Supported carbon-based adsorbent for removing COS in blast furnace gas at low temperature and preparation method

Abstract

The invention discloses a supported carbon-based adsorbent for removing COS in blast furnace gas at low temperature and a 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 a solution B; adding copper nitrate trihydrate into the solution B, stirring and dissolving to obtain a solution C; dropwise adding the solution C into an alkali solution to obtain hydrogel beads D; washing the hydrogel beads D to be neutral, and then performing freeze drying to obtain aerogel beads E; and carbonizing the aerogel beads E to obtain the composite material. All amino groups of the chitosan can be complexed with copper ions, the copper ion utilization efficiency is higher, COS can be effectively removed in a low-temperature environment, and the supported carbon-based adsorbent is renewable and low in operation cost.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorbent preparation, and specifically relates to a supported carbon-based adsorbent for low-temperature removal of COS in blast furnace gas and a preparation method thereof. Background Art

[0002] Carbonyl sulfide (COS) widely exists in various industrial waste gases, such as blast furnace gas (BFG). COS not only pollutes the environment, corrodes pipeline equipment, but also causes sulfur poisoning of catalysts. The presence of trace amounts of COS will have an adverse effect on product quality or cause catalyst poisoning in the subsequent use of BFG. BFG is widely used as an important secondary energy source in iron and steel enterprises. When used as fuel for combustion heating, desulfurization is generally carried out through end-of-pipe treatment. Using traditional end-of-pipe treatment in ultra-low emission technologies has high investment costs and usually does not meet emission standards. Therefore, source treatment and BFG desulfurization are the most economical and simplest methods for managing steel mills. The sulfur components in BFG are very complex because it contains carbonyl sulfide, carbon disulfide and hydrogen sulfide. Among them, organic sulfur accounts for 80% of its components, and the remaining 20% are impurities. In addition to N2, CO2 and CO, BFG also contains water, dust, chlorine, etc. These characteristics make the desulfurization of BFG quite challenging.

[0003] Currently, common methods for removing COS include chemical absorption, adsorption, hydrogenation and hydrolysis adsorption. Due to the insolubility and stability of COS, chemical absorption is difficult to achieve. In addition, wet absorption may corrode the equipment used, especially in an acidic environment. Adsorption is a traditional but effective method, but the adsorbed COS may cause secondary pollution, and the regeneration process requires high temperature and complex operations. The hydrogenation method (hydrogenation) has the disadvantages of high temperature, high pressure and high cost, making its application difficult in industrial production. Relatively speaking, the hydrolysis adsorption method can convert COS into easily treatable H2S and CO2 under mild reaction conditions, and then adsorb and convert H2S, with a relatively high conversion efficiency.

[0004] Currently, the adsorption temperature of most adsorbents for removing carbonyl sulfide in blast furnace gas is above 100°C. The temperature of blast furnace gas after dust removal is relatively low. Reaching a temperature above 100°C requires additional energy consumption for heating. Moreover, under relatively high-temperature conditions, the reaction rate may be too fast, resulting in incomplete reactions, affecting the removal effect, leading to the formation of reaction by-products such as sulfates, affecting the removal efficiency, and increasing the energy consumption and operating costs of the equipment under high-temperature conditions.

[0005] Research reports on the preparation of carbonyl sulfide adsorbents in the prior art include:

[0006] Application No. 202411664702.X discloses a carbonyl sulfide adsorbent, which is made of the following components: γ-Al2O3, cerium dioxide, activated carbon, pore former, binder. This invention provides a method for treating carbonyl sulfide-containing gas 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 adsorbent and its preparation method, the components of which are: pseudo-boehmite, ammonium bicarbonate, sodium carbonate and binder as the catalyst, and it is also unable to remove COS from blast furnace gas at low temperatures. Thus, the prior art needs to be further improved.

[0007] Thus, 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 the present invention is to provide a preparation method of 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 additional nitrogen source.

[0009] To achieve the above objective, the present invention adopts the following technical solutions:

[0010] A preparation method of a supported carbon-based adsorbent for removing COS from blast furnace gas at low temperatures, which successively includes the following steps:

[0011] a. Dissolve chitosan in an acetic acid aqueous solution to obtain solution A; the mass-volume ratio of chitosan to the acetic acid aqueous 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-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 + releases protons, the lone pair electrons are exposed and combine with copper ions to obtain solution C; the mass-volume ratio of the salt containing copper ions to solution B is 0.38 - 1.52 g:100 mL;

[0014] d. Drop solution C into an alkaline solution to obtain hydrogel beads D; wash hydrogel beads D to neutral, and then perform freeze-drying to obtain aerogel beads E;

[0015] e. Carbonize aerogel beads E to obtain the product.

[0016] The conditions for the supported carbon-based adsorbent to remove COS from blast furnace gas are as follows: temperature 25°C, space velocity 10,000 h -1 , and the composition of the simulated gas by volume percentage is: 25% CO, 400 ppm COS, 10% CO2, and balance nitrogen.

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

[0018] Provided is the application of a carbonyl sulfide-supported carbon-based adsorbent loaded with chitosan-supported pyridine nitrogen and copper ions in the catalytic hydrolysis reaction of COS in blast furnace gas. By using the free -NH3 in chitosan to prepare a three-dimensional network structure, activated carbon materials rich in pyridine nitrogen are provided by p-phenylenediamine, and a supported carbon-based adsorbent loaded with copper ions for the catalytic hydrolysis of COS in blast furnace gas is prepared by the complexation of chitosan and copper ions with it. Its preparation method is simple, fast, and time-consuming less.

[0019] In the preparation method of the above-mentioned 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 acetic acid aqueous 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, and copper nitrate trihydrate is added to solution B and stirred until the bubbles disappear.

[0021] 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, the alkali solution is sodium hydroxide solution. By using the sodium hydroxide solution to increase the pH of solution C, hydroxyl groups start to participate in coordination to form an N / O mixed coordination mode; copper ions combine with the amino groups of the chitosan chain to form hydrogel beads D.

[0022] 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, 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%.

[0023] In the preparation method of the above-mentioned supported carbon-based adsorbent for low-temperature removal of COS from blast furnace gas, in step e, the carbonization temperature is 500 - 800°C, and the carbonization time is 1 - 2.5 h.

[0024] 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 mass-volume ratio of the salt containing copper ions to solution B is 1.14 g:100 mL.

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

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

[0027] Another object of the present invention is to provide a supported carbon-based adsorbent for low-temperature removal of COS in blast furnace gas as described above. The pore diameter of the supported carbon-based adsorbent is 2-10 nm, the mesoporous proportion is 54.6%, and the total pore volume is 0.637 cm 3 / g.

[0028] The preparation principle of the supported carbon-based adsorbent of the present 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 dropped into the sodium hydroxide solution, the surface of chitosan gels and coordinates rapidly, and the amino group is deprotonated: the surface of the droplet quickly contacts the high-pH environment, and the amino group (NH3 + →NH2) releases a proton, and the lone pair of electrons is exposed, and it preferentially binds to Cu 2+ Then there is hydroxyl activation: when the surface pH further increases, the hydroxyl group (OH→O - ) starts to participate in coordination to form an N / O mixed coordination mode, enhancing the complex stability. Crosslinking network formation: The surface Cu 2+ binds to the amino groups of multiple chitosan chains to form a dense gel layer, fixing the droplet morphology and forming chitosan microspheres. As the reaction time prolongs, the internal pH gradually increases, and the uncomplexed Cu 2+ binds to more amino groups to form a more stable multidentate chelate. The chitosan microparticles are subjected to freeze-drying reaction to obtain a three-dimensional network material with in-situ doped nitrogen element. The metal ions are completely loaded into the nitrogen-doped adsorption material, and finally carbonization is carried out under a nitrogen atmosphere to obtain a supported carbon-based adsorbent doped with nitrogen element and copper ions.

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

[0031] (1) In terms of the selection of raw materials, the present invention selects chitosan with cheap and easily available raw materials. It has a wide source and is a raw material with sustainable development characteristics. It can be used as a carbon source and can also use its own amino group and copper ions as a "bridge" 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 the preparation method, the obvious advantage of this adsorbent compared with other carbon sources such as cellulose-based and glucose-based adsorbents is that all the amino groups of chitosan can chelate with copper ions, with a higher utilization efficiency of copper ions, enabling it to effectively remove COS in a low-temperature environment. The adsorbent of the present invention is renewable and has a low operating cost.

[0033] (3) In the examples of the present invention, the effects of different loading ratios of active substances, etc. on the COS removal efficiency were studied. The research shows that for the loading of metal ions on the crosslinked chitosan of the present invention, metal ions are first added and then carbonized. Further experiments confirmed that when 1.14 g of copper nitrate trihydrate is added, the desulfurization effect of the supported carbon-based adsorbent is the best. After the supported carbon-based adsorbent reaches the adsorption breakthrough point, the feed gas is stopped from being introduced. The fixed bed is heated to 700 °C and then nitrogen is introduced to purge the sulfided desulfurizer, so that the sulfur components in its pores are desorbed, and the COS adsorption performance test is repeated.

[0034] In summary, the supported carbon-based adsorbent prepared in the present invention solves the technical problem in the prior art that COS cannot be deeply removed under low-temperature conditions. The removal efficiency of the supported carbon-based adsorbent of the present invention can reach 100% within 240 min and over 90% within 360 min, and it can still have an efficiency of 85.2% of the fresh sample after being recycled 3 times at a regeneration temperature of 90 °C. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0036] Figure 1 It is the X-ray photoelectron spectroscopy diagram before and after the reaction in Example 1 of the present invention;

[0037] Figure 2 It is the comparison diagram of the desulfurization effect of the supported carbon-based adsorbent prepared in the examples of the present invention;

[0038] Figure 3 It is the BET specific surface area test diagram of the supported carbon-based adsorbent prepared in the examples of the present invention;

[0039] Figure 4 It is the BET specific surface area test diagram of the supported carbon-based adsorbents prepared in Example 3 and Comparative Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

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

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

[0042] The method for low-temperature removal of COS by the supported carbon-based adsorbent prepared in the present invention is specifically as follows:

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

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

[0045] The main technical concept of the present invention is: Based on the nitrogen doping strategy, an ordered mesoporous morphology is prepared 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 the nitrogen element in p-phenylenediamine. The key to the hydrolysis of COS lies in the adsorption of COS and the activation of water. On the one hand, pyridine nitrogen can combine with the hydrogen atoms dissociated from water molecules to activate water molecules. On the other hand, copper ions are used to remove COS using the original moisture in the blast furnace gas. The specific reactions are 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. At the same time, the introduction of p-phenylenediamine will generate Cu-N bonds, thereby weakening the Cu-O bonds, making the Cu-O bonds easier to break, generating reactive oxygen species to catalyze the hydrolysis of COS. The path for removing COS from PPD-Cu / CA involves (OH - path), and also involves reactive oxygen species (O 2- ). First, promoted by pyridine nitrogen and Cu-O, H2O and COS are captured. Then, the adsorbed H2O dissociates on the surface of pyridine nitrogen and Cu-O to form OH - and H + . At the same time, O in the pyridine nitrogen and Cu-O structure forms reactive oxygen species (O 2- ). Then, the adsorbed COS combines with OH - and O 2- to form intermediates HSCO 2- and SCO2 2- . The intermediate materials are further hydrogenated to form H2S and H2O. Finally, H2S is captured by CuO and finally sulfided to form CuSO4, resulting in the inactivation of the sample. And due to the participation of pyridine nitrogen, the reaction temperature can be maintained at room temperature and extremely high catalytic efficiency can be obtained. This modification helps to further study the adsorbent that can promote the hydrolysis of COS and its application in the manufacturing industry.

[0056] Combining the above technical concepts, the present invention obtains a specific technical solution, that is: a COS hydrolysis adsorbent with chitosan supported pyridine nitrogen and copper ions. The COS hydrolysis adsorbent is a pyridine nitrogen-rich activated carbon material prepared by an in-situ nitrogen element doping strategy, and copper ion adsorbent is supported on it as a carrier for catalytic hydrolysis of COS in blast furnace gas.

[0057] The following further illustrates the present invention with specific examples.

[0058] Example 1:

[0059] A preparation method of a supported carbon-based adsorbent for low-temperature removal of COS in blast furnace gas, comprising the following steps:

[0060] Step 1: Dissolve 0.5 g of chitosan in 100 mL of acetic acid aqueous solution with a volume ratio of 1% to obtain solution A;

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

[0062] Step 3: Add 0.38 g 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 and then slowly add it dropwise to 300 ml of a sodium hydroxide solution with a mass fraction of 5% to obtain hydrogel beads D. Wash the hydrogel beads D until neutral, and then place them in a vacuum freeze dryer for freeze-drying for 10 h to obtain aerogel beads E;

[0064] Step 5: Carbonize the aerogel beads E at a temperature of 500 °C for 1 h to obtain the product.

[0065] The nitrogen-doped metal ion-loaded adsorbent prepared in this example was tested at low temperature with a space velocity of 10,000 h -1 -1 and a temperature of 25 °C. The simulated gas composition was: 25% CO, 400 ppm COS, 10% CO2, and balance nitrogen. A saturator system was used to supply water and the water content was expressed as relative humidity (RH). In this invention, RH was taken as 50% in all cases. A water bath was used to heat and simulate the blast furnace gas environment. A mass flow controller was used to control the total flow rate to 50 mL / min. The results showed that: within 120 min, the removal rate of COS by the supported carbon-based adsorbent prepared in this example remained above 90%, and within 240 min, the removal rate of COS remained above 80%.

[0066] Example 2:

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

[0068] Step 1: Dissolve 1 g of chitosan in 100 mL of an 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-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, wherein the mass-volume ratio of copper nitrate trihydrate to solution B is 0.76 g:100 mL; continue for 2 h until all the bubbles disappear after complete dissolution to obtain solution C;

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

[0072] Step 5: Carbonize the aerogel beads E at a temperature of 600 °C for 2 h to obtain the product.

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

[0074] Example 3:

[0075] A preparation method of a supported carbon-based adsorbent for low-temperature removal of COS in blast furnace gas, comprising the following steps:

[0076] Step 1: Dissolve 1.5 g of chitosan in 100 mL of acetic acid aqueous solution with a volume fraction of 3% to obtain solution A;

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

[0078] Step 3: Add 1.14 g 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, and then drop it into 300 mL of sodium hydroxide solution with a mass fraction of 15% to obtain hydrogel beads D. Wash the hydrogel beads D to neutrality, and then put them into a vacuum freeze dryer for freeze drying for 12 h to obtain aerogel beads E;

[0080] Step 5: Carbonize the aerogel beads E at 700 °C for 2 h to obtain the product.

[0081] Figure 1 This is the X-ray photoelectron spectroscopy diagram before and after the reaction in Example 3 of the present invention. It can be seen from the figure that: Figure 1 In (b), compared with PPD-Cu / CA (used) and Figure 1 in (a) PPD-Cu / CA (fresh), the characteristic peaks of Cu 2+ and Cu + / Cu 0 decreased to varying degrees. This is because Cu 2+ and Cu + / Cu 0 combined with COS to form sulfur species during the reaction, resulting in a decrease in the content of Cu 2+ and Cu + / Cu 0 in the sample.

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

[0083] Example 4:

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

[0085] Step 1: Dissolve 2 g of chitosan in 100 mL of acetic acid aqueous solution with a volume fraction of 4%, to obtain solution A;

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

[0087] Step 3: Add 1.52 g 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 separating funnel, and then drop it into 300 mL of sodium hydroxide solution with a mass fraction of 20% to obtain hydrogel beads D. Wash hydrogel beads D to neutrality, and then put them into a vacuum freeze dryer for freeze-drying for 13 h to obtain aerogel beads E;

[0089] Step 5: Carbonize aerogel beads E at 800 °C for 2.5 h to obtain the product.

[0090] The supported carbon-based adsorbent prepared in this example was experimented at low temperature, and the specific method was the same as that in Example 1. The results showed that: the removal rate of carbonyl sulfide was more than 90% within 90 min, and the desulfurization efficiency remained above 80% within 180 min.

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

[0092] Comparative Example 1:

[0093] Prepare a supported carbon-based adsorbent, and the specific steps are as follows:

[0094] Step 1: Dissolve 1.5 g of chitosan in 100 mL of acetic acid aqueous solution with a volume fraction of 3% to obtain solution A;

[0095] Step 2: Place solution A into a separating funnel, and then drop it into 300 mL of sodium hydroxide solution with a mass fraction of 15% to obtain hydrogel beads B. Wash hydrogel beads B to neutrality, and then put them into a vacuum freeze dryer for reaction for 12 h to obtain aerogel beads C;

[0096] Step 3: Carbonize aerogel beads C in a nitrogen atmosphere at 700 °C for 2 h to obtain the final adsorbent;

[0097] The results show that within 60 minutes, the removal rate of COS by the supported carbon-based adsorbent in this example is always above 90%, and within 90 minutes, the removal rate of COS remains above 80%.

[0098] The BET specific surface area test diagrams of the supported carbon-based adsorbents prepared in this comparative example and Example 3 are as Figure 3 、 Figure 4 shown.

[0099] The BET images of this comparative example and Example 3 are as Figure 3 、 Figure 4 shown, revealing obvious differences in the pore structure. The proportion of 2-10 nm mesopores in the comparative example ( Figure 4 ) is 12.6%, while the proportion of 2-10 nm mesopores in Example 3 ( Figure 4 ) is 54.6%. And although both Example 3 and Comparative Example 1 show a type IV isotherm with an H4-type hysteresis loop ( Figure 3 ), indicating the characteristics of a microporous and mesoporous mixed material. However, the hysteresis loop area of Example 3 is larger and has a higher pore volume, which is more conducive to the catalytic hydrolysis reaction of COS.

[0100] Comparative Example 2:

[0101] Prepare a supported carbon-based adsorbent, and the specific steps are as follows:

[0102] Step 1: Dissolve 1.5 g of chitosan in 100 mL of acetic acid aqueous solution with a volume fraction of 3% to obtain solution A;

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

[0104] Step 3: Place solution B in a separatory funnel, and then drop it into 300 mL of sodium hydroxide solution with a mass fraction of 15% to obtain hydrogel beads C. Wash hydrogel beads C to neutral, and then put them into a vacuum freeze dryer to react for 10 h to obtain aerogel beads D;

[0105] Step 5: Carbonize aerogel beads D in a nitrogen atmosphere at a temperature of 700 °C for 2 h to obtain the final adsorbent;

[0106] The results show that within 80 minutes, the removal rate of COS by the supported carbon-based adsorbent in this comparative example is always above 90%, and within 120 minutes, the removal rate of COS remains above 80%.

[0107] Comparative Example 3:

[0108] Prepare a supported carbon-based adsorbent, and the specific steps are as follows:

[0109] Step 1: Dissolve 1.5 g of chitosan in 100 mL of acetic acid aqueous solution with a volume fraction of 3% to obtain solution A;

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

[0111] Step 3: Place solution B into a separatory funnel, and then drop it into 300 mL of sodium hydroxide solution with a mass fraction of 15% to obtain hydrogel beads C. Wash hydrogel beads C to neutral, and then place them into a vacuum freeze dryer for reaction for 12 h to obtain aerogel beads D;

[0112] Step 5: Carbonize aerogel beads D at 700 °C in a nitrogen atmosphere for 2 h to obtain the final adsorbent;

[0113] The results show that within 100 min, the removal rate of COS by the supported carbon-based adsorbent in this comparative example is always above 90%, and within 120 min, the removal rate of COS remains above 80%.

[0114] Comparative Example 4:

[0115] The difference from Example 3 is that: instead of choosing copper ions for metal ions, ferric ions with a valence of +3 are chosen. Replace 1.14 g of copper nitrate trihydrate with 2.17 g of ferric nitrate nonahydrate.

[0116] The results show that within 70 min, the removal rate of COS by the supported carbon-based adsorbent in this comparative example is always above 90%, and within 100 min, the removal rate of COS remains above 80%.

[0117] Comparative Example 5:

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

[0119] The results show that within 300 min, the removal rate of COS by the supported carbon-based adsorbent in this comparative example is above 90%, and within 410 min, the removal rate of COS remains above 80%.

[0120] Comparative Example 6:

[0121] Prepare a supported carbon-based adsorbent using glucose as a precursor, including the following steps:

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

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

[0124] Step 3: Add 1.14 g 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 carry out hydrothermal reaction at 180 °C for 12 hours to generate a carbon precursor D containing Cu-PDA;

[0126] Step 5: Wash, centrifuge, and dry the carbon precursor D, then place it in a tube furnace and carbonize it at 700 °C for 2 h to obtain the final supported carbon-based adsorbent E;

[0127] The results show that within 30 min, the removal rate of COS by the supported carbon-based adsorbent in this comparative example is more than 90%, and the removal rate of COS remains above 80% within 40 min. It is difficult to effectively adsorb COS under low-temperature conditions.

[0128] Those parts not described in the present invention can be realized by referring to the prior art.

[0129] Ordinary technical personnel in the technical field should recognize that the above embodiments are only used to illustrate the present application, rather than to limit the present application. As long as appropriate changes and variations made to the above embodiments fall within the scope of the spirit of the present application, they fall within the scope of protection required by the present application.

Claims

1. A method for preparing a supported carbon-based adsorbent for removing COS from blast furnace gas at low temperature, characterized in that: The following steps are included in sequence: a. Dissolve chitosan in acetic acid aqueous solution to obtain solution A; the mass volume ratio of chitosan to acetic acid aqueous solution is 0.5-2.0 g / 100 mL; solution A contains free NH3 + ; b. dissolving p-phenylenediamine in solution A to obtain solution B; the mass volume ratio of p-phenylenediamine to solution A is 0.1-0.7 g:100 mL; c. Add salt containing copper ions to solution B and stir until the salt containing copper ions is completely dissolved. At this time, the free NH3 + Protons are released, lone pairs of electrons are exposed and combined with copper ions to obtain solution C; the mass volume ratio of the salt containing copper ions to solution B is 0.38-1.52 g:100 mL; d. adding solution C dropwise to an alkaline solution to obtain hydrogel beads D; washing the hydrogel beads D to neutrality, and then freeze-drying them to obtain aerogel beads E; e. Carbonizing the gas condensation beads E to obtain; The conditions for removing COS from blast furnace gas by the supported carbon-based adsorbent are: temperature 25°C, space velocity 10000h -1 The simulated gas compositions, by volume percentage, are: 25% CO, 400 ppm COS, 10% CO2, and the balance nitrogen.

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

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

4. The method for preparing a supported carbon-based adsorbent for removing COS from blast furnace gas at low temperature 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 the hydroxyl groups begin to participate in the coordination to form a N / O mixed coordination mode; the 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 removing COS from blast furnace gas at low temperature according to claim 4, characterized in that: In step d, the hydrogel beads D are freeze-dried in a vacuum freeze dryer for 10 to 13 hours; the mass fraction of sodium hydroxide in the sodium hydroxide aqueous solution is 5 to 20%.

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

7. The method for preparing a supported carbon-based adsorbent for removing COS from blast furnace gas at low temperature according to claim 1, characterized in that: In step c, the mass 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 removing COS from blast furnace gas at low temperature 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 the alkaline solution.

9. A supported carbon-based adsorbent for removing COS from blast furnace gas at low temperature, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 7.

10. The supported carbon-based adsorbent for removing COS from blast furnace gas at low temperature according to claim 9, characterized in that: The pore size of the supported carbon-based adsorbent is 2-10 nm, the mesopore ratio is 54.6%, and the total pore volume is 0.637 cm 3 / g.

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