Preparation method of zirconium-cobalt-nickel-titanium oxide nano catalytic wet oxidation catalyst as well as product and application of zirconium-cobalt-nickel-titanium oxide nano catalytic wet oxidation catalyst

Abstract

The invention discloses a preparation method of a zirconium-cobalt-nickel-titanium oxide nano catalytic wet oxidation catalyst as well as a product and application thereof. The zirconium-cobalt-nickel-titanium oxide nano catalytic material prepared by the invention can be applied to catalytic wet oxidation treatment of petrochemical and oil-refining wastewater. Tests prove that when the reaction temperature is 200 DEG C, the reaction time is 2.5 hours and the catalyst amount is 2.4 g / L, the removal rates of TOC (initial concentration is 210987 mg / L) and COD (chemical oxygen demand) (initial concentration is 223654 mg / L) in the petrochemical and oil-refining wastewater can be respectively increased to 98.31% and 98.89% by a catalytic wet oxidation system. Under the condition, the TOC concentration and the COD concentration of the final effluent are respectively reduced to 3566 mg / L and 2483 mg / L. The zirconium-cobalt-nickel-titanium oxide nano catalytic wet oxidation catalytic material has a wide application prospect in treatment of other industrial high-concentration organic wastewater.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalytic materials for environmental wastewater treatment, and particularly relates to a preparation method, product and application of a zirconium cobalt nickel titanium oxide nano-catalytic wet air oxidation catalyst. Technical Background

[0002] Petrochemical refinery wastewater is a typical type of wastewater generated in the petrochemical industry, mainly from processes such as petroleum refining, chemical synthesis, desulfurization and deacidification. Such wastewater usually has a very high chemical oxygen demand (COD), total oxygen demand (TOD), oil substances, and certain concentrations of harmful chemical substances, such as aromatic hydrocarbons, phenols, ammonia nitrogen and heavy metals. Due to the complex and high-concentration pollution components of petrochemical refinery wastewater, if directly discharged without effective treatment, it will cause serious harm to water bodies and the ecological environment. Therefore, the efficient treatment of petrochemical refinery wastewater is an important topic in the field of environmental protection. The main pollutants in petrochemical refinery wastewater include organic compounds, ammonia nitrogen, sulfides and oil substances. Since a large number of chemical substances and catalysts are used in the petrochemical industry, these wastewaters often contain high concentrations of organic pollutants, which exist in the wastewater in a form that is difficult to degrade, making it difficult for conventional physicochemical treatment methods (such as adsorption, precipitation, flotation, etc.) to achieve ideal treatment effects. At the same time, the oil pollutants in the wastewater have long-term and potential impacts on the further pollution of water bodies and the destruction of the ecosystem, so more efficient and stable treatment technologies are needed.

[0003] Catalytic wet air oxidation technology (CWO) is a new type of wastewater treatment technology with high treatment efficiency and wide adaptability. This technology oxidizes and decomposes organic pollutants in wastewater with an oxidant (such as air or oxygen) under high temperature and high pressure conditions with the help of a catalyst, converting them into harmless substances such as carbon dioxide and water. Compared with traditional wet air oxidation technology, catalytic wet air oxidation technology can efficiently degrade complex organic compounds at lower reaction temperatures and pressures with the help of a catalyst, thereby reducing energy consumption, improving reaction efficiency, and reducing the negative impact on the environment. The advantage of catalytic wet air oxidation technology is that it can efficiently treat various pollutants including refractory organic compounds, oils, ammonia nitrogen, etc., with fewer by-products generated during the reaction, simple operation and lower energy consumption. In catalytic wet air oxidation technology, the selection of the catalyst is the key to the successful application of this technology. The high efficiency, stability and reasonable cost of the catalyst are the core to promote the wide application of this technology.

[0004] However, currently, environmental and chemical catalytic materials generally have problems such as high cost, difficult preparation and unsatisfactory treatment effects. Therefore, how to prepare an efficient, stable and economical catalyst has become an important topic in the research of catalytic wet air oxidation technology. Summary of the Invention

[0005] Object of the Invention: The technical problem to be solved by the present invention is to provide a preparation method of a zirconium-cobalt-nickel-titanium oxide nano-catalytic wet air oxidation catalyst for efficiently and stably treating petrochemical refinery wastewater.

[0006] Another technical problem to be solved by the present invention is to provide the catalyst obtained by the above preparation method and its application.

[0007] Technical Solution: To solve the above technical problems, the present invention provides a preparation method of a zirconium-cobalt-nickel-titanium oxide nano-catalytic wet air oxidation catalyst, comprising the following steps:

[0008] (1) Tetrabutyl titanate is added to methanol and stirred to obtain an organic solution A;

[0009] (2) Zirconium acetate, cobalt acetate and nickel acetate tetrahydrate are added to methanol and stirred to obtain an organic solution B;

[0010] (3) The organic solution A obtained in step (1) is mixed with the organic solution B obtained in step (2) and magnetically stirred to obtain an organic solution C, and then a condensation reflux reaction is carried out to obtain a reaction organic solution D;

[0011] (4) The reaction organic solution D is placed in a forced air drying oven and heated with the opening, and after the methanol evaporates, a paste-like reaction mixture E is obtained;

[0012] (5) The reaction mixture E is placed in a muffle furnace and slowly heated to obtain a reaction solid F;

[0013] (6) The temperature of the muffle furnace is continued to be slowly raised and maintained, and after completion, the material is directly quenched to room temperature to obtain a reaction product.

[0014] Among them, the volume ratio of tetrabutyl titanate to methanol in step (1) is (5-7):125.

[0015] Among them, the molar volume ratio of zirconium acetate, cobalt acetate, nickel acetate tetrahydrate to methanol in step (2) is (0.01-0.02):125 mol / mL.

[0016] Among them, the magnetic stirring time in step (3) is 60 minutes, the magnetic stirring temperature is controlled at 25-40 °C, the condensation reflux temperature is 70-80 °C, and the condensation reflux time is 60-90 minutes.

[0017] Among them, the heating temperature of the reaction organic solution D in the forced air drying oven in step (4) is 50-80 °C, and the heating time is 120-240 minutes.

[0018] Among them, the heating rate in step (5) is 1-2 °C / minute, the heating temperature is 200-250 °C, and the temperature holding time is 2.0-3.0 hours.

[0019] Among them, in step (6), the heating rate is 1 to 2 °C per minute, the heating temperature is 550 to 650 °C, and the temperature holding time is 2.5 to 3.5 hours.

[0020] The content of the present invention also includes the catalyst prepared by the described preparation method.

[0021] The content of the present invention also includes the application of the described catalyst in the catalytic wet air oxidation treatment of petrochemical refinery wastewater.

[0022] Among them, the temperature of the catalytic wet air oxidation is 170 to 200 °C, the reaction time is 0.5 to 2.5 hours, and the catalyst dosage is 0.2 to 2.5 g / L (wastewater).

[0023] Beneficial effects: Compared with the prior art, the present invention has the following advantages: The zirconium cobalt nickel titanium oxide nano-catalyst prepared by the present invention can be applied to the catalytic wet air oxidation treatment of petrochemical refinery wastewater. Tests have proved that under the conditions of a reaction temperature of 200 °C, a reaction time of 2.5 hours, and a catalyst dosage of 2.4 g / L, the removal rates of TOC (initial concentration 210987 mg / L) and COD (initial concentration 223654 mg / L) of the catalytic wet air oxidation system for petrochemical refinery wastewater reach 98.31% and 98.89% respectively. The concentrations of TOC and COD in the final effluent are only 3566 mg / L and 2483 mg / L. The novel and efficient zirconium cobalt nickel titanium oxide nano-catalytic wet air oxidation catalytic material of the present invention will have wide applications in the treatment of other industrial high-concentration organic wastewater. Description of the Drawings

[0024] Figure 1 It is the scanning electron microscope result diagram (9.2 mm * 3.00 k) of the catalyst sample synthesized in Example 1.

[0025] Figure 2 It is the scanning electron microscope result diagram (14.4 mm * 20.0 k) of the catalyst sample synthesized in Example 1.

[0026] Figure 3 It is the scanning electron microscope result diagram (9.2 mm * 3.00 k) of the catalyst sample synthesized in Example 4.

[0027] Figure 4 The scanning electron microscope result diagram (9.2 mm * 20.0 k) of the catalyst sample synthesized in Example 4.

[0028] Figure 5 It is the scanning electron microscope result diagram (9.4 mm * 3.00 k) of the catalyst sample synthesized in Example 7.

[0029] Figure 6Scanning electron microscope result diagram of the synthesized catalyst sample in Example 7 (9.4mm * 15.0k).

[0030] Figure 7 Flow chart of the preparation process and application of the present invention. Detailed implementation mode

[0031] Preparation of zirconium cobalt nickel titanium oxide nano-catalytic wet air oxidation catalyst in Example 1

[0032] (1) Add 5 mL of tetrabutyl titanate to 125 mL of methanol and stir for 45 minutes to obtain organic solution A;

[0033] (2) Add 0.01 moL each of zirconium acetate (3.274 g), cobalt acetate (1.7702 g), and nickel acetate tetrahydrate (2.4884 g) to 125 mL of methanol and stir for 45 minutes to obtain organic solution B;

[0034] (3) Mix organic solution A and organic solution B and stir magnetically at 25 °C for 60 minutes to obtain organic solution C, and then carry out a reflux reaction at 70 °C for 60 minutes to obtain reaction organic solution D;

[0035] (4) Place reaction organic solution D in an open-air blast drying oven at 50 °C and heat for 120 minutes. After most of the methanol has evaporated, a pasty reaction mixture E is obtained;

[0036] (5) Place reaction mixture E in a muffle furnace and slowly heat it to 200 °C at a rate of 1 °C / min, and keep the temperature for 2.0 hours to obtain reaction solid F;

[0037] (6) Continue to slowly heat the muffle furnace temperature to 550 °C at a rate of 1 °C / min, keep the temperature for 2.5 hours, and directly quench the material to room temperature after completion to obtain the reaction product, which is the zirconium cobalt nickel titanium oxide nano-catalytic wet air oxidation catalyst.

[0038] The scanning electron microscope results of the catalyst prepared by the present invention are as shown in Figure 1 and Figure 2 .

[0039] Application of zirconium cobalt nickel titanium oxide nano-catalytic wet air oxidation catalyst in Example 2

[0040] In this embodiment, the catalyst prepared in Example 1 was used to treat petrochemical refinery wastewater in a catalytic wet air oxidation device (GCF permanent magnet rotary stirring reactor). The specific process is as follows: First, 1000 mL of petrochemical refinery wastewater (the initial TOC concentration of the petrochemical refinery wastewater was 268452 mg / L, and the COD concentration was 281056 mg / L) was poured into a 1.5 L permanent magnet rotary stirring reactor, and an appropriate amount of the catalyst prepared in Example 1 (the final concentration of the catalyst was 0, 0.2, 1.0, or 2.0 g / L) was added and mixed thoroughly. Next, the reactor was sealed, the oxygen partial pressure was maintained at 2.0 MPa, and the reaction temperature was raised to a preset value (170 °C, 180 °C, 190 °C), and the catalytic wet air oxidation reaction was started. After the experiment was completed, the reactor was naturally cooled to room temperature. After the temperature decreased, the reactor was opened, and samples were taken using a disposable syringe and the supernatant was filtered, and the total organic carbon (TOC) and chemical oxygen demand (COD) concentrations were analyzed. The TOC removal rate and COD removal rate were calculated by the following formulas respectively: TOC removal rate = (TOC 反应前 -TOC 反应后 ) / TOC 反应前 × 100%, COD removal rate = (COD 反应前 -COD 反应后 ) / COD 反应前 × 100%. The results are shown in Table 1.

[0041] As can be seen from Table 1, adding the zirconium cobalt nickel titanium oxide nano-catalytic wet air oxidation catalyst under different reaction conditions significantly improved the pollutant removal effect on petrochemical refinery wastewater compared with the wet air oxidation system without adding a catalyst. For example, at a reaction temperature of 170 °C and a reaction time of 2.5 hours, the TOC removal rate of the wet air oxidation system without adding a catalyst was 21.32%, and the COD removal rate was 24.87%. Under the same conditions, for the catalytic wet air oxidation system with 0.2 g / L catalyst added, the TOC removal rate was 59.76%, and the COD removal rate was 61.59%, which was about 35% higher than that of the system without adding a catalyst. When the catalyst dosage increased to 1.0 g / L, the TOC and COD removal rates were 69.40% and 71.64% respectively, which was about 47% higher than that of the catalyst-free system. When the catalyst dosage increased to 2.0 g / L, the TOC removal rate reached 75.32%, and the COD removal rate was 77.06%, which was about 54% higher than that without adding a catalyst.

[0042] The above results indicate that increasing the dosage of the catalyst can effectively improve the removal efficiency of pollutants in the catalytic wet air oxidation system for petrochemical refinery wastewater treatment. In addition, the reaction temperature has a significant impact on the wastewater treatment effect. With the increase in temperature, the removal rate of pollutants in the wastewater has been significantly improved. For example, when the reaction temperature is 180 °C, the reaction time is 2.5 hours, and the catalyst dosage is 2.0 g / L, the removal rates of TOC and COD in the catalytic wet air oxidation system for petrochemical refinery wastewater reach 83.69% and 85.83% respectively. Compared with the same reaction conditions at 170 °C, the removal rates of TOC and COD are increased by about 8%. When the reaction temperature is further increased to 190 °C, the removal rates of TOC and COD in the catalytic wet air oxidation system are increased to 92.18% and 94.32% respectively, which is about 17% higher than the results at 170 °C.

[0043] Table 1 Removal efficiency of the catalytic wet air oxidation system for petrochemical refinery wastewater

[0044]

[0045]

[0046] Example 3 Application of zirconium cobalt nickel titanium oxide nano-catalytic wet air oxidation catalyst

[0047] In this example, the catalyst prepared in Example 1 was used to treat petrochemical refinery wastewater (the initial TOC concentration of the petrochemical refinery wastewater was 271534 mg / L, and the COD concentration was 298905 mg / L) in a catalytic wet air oxidation device (GCF permanent magnet rotary stirring reactor). The specific process is as follows: First, 1000 mL of petrochemical refinery wastewater was poured into a 1.5 L permanent magnet rotary stirring reactor, and an appropriate amount of the catalyst prepared in Example 1 (the final concentration of the catalyst was 0, 0.5, 2.5 g / L) was added for thorough mixing. Next, the reactor was sealed, the oxygen partial pressure was maintained at 2.0 MPa, and the reaction temperature was raised to the preset value (175 °C, 185 °C, 200 °C) to start the catalytic wet air oxidation reaction. After the experiment, the reactor was naturally cooled to room temperature. After the temperature decreased, the reactor was opened, and samples were taken using a disposable syringe and the supernatant was filtered to analyze the total organic carbon (TOC) and chemical oxygen demand (COD) concentrations. The TOC removal rate and COD removal rate were calculated by the following formulas: TOC removal rate = (TOC 反应前 -TOC 反应后 ) / TOC 反应前 × 100%, COD removal rate = (COD 反应前 -COD 反应后 ) / COD 反应前 × 100%. The results are shown in Table 2.

[0048] According to the results in Table 2, it can be seen from the data of the removal rate of petrochemical refinery wastewater by catalytic wet air oxidation using the zirconium-cobalt-nickel-titanium oxide nano-catalyst prepared in Example 1 that the wastewater treatment efficiency of the catalytic wet air oxidation system using this catalyst is significantly higher than that of the wet air oxidation system without adding a catalyst. After adding the catalyst, the removal efficiency of the wastewater is significantly improved, and with the increase of the catalyst dosage, reaction time and reaction temperature, the removal effect of the catalytic wet air oxidation system on wastewater pollutants is further enhanced. When the reaction temperature is 175 °C and the reaction time is 2.5 hours, the TOC removal rate of the wet air oxidation system for petrochemical refinery wastewater is 24.71%, and the COD removal rate is 26.29%. Under the same reaction conditions, after adding 0.5 g / L of the catalyst, the TOC removal rate of the catalytic wet air oxidation system is significantly increased to 65.47%, and the COD removal rate is increased to 68.27%, which is about 41% higher than that of the wet air oxidation system without adding a catalyst. When the catalyst dosage is increased to 2.5 g / L, the TOC removal rate is further increased to 81.08%, and the COD removal rate is increased to 84.37%, which is about 56% higher than that of the wet air oxidation system under the same conditions. In addition, with the increase of the reaction temperature, the removal efficiency of the catalytic wet air oxidation system is also significantly enhanced. For example, when the reaction time is maintained at 2.5 hours and the reaction temperature is increased to 200 °C, after adding 2.5 g / L of the catalyst, the TOC removal rate of the wastewater reaches 97.53%, and the COD removal rate is 98.32%, which is about 16% higher than that at the reaction temperature of 175 °C. Finally, the TOC concentration of the wastewater is reduced to 6707 mg / L, and the COD concentration is only 5022 mg / L, greatly reducing the pollutants with an initial TOC concentration of 271534 mg / L and a COD concentration of 298905 mg / L.

[0049] Table 2 Removal efficiency of petrochemical refinery wastewater by catalytic wet air oxidation system

[0050]

[0051]

[0052] Preparation of zirconium-cobalt-nickel-titanium oxide nano-catalyst for catalytic wet air oxidation in Example 4

[0053] A zirconium-cobalt-nickel-titanium oxide nano-catalyst for catalytic wet air oxidation is prepared by the following method:

[0054] (1) Add 5.5 mL of tetrabutyl titanate to 125 mL of methanol and stir for 45 minutes to obtain organic solution A;

[0055] (2) Add 0.015 moL of zirconium acetate, 0.015 moL of cobalt acetate, and 0.015 moL of nickel acetate tetrahydrate into 125 mL of methanol respectively, and stir for 45 minutes to obtain organic solution B;

[0056] (3) Mix organic solution A and organic solution B, and stir magnetically at 35 °C for 60 minutes to obtain organic solution C. Then, carry out a condensation reflux reaction at 75 °C for 70 minutes to obtain reaction organic solution D;

[0057] (4) Place reaction organic solution D in an open-air blast drying oven at 65 °C and heat for 180 minutes. After most of the methanol has evaporated, a pasty reaction mixture E is obtained;

[0058] (5) Place reaction mixture E in a muffle furnace and slowly heat it to 220 °C at a rate of 1 °C per minute, and keep the temperature for 2.5 hours to obtain reaction solid F;

[0059] (6) Continue to slowly heat the muffle furnace temperature to 600 °C at a rate of 1 °C per minute, keep the temperature for 3.0 hours, and after the end, directly quench the material to room temperature to obtain the reaction product, which is the zirconium cobalt nickel titanium oxide nano-catalytic wet air oxidation catalyst.

[0060] The scanning electron microscope results of the catalyst prepared in the present invention are as Figure 3 and Figure 4 .

[0061] Example 5 Application of Zirconium Cobalt Nickel Titanium Oxide Nano-Catalytic Wet Air Oxidation Catalyst

[0062] In this example, the catalyst prepared in Example 4 is used to treat petrochemical refinery wastewater (the initial TOC concentration of the petrochemical refinery wastewater is 232678 mg / L, and the COD concentration is 249732 mg / L) in a catalytic wet air oxidation device (GCF permanent magnet rotary stirring reactor). The specific process is as follows: First, pour 1000 mL of petrochemical refinery wastewater into a 1.5 L permanent magnet rotary stirring reactor, and add appropriate amounts of the catalyst prepared in Example 4 (the final concentrations of the catalyst are 0, 0.3, 1.5, 2.5 g / L) respectively for thorough mixing. Next, seal the reactor, keep the oxygen partial pressure at 2.0 MPa, and raise the reaction temperature to the preset values (180 °C, 195 °C), and start the catalytic wet air oxidation reaction. After the experiment is over, the reactor is naturally cooled to room temperature. After the temperature drops, open the reactor, use a disposable syringe to take samples and filter the supernatant, and analyze the total organic carbon (TOC) and chemical oxygen demand (COD) concentrations. The TOC removal rate and COD removal rate are calculated by the following formulas respectively: TOC removal rate = (TOC 反应前 -TOC 反应后 ) / TOC 反应前× 100%, COD removal rate = (COD 反应前 - COD 反应后 ) / COD 反应前 × 100%.

[0063] From the removal rate data of the wet oxidation system with zirconium-cobalt-nickel-titanium oxide nano-catalytic wet oxidation catalyst added under different reaction conditions in Table 3 for petrochemical refinery wastewater, it can be seen that the addition of the catalyst significantly improves the removal effect of wet oxidation on pollutants in the wastewater. At a reaction temperature of 180 °C and a reaction time of 2.5 hours, the TOC removal rate of the wet oxidation system for petrochemical refinery wastewater is 30.29%, and the COD removal rate is 34.66%. After adding the catalyst, the removal efficiency of the catalytic wet oxidation system is greatly improved. When the catalyst dosage is 0.3 g / L, the TOC and COD removal rates of the catalytic wet oxidation system for the wastewater are increased by about 25% respectively compared with the wet oxidation system. When the catalyst dosage is further increased to 1.5 g / L, the TOC and COD removal rates of the catalytic wet oxidation system for the wastewater are increased by about 50% compared with the wet oxidation system. In addition, with the increase of the reaction temperature and the catalyst dosage, the removal effect of the catalytic wet oxidation system is further enhanced. For example, at a reaction temperature of 195 °C, a reaction time of 2.5 hours, and a catalyst dosage of 1.5 g / L, the TOC and COD removal rates of the catalytic wet oxidation system for the wastewater are 88.93% and 91.48% respectively. When the catalyst dosage is further increased to 2.5 g / L, the TOC and COD removal effects of the catalytic wet oxidation system for the wastewater are further improved to 94.38% and 97.04%.

[0064] Table 3 Removal efficiency of catalytic wet oxidation system for petrochemical refinery wastewater

[0065]

[0066]

[0067] Example 6 Application of zirconium-cobalt-nickel-titanium oxide nano-catalytic wet oxidation catalyst

[0068] In this embodiment, the catalyst prepared in Example 4 was used to treat petrochemical refining wastewater (the initial TOC concentration of the petrochemical refining wastewater was 210987 mg / L, and the COD concentration was 223654 mg / L) in a catalytic wet air oxidation device (GCF permanent magnet rotating stirring reactor). The specific process is as follows: First, 1000 mL of petrochemical refining wastewater was poured into a 1.5 L permanent magnet rotating stirring reactor, and an appropriate amount of the catalyst prepared in Example 4 (the final concentrations of the catalyst were 0, 0.8, 1.6, 2.4 g / L) was added and mixed thoroughly. Next, the reactor was sealed, the oxygen partial pressure was maintained at 2.0 MPa, and the reaction temperature was raised to the preset values (185 °C, 200 °C), and the catalytic wet air oxidation reaction was started. After the experiment, the reactor was naturally cooled to room temperature. After the temperature decreased, the reactor was opened, and samples were taken using a disposable syringe and the supernatant was filtered to analyze the total organic carbon (TOC) and chemical oxygen demand (COD) concentrations. The TOC removal rate and COD removal rate were calculated by the following formulas respectively: TOC removal rate = (TOC 反应前 -TOC 反应后 ) / TOC 反应前 × 100%, COD removal rate = (COD 反应前 -COD 反应后 ) / COD 反应前 × 100%.

[0069] It can be seen from the experimental results in Table 4 that under different reaction conditions, the removal rate of the wet air oxidation system with the zirconium-cobalt-nickel-titanium oxide nano-catalytic wet air oxidation catalyst for petrochemical refining wastewater showed a significant improvement. By adding the catalyst, the catalytic wet air oxidation system was more efficient in removing pollutants from the wastewater than the wet air oxidation system without the catalyst. Under the same reaction temperature and reaction time conditions, the addition of the catalyst significantly improved the removal effect of pollutants. For example, at a reaction temperature of 185 °C and a reaction time of 2.5 hours, the TOC removal rate of the catalytic wet air oxidation system with 0.8 g / L catalyst added reached 75.28%, and the COD removal rate was 77.54%, which was about 40% higher than that of the wet air oxidation system without the catalyst. When the catalyst dosage increased to 1.6 g / L and 2.4 g / L, the removal rates of the catalytic wet air oxidation system for pollutants increased by about 47% and 55% respectively. In addition, the data in Table 4 also showed that extending the reaction time and increasing the reaction temperature could effectively promote the degradation of pollutants. Under the conditions of a reaction temperature of 200 °C, a reaction time of 2.5 hours, and the addition of 2.4 g / L catalyst, the removal rates of the catalytic wet air oxidation system for the initial TOC (210987 mg / L) and COD (223654 mg / L) of petrochemical refining wastewater were as high as 98.31% and 98.89% respectively, and the TOC and COD concentrations in the final effluent were only 3566 mg / L and 2483 mg / L.

[0070] Table 4 Removal efficiency of the catalytic wet oxidation system for petrochemical refinery wastewater

[0071]

[0072] Example 7 Preparation of zirconium cobalt nickel titanium oxide nano-catalytic wet oxidation catalyst

[0073] A zirconium cobalt nickel titanium oxide nano-catalytic wet oxidation catalyst is prepared by the following method:

[0074] (1) Add 7.0 mL of tetrabutyl titanate to 125 mL of methanol and stir for 45 minutes to obtain organic solution A;

[0075] (2) Respectively add 0.02 moL of zirconium acetate, 0.02 moL of cobalt acetate and 0.02 moL of nickel acetate tetrahydrate to 125 mL of methanol and stir for 45 minutes to obtain organic solution B;

[0076] (3) Mix organic solution A and organic solution B and magnetically stir at 40 °C for 60 minutes to obtain organic solution C, and then carry out a condensation reflux reaction at 80 °C for 90 minutes to obtain reaction organic solution D;

[0077] (4) Place reaction organic solution D in an 80 °C forced air drying oven and heat it for 240 minutes. After most of the methanol has evaporated, a pasty reaction mixture E is obtained;

[0078] (5) Place reaction mixture E in a muffle furnace and slowly heat it to 250 °C at a rate of 2 °C / min, and keep the temperature for 3.0 hours to obtain reaction solid F;

[0079] (6) Continue to slowly heat the muffle furnace temperature to 650 °C at a rate of 2 °C / min, keep the temperature for 3.5 hours, and directly quench the material to room temperature after completion to obtain the reaction product, which is the zirconium cobalt nickel titanium oxide nano-catalytic wet oxidation catalyst.

[0080] The scanning electron microscope results of the catalyst prepared in the present invention are as shown in Figure 5 and Figure 6 .

[0081] Example 8 Application of zirconium cobalt nickel titanium oxide nano-catalytic wet oxidation catalyst

[0082] In this embodiment, the catalyst prepared in Example 7 is used to treat petrochemical refinery wastewater (the initial TOC concentration of petrochemical refinery wastewater is 246731mg / L and the COD concentration is 261238mg / L) in a catalytic wet oxidation device (GCF permanent magnet rotary stirring reactor). The specific process is as follows: First, 1000mL of petrochemical refinery wastewater is poured into a 1.5L permanent magnet rotary stirring reactor, and an appropriate amount of the catalyst prepared in Example 7 (the final concentration of the catalyst is 0, 0.4, 1.2, 2.5g / L) is added respectively for full mixing. Next, the reactor is sealed, the oxygen partial pressure is maintained at 2.0MPa, and the reaction temperature is raised to a preset value (190°C, 200°C), and the catalytic wet oxidation reaction is started. After the experiment, the reactor is naturally cooled to room temperature. After the temperature is lowered, the reactor is opened, and a disposable syringe is used to sample and filter the supernatant, and its total organic carbon (TOC) and chemical oxygen demand (COD) concentrations are analyzed. The TOC removal rate and COD removal rate were calculated by the following formula: TOC removal rate = (TOC 反应前 -TOC 反应后 ) / TOC 反应前 × 100%, COD removal rate = (COD 反应前 -COD 反应后 ) / COD 反应前 ×100%.

[0083] From the results in Table 5, it can be seen that the addition of zirconium cobalt nickel titanium oxide nanocatalytic wet oxidation catalyst significantly improves the removal effect of the catalytic wet oxidation system on petrochemical refinery wastewater pollutants, and with the increase of the amount of catalyst, the pollutant removal rate continues to rise. At the same time, increasing the reaction temperature and extending the reaction time can also effectively promote the performance of the catalytic wet oxidation system. Specifically, when the reaction temperature is 200 ° C, the reaction time is 2.5 hours, and the catalyst dosage is 2.5g / L, the catalytic wet oxidation system has a TOC and COD removal rate of 97.94% and 98.86% in the wastewater, respectively, and the TOC and COD concentrations in the final effluent are reduced to 5083mg / L and 2978mg / L, respectively.

[0084] Table 5 Removal efficiency of petrochemical refinery wastewater by catalytic wet oxidation system

[0085]

[0086]

[0087] Example 9 Application of Zirconium-Cobalt-Nickel-Titanium Oxide Nanocatalyst Wet Oxidation Catalyst

[0088] In this example, using the catalyst prepared in Example 7, petrochemical refinery wastewater (the initial TOC concentration of the petrochemical refinery wastewater is 258544 mg / L, and the COD concentration is 270329 mg / L) is treated in a catalytic wet air oxidation device (GCF permanent magnet rotary stirring reactor). The specific process is as follows: First, 1000 mL of petrochemical refinery wastewater is poured into a 1.5 L permanent magnet rotary stirring reactor, and appropriate amounts of the catalyst prepared in Example 7 (the final concentrations of the catalyst are 0, 0.7, 1.4, 2.2 g / L) are added and mixed thoroughly. Next, the reactor is sealed, the oxygen partial pressure is maintained at 2.0 MPa, and the reaction temperature is raised to the preset values (180 °C, 190 °C, 200 °C), and the catalytic wet air oxidation reaction is started. After the experiment is over, the reactor is naturally cooled to room temperature. After the temperature drops, the reactor is opened, and samples are taken using a disposable syringe and the supernatant is filtered, and the total organic carbon (TOC) and chemical oxygen demand (COD) concentrations are analyzed. The TOC removal rate and COD removal rate are calculated by the following formulas respectively: TOC removal rate = (TOC 反应前 -TOC 反应后 ) / TOC 反应前 × 100%, COD removal rate = (COD 反应前 -COD 反应后 ) / COD 反应前 × 100%.

[0089] According to the data in Table 6, it can be seen that the addition of the zirconium-cobalt-nickel-titanium oxide nano-catalytic wet air oxidation catalyst significantly enhances the removal effect of the catalytic wet air oxidation system on the pollutants in petrochemical refinery wastewater, and as the catalyst dosage increases, the pollutant removal rate gradually increases. In addition, increasing the reaction temperature and prolonging the reaction time can also effectively improve the performance of the catalytic wet air oxidation system. Specifically, when the reaction temperature is 180 °C, the reaction time is 2.5 hours, and the catalyst dosage is 2.2 g / L, the removal rates of TOC and COD in the wastewater by the catalytic wet air oxidation system are 83.07% and 86.62% respectively, which is about 54% higher than that of the wet air oxidation system without adding a catalyst. Under the conditions of the same catalyst dosage and reaction time, increasing the temperature makes the treatment effect of the catalytic wet air oxidation system more significant. For example, when the reaction time is 2.5 hours, the catalyst dosage is 2.2 g / L, and the reaction temperature is 200 °C, the TOC and COD removal rates of the catalytic wet air oxidation system are increased by nearly 12% compared with those at 180 °C.

[0090] Table 6 Removal efficiency of the catalytic wet air oxidation system for petrochemical refinery wastewater

[0091]

[0092]

[0093] In summary, in combination with Figures 1 to 6 it can be seen that for the preparation method of a zirconium-cobalt-nickel-titanium oxide nano-catalytic wet air oxidation catalyst of the present invention, due to the differences in the preparation process, the properties of the catalyst are different. Figure 1 and Figure 2 show that the catalyst obtained in Example 1 presents a structure similar to a micro-rod shape. Figure 3 and Figure 4 show that the catalyst obtained in Example 4 still presents a structure similar to a micro-rod shape. Figure 5 and Figure 6 show that the main body of the catalyst obtained in Example 7 presents a structure similar to a micro-rod shape, and the rod-shaped structure of some particles is not fully formed. When a zirconium-cobalt-nickel-titanium oxide nano-catalytic wet air oxidation catalyst of the present invention is applied to the treatment of petrochemical refinery wastewater, the catalytic effect of the catalyst is stable, and the removal rates of wastewater TOC and COD are as high as over 95%, which can effectively reduce the concentration of pollutants in this type of wastewater and reduce its pollution and harm to the environment.

Claims

1. A method for preparing a zirconium-cobalt-nickel-titanium oxide nanocatalytic wet oxidation catalyst, characterized in that: The following steps are involved: (1) Tetrabutyl titanate is added to methanol and stirred to obtain an organic solution A; (2) adding zirconium acetate, cobalt acetate and nickel acetate tetrahydrate into methanol and stirring to obtain an organic solution B; (3) mixing the organic solution A obtained in step (1) and the organic solution B obtained in step (2) and subjecting them to magnetic stirring to obtain an organic solution C, followed by condensation and reflux reaction to obtain a reaction organic solution D; (4) The reaction organic solution D is placed in an open air drying oven and heated to obtain a paste-like reaction mixture E after methanol is evaporated; (5) placing the reaction mixture E in a muffle furnace and slowly heating it to obtain a reaction solid F; (6) The temperature of the muffle furnace is continued to be slowly raised and maintained, and after completion, the material is directly quenched to room temperature to obtain the reaction product.

2. The method for preparing a zirconium-cobalt-nickel-titanium oxide nanocatalytic wet oxidation catalyst according to claim 1, characterized in that: The volume ratio of tetrabutyl titanate to methanol in step (1) is (5-7):

125.

3. The method for preparing a zirconium-cobalt-nickel-titanium oxide nano-catalyst wet oxidation catalyst according to claim 1, characterized in that: The molar volume ratio of zirconium acetate, cobalt acetate, nickel acetate tetrahydrate and methanol in step (2) is (0.01-0.02): 125 mol / mL.

4. The method for preparing a zirconium-cobalt-nickel-titanium oxide nano-catalytic wet oxidation catalyst according to claim 1, characterized in that: In step (3), the magnetic stirring time is 60 minutes, the magnetic stirring temperature is controlled at 25-40° C., the condensation reflux temperature is 70-80° C., and the condensation reflux time is 60-90 minutes.

5. The method for preparing a zirconium-cobalt-nickel-titanium oxide nano-catalytic wet oxidation catalyst according to claim 1, characterized in that: In step (4), the reaction organic solution D is heated in a forced air drying oven at a temperature of 50 to 80° C. for a heating time of 120 to 240 minutes.

6. The method for preparing a zirconium-cobalt-nickel-titanium oxide nano-catalytic wet oxidation catalyst according to claim 1, characterized in that: In step (5), the heating rate is 1-2°C / min, the heating temperature is 200-250°C, and the temperature holding time is 2.0-3.0 hours.

7. The method for preparing a zirconium-cobalt-nickel-titanium oxide nano-catalytic wet oxidation catalyst according to claim 1, characterized in that: In step (6), the heating rate is 1-2°C / min, the heating temperature is 550-650°C, and the temperature holding time is 2.5-3.5 hours.

8. The catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the catalyst according to claim 8 in catalytic wet oxidation treatment of petrochemical refinery wastewater.

10. The use according to claim 9, characterized in that: The temperature of the catalytic wet oxidation is 170-200° C., the reaction time is 0.5-2.5 hours, and the catalyst dosage is 0.2-2.5 g / L.

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