阅读说明：本技术 一种用于有机硫催化水解的铜锰基催化剂及其制备方法与应用 (Copper-manganese-based catalyst for catalytic hydrolysis of organic sulfur and preparation method and application thereof ) 是由 梁诗景 长孙贵强 江莉龙 曹彦宁 郑勇 刘福建 于 2021-01-21 设计创作，主要内容包括：本发明公开了一种用于有机硫催化水解的铜锰基催化剂及其制备方法与应用,其是利用共沉淀的方法,使金属粒子Cu、Mn均匀分散,然后加入微量的沉淀剂促进结构的搭建,并经高温固化后得到结晶度良好的催化剂。本发明合成条件简单且反应迅速,耗时短,原子利用率高,所制备的铜锰基催化剂呈现出高结晶度、规则的纳米颗粒结构,铜与锰物种之间的相互作用可实现对锰元素d电子结构的调控,优化其酸碱协同催化作用,所具有的弱碱性活性位点可提高对羰基硫(COS)的水解反应性能,因而适用于羰基硫气体的低温催化水解。(The invention discloses a copper-manganese-based catalyst for catalytic hydrolysis of organic sulfur, and a preparation method and application thereof. The method has the advantages of simple synthesis conditions, rapid reaction, short time consumption and high atom utilization rate, the prepared copper-manganese-based catalyst presents a high-crystallinity and regular nanoparticle structure, the interaction between copper and manganese species can realize the regulation and control of the electronic structure of the manganese element d, the acid-base synergistic catalysis effect is optimized, and the weakly alkaline active sites can improve the hydrolysis reaction performance of carbonyl sulfide (COS), so the method is suitable for the low-temperature catalytic hydrolysis of the carbonyl sulfide gas.)

1. A preparation method of a copper-manganese-based catalyst for catalytic hydrolysis of organic sulfur is characterized by comprising the following steps: the method comprises the following steps:

1) adding a copper source and a manganese source into deionized water according to a certain molar ratio, and stirring to completely dissolve the copper source and the manganese source to obtain a mixed solution;

2) dissolving alkali in deionized water to prepare an alkali solution with a certain concentration;

3) slowly dropwise adding the mixed solution obtained in the step 1) into the aqueous alkali obtained in the step 2) under a high-speed stirring state, placing the mixture into an oil bath pot after dropwise adding, continuously stirring and reacting for 6-12 h at 50-100 ℃, aging for 1-6 h at room temperature, centrifuging and filtering the obtained precipitate, washing until the pH of the filtrate is neutral, placing the precipitate into an oven at 80-100 ℃, drying to constant weight, and grinding to obtain a catalyst precursor;

4) roasting the catalyst precursor obtained in the step 3) in a muffle furnace, and then mechanically tabletting, forming and sieving to obtain the copper-doped manganese-based catalyst.

2. The method for preparing a copper manganese-based catalyst according to claim 1, characterized in that: the amounts of the copper source and the manganese source used in step 1) are converted by a molar ratio of n (Cu), n (Mn), and = (0.01-0.3), and 1.

3. The method for preparing a copper manganese-based catalyst according to claim 1 or 2, characterized in that: the copper source is one or more of copper nitrate, copper sulfate, copper chloride and copper acetate;

the manganese source is one or more of manganese sulfate, manganese chloride, manganese acetate and manganese nitrate.

4. The method for preparing a copper manganese-based catalyst according to claim 1, characterized in that: the concentration of the alkali solution in the step 2) is 0.3-1 mol/L; wherein the alkali is one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide and ammonia water.

5. The method for preparing a copper manganese-based catalyst according to claim 1, characterized in that: the amount of the mixed solution and the alkali solution used in the step 3) is n (Mn) to n (OH) according to the molar ratio of n (Mn)^-) Conversion of = (0.1 to 0.3): 1.

6. The method for preparing a copper manganese-based catalyst according to claim 1, characterized in that: in the step 4), the roasting is carried out for 2-8 h at 450-750 ℃ in an air atmosphere.

7. The copper-manganese-based catalyst for catalytic hydrolysis of organic sulfur prepared by the method of claims 1-6.

8. Use of the copper manganese-based catalyst according to claim 7 for catalyzing the hydrolysis reaction of COS.

Technical Field

The invention belongs to the field of gaseous sulfide removal technology and catalyst preparation, and particularly relates to a copper-manganese-based catalyst for catalytic hydrolysis of organic sulfur, and a preparation method and application thereof.

Background

Steel is an important prop industry related to the national civilization, and the pig iron yield of China in 2019 is about 9.96 hundred million tons. About 85 percent of pig iron in China is smelted by a blast furnace with high production rate, low consumption, low cost and long service life. The basic principle of blast furnace iron making is to calcine raw materials such as iron ore, oil, coal and coke in a blast furnace and utilize CO and H generated by gas making₂Iron oxide in iron ore is reduced into pig iron, so that a huge amount of blast furnace gas can be produced as a byproduct in the blast furnace iron making process, and the blast furnace gas yield in China exceeds 18 billion cubic meters in 2019. Blast furnace gas is used as an important energy source in the steel industry, and the efficient and clean utilization of the blast furnace gas is a great demand in China. However, the blast furnace gas contains gaseous sulfide, which not only causes serious problems of pipeline equipment corrosion, catalyst poisoning, salt accumulation and the like, but also causes serious environmental pollution after discharge. Deep desulfurization of blast furnace gas is a key technical problem to be solved first.

Carbonyl sulfide (COS), which is a typical representative of gaseous sulfides in blast furnace gas, is chemically inert and difficult to remove. Currently, the methods for removing COS, which are commonly used in industry, mainly include a hydroconversion method, an absorption method, an oxidation conversion method, a photolysis method and a hydrolysis method. And hydrolysis reaction (COS + H)₂O→CO₂+H₂S) is widely used industrially with its mild reaction conditions and high removal efficiency. So far, alumina supporting alkali metal K, Na has been commonly used as a medium and low temperature COS hydrolysis catalyst. But at high steam concentrationsUnder the condition, the loaded active alkali metal is easy to lose, so that the catalyst is deactivated, and meanwhile, a pipeline is easy to corrode. On the other hand, the deposition of sulfides and sulfates easily causes catalyst poisoning, thereby affecting the service life of the catalyst. Therefore, there is a need to develop an efficient, stable unsupported catalyst for COS hydrolysis.

Transition metal oxide catalysts are considered to be a potential COS hydrolysis catalyst. However, although the preparation method of the single oxide catalyst is simple and easy, the structural composition of the single oxide catalyst is relatively single, and the catalytic activity of the single oxide catalyst is influenced to a certain extent. Compared with single oxide, the catalyst with metal doped in transition metal oxide to form structural alkali center promotes the hydrolysis of COS through the synergistic effect of double metals. Based on the method, the copper-manganese-based catalyst prepared by the green and simple method is creatively developed and applied to the carbonyl sulfide hydrolysis reaction, provides reference for the simple and convenient green preparation of the oxide, has wide and profound research significance, and further expands the application field of the metal oxide.

Disclosure of Invention

The invention provides a copper-manganese-based catalyst and a preparation method thereof for realizing effective catalytic hydrolysis of organic sulfur at low temperature, the operation steps are simple and easy, the used raw materials are green and environment-friendly, the atom utilization rate is high, and the catalyst has weak alkaline active sites, so the catalyst is suitable for low-temperature catalytic hydrolysis of carbonyl sulfur gas.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the preparation method of the copper-manganese-based catalyst for catalytic hydrolysis of organic sulfur comprises the following steps:

1) adding a copper source and a manganese source into deionized water according to a certain molar ratio, and stirring to completely dissolve the copper source and the manganese source to obtain a mixed solution;

2) dissolving alkali in deionized water to prepare 0.3-1 mol/L alkali solution;

3) slowly dropwise adding the mixed solution obtained in the step 1) into the aqueous alkali obtained in the step 2) under the condition that the stirring speed is 700 rpm, placing the mixture into an oil bath pot after dropwise adding is finished, continuously stirring and reacting for 6-12 h at 50-100 ℃, aging for 1-6 h at room temperature, centrifuging and filtering the obtained precipitate, washing until the pH of the filtrate is neutral, placing the precipitate into an oven at 80-100 ℃, drying to constant weight, and grinding to obtain a catalyst precursor;

4) roasting the catalyst precursor obtained in the step 3) in a muffle furnace, and then mechanically tabletting, forming and sieving to obtain the copper-doped manganese-based catalyst.

The amounts of the copper source and the manganese source used in step 1) are converted by a molar ratio of n (Cu), n (Mn), and = (0.01-0.3), and 1.

Wherein the copper source is one or more of copper nitrate, copper sulfate, copper chloride and copper acetate; the manganese source is one or more of manganese sulfate, manganese chloride, manganese acetate and manganese nitrate.

In the step 2), the alkali is one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide and ammonia water.

The amount of the mixed solution and the alkali solution used in the step 3) is n (Mn) to n (OH) according to the molar ratio of n (Mn)^-) Conversion of = (0.1 to 0.3): 1.

In the step 4), the roasting is carried out for 2-8 h at 450-750 ℃ in an air atmosphere.

The obtained copper-manganese-based catalyst can be used for catalyzing hydrolysis of COS, and specifically, the copper-manganese-based catalyst is used as a desulfurization catalyst to hydrolyze gas containing COS under the condition that 40 ℃ water vapor is introduced to remove the COS; the gas flow rate is 20 mL/min, and the temperature of the hydrolysis reaction is 30-170 ℃.

The invention has the advantages that:

(1) the method does not need to adjust the pH, can complete the preparation of the copper-manganese-based catalyst in one step, and has the characteristics of simple and feasible steps, rapidness and high efficiency;

(2) the raw materials used in the method are green and environment-friendly, the atom utilization rate is high, the prepared copper-manganese-based catalyst presents a high-crystallinity and regular nanoparticle structure, the interaction between copper and manganese species can realize the regulation and control of an electronic structure of a manganese element d, the acid-base synergistic catalysis effect of the copper-manganese-based catalyst is optimized, the copper-manganese-based catalyst has weak alkaline active sites, the hydrolysis reaction performance of the COS can be improved, the conversion rate of the COS on 70 ℃ is up to 100%, and the copper-manganese-based catalyst is suitable for the hydrolysis removal of carbonyl sulfide gas through low-temperature catalytic hydrolysis.

Drawings

FIG. 1 shows X-ray powder diffraction patterns (XRD) of catalyst samples obtained in examples 1 to 4.

FIG. 2 is a Scanning Electron Micrograph (SEM) of catalyst samples obtained in example 3 and comparative examples 1 and 2.

FIG. 3 shows Raman spectra (Raman) of catalyst samples obtained in examples 1 to 4.

Detailed Description

In order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.

Example 1

1.0 g (5.05 mmol) of manganese chloride tetrahydrate and 0.0273 g (0.16 mmol) of copper chloride dihydrate were weighed out and added to 40 mL of deionized water, and after stirring to completely dissolve them, the mixed solution was slowly added dropwise to 40 mL of a 0.8M NaOH solution at a stirring speed of 700 rpm. And placing the mixture into a 75 ℃ oil bath pot after the dropwise addition is finished, continuously stirring the mixture for reaction for 10 hours, aging the mixture at room temperature for 2 hours after the reaction is finished, centrifuging, filtering and washing the mixture until the pH value of the filtrate is 7.0, drying the precipitate at 100 ℃ for 12 hours to constant weight, grinding the precipitate, and calcining the precipitate at 650 ℃ in a muffle furnace for 4 hours to obtain a sample a.

Example 2

1.0 g (5.05 mmol) of manganese chloride tetrahydrate and 0.0409 g (0.24 mmol) of copper chloride dihydrate were weighed out and added to 40 mL of deionized water, and after completely dissolving them by stirring, the mixture was slowly added dropwise to 40 mL of a 0.8M NaOH solution at a stirring speed of 700 rpm. And placing the mixture into a 75 ℃ oil bath pot after the dropwise addition is finished, continuously stirring the mixture for reaction for 10 hours, aging the mixture at room temperature for 2 hours after the reaction is finished, centrifuging, filtering and washing the mixture until the pH value of the filtrate is 7.0, drying the precipitate at 100 ℃ for 12 hours to constant weight, grinding the precipitate, and calcining the precipitate at 650 ℃ in a muffle furnace for 4 hours to obtain a sample b.

Example 3

1.0 g (5.05 mmol) of manganese chloride tetrahydrate and 0.0682 g (0.40 mmol) of copper chloride dihydrate were weighed and added to 40 mL of deionized water, and after completely dissolved by stirring, the mixed solution was slowly added dropwise to 40 mL of a 0.8M NaOH solution at a stirring speed of 700 rpm. And placing the mixture into a 75 ℃ oil bath pot after the dropwise addition is finished, continuously stirring the mixture for reaction for 10 hours, aging the mixture at room temperature for 2 hours after the reaction is finished, centrifuging, filtering and washing the mixture until the pH value of the filtrate is 7.0, drying the precipitate at 100 ℃ for 12 hours to constant weight, grinding the precipitate, and calcining the precipitate at 650 ℃ in a muffle furnace for 4 hours to obtain a sample c.

Example 4

1.0 g (5.05 mmol) of manganese chloride tetrahydrate and 0.1364 g (0.80 mmol) of copper chloride dihydrate were weighed out and dissolved in 40 mL of deionized water, and after stirring to completely dissolve them, the mixed solution was slowly added dropwise to 40 mL of a 0.8M NaOH solution at a stirring speed of 700 rpm. And placing the mixture into a 75 ℃ oil bath pot after the dropwise addition is finished, continuously stirring the mixture for reaction for 10 hours, aging the mixture at room temperature for 2 hours after the reaction is finished, centrifuging, filtering and washing the mixture until the pH value of the filtrate is 7.0, drying the precipitate at 100 ℃ for 12 hours to constant weight, grinding the precipitate, and calcining the precipitate at 650 ℃ in a muffle furnace for 4 hours to obtain a sample d.

Comparative example 1

1.0 g (5.05 mmol) of manganese chloride tetrahydrate is weighed out and dissolved in 40 mL of deionized water, and after complete dissolution by stirring, the solution is slowly added dropwise to 40 mL of 0.8M NaOH solution at a stirring speed of 700 rpm. And placing the mixture into a 75 ℃ oil bath pot after the dropwise addition is finished, continuously stirring the mixture for reaction for 10 hours, aging the mixture at room temperature for 2 hours after the reaction is finished, centrifuging, filtering and washing the mixture until the pH value of the filtrate is 7.0, drying the precipitate at 100 ℃ for 12 hours to constant weight, grinding the precipitate, and calcining the precipitate at 650 ℃ in a muffle furnace for 4 hours to obtain a sample e.

Comparative example 2

0.682 g (4.00 mmol) of copper chloride dihydrate was weighed out and dissolved in 40 mL of deionized water, and after stirring to dissolve it completely, the solution was slowly added dropwise to 40 mL of 0.8M NaOH solution at a stirring speed of 700 rpm. And placing the mixture into a 75 ℃ oil bath pot after the dropwise addition is finished, continuously stirring the mixture for reaction for 10 hours, aging the mixture at room temperature for 2 hours after the reaction is finished, centrifuging, filtering and washing the mixture until the pH value of the filtrate is 7.0, drying the precipitate at 100 ℃ for 12 hours to constant weight, grinding the precipitate, and calcining the precipitate at 650 ℃ in a muffle furnace for 4 hours to obtain a sample f.

The catalysts obtained in the examples and comparative examples were analyzed and tested accordingly, the activity and stability results of the catalysts were expressed as COS conversion, and the COS concentration was measured by an on-line chromatography. The test conditions are as follows: the hydrolysis catalytic reaction of COS is carried out on a miniature fixed bed reactor, the loading amount of the catalyst is 0.2 g, the reaction temperature is 30-150 ℃, sampling and measuring are carried out after reaction is carried out for 60 min at each reaction temperature, and the concentration of COS in feed gas is 110 mg/m³，N₂The inner diameter of the reaction tube is 5mm for equilibrium gas, the flow rate of the raw material gas is 20 ml/min, and the temperature of the water vapor in the reactant is 40 ℃. The measurement results are shown in table 1.

TABLE 1 COS conversion by catalytic hydrolysis reaction of each catalyst

As can be seen from table 1, in the copper-manganese-based catalysts prepared by using different amounts of copper chloride in the examples, the COS conversion rate of the catalyst sample c is significantly higher than that of the samples a, b and d, the COS conversion rate at 70 ℃ can reach 100%, while the conversion rates of other catalysts at 90 ℃ are close to or reach 100%, and the catalytic performance of the catalyst sample c is also significantly better than that of a metal oxide prepared from a single metal, and particularly in a low-temperature (30-70 ℃) reaction region, the catalyst sample c has a significant activity advantage.

FIG. 1 is an X-ray powder diffraction pattern of catalyst samples obtained in examples 1-4, wherein peaks at 2 θ of 23.1 °, 32.9 °, 38.2 °, 49.3 °, 55.2 °, 65.8 ° are attributed to Mn₂O₃(PDF # 076-1560); the peaks at 28.9 ° and 36.1 ° 2 θ are attributed to Mn₃O₄(PDF # 075-1560); while the peaks at 30.5 ° and 35.9 ° of 2 θ are attributed to Cu_1.5Mn_1.5O₄(PDF # 070-0260). Comparing the results of XRD pattern and COS hydrolysis activity³⁺Possibly the active site for COS hydrolysis.

FIG. 2 is a scanning electron micrograph of catalyst samples obtained in example 3, comparative example 1 and comparative example 2. As can be seen from FIG. 2, the comparative sample e had a non-uniform particle size and a large particle size; the comparative sample f forms a regular polyhedral structure, and the size of the regular polyhedral structure reaches the micron level; sample c formed nanoparticles of uniform size and smaller size, probably due to the interaction of copper and manganese during the preparation process.

FIG. 3 is a Raman spectrum of a catalyst sample obtained in examples 1 to 4. As shown in FIG. 3, 280, 350, 630 cm^-1The peak at (A) is ascribed to the Mn-O bond. In all copper manganese based catalysts, 630 cm with increasing copper content^-1The peak at (B) is shifted toward the low wavenumber direction, probably due to the change in the Mn-O bond vibration frequency caused by the interaction of Cu-O and Mn-O.

Although the present invention has been described in detail with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.