65wt%; the zirconium component is calculated as ZrO2 and the cerium component is calculated as CeO2, wherein the ZrO2 content is 25wt% and the CeO2 content is 10wt%.

[0063] The Zr-Ce / SBA-15 adsorbent was loaded into a shell-and-tube adsorption tank with an adsorption temperature of 15°C, an adsorption pressure of 0.2 MPag, and a residence time of 6 s.

[0064] On-site side-line tests revealed that the gas phase composition was primarily 54 vol.% Cl₂, 26 vol.% O₂, 14 vol.% CO₂, 6 vol.% N₂, and trace amounts of sulfuric acid droplets. Tracking and comparing the sulfuric acid droplet content before and after passing through the adsorbent revealed that the sulfuric acid droplet content in the gas phase decreased from 350 ppmw to 30 ppmw. After 500 hours of long-term operation, the sulfuric acid droplet content at the gas phase outlet stabilized at 50 ppmw. Particle strength testing of the adsorbent before and after removal revealed a decrease from 60N to 45N, and the proportion of micropores decreased to 26%.

[0065] Example 2

[0066] S1. Add 300 g of template F127 (EO106-PO70-EO106) and 300 g of salt source NH4Cl to 15 kg of 24% sulfuric acid solution, mix well to obtain solution a, slowly add 972.0 g of cyanoethyltriethoxysilane and 486 g of ethyl orthosilicate as silicon source, stir for 6 h, and transfer to Teflon-lined reactor.

[0067] The reactor was placed in an oven at 110°C for activation for 30 hours. The resulting product was filtered, washed with distilled water and then with anhydrous ethanol, and then dried in an oven at 90°C to obtain cyano-functionalized x-CN / SBA-15, where x = 0.66.

[0068] Weigh 200 g of x-CN / SBA-15 and add it to 12 kg of 12 wt% sulfuric acid solution at a mass ratio of 1:60. Stir at 75 °C for 18 h. Filter, wash with water, and dry at 100 °C to obtain 0.66COOH / SBA-15.

[0069] S2. Mix 95 g of cerium nitrate hexahydrate, 190 g of zirconium hydroxide, and 500 g of 0.66 COOH / SBA-15 in a mass ratio of 1:2.0:5.3 to obtain a mixture b, disperse the mixture in 8000 g of ethanol, and stir in a Teflon reactor for 45 min.

[0070] The solvent was removed by heating in a muffle furnace at 190°C and filtered after 15 hours. The product was washed with anhydrous ethanol, dried in a 75°C oven under vacuum, and calcined in a muffle furnace at 500°C for 4 hours to obtain Zr-Ce / SBA-15. BET characterization of the adsorbent revealed a pore size primarily of 1 nm, with micropores comprising 50%.

[0071] The adsorbent for removing sulfuric acid has an SBA-15 molecular sieve content of 72 wt.%; the zirconium component is calculated as ZrO2 and the cerium component is calculated as CeO2, wherein the ZrO2 content is 20 wt.% and the CeO2 content is 8 wt.%.

[0072] The Zr-Ce / SBA-15 adsorbent was loaded into a shell-and-tube adsorption tank with an adsorption temperature of 20°C, an adsorption pressure of 0.3 MPag, and a residence time of 8 s.

[0073] On-site side-line tests revealed that the gas phase composition was primarily 54 vol.% Cl₂, 26 vol.% O₂, 14 vol.% CO₂, 6 vol.% N₂, and trace amounts of sulfuric acid droplets. Tracking and comparing the sulfuric acid droplet content before and after passage through the adsorbent revealed a decrease from 350 ppmw to 5 ppmw. After 500 hours of long-term operation, the sulfuric acid droplet content at the gas phase outlet stabilized at 10 ppmw. Particle strength testing of the sulfuric acid droplet adsorbent before and after removal revealed a decrease from 65N to 60N, and a reduction in the proportion of micropores to 42%.

[0074] Example 3

[0075] S1, 300g of template Brij56 (C 16 H 33 (OCH2CH2) 10 OH)) and 300g salt source NaCl were added to 18kg of 32% nitric acid solution, mixed evenly to obtain solution a, and 715.4g cyanoethyltriethoxysilane and 715.4g ethyl orthosilicate, a silicon source, were slowly added, stirred for 8h, and transferred into a Teflon-lined reactor.

[0076] The reactor was placed in an oven at 120°C for activation for 36 hours. The resulting product was filtered, washed with distilled water and then with anhydrous ethanol, and then dried in an oven at 120°C to obtain cyano-functionalized x-CN / SBA-15, where x = 0.49.

[0077] Weigh 200 g of x-CN / SBA-15 and add it to 14 kg of 18 wt.% nitric acid solution at a mass ratio of 1:70. Stir at 85°C for 24 h, filter, wash with water, and dry at 120°C to obtain 0.49COOH / SBA-15.

[0078] S2, 40g of cerium chloride hydrate, 180g of zirconium oxychloride octahydrate and 500g of 0.49COOH / SBA-15 were mixed at a ratio of 1:4.5:12.5 to obtain a mixture b, which was dispersed in 8000g of ethanol and stirred in a Teflon reactor for 60min;

[0079] The solvent was heated in a muffle furnace at 190°C and filtered after 18 hours. The product was washed with anhydrous ethanol, dried in a vacuum oven at 90°C, and calcined in a muffle furnace at 600°C for 6 hours to obtain Zr-Ce / SBA-15.

[0080] The modified SBA-15 molecular sieve was characterized by BET, and its pore size was mainly 3 nm, with micropores accounting for 38%.

[0081] The adsorbent for removing sulfuric acid has an SBA-15 molecular sieve content of 80 wt. %; the zirconium component is calculated as ZrO2 and the cerium component is calculated as CeO2, wherein the ZrO2 content is 15 wt. %, and the CeO2 content is 5 wt. %.

[0082] The Zr-Ce / SBA-15 adsorbent was loaded into a shell-and-tube adsorption tank and a modified high-efficiency sulfuric acid adsorbent. The adsorption temperature was 30°C, the adsorption pressure was 0.4 MPag, and the residence time was 10 s.

[0083] On-site side-line tests revealed that the gas phase composition was primarily 54 vol.% Cl₂, 26 vol.% O₂, 14 vol.% CO₂, 6 vol.% N₂, and trace amounts of sulfuric acid droplets. Tracking and comparing the sulfuric acid droplet content before and after passing through the sulfuric acid demisting and adsorption device revealed a decrease from 350 ppmw to 15 ppmw. After 500 hours of long-term operation, the sulfuric acid droplet content at the gas phase outlet stabilized at 30 ppmw. Particle strength testing of the sulfuric acid droplet adsorbent before and after removal revealed a decrease from 55N to 37N, and a reduction in the proportion of micropores to 30%.

[0084] Comparative Example 1

[0085] Commercial SBA-15 molecular sieve was characterized by BET, and its pore size was mainly 11nm, with micropores accounting for 12%. The commercial SBA-15 molecular sieve adsorbent was loaded into a shell-and-tube adsorption tank at an adsorption temperature of 20°C, an adsorption pressure of 0.3 MPa, and a residence time of 8 seconds.

[0086] On-site side-line tests revealed that the gas phase composition was primarily 54 vol.% Cl₂, 26 vol.% O₂, 14 vol.% CO₂, 6 vol.% N₂, and trace amounts of sulfuric acid droplets. Tracking and comparing the sulfuric acid droplet content before and after passing through the adsorbent revealed a decrease from 350 ppmw to 100 ppmw. After 500 hours of long-term operation, the sulfuric acid droplet content at the gas phase outlet stabilized at 140 ppmw. Particle strength testing of the adsorbent before and after removal revealed a decrease from 30N to 7N, and a reduction in the proportion of micropores to 4%.

[0087] Comparative Example 2

[0088] Performance testing was conducted on an adsorbent prepared from the residue (solid waste alumina red mud) left after alumina extraction from bauxite (primarily composed of aluminum oxides and hydroxides). Its main components were 45 wt.% Fe₂O₃, 32 wt.% Al₂O₃, 21 wt.% SiO₂, and 2 wt.% CaO. The alumina red mud adsorbent was loaded into a shell-and-tube adsorption tank at a temperature of 20°C, a pressure of 0.3 MPaig, and a residence time of 8 seconds.

[0089] A side-line test was conducted on site, and the gas phase composition was mainly 54 vol.% Cl2, 26 vol.% O2, 14 vol.% CO2, 6 vol.% N2 and trace amounts of sulfuric acid droplets. The sulfuric acid droplet content before and after passing through the adsorbent was tracked and compared. The sulfuric acid droplet content in the gas phase dropped from 350 ppmw to 250 ppmw. After a long-term operation of 500 h, the sulfuric acid droplet content at the gas phase outlet was stabilized at 350 ppmw. The adsorbent could not meet the long-term use requirements.

Claims

1. An adsorbent for removing sulfuric acid, which is an SBA-15 molecular sieve modified with a cerium-zirconium solid solution, comprising an SBA-15 molecular sieve, a zirconium component, and a cerium component.

2. The adsorbent according to claim 1, characterized in that The adsorbent comprises the following components: The content of SBA-15 molecular sieve is 65-80wt%; The zirconium component is calculated as ZrO2, and the content of ZrO2 is 15-25wt%, The cerium component is calculated as CeO2, and the content of CeO2 is 5-10 wt%.

3. A method for preparing the molecular sieve according to claim 1 or 2, comprising the following steps: S1. After the template, salt source, water and acid are uniformly mixed to obtain solution a, a silicon source is added for activation, the solution is filtered, washed and dried to obtain x-CN / SBA-15, which is added to an acid solution for treatment, stirred at a constant temperature, filtered, washed with water and dried to obtain x-COOH / SBA-15; S2. Disperse the zirconium source, cerium source and x-COOH / SBA-15 in alcohol, stir evenly, remove the solvent, separate, wash, dry and calcine.

4. The method according to claim 3, characterized in that The template includes one or more of P123, F127, and Brij56; the salt source is one or more of KCl, NH4Cl, and NaCl; the acid is one or more of hydrochloric acid, sulfuric acid, and nitric acid; the silicon source is any one or more of ethyl orthosilicate and cyanoethyltriethoxysilane; the zirconium source is one or more of zirconium nitrate, zirconyl oxalate, and zirconium hydroxide; and the cerium source is one or more of cerium nitrate, cerium chloride, and cerium sulfate.

5. The method according to claim 3, characterized in that The mass ratio of the template to the salt source is 1:1-3; the mass ratio of the template to the sum of the acid and water is 1:40-60; the acid accounts for 16-32 wt% of the sum of the acid and water.

6. The method according to claim 3, characterized in that In the S2, the mass ratio of the cerium source, the zirconium source and the x-COOH / SBA-15 is 1:(2.6-2.8):(6.7-14.6).

7. The method according to claim 3, characterized in that The following steps are involved: S1. Add the template and salt source to the acid aqueous solution, mix well to obtain solution a, slowly add the silicon source, stir for 4-8 hours, transfer to a Teflon-lined reactor, place the reactor in an oven at 100-120°C, and activate for 24-36 hours; The obtained product is filtered, washed with distilled water and then with anhydrous ethanol, and then dried in an oven at 60-120° C. to obtain cyano-functionalized x-CN / SBA-15; x-CN / SBA-15 is added to a 6-18.0 wt% acid solution at a mass ratio of 1:50-70, stirred at a constant temperature of 65-85° C. for 12-24 hours, filtered, washed with water, and dried at 80-120° C. to obtain x-COOH / SBA-15; S2. Mix the cerium source, the zirconium source and x-COOH / SBA-15 to obtain a mixture b, disperse it in ethanol, stir it for 30 to 60 minutes, remove the solvent, filter it, wash it, dry it, and calcine it.

8. The method according to claim 7, characterized in that In the S1, the mass ratio of the silicon source to the solution a is 1:8.4-13.

9. The method according to claim 7, characterized in that In the step S3 , the drying is vacuum drying at 60-90° C.; and the calcining is calcining at 400-600° C. for 2-6 hours.

10. A method for removing trace amounts of sulfuric acid from chlorine gas, comprising the following steps: The shell-and-tube adsorption tank is filled with the adsorbent according to claim 1 or 2 or the adsorbent prepared by the method according to any one of claims 3 to 9, with an adsorption temperature of 15 to 30° C., an adsorption pressure of 0.2 to 0.4 MPag, and a residence time of 6 to 10 seconds.

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