A supported carbon-based adsorbent for removing COS from blast furnace gas at low temperature and a preparation method thereof

Abstract

The application discloses a kind of supported carbon-based adsorbents for removing COS in blast furnace gas at low temperature and preparation method, and relates to the technical field of preparation of adsorbents.The preparation method comprises the following steps: dissolving p-phenylenediamine in an acetic acid solution of chitosan to obtain solution B;adding copper nitrate trihydrate to solution B and stirring to obtain solution C;dropping solution C into an alkali solution to obtain water condensed beads D;washing water condensed beads D to neutral, then freeze-drying to obtain gas condensed beads E;carbonizing gas condensed beads E, and the supported carbon-based adsorbent is obtained.The application can be complexed with copper ions by all amino groups of chitosan itself, has higher copper ion utilization efficiency, can effectively remove COS in low temperature environment, and the supported carbon-based adsorbent can be regenerated, with low operating cost.

Description

Technical Field

[0001] This invention relates to the field of adsorbent preparation technology, specifically to a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas and its preparation method. Background Technology

[0002] Carbonyl sulfides (COS) are widely present in various industrial waste gases, such as blast furnace gas (BFG). COS not only pollutes the environment and corrodes pipelines and equipment, but also causes sulfur poisoning of catalysts. Even trace amounts of COS can adversely affect product quality or lead to catalyst poisoning during subsequent BFG use. BFG is widely used as an important secondary energy source in steel enterprises. When the fuel is used for combustion heating, desulfurization is generally carried out through end-pipe treatment. Using traditional end-pipe treatment in ultra-low emission technologies is costly and often fails to meet emission standards. Therefore, source treatment and BFG desulfurization are the most economical and simplest methods for managing steel plants. The sulfur composition of BFG is complex, as it contains carbonyl sulfides, carbon disulfide, and hydrogen sulfide. Organic sulfur accounts for 80% of its composition, while the remaining 20% ​​is impurities. In addition to N2, CO2, and CO, BFG also contains water, dust, chlorine, etc. These characteristics make BFG desulfurization quite challenging.

[0003] Currently, common methods for COS removal include chemical absorption, adsorption, hydrogenation, and hydrolysis adsorption. Chemical absorption is difficult to implement due to the insolubility and stability of COS. Furthermore, wet absorption can corrode equipment, especially in acidic environments. Adsorption is a traditional but effective method, but the adsorbed COS can cause secondary pollution, and the regeneration process requires high temperatures and complex operations. Hydrogenation methods suffer from high temperatures, high pressures, and high costs, making their application in industrial production difficult. In contrast, hydrolysis adsorption can convert COS into easily treatable H2S and CO2 under mild reaction conditions, followed by the adsorption and conversion of H2S, resulting in higher conversion efficiency.

[0004] Currently, most adsorbents for removing carbonyl sulfur from blast furnace gas have adsorption temperatures above 100℃. However, the temperature of blast furnace gas after dust removal is relatively low, and reaching temperatures above 100℃ requires further energy consumption for heating. Moreover, high-temperature conditions may lead to excessively fast reaction rates, resulting in incomplete reactions and affecting the removal effect. This can also lead to the formation of reaction byproducts such as sulfates, further impacting removal efficiency. Furthermore, high-temperature conditions increase the energy consumption and operating costs of the equipment.

[0005] Existing research reports on the preparation of carbonyl sulfide adsorbents include:

[0006] Application No. 202411664702.X discloses a carbonyl sulfide adsorbent, composed of γ-Al₂O₃, cerium dioxide, activated carbon, a pore-forming agent, and a binder. This invention provides a method for treating carbonyl sulfide-containing gases using a catalyst. However, this adsorbent is not suitable for removing carbonyl sulfide from coal-fired flue gas at low temperatures. Application No. 202411297921.9 discloses a carbonyl sulfide removal adsorbent and its preparation method, whose components are boehmite, ammonium bicarbonate, sodium carbonate, and a binder catalyst. This also fails to remove COS from blast furnace gas at low temperatures. Therefore, the existing technology needs further improvement.

[0007] Therefore, there is an urgent need to study an adsorbent for removing COS under low-temperature conditions. Summary of the Invention

[0008] One of the objectives of this invention is to provide a method for preparing a supported carbon-based adsorbent for removing COS from blast furnace gas at low temperatures. The adsorbent prepared by this method can remove COS from blast furnace gas after dust removal at low temperatures (25°C) without the addition of an additional nitrogen source.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, comprising the following steps:

[0011] a. Chitosan is dissolved in an aqueous acetic acid solution to obtain solution A; the mass-to-volume ratio of chitosan to aqueous acetic acid solution is 0.5–2.0 g / 100 mL; solution A contains free NH3. + ;

[0012] b. Dissolve p-phenylenediamine in solution A to obtain solution B; the mass-to-volume ratio of p-phenylenediamine to solution A is 0.1–0.7 g: 100 mL;

[0013] c. Add a salt containing copper ions to solution B, and stir until the salt containing copper ions is completely dissolved. At this time, the free NH3 in solution A... + Protons are released, and lone pairs of electrons are exposed and combine with copper ions to form solution C; the mass-to-volume ratio of the salt containing copper ions to solution B is 0.38–1.52 g: 100 mL.

[0014] d. Add solution C dropwise to an alkaline solution to obtain hydrogel beads D; wash hydrogel beads D until neutral, and then freeze-dry to obtain aerogel beads E;

[0015] e. Carbonize the aerosol beads E to obtain the final product;

[0016] The conditions for COS removal in blast furnace gas using the supported carbon-based adsorbent are: temperature 25℃ and space velocity 10000 h⁻¹. -1 The simulated gas composition, by volume percentage, is: 25% CO, 400ppm COS, 10% CO2, and balanced nitrogen.

[0017] The beneficial technical effects directly brought about by the above technical solution are as follows:

[0018] This paper presents the application of a carbonyl sulfur-supported carbon-based adsorbent with chitosan carrying pyridine nitrogen and copper ions in the COS catalytic hydrolysis reaction of blast furnace gas. A three-dimensional network structure is prepared by utilizing the free -NH3 in chitosan. Phenylenediamine provides an activated carbon material rich in pyridine nitrogen, which is then used as a carrier to prepare a supported carbon-based adsorbent for COS catalytic hydrolysis of blast furnace gas through the complexation of chitosan and copper ions. The preparation method is simple, quick, and time-saving.

[0019] In the above-mentioned method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, in step a, the volume fraction of acetic acid in the aqueous acetic acid solution is 1-4%.

[0020] In the preparation method of the above-mentioned supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, in step c, the salt containing copper ions is copper nitrate trihydrate, which is added to solution B and stirred until the bubbles disappear.

[0021] In the above-mentioned method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, in step d, the alkaline solution is a sodium hydroxide solution. By increasing the pH of solution C with sodium hydroxide solution, hydroxyl groups begin to participate in coordination to form an N / O mixed coordination mode; copper ions combine with the amino groups of chitosan chains to form hydrogel beads D.

[0022] In the above-mentioned method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, in step d, the hydrogel beads D are freeze-dried in a vacuum freeze dryer for 10-13 hours; the mass fraction of sodium hydroxide in the sodium hydroxide aqueous solution is 5-20%.

[0023] In the above-mentioned method for preparing a supported carbon-based adsorbent for removing COS from blast furnace gas at low temperature, step e involves a carbonization temperature of 500–800°C and a carbonization time of 1–2.5 h.

[0024] In the above-mentioned method for preparing a supported carbon-based adsorbent for removing COS from blast furnace gas at low temperature, in step c, the mass-to-volume ratio of the salt containing copper ions to solution B is 1.14 g: 100 mL.

[0025] In the preparation method of the above-mentioned supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, in step d, solution C is placed in a separatory funnel and then added dropwise to 300 mL of alkaline solution.

[0026] Another objective of this invention is to provide a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, which is prepared using the above-described preparation method.

[0027] Another object of the present invention is to provide a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, wherein the supported carbon-based adsorbent has a pore size of 2-10 nm, a mesopore content of 54.6%, and a total pore volume of 0.637 cm³. 3 / g.

[0028] The preparation principle of the supported carbon-based adsorbent of this invention is as follows:

[0029] Crosslinking chitosan with p-phenylenediamine can introduce basic pyridine nitrogen and increase the number of basic sites on the adsorbent; when solution C is added dropwise to sodium hydroxide solution, the chitosan surface rapidly gels and coordinates, and the amino groups are deprotonated: the droplet surface quickly comes into contact with a high pH environment, and the amino groups (NH3) undergo deprotonation. + →NH2) releases a proton, exposing a lone pair of electrons, which preferentially react with Cu. 2+ Binding. Then comes hydroxyl activation: as the surface pH increases further, hydroxyl groups (OH→O) - It begins to participate in coordination, forming an N / O mixed coordination mode, which enhances complex stability. Cross-linked network formation: surface Cu 2+ The amino groups of multiple chitosan chains bind to form a dense gel layer, fixing the droplet morphology and forming chitosan microspheres. As the reaction time increases, the internal pH gradually rises, and uncomplexed Cu... 2+ By combining with more amino groups, more stable multidentate chelates are formed. Chitosan microparticles are freeze-dried to obtain a three-dimensional network material doped with nitrogen in situ. Metal ions are completely loaded into the nitrogen-doped adsorbent material. Finally, carbonization is carried out under a nitrogen atmosphere to obtain a supported carbon-based adsorbent doped with nitrogen and copper ions.

[0030] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0031] (1) In terms of raw material selection, this invention uses chitosan, which is inexpensive and readily available. It has a wide range of sources and is a raw material with sustainable development characteristics. It can be used as a carbon source, and its own amino groups and copper ions can be used as "bridges" to connect multiple chitosan chains. The three-dimensional network structure formed by coordination bonds is the core driving force for microsphere gelation.

[0032] (2) In terms of preparation method, the adsorbent of this invention has a significant advantage over other carbon sources such as cellulose-based and glucose-based adsorbents in that all amino groups of chitosan can complex with copper ions, resulting in higher copper ion utilization efficiency and enabling effective removal of COS in low-temperature environments. The adsorbent of this invention is regenerable and has low operating costs.

[0033] (3) The embodiments of this invention studied the effects of different loading ratios of active materials on COS removal efficiency. The study showed that the metal ions were first added to the chitosan after cross-linking and then carbonized to load the metal ions. Further experiments confirmed that the supported carbon-based adsorbent had the best desulfurization effect when 1.14 g of copper nitrate trihydrate was added. After the supported carbon-based adsorbent reached the adsorption breakthrough point, the feed gas was stopped, the fixed bed was raised to 700°C, and nitrogen was introduced to purge the sulfurized desulfurizing agent, so that the sulfur components in its pores were desorbed. The COS adsorption performance test was repeated.

[0034] In summary, the supported carbon-based adsorbent prepared by this invention solves the technical problem that existing technologies cannot deeply remove COS under low-temperature conditions. The removal efficiency of the supported carbon-based adsorbent of this invention can reach 100% within 240 minutes and more than 90% within 360 minutes. Furthermore, it can be cycled three times at a regeneration temperature of 90°C and still retain an efficiency of 85.2% for fresh samples. Attached Figure Description

[0035] The present invention will be further described below with reference to the accompanying drawings:

[0036] Figure 1 The X-ray photoelectron spectra before and after the reaction in Example 1 of the present invention are shown below.

[0037] Figure 2 A comparison diagram of the desulfurization effects of the supported carbon-based adsorbents prepared in the embodiments of the present invention;

[0038] Figure 3 The BET specific surface area test diagram of the supported carbon-based adsorbent prepared in the embodiments of the present invention is shown.

[0039] Figure 4 The BET specific surface area test graphs are shown for the supported carbon-based adsorbents prepared in Example 3 and Comparative Example 1. Detailed Implementation

[0040] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0041] All the raw materials required for this invention can be purchased through commercial channels.

[0042] The method for low-temperature COS removal using the supported carbon-based adsorbent prepared by this invention is as follows:

[0043] Detection method: A fixed-bed reactor was used, and the concentration of COS at the outlet was detected by gas chromatograph (GC-9720P1us).

[0044] Experimental conditions: air velocity 10000 h⁻¹ -1 The temperature was 25°C. The simulated gas composition, by volume percentage, was: 25% CO, 200ppm COS, 10% CO2, and balanced nitrogen. A saturator system was used for water supply, and the water content was expressed as relative humidity (RH). A fixed-bed heating system simulated a blast furnace gas environment. A mass flow controller was used to control the total flow rate at 50 mL / min.

[0045] The main technical concept of this invention is to prepare carbon-based adsorbents with ordered mesoporous morphology based on a nitrogen doping strategy to obtain more catalytic sites, thereby extending the service life of the supported carbon-based adsorbent. Carbon materials with pyridine nitrogen loading are synthesized using nitrogen from p-phenylenediamine. The key to COS hydrolysis lies in COS adsorption and water activation. On the one hand, pyridine nitrogen can combine with hydrogen atoms dissociated from water molecules to activate water molecules; on the other hand, COS is removed by utilizing the existing moisture in the blast furnace gas through copper ions. The specific reaction is as follows:

[0046] COS(g)→COS(ads);

[0047] H2O(g)→H2O(ads);

[0048] H2O(ads)→OH - +H + ;

[0049] COS(ads) + OH - →HSCO2 - ;

[0050] HSCO2 - +H + →H2S + CO2;

[0051] COS(ads)+O 2- →SCO2 2- ;

[0052] SCO2 2- +2H + →H2S + CO2;

[0053] CuO + H₂S → CuS + H₂O;

[0054] 4O 2- +CuS→CuSO4+8e - ;

[0055] Crosslinking chitosan with p-phenylenediamine can introduce basic pyridine nitrogen and increase the number of basic sites on the supported carbon-based adsorbent. Simultaneously, the introduction of p-phenylenediamine generates Cu-N bonds, thereby weakening Cu-O bonds and making them easier to break. This generates reactive oxygen species to catalyze the hydrolysis of COS, removing COS from PPD-Cu / CA via the OH pathway. - The pathway also involves reactive oxygen species (O2). 2- The pathway involves the capture of H₂O and COS, facilitated by pyridine nitrogen and Cu-O. Then, the adsorbed H₂O dissociates on the surfaces of pyridine nitrogen and Cu-O to form OH⁻. - and H + Simultaneously, the pyridine nitrogen and the O in the Cu-O structure form reactive oxygen species (O₂). 2- Then, the adsorbed COS reacts with OH-. - and O 2- Combined, forming the intermediate HSCO 2- and SCO2 2- The intermediate material is further hydrogenated to form H2S and H2O. Finally, H2S is captured by CuO and eventually sulfides to form CuSO4, leading to sample deactivation. Furthermore, the participation of pyridine nitrogen keeps the reaction temperature at room temperature and achieves extremely high catalytic efficiency. This modification facilitates further research on adsorbents that can promote COS hydrolysis and their applications in manufacturing.

[0056] Based on the above technical concept, the present invention yields a specific technical solution: a COS hydrolysis adsorbent supported on chitosan and pyridine nitrogen and copper ions. The COS hydrolysis adsorbent is a pyridine nitrogen-rich activated carbon material prepared by in-situ nitrogen doping strategy, which is used as a carrier to support copper ion adsorbent for COS catalytic hydrolysis in blast furnace gas.

[0057] The present invention will be further described below with reference to specific embodiments.

[0058] Example 1:

[0059] A method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas includes the following steps:

[0060] Step 1: Dissolve 0.5g of chitosan in 100mL of 1% (v / v) acetic acid aqueous solution to obtain solution A;

[0061] Step 2: Dissolve 0.1g of p-phenylenediamine in solution A to obtain solution B;

[0062] Step 3: Add 0.38g of copper nitrate trihydrate to solution B and stir until completely dissolved to obtain solution C;

[0063] Step 4: Place solution C into a separatory funnel, then add it dropwise to 300 ml of a 5% sodium hydroxide solution to obtain hydrogel beads D. Wash hydrogel beads D until neutral, then freeze-dry them in a vacuum freeze dryer for 10 hours to obtain aerogel beads E;

[0064] Step 5: Carbonize the aerosol beads E at 500℃ for 1 hour to obtain the product.

[0065] The nitrogen-doped metal ion-supported adsorbent material prepared in this embodiment was tested at low temperature with a space velocity of 10000 h⁻¹. -1 The temperature was 25℃. The simulated gas composition was: 25% CO, 400ppm COS, 10% CO2, and balanced nitrogen. A saturator system was used to supply water, and the water content was expressed as relative humidity (RH). In this invention, RH was always taken as 50%. A water bath heating method was used to simulate the blast furnace gas environment. A mass flow controller was used to control the total flow rate at 50mL / min. The results showed that the COS removal rate of the supported carbon-based adsorbent prepared in this embodiment remained above 90% within 120min, and above 80% within 240min.

[0066] Example 2:

[0067] A method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas includes the following steps:

[0068] Step 1: Dissolve 1g of chitosan in 100mL of acetic acid aqueous solution with a volume ratio of 2% to obtain solution A;

[0069] Step 2: Dissolve p-phenylenediamine in solution A to obtain solution B; wherein the mass-to-volume ratio of p-phenylenediamine to solution A is 0.3 g: 100 mL;

[0070] Step 3: Add copper nitrate trihydrate to solution B and stir until completely dissolved. The mass-to-volume ratio of copper nitrate trihydrate to solution B is 0.76 g: 100 mL. Continue stirring for 2 hours until the solution is completely dissolved and the bubbles disappear, to obtain solution C.

[0071] Step 4: Place solution C into a separatory funnel, then add it dropwise to 300 mL of 10% sodium hydroxide solution to obtain hydrogel beads D. Wash hydrogel beads D until neutral, then place them in a vacuum freeze dryer and freeze-dry for 11 hours to obtain aerogel beads E;

[0072] Step 5: Carbonize the aerosol beads E at 600℃ for 2 hours to obtain the product.

[0073] The supported carbon-based adsorbent prepared in this embodiment was tested at low temperature using the same method as in Example 1. The results showed that the COS removal rate of the supported carbon-based adsorbent in this embodiment was over 90% within 360 min, and remained above 80% within 510 min.

[0074] Example 3:

[0075] A method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas includes the following steps:

[0076] Step 1: Dissolve 1.5g of chitosan in 100mL of 3% (v / v) acetic acid aqueous solution to obtain solution A;

[0077] Step 2: Dissolve 0.5g of p-phenylenediamine in solution A to obtain solution B;

[0078] Step 3: Add 1.14g of copper nitrate trihydrate to solution B and stir until completely dissolved and the bubbles disappear to obtain solution C;

[0079] Step 4: Place solution C into a separatory funnel, then add it dropwise to 300 mL of 15% sodium hydroxide solution to obtain hydrogel beads D. Wash hydrogel beads D until neutral, then freeze-dry them in a vacuum freeze dryer for 12 hours to obtain aerogel beads E;

[0080] Step 5: Carbonize the aerosol beads E at 700℃ for 2 hours to obtain the product.

[0081] Figure 1 The X-ray photoelectron spectra before and after the reaction in Example 3 of the present invention show that: Figure 1 (b) with PPD-Cu / CA (already used) and Figure 1 Compared to (a) PPD-Cu / CA (fresh), Cu 2+ and Cu + / Cu 0 The characteristic peaks of Cu decreased to varying degrees, which is due to Cu 2+ and Cu + / Cu 0 During the reaction, it combines with COS to form sulfur species, resulting in Cu in the sample. 2+ and Cu + / Cu 0 The content decreased.

[0082] The supported carbon-based adsorbent prepared in this embodiment was tested at low temperature using the same method as in Example 1. The results showed that the COS removal rate of the supported carbon-based adsorbent in this embodiment was over 90% within 420 min, and remained above 80% within 540 min.

[0083] Example 4:

[0084] A method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas includes the following steps:

[0085] Step 1: Dissolve 2g of chitosan in 100mL of 4% (v / v) acetic acid aqueous solution to obtain solution A;

[0086] Step 2: Dissolve 0.7g of p-phenylenediamine in solution A to obtain solution B;

[0087] Step 3: Add 1.52g of copper nitrate trihydrate to solution B and stir until completely dissolved and the bubbles disappear to obtain solution C;

[0088] Step 4: Place solution C into a separatory funnel, then add it dropwise to 300 mL of 20% sodium hydroxide solution to obtain hydrogel beads D. Wash hydrogel beads D until neutral, then freeze-dry them in a vacuum freeze dryer for 13 hours to obtain aerogel beads E;

[0089] Step 5: Carbonize the aerosol beads E at 800℃ for 2.5 hours to obtain the product.

[0090] The supported carbon-based adsorbent prepared in this embodiment was tested at low temperature using the same method as in Example 1. The results showed that the carbonyl sulfur removal rate was over 90% within 90 minutes, and the desulfurization efficiency remained above 80% within 180 minutes.

[0091] The COS removal efficiency of the supported carbon-based adsorbents prepared in Examples 1 to 4 above under the same conditions is as follows: Figure 2 As shown.

[0092] Comparative Example 1:

[0093] The specific steps for preparing supported carbon-based adsorbents are as follows:

[0094] Step 1: Dissolve 1.5g of chitosan in 100mL of 3% (v / v) acetic acid aqueous solution to obtain solution A;

[0095] Step 2: Place solution A into a separatory funnel, then add it dropwise to 300 mL of a 15% sodium hydroxide solution to obtain hydrogel beads B. Wash hydrogel beads B until neutral, then place them in a vacuum freeze dryer and react for 12 hours to obtain aerogel beads C.

[0096] Step 3: Carbonize the aerosol beads C in a nitrogen atmosphere at 700℃ for 2 hours to obtain the final adsorbent;

[0097] The results showed that the removal rate of COS by the supported carbon-based adsorbent in this embodiment was consistently above 90% within 60 minutes, and remained above 80% within 90 minutes.

[0098] The BET specific surface area test results of the supported carbon-based adsorbents prepared in this comparative example and Example 3 are shown in the figure below. Figure 3 , Figure 4 As shown.

[0099] The BET images of this comparative example and Example 3 are as follows: Figure 3 , Figure 4 As shown, this reveals significant differences in pore structure. Comparative example ( Figure 4 The proportion of 2-10nm mesopores in Example 3 was 12.6%, however, in Example 3 ( Figure 4 The 2-10nm mesopore content was 54.6%, and both Example 3 and Comparative Example 1 showed a Type IV isotherm with an H4 type hysteresis loop ( Figure 3 This indicates the characteristics of a mixture of microporous and mesoporous materials. However, the hysteresis loop in Example 3 has a larger area and higher pore volume, which is more conducive to the catalytic hydrolysis reaction of COS.

[0100] Comparative Example 2:

[0101] The specific steps for preparing supported carbon-based adsorbents are as follows:

[0102] Step 1: Dissolve 1.5g of chitosan in 100mL of 3% (v / v) acetic acid aqueous solution to obtain solution A;

[0103] Step 2: Dissolve 0.5g of p-phenylenediamine in solution A to obtain solution B;

[0104] Step 3: Place solution B into a separatory funnel, then add it dropwise to 300 mL of a 15% sodium hydroxide solution to obtain hydrogel beads C. Wash hydrogel beads C until neutral, then place them in a vacuum freeze dryer and react for 10 hours to obtain aerogel beads D;

[0105] Step 5: Carbonize the aerosol beads D in a nitrogen atmosphere at 700℃ for 2 hours to obtain the final adsorbent;

[0106] The results showed that the removal rate of COS by the comparative supported carbon-based adsorbent remained above 90% within 80 minutes, and remained above 80% within 120 minutes.

[0107] Comparative Example 3:

[0108] The specific steps for preparing supported carbon-based adsorbents are as follows:

[0109] Step 1: Dissolve 1.5g of chitosan in 100mL of 3% (v / v) acetic acid aqueous solution to obtain solution A;

[0110] Step 2: Dissolve 1.14g of copper nitrate trihydrate in solution A to obtain solution B;

[0111] Step 3: Place solution B into a separatory funnel, then add it dropwise to 300 mL of a 15% sodium hydroxide solution to obtain hydrogel beads C. Wash hydrogel beads C until neutral, then place them in a vacuum freeze dryer and react for 12 hours to obtain aerogel beads D;

[0112] Step 5: Carbonize the aerosol beads D in a nitrogen atmosphere at 700℃ for 2 hours to obtain the final adsorbent;

[0113] The results showed that the removal rate of COS by the comparative supported carbon-based adsorbent remained above 90% within 100 min, and remained above 80% within 120 min.

[0114] Comparative Example 4:

[0115] The difference from Example 3 is that copper ions are not selected as the metal ion; instead, iron ions with a positive valence (+3) are selected. 1.14g of copper nitrate trihydrate is replaced with 2.17g of ferric nitrate nonahydrate.

[0116] The results showed that the removal rate of COS by the comparative supported carbon-based adsorbent remained above 90% within 70 minutes and above 80% within 100 minutes.

[0117] Comparative Example 5:

[0118] The difference from Example 3 is that p-phenylenediamine is replaced with 0.5g of urea.

[0119] The results showed that the comparative supported carbon-based adsorbent achieved a COS removal rate of over 90% within 300 min, and maintained a COS removal rate of over 80% within 410 min.

[0120] Comparative Example 6:

[0121] The preparation of a supported carbon-based adsorbent using glucose as a precursor includes the following steps:

[0122] Step 1: Dissolve 1.5g of glucose in 100mL of water at 60℃ to obtain solution A;

[0123] Step 2: Dissolve 0.5g of p-phenylenediamine in solution A to obtain solution B;

[0124] Step 3: Add 1.14g of copper nitrate trihydrate to solution B and stir until completely dissolved to obtain solution C;

[0125] Step 4: Transfer solution C to a high-pressure reactor and hydrothermally react at 180°C for 12 hours to generate carbon precursor D containing Cu-PDA;

[0126] Step 5: After washing, centrifuging and drying the carbon precursor D, place it in a tube furnace and carbonize it at 700℃ for 2 hours to obtain the final supported carbon-based adsorbent E.

[0127] The results showed that the comparative supported carbon-based adsorbent achieved a COS removal rate of over 90% within 30 minutes, and maintained a COS removal rate of over 80% within 40 minutes. However, it was difficult to achieve effective COS adsorption under low-temperature conditions.

[0128] Any parts not mentioned in this invention can be achieved by referring to existing technologies.

[0129] Those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of protection claimed in this application.

Claims

1. A method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, characterized in that, The steps are as follows: a. Chitosan is dissolved in an aqueous acetic acid solution to obtain solution A; the mass-to-volume ratio of chitosan to aqueous acetic acid solution is 0.5–2.0 g / 100 mL; solution A contains free NH3. + ; b. Dissolve p-phenylenediamine in solution A to obtain solution B; the mass-to-volume ratio of p-phenylenediamine to solution A is 0.1–0.7 g: 100 mL; c. Add a salt containing copper ions to solution B, and stir until the salt containing copper ions is completely dissolved. At this time, the free NH3 in solution A... + Protons are released, and lone pairs of electrons are exposed and combine with copper ions to form solution C; the mass-to-volume ratio of the salt containing copper ions to solution B is 0.38–1.52 g: 100 mL. d. Add solution C dropwise to an alkaline solution to obtain hydrogel beads D; wash hydrogel beads D until neutral, and then freeze-dry to obtain aerogel beads E; e. Carbonize the aerosol beads E to obtain the final product; The conditions for COS removal in blast furnace gas using the supported carbon-based adsorbent are: temperature 25℃ and space velocity 10000 h⁻¹. -1 The simulated gas composition, by volume percentage, is: 25% CO, 400ppm COS, 10% CO2, and balanced nitrogen.

2. The method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas according to claim 1, characterized in that: In step a, the volume fraction of acetic acid in the aqueous acetic acid solution is 1-4%.

3. The method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas according to claim 1, characterized in that: In step c, the salt containing copper ions is copper nitrate trihydrate. Copper nitrate trihydrate is added to solution B and stirred until the bubbles disappear.

4. The method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas according to claim 1, characterized in that: In step d, the alkaline solution is a sodium hydroxide solution. The pH of solution C is increased by the sodium hydroxide solution, and hydroxyl groups begin to participate in coordination to form an N / O mixed coordination mode; copper ions combine with the amino groups of the chitosan chains to form hydrogel beads D.

5. The method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas according to claim 4, characterized in that: In step d, the hydrogel beads D are freeze-dried in a vacuum freeze dryer for 10–13 h; the mass fraction of sodium hydroxide in the sodium hydroxide aqueous solution is 5–20%.

6. The method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas according to claim 1, characterized in that: In step e, the carbonization temperature is 500–800℃ and the carbonization time is 1–2.5 h.

7. The method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas according to claim 1, characterized in that: In step c, the mass-to-volume ratio of the salt containing copper ions to solution B is 1.14 g: 100 mL.

8. The method for preparing a supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas according to claim 1, characterized in that: In step d, solution C is placed in a separatory funnel and then added dropwise to 300 mL of alkaline solution.

9. A supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 7.

10. A supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas according to claim 9, characterized in that: The supported carbon-based adsorbent has a pore size of 2–10 nm, a mesopore content of 54.6%, and a total pore volume of 0.637 cm³. 3 / g.

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