A copper-iron hydrotalcite-like oxide adsorbent, its preparation method and use

Abstract

This invention relates to the technical field, disclosing a copper-iron hydrotalcite-derived oxide adsorbent, its preparation method, and its application. The method includes the following steps: S1, dissolving a ferric salt and a divalent copper salt in water at room temperature to obtain solution A; dissolving an alkaline substance and a carbonate in water to obtain solution B; S2, simultaneously adding solutions A and B dropwise into a three-necked flask, stirring, maintaining the pH value, obtaining a suspension, crystallizing the suspension to obtain a crystallized product; filtering and washing the crystallized product until the pH is neutral, drying, to obtain a copper-iron hydrotalcite precursor; S3, grinding the copper-iron hydrotalcite precursor into powder and calcining it to obtain a copper-iron hydrotalcite-derived oxide; in solution A, the molar ratio of copper to iron is 1-2, excluding 2; in solution B, n(OH) ‑ )=2n(Cu 2+ )+3n(Fe 3+ It has been well applied in the removal of carbonyl sulfur, achieving fine desulfurization of coal gas and realizing the goal of emission reduction at the source.

Description

Technical Field

[0001] This invention relates to the field of adsorbent technology, and in particular to a copper-iron hydrotalcite-derived oxide adsorbent, its preparation method, and its application. Background Technology

[0002] Blast furnaces, as the mainstream ironmaking equipment in long-process steelmaking, hold a pivotal position in the steel industry. Blast furnace ironmaking produces blast furnace gas containing various sulfur-containing pollutants. These pollutants not only corrode chemical industry pipelines and reaction equipment but also cause catalyst poisoning and deactivation. Carbonyl sulfide (COS), emitted into the atmosphere, undergoes chemical reactions in the stratosphere and troposphere to form sulfate aerosol particles, severely impacting atmospheric radiation intensity, global climate change, and public health. Carbonyl sulfide (COS) accounts for 70%–80% of the total sulfur content in blast furnace gas; it has an unpleasant odor and is difficult to decompose. To further achieve environmental protection goals and serve the ecological civilization strategy, and to promote ultra-low emissions in the steel industry, the utilization of blast furnace gas in the steel industry requires desulfurization treatment.

[0003] Carbonyl sulfide (COS) molecules are linear, with a stable planar triangular structure similar to carbon disulfide and sulfur dioxide, but they still possess certain chemical reactivity. Their acidity and polarity are weaker than H₂S gas, making their removal more difficult. Current carbonyl sulfide (COS) removal technologies mainly include catalytic hydrolysis, hydrogenation conversion, and adsorption. Catalytic hydrolysis is a complex process, requiring the first hydrolysis of COS into H₂S before H₂S removal. This process suffers from high solvent consumption and severe equipment corrosion. Hydrogenation conversion requires high reaction temperatures and an external hydrogen source. Adsorption methods can mineralize carbonyl sulfide (COS), offering advantages such as moderate reaction temperatures and fewer side reactions. It also avoids the investment required for the carbonyl sulfide (COS) conversion process, thus attracting significant attention.

[0004] Layered double hydroxides (HTLCs), also known as hydrotalcite-like compounds, have attracted much attention due to their unique carbonyl sulfide (COS) removal properties. HTLCs are anionic clays that, during calcination, lose their water of crystallization and interlayer anions, exposing numerous active sites. Due to their well-developed porous structure and unique acid-base properties, calcined HTLCs exhibit excellent desulfurization activity against carbonyl sulfide (COS).

[0005] Currently, the synthesis of copper-containing layered double hydroxides (LDHs) is subject to stringent conditions due to the severe Jamie-Taylor effect of copper. However, the properties of copper ions make copper-based catalysts widely used in catalysis. Copper-iron LDH-derived oxides have been used to remove pollutants from wastewater, but have never been used to remove air pollutants, especially carbonyl sulfide (COS). Copper-iron LDHs, as precursors, produce oxides with large specific surface areas, high copper dispersion, and uniform particle size after calcination, enabling the mineralization of carbonyl sulfide (COS) and avoiding secondary pollution. Therefore, research on the preparation and application of copper-containing LDHs is of great significance. Summary of the Invention

[0006] Based on the above, the purpose of this invention is to provide a copper-iron hydrotalcite-derived oxide adsorbent, its preparation method and application, which can be well applied in the removal of carbonyl sulfur, to achieve fine desulfurization of coal gas and achieve the goal of emission reduction at the source.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing a copper-iron hydrotalcite-derived oxide adsorbent includes the following steps:

[0009] S1. Dissolve ferric salt and copper salt in water at room temperature to prepare solution A; dissolve alkaline substance and carbonate in water to prepare solution B;

[0010] S2. Add solutions A and B dropwise into a three-necked flask, stir, maintain pH value, and obtain a suspension. Liquidize the suspension to obtain a crystallized product. Filter and wash the crystallized product until the pH is neutral, and dry it to obtain a copper-iron hydrotalcite precursor.

[0011] S3. Grind the copper-iron hydrotalcite precursor into powder and then calcine it to obtain copper-iron hydrotalcite derivative oxide.

[0012] In solution A, the molar ratio of copper to iron is 1 to 2, excluding 2; in solution B, n(OH-) = 2n(Cu) 2+ )+3n(Fe 3+ ).

[0013] In a preferred embodiment of a method for preparing a copper-iron hydrotalcite-derived oxide adsorbent, in step S1, the sum of the concentrations of copper ions and iron ions in solution A is 0.9 mol / L to 1.1 mol / L.

[0014] In a preferred embodiment of a method for preparing a copper-iron hydrotalcite-derived oxide adsorbent, in step S1, the alkaline substance includes one or more of KOH, NaOH, Na2CO3, and K2CO3.

[0015] In a preferred embodiment of a method for preparing a copper-iron hydrotalcite-derived oxide adsorbent, in step S2, the content of deionized water in the three-necked flask is 30 ml, the dropping rate of solution A and solution B is 1-2 drops / s, the pH value is maintained at 4.0-5.2, and the stirring time is 30-60 min.

[0016] In a preferred embodiment of a method for preparing a copper-iron hydrotalcite-derived oxide adsorbent, in step S2, the crystallization temperature is 100–120°C and the crystallization time is 4–6 h.

[0017] In a preferred embodiment of a method for preparing a copper-iron hydrotalcite-derived oxide adsorbent, in step S2, the drying process is carried out at a temperature of 80–100°C for 12–16 hours.

[0018] In a preferred embodiment of a method for preparing a copper-iron hydrotalcite-derived oxide adsorbent, in step S3, the calcination process involves raising the temperature from room temperature to 300–600°C and calcining at 300–600°C for 3–5 hours.

[0019] A copper-iron hydrotalcite-derived oxide adsorbent, characterized in that it is prepared by any one of the above-described preparation methods.

[0020] Application of a copper-iron hydrotalcite-derived oxide adsorbent, wherein the adsorbent is used to remove carbonyl sulfides.

[0021] As a preferred embodiment of the application of copper-iron hydrotalcite-derived oxide adsorbent, the adsorbent, during the removal of carbonyl sulfide, has a carbonyl sulfide concentration of 800–1200 ppm and a reaction temperature of 100°C–200°C. The beneficial effects of this invention are:

[0022] This invention provides a method for preparing copper-iron layered double hydroxide (LDH)-derived oxide adsorbents. A mixed solution of copper and iron salts is simultaneously added dropwise to a three-necked flask along with a mixed solution of alkali and carbonate. The mixture is then sequentially crystallized, filtered, washed, and dried to obtain a copper-iron LDH precursor. This precursor is then calcined to obtain copper-iron oxides. When applied to the adsorption and removal of carbonyl sulfides, these oxides exhibit excellent desulfurization performance. Furthermore, they can effectively treat high concentrations of carbonyl sulfide gas. The process is carried out at medium to low temperatures and ambient pressure, resulting in mild reaction conditions and reduced energy consumption and resource waste.

[0023] This invention also provides an application of copper-iron hydrotalcite-derived oxide adsorbents, which effectively remove sulfides, achieve fine desulfurization of coal gas, meet the source emission reduction target, and prevent sulfides from corroding pipelines or equipment and causing environmental pollution. Furthermore, the adsorption device used is simple to operate, the reaction is easy to control, and it is highly feasible. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0025] Figure 1 This is a comparison chart of the activity evaluation of the desulfurization adsorbents prepared in the embodiments and comparative examples of the present invention;

[0026] Figure 2 These are diffraction patterns of copper-iron hydrotalcite precursors prepared in the embodiments and comparative examples of this invention. Detailed Implementation

[0027] To facilitate understanding of the present invention, a more comprehensive description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention. Unless otherwise defined, all technical and scientific terms used in this invention pertain to the technical field of the invention.

[0028] This embodiment provides a method for preparing a copper-iron hydrotalcite-derived oxide adsorbent, comprising the following steps:

[0029] S1: Dissolve ferric salt and copper salt in water at room temperature to prepare solution A; dissolve alkaline substance and carbonate in water to prepare solution B;

[0030] Preferably, in solution A, the molar ratio of copper to iron is 1–4, and the sum of the concentrations of copper ions and iron ions is 0.9 mol / L–1.1 mol / L. This allows for the successful preparation of copper-iron hydrotalcite, and the resulting copper-iron hydrotalcite has high crystallinity, thereby improving the desulfurization performance of the adsorbent. In solution B, n(OH-) = 2n(Cu 2+ )+3n(Fe 3+ ), n(CO3) 2- )=0.5n(Fe 3 + This allows copper and iron ions to precipitate completely after subsequent mixing of solutions A and B. The alkaline substances include one or more of KOH, NaOH, Na2CO3, and K2CO3.

[0031] S2: Add solutions A and B dropwise into a three-necked flask simultaneously, stir, maintain pH value, and obtain a suspension. Liquidize the suspension to obtain a crystallized product. Filter and wash the crystallized product until the pH is neutral, and dry it to obtain a copper-iron hydrotalcite precursor, namely Cu-Fe-N-HTLcs precursor, where N is 1 to 2 (excluding 2).

[0032] Preferably, the dropwise addition process of solution A and solution B includes: placing a three-necked flask containing 30 ml of deionized water on a magnetic stirrer, and simultaneously and slowly adding solution A and solution B into the three-necked flask at a rate of 1 to 2 drops / s while stirring, and observing the pH of the solution with a pH meter to maintain the pH in the range of 4.0 to 5.2. After the addition is complete, continue stirring for 30 to 60 minutes to obtain the desired suspension.

[0033] Preferably, during the crystallization process, the obtained suspension is transferred into a stainless steel reactor for crystallization at a temperature of 100–120°C for 4–6 hours.

[0034] More preferably, during the drying process, the reactants are placed in an oven at a temperature of 80–100°C for 12–16 hours.

[0035] S3: Copper-iron hydrotalcite precursors are ground into powder and then calcined to obtain copper-iron hydrotalcite derived oxides (Cu). x Fe y O) is a composite metal oxide that can effectively adsorb and desulfurize.

[0036] Preferably, the copper-iron hydrotalcite precursor is ground into powder and then calcined in a muffle furnace. During calcination, the temperature is raised from room temperature to 300-600°C, and then roasted at 300-600°C for 3-5 hours.

[0037] The adsorbent prepared above can effectively treat high concentrations of carbonyl sulfur gas. The reaction is carried out at medium and low temperatures and normal pressure, with mild reaction conditions, reducing energy consumption and resource waste.

[0038] This embodiment also provides an application of a copper-iron hydrotalcite-derived oxide adsorbent, including the following steps:

[0039] S4: Compress and granulate the desulfurization adsorbent, sieve it, and pass it through a 40-60 mesh sieve; weigh the set amount of the desulfurization adsorbent and place it in the center of a quartz tube, and fill both ends of the quartz tube with quartz wool and quartz sand; place the quartz tube containing the desulfurization adsorbent in a reaction device, and introduce carbonyl sulfide (COS) gas, with N2 as the balance gas.

[0040] Preferably, the total flow rate of the mixed gas in the equipment is 60-100 ml / min, the carbonyl sulfide (COS) concentration is 800-1200 ppm, and the reaction temperature is 100-200℃.

[0041] Desulfurization adsorbents are used in blast furnace gas desulfurization to effectively remove sulfides from blast furnace gas, achieve fine desulfurization of gas, achieve emission reduction targets at the source, and avoid corrosion of pipelines or equipment and environmental pollution caused by sulfides.

[0042] The present invention will be further described below through specific embodiments.

[0043] Example 1

[0044] Weigh 5.0333g Cu(NO3)2·3H2O and 8.2030g Fe(NO3)3·9H2O at room temperature (the molar ratio of Cu to Fe is 1), dissolve them in 60ml of deionized water, and sonicate to obtain mixed solution A, with the sum of metal cation concentrations being 1mol / L.

[0045] Weigh 4.0g NaOH and 1.0621Na2CO3 into a beaker, dissolve them in 110ml deionized water, and sonicate to obtain mixed solution B, which can be used as a precipitant.

[0046] With the magnetic stirrer running at 1000 rpm, solutions A and B were added dropwise at a rate of 1-2 drops / s to a three-necked flask containing 30 ml of deionized water. The pH was measured while adding the solutions to ensure that the pH was between 4.0 and 5.2. After titration, the solution was stirred for 30 minutes to obtain a suspension.

[0047] The obtained suspension was transferred into a polytetrafluoroethylene liner and placed in a hydrothermal reactor, where it was hydrothermally heated at 110°C for 5 hours.

[0048] The crystallized product obtained in the previous step was filtered and washed several times until the product pH was neutral. Then it was placed in an oven and dried at 80°C for 12 hours. After drying, it was ground and sieved to obtain a powder that is a copper-iron hydrotalcite precursor, denoted as Cu-Fe-1-HTLcs, i.e., Cu-Fe-N-HTLcs precursor, where N is 1.

[0049] The powder was placed in a crucible and then placed in a muffle furnace and calcined at 400°C for 3 hours to obtain the final copper-iron oxide, which is the adsorbent Cu-Fe-1-HTO.

[0050] like Figure 1 As shown, the removal efficiency of carbonyl sulfide (COS) first increases and then decreases as the molar ratio decreases, with the best removal efficiency observed when the Cu / Fe molar ratio is 1:1.

[0051] Example 2

[0052] Weigh 5.0333g Cu(NO3)2·3H2O and 3.2338g Fe(NO3)3·9H2O at room temperature (the molar ratio of Cu to Fe is 1.8), dissolve them in 40ml of deionized water, and sonicate to obtain mixed solution A, with the sum of metal cation concentrations being 1mol / L.

[0053] Weigh 2.8g NaOH and 0.5311g Na2CO3 into a beaker, dissolve them in 120ml deionized water, and sonicate to obtain mixed solution B, which can be used as a precipitant.

[0054] With the magnetic stirrer running at 1000 rpm, solutions A and B were added dropwise at a rate of 1-2 drops / s to a three-necked flask containing 30 ml of deionized water. The pH was measured while adding the solutions to ensure that the pH was between 4.0 and 5.2. After titration, the solution was stirred for 30 minutes to obtain a suspension.

[0055] The obtained suspension was transferred into a polytetrafluoroethylene liner and placed in a hydrothermal reactor, where it was hydrothermally heated at 110°C for 5 hours.

[0056] The crystallized product obtained in the previous step was filtered and washed several times until the pH of the product was neutral. Then it was placed in an oven and dried at 80°C for 12 hours. After drying, it was ground and sieved to obtain a powder that is a copper-iron hydrotalcite precursor, denoted as Cu-Fe-1.8-HTLcs, i.e. Cu-Fe-N-HTLcs precursor, where N is 1.8.

[0057] The powder was placed in a crucible and then placed in a muffle furnace and calcined at 400°C for 3 hours to obtain the final copper-iron oxide, which is the adsorbent Cu-Fe-1.8-HTO.

[0058] Comparative Example 1

[0059] Weigh 10.0666g Cu(NO3)2·3H2O and 4.1015g Fe(NO3)3·9H2O at room temperature (the molar ratio of Cu to Fe is 4), dissolve them in 50ml of deionized water, and sonicate to obtain mixed solution A, with the sum of metal cation concentrations being 1mol / L.

[0060] Weigh 4.4g NaOH and 0.5311g Na2CO3 into a beaker, dissolve them in 115ml deionized water, and sonicate to obtain mixed solution B, which is used as a precipitant.

[0061] With the magnetic stirrer running at 1000 rpm, solutions A and B were added dropwise at a rate of 1-2 drops / s to a three-necked flask containing 30 ml of deionized water. The pH was measured while adding the solutions to ensure that the pH was between 4.0 and 5.2. After titration, the solution was stirred for 30 minutes to obtain a suspension.

[0062] The obtained suspension was transferred into a polytetrafluoroethylene liner and placed in a hydrothermal reactor, where it was hydrothermally heated at 110°C for 5 hours.

[0063] The crystallized product obtained in the previous step was filtered and washed several times until the product pH was neutral. Then it was placed in an oven and dried at 80°C for 12 hours. After drying, it was ground and sieved to obtain a powdered copper-iron hydrotalcite precursor, denoted as Cu-Fe-4-HTLcs.

[0064] The powder was placed in a crucible and then placed in a muffle furnace and calcined at 400°C for 3 hours to obtain the final copper-iron oxide, which is the adsorbent Cu-Fe-4-HTO.

[0065] Comparative Example 2

[0066] Weigh 7.55g Cu(NO3)2·3H2O and 4.1015g Fe(NO3)3·9H2O at room temperature (the molar ratio of Cu to Fe is 3), dissolve them in 40ml of deionized water, and sonicate to obtain mixed solution A, with the sum of metal cation concentrations being 1mol / L.

[0067] Weigh 3.6g NaOH and 0.5311g Na2CO3 into a beaker, dissolve them in 95ml of deionized water, and sonicate to obtain mixed solution B, which is used as a precipitant.

[0068] With the magnetic stirrer running at 1000 rpm, solutions A and B were added dropwise at a rate of 1-2 drops / s to a three-necked flask containing 30 ml of deionized water. The pH was measured while adding the solutions to ensure that the pH was between 4.0 and 5.2. After titration, the solution was stirred for 30 minutes to obtain a suspension.

[0069] The obtained suspension was transferred into a polytetrafluoroethylene liner and placed in a hydrothermal reactor, where it was hydrothermally heated at 110°C for 5 hours.

[0070] The crystallized product obtained in the previous step was filtered and washed several times until the product pH was neutral. Then it was placed in an oven at 80°C for 12 hours to dry. After drying, it was ground and sieved to obtain a powder that is a copper-iron hydrotalcite precursor, denoted as Cu-Fe-3-HTLcs.

[0071] The powder was placed in a crucible and then placed in a muffle furnace and calcined at 400°C for 3 hours to obtain the final copper-iron oxide, which is the adsorbent Cu-Fe-3-HTO.

[0072] Comparative Example 3

[0073] Weigh 2.5166g Cu(NO3)2·3H2O and 8.2030g Fe(NO3)3·9H2O at room temperature (the molar ratio of Cu to Fe is 0.5), dissolve them in 30ml of deionized water, and sonicate to obtain mixed solution A, with the sum of metal cation concentrations being 1mol / L.

[0074] Weigh 3.2g NaOH and 1.0621Na2CO3 into a beaker, dissolve them in 90ml deionized water, and sonicate to obtain mixed solution B, which can be used as a precipitant.

[0075] With the magnetic stirrer running at 1000 rpm, solutions A and B were added dropwise at a rate of 1-2 drops / s to a three-necked flask containing 30 ml of deionized water. The pH was measured while adding the solutions to ensure that the pH was between 4.0 and 5.2. After titration, the solution was stirred for 30 minutes to obtain a suspension.

[0076] The obtained suspension was transferred into a polytetrafluoroethylene liner and placed in a hydrothermal reactor, where it was hydrothermally heated at 110°C for 5 hours.

[0077] The crystallized product obtained in the previous step was filtered and washed several times until the product pH was neutral. Then it was placed in an oven at 80°C for 12 hours to dry. After drying, it was ground and sieved to obtain a powder that is a copper-iron hydrotalcite precursor, denoted as Cu-Fe-0.5-HTLcs.

[0078] The powder was placed in a crucible and then placed in a muffle furnace and calcined at 400°C for 3 hours to obtain the final copper-iron oxide, which is the adsorbent Cu-Fe-0.5-HTO.

[0079] Desulfurization evaluation experiments were conducted on the desulfurization adsorbents prepared in the above embodiments and comparative examples:

[0080] The desulfurization adsorbent was placed on a tablet press and kept under a pressure of 15 MPa for 180 seconds. Then it was crushed with a pestle and sieved into 40-60 mesh particles.

[0081] Weigh out 0.5g of desulfurization adsorbent and place it in a quartz tube with an inner diameter of 7mm. Fill both ends of the quartz tube with quartz wool and quartz sand. Place the quartz tube containing the desulfurization adsorbent in a tube furnace.

[0082] The temperature of the tubular furnace is raised to 100℃, and nitrogen gas at a rate of 100 ml / min is introduced to purge the desulfurization adsorbent for 1 hour to remove moisture and other adsorbed impurities.

[0083] The nitrogen gas was switched to a mixed gas with a total flow rate of 100 ml / min and a carbonyl sulfide (COS) / N2 concentration of 100 ppm. The temperature inside the furnace was maintained by a temperature controller, and the desulfurization adsorbent and the gas were in full contact inside the quartz tube.

[0084] The carbonyl sulfide (COS) concentration at the outlet is detected by gas chromatography (FPD detector) to obtain the breakthrough adsorption curve. The breakthrough adsorption is defined as when the carbonyl sulfide concentration in the outlet gas reaches 10% of the concentration in the inlet gas, which is also the effective adsorption time. At this point, the feed gas is stopped and the reaction ends.

[0085] like Figure 1 As shown, the removal efficiency of carbonyl sulfide (COS) first increases and then decreases as the molar ratio decreases, with the best removal efficiency achieved when the molar ratio is 1:1.

[0086] like Figure 2 As shown, X-ray diffraction analysis was performed on the copper-iron layered double hydroxide (TLH) precursors synthesized by co-precipitation in the examples and comparative examples. The characteristic peaks in the spectra with a sum of metal cation concentrations of 1 mol / L all belong to the characteristic peaks of copper-iron LDH with intercalated carbonate ions. When the molar ratio of Cu to Fe is between 2 (excluding 2) and 1, the LDH precursors formed at this molar ratio have good crystallinity, high orderliness of crystal face growth, and no crystal defects. When the molar ratio of Cu to Fe decreases to 0.5, the crystal faces are difficult to show, and the structure may be amorphous. When the molar ratio of Cu to Fe is greater than 2, the COS removal efficiency is significantly reduced.

[0087] The above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. An application of a copper-iron hydrotalcite-derived oxide adsorbent, characterized in that, The adsorbent is used to remove carbonyl sulfide. During the carbonyl sulfide removal process, the concentration of carbonyl sulfide is 800-1200 ppm, and the reaction temperature is 100℃-200℃. The adsorbent preparation method includes the following steps: S1. Dissolve ferric salt and copper salt in water at room temperature to prepare solution A; dissolve sodium hydroxide and sodium carbonate in water to prepare solution B; S2. Add solutions A and B dropwise into a three-necked flask, stir, maintain pH value, and obtain a suspension. Liquidize the suspension to obtain a crystallized product. Filter and wash the crystallized product until the pH is neutral, and dry it to obtain a copper-iron hydrotalcite precursor. S3. Grind the copper-iron hydrotalcite precursor into powder and then calcine it to obtain copper-iron hydrotalcite derivative oxide. In solution A, the molar ratio of copper to iron is 1; in solution B, n(OH⁻) = 2n(Cu⁻) 2+ ) + 3n(Fe 3+ ); In step S2, the crystallization temperature is 100~120 ℃ and the crystallization time is 4~6 h; In step S2, the three-necked flask contains 30 mL of deionized water, the dropping rate of solution A and solution B is 1-2 drops / s, the pH value is maintained at 4.0-5.2, and the stirring time is 30-60 min.

2. The application of the copper-iron hydrotalcite-derived oxide adsorbent according to claim 1, characterized in that, In S1, the sum of the concentrations of copper ions and iron ions in solution A is 0.9 mol / L to 1.1 mol / L.

3. The application of the copper-iron hydrotalcite-derived oxide adsorbent according to claim 1, characterized in that, In step S2, the drying process is carried out at a temperature of 80-100 ℃ and a drying time of 12-16 h.

4. The application of the copper-iron hydrotalcite-derived oxide adsorbent according to claim 1, characterized in that, In step S3, during the calcination process, the temperature is raised from room temperature to 300-600 ℃, and then calcined at 300-600 ℃ for 3-5 h.

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