Medical intermediate wastewater treatment process

Abstract

The invention discloses a medical intermediate wastewater treatment process, and belongs to the technical field of medical intermediate wastewater treatment. The medical intermediate wastewater treatment process comprises the following specific steps: (1) adjusting the pH value and phenol concentration of medical intermediate wastewater; (2) adding a composite catalyst into the wastewater obtained in the step (1) under the conditions of normal temperature, normal pressure, light shielding and stirring, uniformly mixing and dispersing, and then stirring and reacting for 55-65 minutes under the illumination condition; the preparation method of the composite catalyst comprises the following steps: preparing a catalyst blank by adopting a sol-gel method and taking soluble cobalt salt, soluble copper salt, ethyl acetate, ethanol and ultrapure water as initial reactants and solvents; mixing the catalyst blank with oxalic acid, melamine and ultrapure water, heating, carrying out secondary calcination under an anaerobic condition, and acidifying to obtain the catalyst. By means of the medical intermediate wastewater treatment process, organic pollutants in the medical intermediate wastewater can be effectively removed.

Description

Technical Field

[0001] The present invention relates to a process for treating wastewater from pharmaceutical intermediates. Background Art

[0002] In today's chemical and pharmaceutical fields, phenol, as a key basic organic compound, has a wide range of applications. Its chemical structural formula is C2H6O, also known as carbolic acid, and it is mainly produced through the oxidation and decomposition process of cumene. It is not only an important raw material for the production of chemical products and intermediates such as phenolic resins and bisphenol A, but also plays an indispensable role in the pharmaceutical field due to its functions as both a solvent and a disinfectant. The synthesis of many fungicides, preservatives, and drugs (such as aspirin) uses phenol as the core raw material.

[0003] However, the strong penetration ability and toxicity of phenol also pose great hazards to humans and the ecological environment. It can directly penetrate the skin and mucous membranes, react with proteins in human cells, cause protein denaturation and coagulation, inactivate cells, and ultimately lead to tissue necrosis. At the same time, phenol is toxic to all living organisms. Although it has a bactericidal effect at low concentrations (0.2 g / L), a concentration of about 1% can kill common bacteria, and a concentration of 1.3% can eliminate fungi, once untreated phenol-containing wastewater is discharged into water bodies, the consequences will be unimaginable.

[0004] After the wastewater containing phenol is discharged into water bodies, it will make the water body stink, affect fish reproduction, reduce the quality of aquatic products, and even make the aquatic products have a phenolic taste and become unusable. When high concentrations (6.5 - 9.3 g / L) of phenol enter the water body, it will cause fish to be poisoned to death or even become extinct, seriously damaging biodiversity. If the phenol content in the water body exceeds 100 g / L, using it for irrigation will cause crops to wither and result in a serious reduction in production.

[0005] During the production process of pharmaceutical intermediates, a large amount of wastewater containing phenol is generated. To avoid the occurrence of the above hazards, it is necessary to treat this wastewater to effectively remove phenol. However, some current treatment processes have problems such as complex operation and high cost. Therefore, it is extremely urgent to develop a treatment process that is simple to operate and can effectively remove phenol from wastewater of pharmaceutical intermediates. Summary of the Invention

[0006] The object of the present invention is to provide a process for treating wastewater from pharmaceutical intermediates to solve the technical problems mentioned in the above background art.

[0007] The technical solution for achieving the object of the present invention is: The present invention provides a process for treating wastewater from pharmaceutical intermediates, including the following preparation steps: (1) Adjust the pH and phenol concentration of the wastewater from pharmaceutical intermediates; (2) Under normal temperature and pressure, in the dark and with stirring, a composite catalyst is added to the wastewater in step (1), mixed and dispersed evenly, and then stirred and reacted for 55 - 65 min under light conditions.

[0008] The wastewater treatment process for pharmaceutical intermediates of the present invention treats the wastewater with a composite catalyst under light environment and normal temperature and pressure conditions, which can effectively remove phenol therein, and the operation process is simple.

[0009] Further, the pH of the pharmaceutical intermediate wastewater is adjusted to 3 - 11; the phenol concentration in the pharmaceutical intermediate wastewater is adjusted to 10 - 40 mg / L.

[0010] The wastewater treatment process for pharmaceutical intermediates of the present invention is applicable to treating pharmaceutical intermediate wastewater with a wide pH range and has strong adaptability.

[0011] Further, the dosage of the composite catalyst in the pharmaceutical intermediate wastewater is 0.2 - 0.4 g / L.

[0012] In the wastewater treatment process for pharmaceutical intermediates of the present invention, phenol contained in the pharmaceutical intermediate wastewater can be effectively removed with less catalyst dosage, which has the advantages of high efficiency and economy.

[0013] Further, the wavelength of the light source is greater than 420 nm.

[0014] The light source used in the wastewater treatment process for pharmaceutical intermediates of the present invention has a wavelength greater than 420 nm, and this light source is easy to obtain, facilitating practical application and promotion.

[0015] Further, the preparation steps of the composite catalyst are as follows: A1. Weigh soluble cobalt salt, soluble copper salt, tetraethyl orthosilicate, ethanol, and ultrapure water and mix them evenly to obtain solution A; A2. Weigh alkaline solution B; A3. Under stirring conditions, add alkaline solution B dropwise to solution A at a dropping rate of 1 drop / s. After reacting for 4.5 - 5.5 h, pour it into a petri dish and place it in an oven to dry at 60 °C until a gel is formed. Then put it into a muffle furnace and calcine at 600 °C for 3 h to obtain a catalyst blank; A4. Mix oxalic acid, the catalyst blank, and ultrapure water for 4 - 6 min, then add melamine and continue stirring for 25 - 35 min. Subsequently, transfer it to a stainless - steel autoclave with a polytetrafluoroethylene inner lining, seal it, and heat it at 105 - 115 °C for 23 - 25 h. After naturally cooling to room temperature, wash it 2 - 4 times with deionized water, dry it at 88 - 92 °C for 2.5 - 3.5 h, then put it into a tubular furnace purged with high - purity nitrogen for secondary calcination. After cooling to room temperature, obtain a composite catalyst blank; A5. Disperse 4.8 - 5.2 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution, stir and disperse for 6 - 12 h to obtain a suspension. Add ultrapure water to dilute the volume of the suspension to 1 L, then filter, wash the filter residue with deionized water until neutral, and dry at 88 - 92 °C to obtain the composite catalyst.

[0016] Furthermore, the molar volume ratio of the soluble cobalt salt, soluble copper salt to ultrapure water in solution A is 1 mmol : 1 mmol : 3 mL; the volume ratio of tetraethyl orthosilicate, ethanol, and ultrapure water is 0.14 - 0.16 : 3 : 1.

[0017] Furthermore, the alkaline solution B is 30 wt% ammonia water; the volume ratio of ultrapure water to alkaline solution B in solution A is 3 : 2.

[0018] Furthermore, the mass ratio of oxalic acid, catalyst blank, ultrapure water, and melamine is 0.25 : 1.8 - 1.84 : 50 : 0.58 - 0.6.

[0019] Furthermore, the specific steps of the secondary calcination process are as follows: First, heat from room temperature to 500 - 600 °C at a heating rate of 2 °C / min, then calcine for 3.5 - 4.5 h, cool to room temperature, and then heat from room temperature to 450 - 550 °C at a heating rate of 5 °C / min and keep warm for 2.5 - 3.5 h.

[0020] Adopting the above - mentioned technical solutions, the present invention has the following beneficial effects: (1) The pharmaceutical intermediate wastewater treatment process of the present invention treats the wastewater with a composite catalyst under light environment and normal temperature and pressure conditions, can effectively remove phenol therein, and the operation process is simple.

[0021] (2) The pharmaceutical intermediate wastewater treatment process of the present invention is applicable to treating pharmaceutical intermediate wastewater with a wide pH range and has strong adaptability.

[0022] (3) In the pharmaceutical intermediate wastewater treatment process of the present invention, it can effectively remove phenol contained in the pharmaceutical intermediate wastewater with less catalyst dosage, and has the advantages of high efficiency and economy.

[0023] (4) The light source used in the pharmaceutical intermediate wastewater treatment process of the present invention has a wavelength greater than 420 nm, and this light source is easy to obtain, which is convenient for practical application and promotion.

[0024] (5) The composite catalyst of the present invention is first prepared by a sol-gel method using soluble cobalt salt, soluble copper salt, ethyl acetate, ethanol, and ultrapure water as initial reactants and solvents to obtain a catalyst blank whose main components are cobalt trioxide, copper oxide, and silicon oxide and which has a relatively large number of micropores and mesoporous structures; the catalyst blank is then mixed with oxalic acid, melamine, and ultrapure water, heated, and calcined twice under oxygen-free conditions and then acidified to obtain the catalyst blank. Oxalic acid activates the surface of the catalyst blank and is adsorbed on the surface of the catalyst blank and the surface of the pores; melamine is then added, and the melamine and oxalic acid are cross-linked and coated on the surface of the catalyst blank and the surface of the pores; the catalyst blank is calcined and the catalyst blank is acidified. Melamine and oxalic acid jointly reduce cobalt tetroxide in contact with melamine and oxalic acid to form metallic cobalt crystal active sites. At the same time, a graphite phase carbon nitride polymer layer is formed on the surface of the catalyst blank and the surface of the pores. After secondary calcination and acidification, a large number of mesoporous structures are formed in the graphite phase carbon nitride polymer layer. When the pharmaceutical intermediate wastewater is treated with light, the surface graphite phase carbon nitride polymer layer is excited by visible light and near-infrared light, generating photoexcited electrons on the CB of the surface graphite phase carbon nitride polymer layer and an equal amount of photoexcited holes on the VB. The photoexcited electrons and holes are separated in space, and h + The reaction generates H + , and e - is captured by carbon vacancies and immediately transferred to the adsorbed O2 molecules and reacts with H + A reduction reaction occurs to generate hydrogen peroxide in the solution. The hydrogen peroxide synergistically acts with the active sites of the metal cobalt crystals in the composite catalyst and the catalyst blank body whose main components are cobalt trioxide, copper oxide, and silicon oxide and has a large number of micropores and mesoporous structures, effectively improving the composite catalyst's effect on the degradation of phenol in pharmaceutical intermediate wastewater. DETAILED DESCRIPTION

[0025] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0026] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0027] The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0028] The pharmaceutical intermediate wastewater in the examples and comparative examples all used a phenol solution with a pH of 7 and a concentration of 10 mg / L.

[0029] Water-soluble cobalt salt: cobalt nitrate, analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0030] Water-soluble copper salt: copper nitrate, analytically pure, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0031] Hydrogen peroxide was analytically pure and purchased from Sinopharm Chemical Reagent Co., Ltd.; A 300 W xenon lamp equipped with a cut-off filter for wavelengths above 400 nm was used as the light source to simulate sunlight, and a 420 nm filter was added to simulate visible light.

[0032] Example 1 A process for treating pharmaceutical intermediate wastewater includes the following preparation steps: (1) Take 100 mL of phenol solution with a pH of 7 and a concentration of 10 mg / L as the pharmaceutical intermediate wastewater; (2) Under normal temperature and pressure, in the dark and with stirring, add 20 mg of the composite catalyst to the wastewater in step (1), mix and disperse evenly, and then stir and react for 55 min under the illumination of the light source.

[0033] Further, the preparation steps of the composite catalyst are as follows: A1. Weigh 10 mmol of soluble cobalt salt, 10 mL of soluble copper salt, 4.5 mL of tetraethyl orthosilicate, 90 mL of ethanol, and 30 mL of ultrapure water and mix them evenly to obtain solution A; A2. Weigh 20 mL of 30 wt% ammonia water as alkali solution B; A3. Under stirring conditions, add alkali solution B dropwise to solution A at a rate of 1 drop / s. After reacting for 4.5 h, pour it into a petri dish and place it in an oven to dry at 60 °C until a gel is formed. Then place it in a muffle furnace and calcine it at 600 °C for 3 h to obtain a catalyst blank; A4. Mix oxalic acid, the catalyst blank, and ultrapure water for 4 min, then add melamine and continue stirring for 25 min. Subsequently, transfer it to a stainless-steel autoclave with a polytetrafluoroethylene liner, seal it, and heat it at 105 °C for 23 h. After naturally cooling to room temperature, wash it twice with deionized water, dry it at 88 °C for 2.5 h, then place it in a tubular furnace purged with high-purity nitrogen. First, heat it from room temperature to 500 °C at a heating rate of 2 °C / min, then calcine it for 3.5 h, cool it to room temperature, then heat it from room temperature to 450 °C at a heating rate of 5 °C / min, hold it for 2.5 h, and cool it to room temperature to obtain a composite catalyst blank; among them, the mass ratio of oxalic acid, the catalyst blank, ultrapure water, and melamine is 0.25:1.8:50:0.58.

[0034] A5. Disperse 4.8 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution, stir and disperse for 6 h to obtain a suspension. Add ultrapure water to dilute the volume of the suspension to 1 L, then filter, wash the filter residue with deionized water until it is neutral, and dry it at 88 °C to obtain the composite catalyst.

[0035] Example 2 A pharmaceutical intermediate wastewater treatment process includes the following preparation steps: (1) Take 100 mL of phenol solution with a pH of 7 and a concentration of 10 mg / L as the pharmaceutical intermediate wastewater; (2) Under normal temperature and pressure, in the dark and with stirring, add 30 mg of the composite catalyst to the wastewater in step (1), mix and disperse evenly, and then stir and react for 60 min under the illumination of a light source.

[0036] Further, the preparation steps of the composite catalyst are as follows: A1. Weigh 10 mmol of soluble cobalt salt, 10 mL of soluble copper salt, 4.5 mL of tetraethyl orthosilicate, 90 mL of ethanol, and 30 mL of ultrapure water, and mix them evenly to obtain solution A; A2. Weigh 20 mL of 30 wt% ammonia water as alkaline solution B; A3. Under stirring conditions, add alkaline solution B dropwise to solution A at a rate of 1 drop / s. After reacting for 5 h, pour it into a petri dish and place it in an oven to dry at 60 °C until a gel is formed. Then, place it in a muffle furnace and calcine it at 600 °C for 3 h to obtain a catalyst blank, the main components of which are copper oxide, silicon dioxide, and cobalt tetroxide; the specific surface area of the catalyst blank is 11.668 m 2 / g, the average pore diameter is 28.495 nm, and the average pore volume is 0.087 cm 3 / g; A4. Mix oxalic acid, the catalyst blank, and ultrapure water for 5 min, then add melamine and continue stirring for 30 min. Subsequently, transfer it to a stainless-steel autoclave with a polytetrafluoroethylene inner lining, seal it, and heat it at 110 °C for 24 h. After naturally cooling to room temperature, wash it 3 times with deionized water, dry it at 90 °C for 3 h, then place it in a tubular furnace purged with high-purity nitrogen. First, heat it from room temperature to 550 °C at a heating rate of 2 °C / min, then calcine it for 4 h, cool it to room temperature, then heat it from room temperature to 500 °C at a heating rate of 5 °C / min, keep it warm for 3 h, and after cooling to room temperature, obtain a composite catalyst blank; among them, the mass ratio of oxalic acid, the catalyst blank, ultrapure water, and melamine is 0.25:1.82:50:0.59.

[0037] A5. Disperse 5 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution, stir and disperse for 10 h to obtain a suspension. Add ultrapure water to dilute the volume of the suspension to 1 L, then filter it, wash the filter residue with deionized water until it is neutral, and dry it at 90 °C to obtain the composite catalyst.

[0038] Example 3 A pharmaceutical intermediate wastewater treatment process includes the following preparation steps: (1) Take 100 mL of phenol solution with a pH of 7 and a concentration of 10 mg / L as the wastewater from pharmaceutical intermediates. (2) Under normal temperature and pressure, in the dark and with stirring, add 40 mg of the composite catalyst to the wastewater in step (1), mix and disperse evenly, and then stir and react for 65 min under the illumination of a light source.

[0039] Further, the preparation steps of the composite catalyst are as follows: A1. Weigh 10 mmol of soluble cobalt salt, 10 mL of soluble copper salt, 4.5 mL of tetraethyl orthosilicate, 90 mL of ethanol, and 30 mL of ultrapure water and mix them evenly to obtain solution A. A2. Weigh 20 mL of 30 wt% ammonia water as alkaline solution B. A3. Under stirring conditions, drop alkaline solution B into solution A at a dropping rate of 1 drop / s. After reacting for 5.5 h, pour it into a petri dish and place it in an oven to dry at 60 °C until a gel is formed. Then put it into a muffle furnace and calcine it at 600 °C for 3 h to obtain the catalyst blank. A4. Mix oxalic acid, the catalyst blank, and ultrapure water for 6 min, then add melamine and continue stirring for 35 min. Subsequently, transfer it to a stainless-steel autoclave with a polytetrafluoroethylene inner lining, seal it, and heat it at 115 °C for 25 h. After natural cooling to room temperature, wash it 4 times with deionized water, dry it at 92 °C for 3.5 h, and then put it into a tubular furnace purged with high-purity nitrogen. First, heat it from room temperature to 600 °C at a heating rate of 2 °C / min, then calcine it for 4.5 h, cool it to room temperature, then heat it from room temperature to 550 °C at a heating rate of 5 °C / min, hold it for 3.5 h, and cool it to room temperature to obtain the composite catalyst blank; among them, the mass ratio of oxalic acid, the catalyst blank, ultrapure water, and melamine is 0.25:1.84:50:0.6.

[0040] A5. Disperse 5.2 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution, stir and disperse for 12 h to obtain a suspension, add ultrapure water to dilute the volume of the suspension to 1 L, then filter, wash the filter residue with deionized water until it is neutral, dry it at 92 °C to obtain the composite catalyst.

[0041] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that the composite catalyst is only prepared by the sol-gel method using soluble cobalt salt, soluble copper salt, ethyl acetate, ethanol, and ultrapure water as the initial reactants and solvents. The specific steps are as follows: A1. Weigh 10 mmol of soluble cobalt salt, 10 mL of soluble copper salt, 4.5 mL of tetraethyl orthosilicate, 90 mL of ethanol, and 30 mL of ultrapure water and mix them evenly to obtain solution A. A2. Weigh 20 mL of 30 wt% ammonia water as alkaline solution B. A3. Under stirring conditions, add alkaline solution B dropwise to solution A at a dropping rate of 1 drop / s. After reacting for 5 h, pour it into a petri dish and place it in an oven to dry at 60 °C until a gel is formed. Then place it in a muffle furnace and calcine it at 600 °C for 3 h to obtain a composite catalyst, the main components of which are copper oxide, silicon dioxide, and cobalt tetroxide; the specific surface area of the composite catalyst is 11.668 m 2 / g, the average pore diameter is 28.495 nm, and the average pore volume is 0.087 cm 3 / g; the other components, steps, and dosages are the same as those in Example 2.

[0042] Comparative Example 2 The difference between Comparative Example 2 and Comparative Example 1 lies in step (2), and step (2) is as follows: Under normal temperature and pressure, in the dark and under stirring conditions, add 30 mg of the composite catalyst and 1.5 mL of hydrogen peroxide to the wastewater in step (1), mix and disperse evenly, and then stir and react for 60 min under the illumination of a light source. The other components, steps, and dosages are the same as those in Example 2.

[0043] Comparative Example 3 The difference between Comparative Example 3 and Example 2 lies in the preparation method of the composite catalyst as follows: First, add 0.25 oxalic acid, 0.5 g of melamine, and 0.40 parts by mass of cobalt nitrate to a beaker containing 50 mL of distilled water in sequence. Stir the obtained solution at room temperature for 30 min, then transfer it to a stainless-steel autoclave lined with polytetrafluoroethylene, seal it, and heat it at 110 °C for 24 h. After naturally cooling to room temperature, wash it three times with deionized water, then dry it in an air drying oven at 90 °C for 3 h. Then place the dried solid in a tubular furnace purged with high-purity nitrogen, and heat it from room temperature to 550 °C at a heating rate of 2 °C / min, then calcine it for 4 h. After cooling to room temperature, then heat it from room temperature to 500 °C at a heating rate of 5 °C / min, hold for 3 h, and after cooling to room temperature, obtain a composite catalyst blank; Disperse 5 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution, stir and disperse for 12 h to obtain a suspension, add ultrapure water to dilute the volume of the suspension to 1 L, then filter, wash the filter residue with deionized water until neutral, and dry it at 90 °C to obtain the composite catalyst; the other components, steps, and dosages are the same as those in Example 2.

[0044] Comparative Example 4 The difference between Comparative Example 4 and Example 2 lies in the preparation steps of the composite catalyst as follows: A1. Weigh 10 mmol of soluble cobalt salt, 10 mL of soluble copper salt, 4.5 mL of tetraethyl orthosilicate, 90 mL of ethanol, and 30 mL of ultrapure water and mix them evenly to obtain solution A; A2. Weigh 20 mL of 30 wt% ammonia water as alkaline solution B; A3. Under stirring conditions, add alkali solution B dropwise to solution A at a dropping rate of 1 drop / s. After reacting for 5 h, transfer the mixture to a petri dish and place it in an oven to dry at 60 °C until a gel is formed. Then, place it in a muffle furnace and calcine it at 600 °C for 3 h to obtain a catalyst blank, the main components of which are copper oxide, silicon dioxide, and cobalt tetroxide; the specific surface area of the catalyst blank is 11.668 m 2 / g, the average pore diameter is 28.495 nm, and the average pore volume is 0.087 cm 3 / g; A4. Mix oxalic acid, the catalyst blank, and ultrapure water for 5 min, then add melamine and continue stirring for 30 min. Subsequently, transfer the mixture to a stainless-steel autoclave lined with polytetrafluoroethylene, seal it, and heat it at 110 °C for 24 h. After natural cooling to room temperature, wash it 3 times with deionized water, dry it at 90 °C for 3 h, and then place it in a tubular furnace purged with high-purity nitrogen. First, heat it from room temperature to 550 °C at a heating rate of 5 °C / min, and then calcine it for 4 h to obtain a composite catalyst; among them, the mass ratio of oxalic acid, the catalyst blank, ultrapure water, and melamine is 0.25:1.82:50:0.59; the other components, steps, and dosages are the same as those in Example 2.

[0045] Comparative Example 5 The difference between Comparative Example 5 and Example 2 lies in step (2), and step (2) is specifically as follows: Under normal temperature and pressure, in the dark and under stirring conditions, add 30 mg of the composite catalyst to the wastewater in step (1), mix and disperse it evenly, and then stir and react for 60 min; the other components, steps, and dosages are the same as those in Example 2.

[0046] Effect Example Use high-performance liquid chromatography for quantitative analysis of the removal rate of phenol solution treated by the pharmaceutical intermediate wastewater treatment process for 60 min. The actual data is shown in Table 1 below: Table 1

[0047] It can be seen from Table 1 above that the phenol treated by the pharmaceutical intermediate wastewater treatment processes of Examples 1 to 3 is completely removed.

[0048] The difference between Comparative Example 1 and Example 2 is that the composite catalyst is only prepared by the sol-gel method using soluble cobalt salts, soluble copper salts, ethyl acetate, ethanol, and ultrapure water as the initial reactants and solvents. The removal effect of phenol treated by the composite catalyst of Comparative Example 1 in the pharmaceutical intermediate wastewater treatment process is not ideal.

[0049] The difference between Comparative Example 2 and Example 2 is that the composite catalyst is prepared only by the sol-gel method using soluble cobalt salt, soluble copper salt, ethyl acetate, ethanol, and ultrapure water as the initial reactants and solvents, and 1.5 mL of hydrogen peroxide is introduced in the pharmaceutical intermediate wastewater treatment process stage. Compared with Comparative Example 1, the introduction of hydrogen peroxide in Comparative Example 2 significantly improves the removal effect of organic pollutants, indicating that the composite catalyst in Comparative Example 1 must rely on the combined action of hydrogen peroxide to remove organic pollutants.

[0050] The difference between Comparative Example 3 and Example 2 is that the composite catalyst is obtained by hydrothermal reaction of oxalic acid, melamine, and cobalt nitrate followed by secondary calcination and acidification by the hydrothermal method. The removal effect of phenol treated by the composite catalyst of Comparative Example 1 in the pharmaceutical intermediate wastewater treatment process is significantly inferior to that of Examples 1 to 3.

[0051] The difference between Comparative Example 4 and Example 2 is that the composite catalyst is obtained by traditional single calcination without secondary calcination and acidification. A large amount of graphitic carbon nitride coats the pores and surface of the catalyst blank, preventing phenol from fully and closely contacting the active sites in the catalyst, resulting in a significant decrease in the phenol removal effect.

[0052] The difference between Comparative Example 5 and Example 2 is that no light is applied during the treatment process of the pharmaceutical intermediate wastewater. The phenol removal rate of Comparative Example 5 is higher than that of Comparative Example 1 and Comparative Example 3. It may be that the graphitic carbon nitride-coated catalyst blank with a mesoporous structure enhances the phenol removal effect of the composite catalyst, but the phenol removal effect is significantly worse compared with Example 2, indicating that the composite catalyst has a significantly enhanced phenol removal effect under light conditions.

[0053] In summary, for the pharmaceutical intermediate wastewater treatment process of the present invention, under light environment and normal temperature and pressure conditions, a catalyst blank mainly composed of cobalt tetroxide, copper oxide, and silicon oxide with a large number of micropores and mesoporous structures is first prepared by the sol-gel method using soluble cobalt salt, soluble copper salt, ethyl acetate, ethanol, and ultrapure water as the initial reactants and solvents; then the composite catalyst obtained by mixing the catalyst blank with oxalic acid, melamine, and ultrapure water, heating, and performing secondary calcination and acidification under anaerobic conditions is used to treat the wastewater, with a better phenol removal effect and a simple operation process.

[0054] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A wastewater treatment process for pharmaceutical intermediates, characterized in that, It includes the following preparation steps: (1) Adjust the pH and phenol concentration of the pharmaceutical intermediate wastewater; (2) Under normal temperature and pressure, in the dark and with stirring, add a composite catalyst to the wastewater in step (1), mix and disperse evenly, and then stir and react for 55 - 65 min under light conditions.

2. The pharmaceutical intermediate wastewater treatment process according to claim 1, wherein, The pH of the pharmaceutical intermediate wastewater is adjusted to 3 - 11; the phenol concentration in the pharmaceutical intermediate wastewater is adjusted to 10 - 40 mg / L.

3. The pharmaceutical intermediate wastewater treatment process according to claim 1, characterized in that, The dosage of the composite catalyst in the pharmaceutical intermediate wastewater is 0.2 - 0.4 g / L.

4. The pharmaceutical intermediate wastewater treatment process according to claim 1, characterized in that, The wavelength of the light source is greater than 420 nm.

5. The pharmaceutical intermediate wastewater treatment process according to claim 1, characterized in that, The preparation steps of the composite catalyst are as follows: A1. Weigh soluble cobalt salt, soluble copper salt, tetraethyl orthosilicate, ethanol, and ultrapure water and mix them evenly to obtain solution A; A2. Weigh alkaline solution B; A3. Under stirring conditions, add alkaline solution B dropwise to solution A at a dropping rate of 1 drop / s. After reacting for 4.5 - 5.5 h, pour it into a petri dish and place it in an oven to dry at 60 °C until a gel is formed. Then place it in a muffle furnace and calcine at 600 °C for 3 h to obtain a catalyst blank; A4. Mix oxalic acid, catalyst blank, and ultrapure water for 4 - 6 min, then add melamine and continue stirring for 25 - 35 min. Subsequently, transfer it to a stainless - steel autoclave lined with polytetrafluoroethylene, seal it, and heat it at 105 - 115 °C for 23 - 25 h. After natural cooling to room temperature, wash it with deionized water 2 - 4 times, dry it at 88 - 92 °C for 2.5 - 3.5 h, then place it in a tubular furnace purged with high - purity nitrogen for secondary calcination. After cooling to room temperature, obtain a composite catalyst blank; A5. Disperse 4.8 - 5.2 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution, stir and disperse for 6 - 6. The pharmaceutical intermediate wastewater treatment process according to claim 5, wherein, ​ 7. The pharmaceutical intermediate wastewater treatment process according to claim 5, characterized in that, ​ 8. The pharmaceutical intermediate wastewater treatment process according to claim 5, wherein, ​ 9. The pharmaceutical intermediate wastewater treatment process according to claim 5, characterized in that, ​

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