CN103447046B - Wet oxidizing catalyst of a kind of stability and high efficiency and preparation method thereof - Google Patents

Abstract

The invention discloses a stable and efficient wet oxidation catalyst and a preparation method thereof, belonging to the technical field of water treatment and material preparation. The catalyst is prepared by adding the mixed salt solution containing copper, zinc, aluminum, iron and lanthanum and sodium hydroxide solution into the sodium carbonate solution, and then undergoes crystallization, filtration, washing, drying and roasting. A composite oxide catalyst whose precursor has layered hydrotalcite-like characteristics. The catalyst showed efficient and stable catalytic effect on wet catalytic oxidation of industrial wastewater and simulated pollutant phenol. The preparation method improves the activity and stability of the copper-based catalyst, broadens the application field of the copper-based catalyst, and the synthesized composite oxide catalyst has important application value and prospects in the field of wet catalytic oxidation treatment of high-concentration organic wastewater.

Description

A stable and efficient wet oxidation catalyst and preparation method thereof

technical field

The invention belongs to the technical field of water treatment and material preparation, and more specifically relates to a composite metal oxide catalyst used in wet catalytic oxidation treatment of high-concentration organic wastewater and a preparation method thereof.

Background technique

With the development of world population, industrialization, agriculture and urbanization, a large amount of refractory organic matter continuously enters the water body, which not only deteriorates the living environment of human beings, hinders the development of related industries, but also makes the quantity and quality of the world's available fresh water resources continue to decline. . Wastewater treatment has become an important social, technical, economic and political issue. The removal of pollutants in water has also become an important research field. The chemical and petroleum industries generate a wide variety of highly toxic organic wastes. Among them, phenolic wastewater has a wide range of sources and is more harmful. Unsubstituted phenols are often used as model compounds in wastewater treatment studies. For the purification and treatment of high-concentration industrial wastewater, there are currently many researches at home and abroad mainly including wet air oxidation technology (WAO), wet catalytic oxidation technology (CWO), supercritical water oxidation technology (SCWO) and so on. Wet catalytic oxidation of hydrogen peroxide (WHPCO), as an advanced oxidation process (AOPs), can effectively and gently treat toxic wastewater. Transition metal compounds, especially copper-based catalysts, are currently the most common and economical catalysts, showing high catalytic activity in AOPs reactions. However, the dissolution of transition metal oxide active components during the reaction process and the catalyst deactivation caused by sintering during heat treatment have become problems to be solved urgently in this system. Choosing an appropriate catalyst preparation method is the most direct way to solve the stability of the above-mentioned heterogeneous oxidation catalysts.

Hydrotalcite-like materials (LDHs), also known as anionic clays or layered double hydroxides, are inorganic functional materials with a layered structure. Its laminates are arranged in a certain proportion and sequence by divalent and trivalent metal cations and can be adjusted, and the interlayer anions that balance the charge can be exchanged. Its topological decomposition feature makes the calcined product have high specific surface area and high thermal stability, and each metal ion can be evenly distributed at the molecular level. Therefore, the characteristics of hydrotalcite-like and its calcined products can be used to introduce active components, additives and carriers into the hydrotalcite-like laminates, and then calcined to obtain metal oxide catalysts.

Copper-based oxide catalysts are commonly used in wet catalytic oxidation. When the copper-based hydrotalcite-like precursor is roasted, it will inevitably produce a small amount of copper oxide. Under acidic reaction conditions or affected by intermediate products, copper ions are easily eluted , causing secondary pollution to the water body, and a large number of composite metal oxides formed at the same time, such as copper-based spinel oxides, because the structure is more stable than single copper oxide, it is difficult to dissolve under the same conditions, so the oxide is used Acid pretreatment can obtain a stable composite metal oxide catalyst, which can improve the stability of the catalyst.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a stable and efficient wet oxidation catalyst and its preparation method, which are used for wet catalytic oxidation of high-concentration organic wastewater. The technical solution can not only make the metal components of the catalyst highly uniformly dispersed, improve the activity of the catalyst, but also suppress the loss of the metal components, especially the active components, and improve the stability of the catalyst.

Technical purpose of the present invention is achieved through the following technical solutions:

The catalyst prepared by the present invention is a CuZnAlFeLa composite oxide catalyst, wherein Cu and Zn are divalent metal ions M ²⁺ , Al, Fe and La are trivalent metal ions M ³⁺ , and its preparation method is carried out according to the following steps:

(1) Step 1, prepare a salt solution, weigh soluble copper salt, zinc salt, aluminum salt, iron salt and lanthanum salt and dissolve in water to prepare a mixed salt solution with a total metal ion concentration of 0.01-1.50mol/L, wherein The molar ratio of divalent and trivalent metal ions n[M ²⁺ ]: n[M ³⁺ ]=(2.0～4.0): 1, the molar ratio of divalent copper and zinc ions n[Cu ²⁺ ]: n[Zn ^{2 +} ]=(0.3～3.0): 1, preferably (1～2): 1; the molar ratio of trivalent aluminum ions to the sum of other trivalent ions n[Al ³⁺ ]: n[Fe ³⁺ +La ³⁺ ] =(0.1～10.0): 1, preferably (1.5～2.5): 1; molar ratio of trivalent lanthanum to iron n[La ³⁺ ]: n[Fe ³⁺ ]=(0.05～2.0): 1, preferably ( 0.1～1): 1;

In the step 1, the soluble copper salts, zinc salts, aluminum salts, iron salts and lanthanum salts are intended to provide corresponding metal elements, and nitrates, sulfates, phosphates, acetates or chlorides are selected.

(2) Step 2, prepare lye and carbonate solution respectively, choose alkali and carbonate to be dissolved in water respectively to prepare lye and corresponding carbonate solution, wherein the carbonate radical (CO ₃ ^2- ) and hydroxide (OH ^- ), and the ratio of cations in the mixed salt solution prepared in step 1 is as follows: molar ratio of CO ₃ ^2- to trivalent metal ions (ie the sum of Al, Fe and La metal ions) n[CO ₃ ^2- ]/n[M ³⁺ ]=(2.0～2.5): 1, molar ratio of OH ^- to total metal ions n[OH ^- ]/(2n[M ²⁺ ]+3n[M ³⁺ ])=(1.6～2.0): 1, preferably (1.6～1.8): 1, wherein the total metal ions are the total valence charges of metal ions in the mixed salt solution (Cu and Zn are divalent metal ions M ²⁺ , Al, Fe and La are trivalent metal ions M ³⁺ ), the above n[CO ₃ ^2- ] and n[OH ^- ] are the total moles of CO ₃ ^2- and OH ^- in carbonate and lye, respectively total moles

In said step 2, sodium hydroxide, potassium hydroxide or ammonia water are selected as the alkali providing hydroxide; sodium carbonate, potassium carbonate or ammonium carbonate are selected as carbonate providing carbonate. When choosing ammonia water, it is necessary to assume that all the ammonia water is ionized, and the amount of ammonia water needs to be added can be calculated according to the calculated hydroxide; in the final prepared solution, the concentration of OH ^- in the lye is selected to be 0.01-3.00mol/L, carbon The concentration of CO ₃ ^2- in the salt solution is selected to be 0.01-3.00 mol/L.

(3) Step 3, titration, add the mixed salt solution (pH value is acidic) in step (1) and alkali solution (pH value is basic) in step (2) to the carbon prepared in step (2). In the salt solution, the pH of the whole titration system is kept at 10±0.2 by controlling the titration speed of the two solutions

In the step 3, stirring is performed while adding dropwise, for example, at 200-500 rpm, and a precipitate is obtained while adding dropwise.

(4) Step 4: Stir and crystallize the precipitate obtained in step (3) at 40-90°C for 4-72 hours, preferably at 50-80°C for 24-60 hours, stirring at a speed of 100-300°C rev/min; then the obtained slurry was repeatedly filtered and washed until neutral, dried at 40-150°C, and ground into fine powder to obtain a catalyst precursor

In the step 4, the obtained slurry is repeatedly filtered and washed until neutral, and the temperature of the aqueous solution is controlled at 20-60°C; the drying temperature is preferably 50-120°C, and an oven is selected for drying, and the time is selected for 12-24h .

(5) Step 5, roasting: put the catalyst precursor (powder) obtained in step (4) in a muffle furnace, and raise the temperature from room temperature 20°C to 400-800°C at a heating rate of 1-10°C·min ^-1 Calcining for 1-10 hours, and then cooling to room temperature with the furnace to obtain the catalyst, preferably calcination at 500-700°C for 2-6 hours.

(6) Step 6, acid treatment: filter and wash the oxide powder obtained in step (5) with 0.10-1.00mol/L dilute acid until no metal ions are detected in the filtrate, then filter and wash with water 4 times, Then repeat the conditions of step (5) to roast the sample for 2 hours to obtain the catalyst.

In step 6, the dilute acid is selected from hydrochloric acid, sulfuric acid or nitric acid.

In the above preparation method, the precursor obtained in step (5) mainly has a hydrotalcite-like structure, and the catalyst obtained after roasting in step (5) is a composite metal oxide.

The technical scheme of the present invention is based on the characteristics of adjustable elements of hydrotalcite-like laminates and uniform distribution of elements, and simultaneously introduces catalyst active components, additives and carrier elements into the laminates to prepare hydrotalcite-like precursors, and then utilizes layered The characteristics of topological decomposition of hydrotalcite-like materials, composite metal oxide catalyst materials obtained by roasting and acid treatment, to achieve stable and efficient performance under wet oxidation conditions of high-concentration wastewater: the prepared catalyst is mixed with hydrogen peroxide, used for phenol wastewater, saccharin Wet oxidation catalysis of comprehensive sodium production wastewater (chemical oxygen demand COD _Cr = 17339.32mg/l measured by potassium dichromate method, ammonia nitrogen content NH ₃ -N = 6439.22mg/l, pH = 8.17, black).

The method of the invention broadens the working conditions of the hydrotalcite-like composite metal oxide, enabling it to be used stably in an acid-base environment. The composite oxide catalyst prepared by the method has good application value and prospect in the field of wet catalytic oxidation treatment of high-concentration organic wastewater. Compared with the prior art, the present invention uses hydrotalcite-like precursors to prepare composite metal oxides, which is beneficial to the uniform and stable distribution of active components and improves the utilization efficiency of active components; the introduction of components Fe and La is beneficial to Control the activation and decomposition of hydrogen peroxide, the dispersion of active components and the activity of oxygen and lattice oxygen on the surface of the composite oxide; the raw materials used in the preparation are low in cost, simple in operation and easy in large-scale production.

Description of drawings

Fig. 1 is the XRD spectrogram of catalyst and its precursor before and after acid treatment in embodiment 1, among the figure, a: the catalyst precursor obtained in embodiment 1, b: the catalyst precursor calcined product obtained in embodiment 1, c: embodiment 1 The composite metal oxide catalyst obtained after acid treatment.

Figure 2 is the XRD spectrum of the acid-treated pre-catalyst and its precursor in Example 2. In the figure, a: the catalyst precursor obtained in Example 2, b: the roasted product of the catalyst precursor obtained in Example 2.

detailed description

The technical solutions of the present invention will be further described below in conjunction with specific embodiments. The ammonia water used was purchased from Tianjin Kewei Company's analytically pure ammonia water with a mass percentage of 25%, and was diluted to prepare dilute ammonia water with a mass percentage of 7.0%.

Example 1

Dissolve 8.46g of copper nitrate, 9.52g of zinc nitrate, 9.38g of aluminum nitrate, 3.23g of ferric nitrate and 0.15g of lanthanum nitrate in 100ml of water to prepare a mixed salt solution. Dissolve 11.20g of potassium hydroxide and 6.30g of sodium carbonate in 100ml of water to prepare alkali solution and carbonate solution. Add the mixed salt solution and potassium hydroxide solution slowly and dropwise to the vigorously stirred sodium carbonate solution at the same time, control the drop rate of the salt and alkali, and keep the pH value of the solution at 10±0.2. After the mixed salt solution is consumed, stop the dropwise addition. Stir and crystallize the precipitate in a water bath at 60°C for 24 hours, filter and wash the obtained slurry to neutrality, and dry the filter cake in an oven at 60°C overnight. As can be seen from a in Figure 1, the obtained powder is similar to Hydrotalcite, the precursor powder is placed in a muffle furnace, and the temperature is raised from room temperature to 550°C for 4 hours at a rate of 2°C·min ^-1 to obtain a calcined product. It can be seen from b in Figure 1 that the calcined product is mainly a composite metal Oxides, it was filtered and washed with ^1mol /l dilute nitric acid until no metal ions were detected in the filtrate, then filtered and washed with water for 4 times, and then heated from room temperature to The temperature was raised to 550°C and calcined for 2 hours. The XRD spectrum is shown in c in Figure 1. It can be seen that the treated catalyst sample has a composite metal oxide structure.

Weigh 1g of the above catalyst and put it into 100ml of phenol wastewater with a concentration of 500mg/l, add 5ml (30%) hydrogen peroxide under stirring conditions, stir vigorously in a closed system at normal temperature and pressure for 1h, and use high performance liquid chromatography to measure the conversion rate of phenol It was 91%, and the inductively coupled plasma spectrometer determined that the reaction solution did not detect metal ions.

Weigh 7.5g of the above catalyst and put it into 100ml of comprehensive wastewater from the production of sodium saccharin (COD _Cr = 17339.32mg/l, NH ₃ -N = 6439.22mg/l, pH = 8.17, black), and add 20ml (30 %) hydrogen peroxide, vigorously stirred in a closed system at normal temperature and pressure for 24 hours, COD _Cr decreased to 4832.33mg/l, NH ₃ -N decreased to 3530.62mg/l, pH was 7.50, the color was colorless, and the copper ions dissolved in the reaction solution The concentration is less than 0.2mg/l.

Example 2

Dissolve 9.38g of copper nitrate, 14.87g of zinc nitrate, 13.13g of aluminum nitrate, 5.05g of ferric nitrate and 1.08g of lanthanum nitrate in 150ml of water to prepare a mixed salt solution. Dissolve 16.20g of sodium hydroxide and 5.30g of sodium carbonate in 100ml of water to prepare alkali solution and carbonate solution. Slowly add the mixed salt solution and sodium hydroxide solution dropwise into the vigorously stirred sodium carbonate solution at the same time, control the drop rate of salt and alkali, and keep the pH value of the solution at 10±0.2. After the mixed salt solution is consumed, stop the dropwise addition. Stir and crystallize the precipitate in a water bath at 60°C for 48 hours, filter and wash the obtained slurry to neutrality, and dry the filter cake in an oven at 60°C overnight. As can be seen from a in Figure 2, the obtained powder is similar to Hydrotalcite, put the precursor powder in a muffle furnace, and heat up from room temperature to 500°C at a heating rate of 5°C min ^-1 for 4 hours to obtain a calcined product, and it can be seen from b in Figure 2 that the calcined product is mainly a composite metal oxides, and finally filtered and washed with ^0.1mol /l dilute hydrochloric acid until no metal ions were detected in the filtrate, then filtered and washed with water for 4 times, and then heated from room temperature to The temperature was raised to 500° C. and calcined for 2 hours to obtain a composite metal oxide catalyst.

The catalyst was used for the comprehensive wastewater treatment of phenol solution and sodium saccharin production, and the conditions were the same as in Example 1. After 1 hour of reaction, the conversion rate of phenol was 98%, and no metal ions were detected in the solution after the reaction. After comprehensive wastewater treatment of sodium saccharin production, COD _Cr drops to 1330.77mg/l, NH ₃ -N drops to 530.04mg/l, pH is 7.53, color is colorless, and the concentration of copper ions dissolved in the reaction solution is less than 0.1mg/l .

Example 3

Dissolve 6.25g of copper nitrate, 6.11g of zinc acetate, 7.99g of aluminum sulfate, 2.00g of ferric sulfate and 2.17g of lanthanum nitrate in 100ml of water to prepare a mixed salt solution. Prepare 100ml of 7.0% dilute ammonia water, and dissolve 4.80g of ammonium carbonate in 100ml of water to prepare alkali solution and carbonate solution. Add the mixed salt solution and dilute ammonia water slowly and dropwise to the vigorously stirred ammonium carbonate solution at the same time, control the drop rate of salt and alkali, and keep the pH value of the solution at 10±0.2. Stir and crystallize the material in a water bath at 60°C for 20 hours, filter and wash the obtained slurry to neutrality, and dry the filter cake in an oven at 80°C overnight, then place the precursor powder in a muffle furnace at 10°C The heating rate of min ^-1 was raised from room temperature to 650°C and roasted for 2 hours to obtain the roasted product, which was filtered and washed with 0.5 mol/l dilute hydrochloric acid until no metal ions were detected in the filtrate, then washed with water for 4 times, and then Then, it was calcined in a muffle furnace from room temperature to 650°C at a heating rate of 10°C·min ^-1 for 2 hours to obtain a composite metal oxide catalyst.

The catalyst was used for the comprehensive wastewater treatment of phenol solution and sodium saccharin production, the conditions were the same as in Example 1, the conversion rate of phenol was 95% after 1 hour of reaction, and no metal ions were detected in the solution after reaction. After comprehensive wastewater treatment of sodium saccharin production, COD _Cr drops to 3346.15mg/l, NH ₃ -N drops to 1440.21mg/l, pH is 7.71, color is colorless, and the concentration of copper ions dissolved in the reaction solution is less than 0.2mg/l .

Example 4

Dissolve 12.50g of copper sulfate, 8.05g of zinc sulfate, 11.89g of aluminum phosphate, 6.00g of iron sulfate and 0.75g of lanthanum chloride in 150ml of water to prepare a mixed salt solution. Dissolve 6.40g of sodium hydroxide and 6.30g of sodium carbonate in 100ml of water to prepare alkali solution and carbonate solution. Slowly add the mixed salt solution and sodium hydroxide solution dropwise into the vigorously stirred sodium carbonate solution at the same time, control the drop rate of salt and alkali, and keep the pH value of the solution at 10±0.2. After the mixed salt solution is consumed, stop the dropwise addition. The precipitate was stirred and crystallized in a water bath at 50°C for 30 hours, the obtained slurry was filtered and washed until neutral, and the filter cake was dried in an oven at 100°C overnight, and the precursor powder was placed in a muffle furnace for 5 °C·min ^-1 heating rate from room temperature to 450 °C and roast for 4 hours to obtain the roasted product, which was filtered and washed with 0.5 mol/l dilute sulfuric acid until no metal ions were detected in the filtrate, and then washed with water for 4 times. Then, it was calcined in a muffle furnace from room temperature to 450° C. at a heating rate of 5° C.min ⁻¹ for 2 hours to obtain a composite metal oxide catalyst.

The catalyst was used for the comprehensive wastewater treatment of phenol solution and sodium saccharin production, the conditions were the same as in Example 1, the conversion rate of phenol was 96% after 1 hour of reaction, and no metal ions were detected in the solution after reaction. After comprehensive wastewater treatment of sodium saccharin production, COD _Cr drops to 2038.46mg/l, NH ₃ -N drops to 2238.17mg/l, pH is 7.56, color is colorless, and the concentration of copper ions dissolved in the reaction solution is less than 0.3mg/l .

Example 5

Dissolve 8.52g of copper chloride, 6.82g of zinc chloride, 4.00g of aluminum chloride, 4.05g of ferric chloride and 1.50g of lanthanum chloride in 150ml of water to prepare a mixed salt solution. Dissolve 34.08g of potassium hydroxide and 10.36g of potassium carbonate in 150ml of water to prepare alkali solution and carbonate solution. Slowly add the mixed salt solution and potassium hydroxide solution into the vigorously stirred potassium carbonate solution at the same time, control the drop rate of salt and alkali, and keep the pH value of the solution at 10 ± 0.2. After the mixed salt solution is consumed, stop the dropwise addition. The precipitate was stirred and crystallized in a water bath at 50°C for 72 hours, the obtained slurry was filtered and washed until neutral, and the filter cake was dried overnight in an oven at 120°C, and the obtained powder was placed in a muffle furnace for 5 °C·min ^-1 heating rate from room temperature to 750 °C and roast for 2 hours to obtain the roasted product, which was filtered and washed with 1.5 mol/l dilute hydrochloric acid until no metal ions were detected in the filtrate, and then filtered and washed with water for 4 times. Then, it was calcined in a muffle furnace from room temperature to 750° C. at a heating rate of 5° C.min ⁻¹ for 2 hours to obtain a composite metal oxide catalyst.

The catalyst was used for the comprehensive wastewater treatment of phenol solution and sodium saccharin production, the conditions were the same as in Example 1, the conversion rate of phenol was 92% after 1 hour of reaction, and no metal ions were detected in the solution after reaction. After comprehensive wastewater treatment of sodium saccharin production, COD _Cr drops to 4769.23mg/l, NH ₃ -N drops to 3314.73mg/l, pH is 7.53, color is colorless, and the concentration of copper ions dissolved in the reaction solution is less than 0.3mg/l .

Example 6

Dissolve 8.46g of copper nitrate, 9.52g of zinc nitrate, 10.27g of aluminum sulfate, 4.05g of ferric chloride and 1.58g of lanthanum acetate in 150ml of water to prepare a mixed salt solution. Dissolve 34.08g of potassium hydroxide and 10.36g of potassium carbonate in 150ml of water to prepare alkali solution and carbonate solution. Slowly add the mixed salt solution and potassium hydroxide solution into the vigorously stirred potassium carbonate solution at the same time, control the drop rate of salt and alkali, and keep the pH value of the solution at 10 ± 0.2. After the mixed salt solution is consumed, stop the dropwise addition. Stir and crystallize the precipitate in a water bath at 70°C for 48 hours, filter and wash the obtained slurry to neutrality, and dry the filter cake in an oven at 90°C overnight to obtain a powder in a muffle furnace at 1 °C·min ^-1 heating rate from room temperature to 600 °C and roast for 3 hours to obtain the roasted product, which was filtered and washed with 1.0 mol/l dilute nitric acid until no metal ions were detected in the filtrate, and then filtered and washed with water for 4 times. Then, it was calcined in a muffle furnace from room temperature to 600°C at a heating rate of 5°C·min ⁻¹ for 3 hours to obtain a composite metal oxide catalyst.

The catalyst was used for comprehensive wastewater treatment of phenol solution and sodium saccharin production, the conditions were the same as in Example 1, the conversion rate of phenol was 93% after 1 hour of reaction, and no metal ions were detected in the solution after reaction. After comprehensive wastewater treatment of sodium saccharin production, COD _Cr drops to 4230.76mg/l, NH ₃ -N drops to 2769.82mg/l, pH is 7.98, color is colorless, and the concentration of copper ions dissolved in the reaction solution is less than 0.2mg/l .

Example 7

Dissolve 5.00g of copper sulfate, 11.50g of zinc sulfate, 6.66g of aluminum sulfate, 4.00g of iron sulfate and 0.20g of lanthanum nitrate in 100ml of water to prepare a mixed salt solution. Dissolve 4.80g of sodium hydroxide and 3.07g of ammonium carbonate in 100ml of water to prepare alkali solution and carbonate solution. Add the mixed salt solution and sodium hydroxide solution slowly and dropwise to the vigorously stirred ammonium carbonate solution at the same time, control the drop rate of the salt and alkali, and keep the pH value of the solution at 10±0.2. When the mixed salt solution is consumed, stop the dropwise addition. The precipitate was stirred and crystallized in a water bath at 40°C for 24 hours, and the obtained slurry was filtered and washed until neutral, and the filter cake was dried in an oven at 40°C overnight, and then placed in a muffle furnace at 5°C. Min ^-1 heating rate from room temperature to 600 ° C for 4 h, the roasted product was filtered and washed with 0.5 mol/l dilute sulfuric acid until no metal ions were detected in the filtrate, then filtered and washed with water for 4 times, and then placed in a muffler The composite metal oxide catalyst was obtained by heating up from room temperature to 600°C for 2 hours in a furnace at a heating rate of 5°C·min ^-1 .

The catalyst was used for comprehensive wastewater treatment of phenol solution and sodium saccharin production, the conditions were the same as in Example 1, the conversion rate of phenol was 86% after 1 hour of reaction, and no metal ions were detected in the solution after reaction. After comprehensive wastewater treatment of sodium saccharin production, COD _Cr drops to 6419.32mg/l, NH ₃ -N drops to 3651.71mg/l, pH is 7.51, color is colorless, and the concentration of copper ions dissolved in the reaction solution is less than 0.1mg/l .

Example 8

Dissolve 2.56g of copper chloride, 2.04g of zinc chloride, 1.07g of aluminum chloride, 0.32g of ferric chloride and 0.20g of lanthanum nitrate in 100ml of water to prepare a mixed salt solution. Dissolve 3.20g of sodium hydroxide and 1.59g of ammonium carbonate in 100ml of water to prepare alkali solution and carbonate solution. Add the mixed salt solution and sodium hydroxide solution slowly and dropwise to the vigorously stirred ammonium carbonate solution at the same time, control the drop rate of the salt and alkali, and keep the pH value of the solution at 10±0.2. When the mixed salt solution is consumed, stop the dropwise addition. The precipitate was stirred and crystallized in a water bath at 60°C for 24 hours, and the obtained slurry was filtered and washed until neutral, and the filter cake was dried in an oven at 60°C overnight, and then placed in a muffle furnace at 10°C. Min ^-1 heating rate from room temperature to 650 ° C for 4 h, the roasted product was filtered and washed with 0.2 mol/l dilute hydrochloric acid until no metal ions were detected in the filtrate, then filtered and washed with water for 4 times, and then placed in a muffle The composite metal oxide catalyst was obtained by heating up from room temperature to 650°C for 2 hours in a furnace at a heating rate of 10°C·min ^-1 .

The catalyst was used for the comprehensive wastewater treatment of phenol solution and sodium saccharin production, the conditions were the same as in Example 1, the conversion rate of phenol was 95% after 1 hour of reaction, and no metal ions were detected in the solution after reaction. After comprehensive wastewater treatment of sodium saccharin production, COD _Cr drops to 4230.21mg/l, NH ₃ -N drops to 2769.22mg/l, pH is 7.98, color is colorless, and the concentration of copper ions dissolved in the reaction solution is less than 0.2mg/l .

The above-mentioned examples basically show the same or consistent properties as Example 1, and the structure of the catalyst is the same as before the reaction, indicating the stability of its structure.

The present invention has been described as an example above, and it should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacements that can be made by those skilled in the art without creative labor all fall within the scope of this invention. protection scope of the invention.

Claims (10)

1. A stable and efficient wet oxidation catalyst, characterized in that the catalyst is a CuZnAlFeLa composite oxide catalyst, wherein Cu and Zn are divalent metal ions M ²⁺ , and Al, Fe and La are trivalent metal ions M ^{3 +} , its preparation method is carried out according to the following steps: (1) Preparation of salt solution: Take soluble copper salt, zinc salt, aluminum salt, iron salt and lanthanum salt and dissolve them in water to prepare a mixed salt solution with a total metal ion concentration of 0.01 to 1.50 mol/L. Trivalent metal ion molar ratio n[M ²⁺ ]: n[M ³⁺ ]=(2.0～4.0):1, divalent copper and zinc ion molar ratio n[Cu ²⁺ ]: n[Zn ²⁺ ]= (0.3～3.0): 1; molar ratio of trivalent aluminum ion to the sum of other trivalent ions n[Al ³⁺ ]: n[Fe ³⁺ +La ³⁺ ]=(0.1～10.0): 1; trivalent lanthanum Molar ratio to iron n[La ³⁺ ]: n[Fe ³⁺ ]=(0.05～2.0):1; (2) prepare lye and carbonate solution respectively: alkali and carbonate are dissolved in water respectively and prepare lye and corresponding carbonate solution, wherein in the two kinds of solutions, carbonate and hydroxide, and The ratio of cations in the mixed salt solution prepared in step (1) requires the following: the molar ratio n[CO ₃ ^2- ]/n[M ³⁺ ] of CO ₃ ^2- to the sum of trivalent metal ions Al, Fe and La is (2.0～2.5): 1, the molar ratio of OH ^- to total metal ions n[OH ^- ]/(2n[M ²⁺ ]+3n[M ³⁺ ]) is (1.6～2.0): 1, wherein the total The metal ion is the total valence charge of the metal ion in the mixed salt solution, and the above n[CO ₃ ^2- ] and n[OH ^- ] are the total moles of CO ₃ ^2- and the total number of OH ^- in carbonate and lye, respectively. number of moles; (3) Titration: Add the mixed salt solution in the step (1) and the lye in the step (2) to the carbonate solution prepared in the step (2) side by side, by controlling the titration speed of the two solutions to keep the whole The pH of the titration system is 10±0.2; (4) Stir and crystallize the precipitate obtained in step (3) at 40-90°C for 4-72 hours; then repeatedly filter and wash the obtained slurry until neutral, and dry it at 40-150°C, Grinding into a fine powder to obtain a catalyst precursor; (5) Roasting: put the catalyst precursor obtained in step (4) in a muffle furnace, heat up from room temperature 20°C to 400-800°C at a heating rate of 1-10°C·min ^- 1 for 1-10 hours, and then Cool the furnace to room temperature; (6) Acid treatment: filter and wash the oxide powder obtained in step (5) with 0.10-1.00mol/L dilute acid until no metal ions are detected in the filtrate, then filter and wash with water 4 times, and then repeat the steps The condition of (5) roasted the sample for 2 hours to obtain the catalyst. 2. A stable and efficient wet oxidation catalyst according to claim 1, characterized in that, in the step (1), the soluble copper salt, zinc salt, aluminum salt, iron salt and lanthanum salt are intended to Provide corresponding metal elements, choose nitrate, sulfate, phosphate, acetate or chloride, divalent copper and zinc ion molar ratio n[Cu ²⁺ ]: n[Zn ²⁺ ]=(1～2) : 1, the molar ratio of trivalent aluminum ions to the sum of other trivalent ions n[Al ³⁺ ]: n[Fe ³⁺ +La ³⁺ ]=(1.5～2.5): 1; the molar ratio of trivalent lanthanum to iron n[La ³⁺ ]: n[Fe ³⁺ ]=(0.1-1):1. 3. A kind of stable and efficient wet oxidation catalyst according to claim 1, is characterized in that, in described step (2), the alkali that provides hydroxide is sodium hydroxide, potassium hydroxide or ammoniacal liquor; Provides carbonate The carbonate is sodium carbonate, potassium carbonate or ammonium carbonate; the molar ratio of OH ^- to total metal ions n[OH ^- ]/(2n[M ²⁺ ]+3n[M ³⁺ ])=(1.6～1.8): 1. The concentration of ^OH- in lye is 0.01-3.00mol/L, and the concentration of CO ₃ ^2- in carbonate solution is 0.01-3.00mol/L. 4. A stable and efficient wet oxidation catalyst according to claim 1, characterized in that, in the step (3), stirring at a speed of 200 to 500 revolutions/min while adding drops, The precipitate is obtained while adding; in the step (4), the precipitate obtained in the step (3) is stirred and crystallized for 24 to 60 hours at a temperature of 50 to 80° C., and the stirring speed is 100 to 300 rpm; The obtained slurry is repeatedly filtered and washed until it becomes neutral, and the temperature of the aqueous solution is controlled at 20-60°C; it is dried in an oven at a drying temperature of 50-120°C and a drying time of 12-24 hours. 5. A stable and efficient wet oxidation catalyst according to claim 1, characterized in that, in the step (5), the roasting is at 500-700° C. for 2-6 hours; in the step (6), , the dilute acid is hydrochloric acid, sulfuric acid or nitric acid. 6. A preparation method of a stable and efficient wet oxidation catalyst, characterized in that, it is carried out according to the following steps: (1) Preparation of salt solution: Take soluble copper salt, zinc salt, aluminum salt, iron salt and lanthanum salt and dissolve them in water to prepare a mixed salt solution with a total metal ion concentration of 0.01 to 1.50 mol/L. Trivalent metal ion molar ratio n[M ²⁺ ]: n[M ³⁺ ]=(2.0～4.0):1, divalent copper and zinc ion molar ratio n[Cu ²⁺ ]: n[Zn ²⁺ ]= (0.3～3.0): 1; molar ratio of trivalent aluminum ion to the sum of other trivalent ions n[Al ³⁺ ]: n[Fe ³⁺ +La ³⁺ ]=(0.1～10.0): 1; trivalent lanthanum Molar ratio to iron n[La ³⁺ ]: n[Fe ³⁺ ]=(0.05～2.0):1; (2) prepare lye and carbonate solution respectively: alkali and carbonate are dissolved in water respectively and prepare lye and corresponding carbonate solution, wherein in the two kinds of solutions, carbonate and hydroxide, and The ratio of cations in the mixed ^{salt solution prepared in step (1) requires the following: the molar ratio n[CO 3 2- ]} _/ ⁿ [M ₃₊ ] is (2.0～2.5): 1, the molar ratio of OH ^- to total metal ions n[OH ^- ]/(2n[M ²⁺ ]+3n[M ³⁺ ])=(1.6～2.0): 1, where The total metal ions are the total valence charges of metal ions in the mixed salt solution, and the above n[CO ₃ ^2- ] and n[OH ^- ] are the total moles of CO ₃ ^2- and OH ^- The total number of moles; (3) Titration: Add the mixed salt solution in the step (1) and the lye in the step (2) to the carbonate solution prepared in the step (2) side by side, by controlling the titration speed of the two solutions to keep the whole The pH of the titration system is 10±0.2; (4) Stir and crystallize the precipitate obtained in step (3) at 40-90°C for 4-72 hours; then repeatedly filter and wash the obtained slurry until neutral, and dry it at 40-150°C, Grinding into a fine powder to obtain a catalyst precursor; (5) Roasting: put the catalyst precursor obtained in step (4) in a muffle furnace, heat up from room temperature 20°C to 400-800°C at a heating rate of 1-10°C·min ^- 1 for 1-10 hours, and then Cool the furnace to room temperature; (6) Acid treatment: filter and wash the oxide powder obtained in step (5) with 0.10-1.00mol/L dilute acid until no metal ions are detected in the filtrate, then filter and wash with water 4 times, and then repeat the steps The condition of (5) roasted the sample for 2 hours to obtain the catalyst. 7. the preparation method of a kind of stable and efficient wet oxidation catalyst according to claim 6 is characterized in that, in described step (1), described soluble copper salt, zinc salt, aluminum salt, iron salt and lanthanum The salt is designed to provide the corresponding metal elements, select nitrate, sulfate, phosphate, acetate or chloride, the molar ratio of divalent copper to zinc ions n[Cu ²⁺ ]: n[Zn ²⁺ ]=(1 ～2): 1, the molar ratio of trivalent aluminum ion to the sum of other trivalent ions n[Al ³⁺ ]: n[Fe ³⁺ +La ³⁺ ]=(1.5～2.5): 1; trivalent lanthanum and iron The molar ratio n[La ³⁺ ]:n[Fe ³⁺ ]=(0.1～1):1. 8. the preparation method of a kind of stable and efficient wet oxidation catalyst according to claim 6, is characterized in that, in described step (2), the alkali that provides hydroxide is sodium hydroxide, potassium hydroxide or ammoniacal liquor; The carbonate that provides carbonate is sodium carbonate, potassium carbonate or ammonium carbonate; the molar ratio of OH ^- to total metal ions n[OH ^- ]/(2n[M ²⁺ ]+3n[M ³⁺ ])=(1.6～ 1.8): 1. The concentration of ^OH- in the lye is 0.01-3.00mol/L, and the concentration of CO ₃ ^2- in the carbonate solution is 0.01-3.00mol/L. 9. The preparation method of a stable and efficient wet oxidation catalyst according to claim 6, characterized in that, in the step (3), stirring at a speed of 200 to 500 rpm while adding dropwise , to obtain a precipitate while adding it dropwise; in the step (4), the precipitate obtained in the step (3) is stirred and crystallized for 24 to 60 hours at a temperature of 50 to 80 ° C, and the stirring speed is 100 to 300 rpm min; in the process of repeatedly filtering and washing the obtained slurry to neutrality, the temperature of the aqueous solution is controlled at 20-60°C; it is dried in an oven, the drying temperature is 50-120°C, and the drying time is 12-24h; The roasting in the step (5) is at 500-700° C. for 2-6 hours; in the step (6), the dilute acid is hydrochloric acid, sulfuric acid or nitric acid. 10. The application of the wet oxidation catalyst as claimed in any one of claims 1 to 5 in the wet oxidation catalytic treatment of phenol wastewater or the comprehensive wastewater produced by sodium saccharin, wherein in the comprehensive wastewater produced by sodium saccharin, the potassium dichromate method is used to determine the Chemical oxygen demand COD _Cr = 17339.32 mg/l, ammonia nitrogen content NH ₃ -N = 6439.22 mg/l, pH = 8.17, black.