A pharmaceutical intermediate wastewater treatment process

Abstract

The invention discloses a pharmaceutical intermediate wastewater treatment process, which belongs to the technical field of pharmaceutical intermediate wastewater treatment. The pharmaceutical intermediate wastewater treatment process of the invention comprises the following specific steps: (1) adjusting the pH value and phenol concentration of the pharmaceutical intermediate wastewater; (2) adding a composite catalyst to the wastewater in step (1) under normal temperature and pressure, light-proof and stirring conditions, mixing and dispersing the mixture uniformly, and then stirring and reacting the mixture under light conditions for 55 to 65 minutes; the composite catalyst 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 solvent to form a catalyst blank; the catalyst blank is then mixed with oxalic acid, melamine and ultrapure water, heated, and subjected to secondary calcination under anaerobic conditions and then acidified to obtain the catalyst blank; the pharmaceutical intermediate wastewater treatment process of the invention can effectively remove organic pollutants in the pharmaceutical intermediate wastewater.

Description

Technical Field

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

[0002] Phenol, a key organic compound, is widely used in today's chemical and pharmaceutical industries. Its chemical formula is C2H6O, also known as carbolic acid. It is primarily produced through the oxidation and decomposition of cumene. It is not only a crucial 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 combined functions as a solvent and disinfectant. Phenol is a core raw material in the synthesis of numerous fungicides, preservatives, and pharmaceuticals such as aspirin.

[0003] However, phenol's powerful penetrating power and toxicity also pose significant risks to humans and the ecological environment. It can directly penetrate the skin and mucous membranes, reacting with proteins within human cells, causing them to denature and coagulate, rendering them inactive and ultimately leading to tissue necrosis. Phenol is also toxic to all living things. While it has a bactericidal effect at low concentrations (0.2 g / L), with approximately 1% killing common bacteria and 1.3% killing fungi, the consequences of discharging untreated phenol wastewater into water bodies are disastrous.

[0004] When phenol-containing wastewater is discharged into water bodies, it can cause the water to stink, impacting fish reproduction, reducing the quality of aquatic products, and even rendering them unusable due to a phenolic odor. High concentrations of phenol (6.5-9.3 g / L) entering water bodies can poison and kill fish, even leading to extinction and severe damage to biodiversity. If phenol levels exceed 100 g / L in water, using it for irrigation can kill crops and lead to significant yield losses.

[0005] The production of pharmaceutical intermediates generates large amounts of phenol-containing wastewater. To prevent the hazards described above, these wastewaters must be treated to effectively remove phenol. However, some current treatment processes are complex and expensive. Therefore, developing a simple, yet effective, treatment process for removing phenol from pharmaceutical intermediate wastewater is urgently needed. Summary of the Invention

[0006] The purpose of the present invention is to provide a pharmaceutical intermediate wastewater treatment process to solve the technical problems mentioned in the above background technology.

[0007] The technical solution for achieving the purpose of the present invention is:

[0008] The present invention provides a pharmaceutical intermediate wastewater treatment process, comprising the following preparation steps:

[0009] (1) Adjust the pH and phenol concentration of pharmaceutical intermediate wastewater;

[0010] (2) Under normal temperature and pressure, in the dark and with stirring, add the composite catalyst to the wastewater in step (1), mix and disperse evenly, and then stir and react for 55 to 65 minutes under light conditions.

[0011] The pharmaceutical intermediate wastewater treatment process of the present invention uses a composite catalyst to treat the wastewater under a light environment and normal temperature and pressure conditions, can effectively remove phenol therein, and has a simple operation process.

[0012] Furthermore, the pH of the pharmaceutical intermediate wastewater is controlled to 3-11; and the phenol concentration in the pharmaceutical intermediate wastewater is controlled to 10-40 mg / L.

[0013] The pharmaceutical intermediate wastewater treatment process of the present invention is suitable for treating pharmaceutical intermediate wastewater with a wide pH range and has strong adaptability.

[0014] Furthermore, the usage of the composite catalyst in pharmaceutical intermediate wastewater is 0.2-0.4 g / L.

[0015] In the pharmaceutical intermediate wastewater treatment process of the present invention, phenol contained in the pharmaceutical intermediate wastewater can be effectively removed with a small amount of catalyst used, and has the advantages of high efficiency and economy.

[0016] Furthermore, the wavelength of the illumination light source is greater than 420 nm.

[0017] The light source used in the pharmaceutical intermediate wastewater treatment process of the present invention has a wavelength greater than 420 nm, is easy to obtain, and is convenient for practical application and promotion.

[0018] Furthermore, the preparation steps of the composite catalyst are as follows:

[0019] A1. Weigh a soluble cobalt salt, a soluble copper salt, ethyl tetrasilicate, ethanol, and ultrapure water and mix them to obtain solution A.

[0020] A2. Weigh alkaline solution B;

[0021] A3. Alkaline solution B was added dropwise to solution A at a rate of 1 drop / s under stirring. After reacting for 4.5–5.5 h, the mixture was placed in a Petri dish and dried in an oven at 60°C until a gel formed. The mixture was then calcined in a muffle furnace at 600°C for 3 h to obtain a catalyst blank.

[0022] A4. Oxalic acid, the catalyst blank, and ultrapure water were mixed for 4–6 minutes, followed by the addition of melamine and continued stirring for 25–35 minutes. The mixture was then transferred to a Teflon-lined stainless steel autoclave, sealed, and heated at 105–115°C for 23–25 hours. After cooling to room temperature, the mixture was washed two to four times with deionized water and dried at 88–92°C for 2.5–3.5 hours. The mixture was then placed in a tubular furnace purged with high-purity nitrogen for a second calcination. After cooling to room temperature, the composite catalyst blank was obtained.

[0023] A5. Disperse 4.8-5.2 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution and stir for 6-12 hours to obtain a suspension. Add ultrapure water to dilute the suspension to 1 L. Filter the suspension and wash the filter residue with deionized water until neutral. Dry at 88-92°C to obtain the composite catalyst.

[0024] Furthermore, the molar volume ratio of the soluble cobalt salt, the soluble copper salt and the ultrapure water in the solution A is 1 mmol:1 mmol:3 mL; and the volume ratio of the ethyl tetrasilicate, ethanol and the ultrapure water is 0.14-0.16:3:1.

[0025] 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.

[0026] Furthermore, the mass ratio of the oxalic acid, the catalyst blank, the ultrapure water and the melamine is 0.25:1.8~1.84:50:0.58~0.6.

[0027] Furthermore, the specific steps of the secondary calcination process are as follows: first, heating from room temperature to 500-600°C at a heating rate of 2°C / min, then calcining for 3.5-4.5 hours, cooling to room temperature, and then heating from room temperature to 450-550°C at a heating rate of 5°C / min, and keeping warm for 2.5-3.5 hours.

[0028] By adopting the above technical solution, the present invention has the following beneficial effects:

[0029] (1) The pharmaceutical intermediate wastewater treatment process of the present invention uses a composite catalyst to treat the wastewater under a light environment and normal temperature and pressure conditions, which can effectively remove phenol therein and has a simple operation process.

[0030] (2) The pharmaceutical intermediate wastewater treatment process of the present invention is suitable for treating pharmaceutical intermediate wastewater with a wide pH range and has strong adaptability.

[0031] (3) The pharmaceutical intermediate wastewater treatment process of the present invention can effectively remove phenol contained in the pharmaceutical intermediate wastewater with a small amount of catalyst, which has the advantages of high efficiency and economy.

[0032] (4) The wavelength of the light source used in the pharmaceutical intermediate wastewater treatment process of the present invention is greater than 420 nm. The light source is easy to obtain and is convenient for practical application and promotion.

[0033] (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

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] Water-soluble cobalt salt: cobalt nitrate, analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0039] Water-soluble copper salt: copper nitrate, analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0040] Hydrogen peroxide was of analytical grade and purchased from Sinopharm Chemical Reagent Co., Ltd.

[0041] The light source used was a 300W xenon lamp equipped with a cut-off filter above 400 nm to simulate sunlight, and a 420 nm filter was added to simulate visible light.

[0042] Example 1

[0043] A pharmaceutical intermediate wastewater treatment process comprises the following preparation steps:

[0044] (1) Take 100 mL of phenol solution with a pH of 7 and a concentration of 10 mg / L as pharmaceutical intermediate wastewater;

[0045] (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 under light conditions for 55 minutes.

[0046] Furthermore, the preparation steps of the composite catalyst are as follows:

[0047] A1. Weigh 10 mmol of a soluble cobalt salt, 10 mL of a soluble copper salt, 4.5 mL of ethyl tetrasilicate, 90 mL of ethanol, and 30 mL of ultrapure water and mix thoroughly to obtain solution A.

[0048] A2. Weigh 20 mL of 30 wt% aqueous ammonia as alkaline solution B;

[0049] A3. Under stirring conditions, alkaline solution B was added dropwise to solution A at a rate of 1 drop / s. After reacting for 4.5 hours, the mixture was placed in a Petri dish and dried in an oven at 60°C until a gel formed. The mixture was then calcined in a muffle furnace at 600°C for 3 hours to obtain a catalyst blank.

[0050] A4. After mixing oxalic acid, catalyst blank, and ultrapure water for 4 minutes, melamine was added and stirring was continued for 25 minutes. The mixture was then transferred to a polytetrafluoroethylene-lined stainless steel autoclave, sealed, and heated at 105°C for 23 hours. After naturally cooling to room temperature, the mixture was washed twice with deionized water and dried at 88°C for 2.5 hours. The mixture was then placed in a tubular furnace purged with high-purity nitrogen and heated from room temperature to 500°C at a heating rate of 2°C / min. The mixture was then calcined for 3.5 hours, cooled to room temperature, and then heated from room temperature to 450°C at a heating rate of 5°C / min. The mixture was kept warm for 2.5 hours and cooled to room temperature to obtain a composite catalyst blank. The mass ratio of oxalic acid, catalyst blank, ultrapure water, and melamine was 0.25:1.8:50:0.58.

[0051] A5. Disperse 4.8 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution and stir for 6 h to obtain a suspension. Add ultrapure water to dilute the suspension to 1 L, then filter. Wash the filter residue with deionized water until neutral, and dry at 88°C to obtain the composite catalyst.

[0052] Example 2

[0053] A pharmaceutical intermediate wastewater treatment process comprises the following preparation steps:

[0054] (1) Take 100 mL of phenol solution with a pH of 7 and a concentration of 10 mg / L as pharmaceutical intermediate wastewater;

[0055] (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 minutes under light conditions.

[0056] Furthermore, the preparation steps of the composite catalyst are as follows:

[0057] A1. Weigh 10 mmol of a soluble cobalt salt, 10 mL of a soluble copper salt, 4.5 mL of ethyl tetrasilicate, 90 mL of ethanol, and 30 mL of ultrapure water and mix thoroughly to obtain solution A.

[0058] A2. Weigh 20 mL of 30 wt% aqueous ammonia as alkaline solution B;

[0059] A3. Alkaline solution B was added dropwise to solution A at a rate of 1 drop / s under stirring. After 5 hours of reaction, the mixture was placed in a Petri dish and dried in an oven at 60°C until a gel formed. The mixture was then calcined in a muffle furnace at 600°C for 3 hours to obtain a catalyst blank. The main components were copper oxide, silicon dioxide, and cobalt tetroxide. The specific surface area of ​​the catalyst blank was 11.668 m 2 / g, the average pore diameter is 28.495nm, and the average pore volume is 0.087cm 3 / g;

[0060] A4. After mixing oxalic acid, catalyst blank, and ultrapure water for 5 minutes, melamine was added and stirring was continued for 30 minutes. The mixture was then transferred to a polytetrafluoroethylene-lined stainless steel autoclave, sealed, and heated at 110°C for 24 hours. After naturally cooling to room temperature, the mixture was washed three times with deionized water and dried at 90°C for 3 hours. The mixture was then placed in a tubular furnace purged with high-purity nitrogen and heated from room temperature to 550°C at a heating rate of 2°C / min. The mixture was then calcined for 4 hours, cooled to room temperature, and then heated from room temperature to 500°C at a heating rate of 5°C / min. The mixture was kept warm for 3 hours and cooled to room temperature to obtain a composite catalyst blank. The mass ratio of oxalic acid, catalyst blank, ultrapure water, and melamine was 0.25:1.82:50:0.59.

[0061] A5. Disperse 5 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution and stir for 10 h to obtain a suspension. Add ultrapure water to dilute the suspension to 1 L, then filter. Wash the filter residue with deionized water until neutral, and dry at 90°C to obtain the composite catalyst.

[0062] Example 3

[0063] A pharmaceutical intermediate wastewater treatment process comprises the following preparation steps:

[0064] (1) Take 100 mL of phenol solution with a pH of 7 and a concentration of 10 mg / L as pharmaceutical intermediate wastewater;

[0065] (2) At room 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 minutes under light conditions.

[0066] Furthermore, the preparation steps of the composite catalyst are as follows:

[0067] A1. Weigh 10 mmol of a soluble cobalt salt, 10 mL of a soluble copper salt, 4.5 mL of ethyl tetrasilicate, 90 mL of ethanol, and 30 mL of ultrapure water and mix thoroughly to obtain solution A.

[0068] A2. Weigh 20 mL of 30 wt% aqueous ammonia as alkaline solution B;

[0069] A3. Under stirring conditions, alkaline solution B was added dropwise to solution A at a rate of 1 drop / s. After reacting for 5.5 h, the mixture was placed in a Petri dish and dried in an oven at 60°C until a gel formed. The mixture was then calcined in a muffle furnace at 600°C for 3 h to obtain a catalyst blank.

[0070] A4. After mixing oxalic acid, catalyst blank, and ultrapure water for 6 minutes, melamine was added and stirring was continued for 35 minutes. The mixture was then transferred to a polytetrafluoroethylene-lined stainless steel autoclave, sealed, and heated at 115°C for 25 hours. After cooling naturally to room temperature, the mixture was washed four times with deionized water and dried at 92°C for 3.5 hours. The mixture was then placed in a tubular furnace purged with high-purity nitrogen and heated from room temperature to 600°C at a heating rate of 2°C / min. The mixture was then calcined for 4.5 hours, cooled to room temperature, and then heated from room temperature to 550°C at a heating rate of 5°C / min. The mixture was kept at this temperature for 3.5 hours. After cooling to room temperature, a composite catalyst blank was obtained. The mass ratio of oxalic acid, catalyst blank, ultrapure water, and melamine was 0.25:1.84:50:0.6.

[0071] A5. Disperse 5.2 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution and stir for 12 h to obtain a suspension. Add ultrapure water to dilute the suspension to 1 L, then filter. Wash the filter residue with deionized water until neutral, and dry at 92°C to obtain the composite catalyst.

[0072] Comparative Example 1

[0073] Comparative Example 1 differs from Example 2 in that the composite catalyst is prepared using only a sol-gel method with soluble cobalt salt, soluble copper salt, ethyl acetate, ethanol, and ultrapure water as the initial reactants and solvent. The specific steps are as follows: A1. Weigh 10 mmol of soluble cobalt salt, 10 mL of soluble copper salt, 4.5 mL of ethyl tetrasilicate, 90 mL of ethanol, and 30 mL of ultrapure water and mix them uniformly to obtain solution A;

[0074] A2. Weigh 20 mL of 30 wt% aqueous ammonia as alkaline solution B;

[0075] A3. Alkaline solution B was added dropwise to solution A at a rate of 1 drop / s under stirring. After 5 hours of reaction, the mixture was placed in a Petri dish and dried in an oven at 60°C until a gel formed. The mixture was then calcined in a muffle furnace at 600°C for 3 hours to obtain a composite catalyst. The main components were copper oxide, silicon dioxide, and cobalt tetroxide. The specific surface area of ​​the composite catalyst was 11.668 m 2 / g, the average pore diameter is 28.495nm, and the average pore volume is 0.087cm 3 / g; the remaining components, steps and amounts are the same as those in Example 2.

[0076] Comparative Example 2

[0077] The difference between Comparative Example 2 and Comparative Example 1 lies in step (2). Step (2) is as follows: 30 mg of the composite catalyst and 1.5 mL of hydrogen peroxide are added to the wastewater in step (1) under normal temperature and pressure, in the dark, and with stirring, and the mixture is mixed and dispersed uniformly. The mixture is then stirred and reacted for 60 minutes under light illumination. The remaining components, steps, and amounts are the same as those in Example 2.

[0078] Comparative Example 3

[0079] The difference between Comparative Example 3 and Example 2 is that the composite catalyst is prepared as follows: 0.25 g of oxalic acid, 0.5 g of melamine and 0.40 parts by mass of cobalt nitrate are sequentially added to a beaker containing 50 mL of distilled water, and the resulting solution is stirred at room temperature for 30 min. min, then transferred to a polytetrafluoroethylene-lined stainless steel autoclave, sealed and heated at 110 ° C for 24 h, naturally cooled to room temperature, washed three times with deionized water, and then dried in an air drying oven at 90 ° C for 3 h, and then the dried solid was placed in a tubular furnace purged with high-purity nitrogen and heated from room temperature to 550 ° C at a heating rate of 2 ° C / min, then calcined for 4 h, cooled to room temperature, and then heated from room temperature to 500 ° C at a heating rate of 5 ° C / min, kept warm for 3 h, and cooled to room temperature to obtain a composite catalyst blank; 5 parts by mass of the composite catalyst blank were dispersed in 100 mL of 65% nitric acid solution, stirred and dispersed for 12 h to obtain a suspension, ultrapure water was added to dilute the suspension to a volume of 1 L, then filtered, the filter residue was washed with deionized water to neutrality, and dried at 90 ° C to obtain a composite catalyst; the remaining components, steps, and amounts were the same as in Example 2.

[0080] Comparative Example 4

[0081] The difference between Comparative Example 4 and Example 2 is that the preparation steps of the composite catalyst are as follows:

[0082] A1. Weigh 10 mmol of a soluble cobalt salt, 10 mL of a soluble copper salt, 4.5 mL of ethyl tetrasilicate, 90 mL of ethanol, and 30 mL of ultrapure water and mix thoroughly to obtain solution A.

[0083] A2. Weigh 20 mL of 30 wt% aqueous ammonia as alkaline solution B;

[0084] A3. Alkaline solution B was added dropwise to solution A at a rate of 1 drop / s under stirring. After 5 hours of reaction, the mixture was placed in a Petri dish and dried in an oven at 60°C until a gel formed. The mixture was then calcined in a muffle furnace at 600°C for 3 hours to obtain a catalyst blank. The main components were copper oxide, silicon dioxide, and cobalt tetroxide. The specific surface area of ​​the catalyst blank was 11.668 m 2 / g, the average pore diameter is 28.495nm, and the average pore volume is 0.087cm 3 / g;

[0085] A4. After mixing oxalic acid, catalyst blank, and ultrapure water for 5 minutes, melamine was added and stirring was continued for 30 minutes. The mixture was then transferred to a polytetrafluoroethylene-lined stainless steel autoclave, sealed, and heated at 110°C for 24 hours. After cooling naturally to room temperature, the mixture was washed three times with deionized water and dried at 90°C for 3 hours. The mixture was then placed in a tubular furnace purged with high-purity nitrogen and heated from room temperature to 550°C at a heating rate of 5°C / min, followed by calcination for 4 hours to obtain a composite catalyst; wherein the mass ratio of oxalic acid, catalyst blank, ultrapure water, and melamine was 0.25:1.82:50:0.59; the remaining components, steps, and amounts were the same as in Example 2.

[0086] Comparative Example 5

[0087] The difference between Comparative Example 5 and Example 2 lies in step (2). Step (2) is as follows: 30 mg of the composite catalyst is added to the wastewater of step (1) under normal temperature and pressure, in the dark, and with stirring, and the mixture is mixed and dispersed uniformly, followed by stirring and reacting for 60 minutes; the remaining components, steps, and amounts are the same as those in Example 2.

[0088] Effect Examples

[0089] High performance liquid chromatography was used to quantitatively analyze the removal rate of phenol solution after 60 minutes of treatment by the pharmaceutical intermediate wastewater treatment process. The actual data are shown in Table 1 below:

[0090] Table 1

[0091]

[0092] As can be seen from Table 1 above, phenol was completely removed by the pharmaceutical intermediate wastewater treatment processes of Examples 1 to 3.

[0093] The difference between Comparative Example 1 and Example 2 is that the composite catalyst is prepared only by the sol-gel method with soluble cobalt salt, soluble copper salt, ethyl acetate, ethanol, and ultrapure water as initial reactants and solvents. The phenol removal effect of the composite catalyst in Comparative Example 1 in the pharmaceutical intermediate wastewater treatment process is not ideal.

[0094] The difference between Comparative Example 2 and Example 2 is that the composite catalyst is prepared only by the sol-gel method with soluble cobalt salt, soluble copper salt, ethyl acetate, ethanol, and ultrapure water as initial reactants and solvents, and 1.5 mL of hydrogen peroxide is introduced in the pharmaceutical intermediate wastewater treatment process. Compared with Comparative Example 1, the hydrogen peroxide introduced 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 joint action of hydrogen peroxide to remove organic pollutants.

[0095] The difference between Comparative Example 3 and Example 2 is that the composite catalyst is obtained by a hydrothermal method through a hydrothermal reaction of oxalic acid, melamine and cobalt nitrate followed by secondary calcination and acidification. The phenol removal effect of the composite catalyst of Comparative Example 1 in the pharmaceutical intermediate wastewater treatment process is significantly inferior to the phenol removal effect of Examples 1 to 3.

[0096] The difference between Comparative Example 4 and Example 2 is that the composite catalyst is obtained by traditional primary calcination without secondary calcination and acidification. A large amount of graphite phase carbon nitride is coated on the pores and surface of the catalyst blank, which prevents phenol from fully and closely contacting the active sites in the catalyst, resulting in a significant decrease in the phenol removal effect.

[0097] The difference between Comparative Example 5 and Example 2 is that no illumination is performed during the pharmaceutical intermediate wastewater treatment process. The phenol removal rate of Comparative Example 5 is higher than that of Comparative Example 1 and Comparative Example 3. This may be because the catalyst blank is coated with the mesoporous graphite phase carbon nitride, which enhances the phenol removal effect of the composite catalyst. However, compared with Example 2, the phenol removal effect is significantly worse, indicating that the phenol removal effect of the composite catalyst is significantly enhanced under illumination conditions.

[0098] In summary, the pharmaceutical intermediate wastewater treatment process of the present invention adopts a sol-gel method under light environment and normal temperature and pressure conditions, firstly using soluble cobalt salt, soluble copper salt, ethyl acetate, ethanol, and ultrapure water as initial reactants and solvent to prepare a catalyst blank whose main components are cobalt trioxide, copper oxide, and silicon oxide and has a large number of micropores and mesoporous structures; then the catalyst blank is mixed with oxalic acid, melamine, and ultrapure water, heated, and secondary calcined under anaerobic conditions and then acidified to obtain a composite catalyst for treating wastewater, which has better phenol removal effect and simple operation process.

[0099] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pharmaceutical intermediate wastewater treatment process, characterized in that: The method comprises the following preparation steps: (1) Adjust the pH and phenol concentration of pharmaceutical intermediate wastewater; (2) Add the composite catalyst to the wastewater in step (1) at room temperature and pressure, in the dark, and with stirring, mix and disperse evenly, and then stir and react for 55 to 65 minutes under light conditions; The preparation steps of the composite catalyst are as follows: A1. Weigh a soluble cobalt salt, a soluble copper salt, ethyl tetrasilicate, ethanol, and ultrapure water and mix them to obtain solution A. A2. Weigh alkaline solution B; A3. Alkaline solution B was added dropwise to solution A at a rate of 1 drop / s under stirring. After reacting for 4.5–5.5 h, the mixture was placed in a Petri dish and dried in an oven at 60°C until a gel formed. The mixture was then calcined in a muffle furnace at 600°C for 3 h to obtain a catalyst blank. A4. Oxalic acid, the catalyst blank, and ultrapure water were mixed for 4–6 minutes, followed by the addition of melamine and continued stirring for 25–35 minutes. The mixture was then transferred to a Teflon-lined stainless steel autoclave, sealed, and heated at 105–115°C for 23–25 hours. After cooling to room temperature, the mixture was washed two to four times with deionized water and dried at 88–92°C for 2.5–3.5 hours. The mixture was then placed in a tubular furnace purged with high-purity nitrogen for a second calcination. After cooling to room temperature, the composite catalyst blank was obtained. A5. Disperse 4.8-5.2 parts by mass of the composite catalyst blank in 100 mL of 65% nitric acid solution and stir for 6-12 hours to obtain a suspension. Add ultrapure water to dilute the suspension to 1 L. Filter the suspension and wash the filter residue with deionized water until neutral. Dry at 88-92°C to obtain the composite catalyst.

2. The pharmaceutical intermediate wastewater treatment process according to claim 1, characterized in that: The pH of the pharmaceutical intermediate wastewater is adjusted to 3-11; and 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 usage of the composite catalyst in 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 illumination light source is greater than 420 nm.

5. The pharmaceutical intermediate wastewater treatment process according to claim 1, characterized in that: The molar volume ratio of the soluble cobalt salt, the soluble copper salt and the ultrapure water in the solution A is 1 mmol:1 mmol:3 mL; the volume ratio of the ethyl tetrasilicate, ethanol and the ultrapure water is 0.14-0.16:3:

1.

6. The pharmaceutical intermediate wastewater treatment process according to claim 1, characterized in that: 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.

7. The pharmaceutical intermediate wastewater treatment process according to claim 1, characterized in that: The mass ratio of the oxalic acid, the catalyst blank, the ultrapure water and the melamine is 0.25:1.8-1.84:50:0.58-0.

6.

8. The pharmaceutical intermediate wastewater treatment process according to claim 1, characterized in that: The specific steps of the secondary calcination process are as follows: first, heating from room temperature to 500-600°C at a heating rate of 2°C / min, then calcining for 3.5-4.5 hours, cooling to room temperature, and then heating from room temperature to 450-550°C at a heating rate of 5°C / min, and keeping warm for 2.5-3.5 hours.