A wastewater treatment process for p-aminophenol production

Abstract

The application discloses a kind of wastewater treatment processes for p-aminophenol production, belong to p-aminophenol wastewater treatment technical field.First by graphene, anion exchange resin and hyperbranched polyether amine as raw material, prepared adsorption material, to wastewater is first step processing, reduce the content of TOC and metal ion, then through Fenton process second step processing, make hydrogen peroxide and ferrous ion reaction produce strong oxidizing hydroxyl radical, to attack difficult degradation organic matter chemical bond, and reduce COD in wastewater, reduce the harm to environment, finally into ceramic membrane filtration, ceramic membrane has good performance in wastewater treatment, by cross-flow filtration mode, can long-term stable in wastewater separation pollutant, complete p-aminophenol production wastewater treatment process.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a wastewater treatment process for the production of p-aminophenol. Background Technology

[0002] p-Aminophenol is an important organic intermediate with wide applications in pharmaceuticals, dyes, and rubber. It is also a raw material for the preparation of acetaminophen, a well-known antipyretic and analgesic drug. The production of p-aminophenol generates large amounts of high-concentration phenol-containing wastewater. Phenols are highly hazardous compounds; even at very low concentrations, they can cause gene mutations and are carcinogenic. They are difficult to degrade naturally, persisting in the environment for extended periods and accumulating in the food chain. Therefore, countries have strict limits on the concentration of phenols in wastewater. p-Aminophenol possesses the dual toxicity of aniline and phenol; skin absorption can cause dermatitis, methemoglobinemia, and asthma. In Europe, p-Aminophenol is classified as a hazardous substance. The wastewater from p-Aminophenol production generates large amounts of organic matter, particularly in the byproduct brine (NaCl solution). Direct discharge of this wastewater without treatment can easily cause environmental pollution and ecological damage. Therefore, developing an efficient and environmentally friendly wastewater treatment process for p-Aminophenol production is of great significance for achieving sustainable industrial development.

[0003] Chinese patent application CN1803641A discloses an integrated process for treating wastewater from the production of p-aminophenol and for resource recovery. The wastewater is treated by adjusting its pH value, selectively adsorbing p-aminophenol with an amine-modified composite functional resin, and then chemically oxidizing the wastewater. This wastewater has a high organic content and metal ions that are difficult to meet emission standards. Summary of the Invention

[0004] The purpose of this invention is to provide a wastewater treatment process for the production of p-aminophenol, so as to solve the problems of high organic content and difficulty in meeting emission standards for metal ions after existing wastewater treatment.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A wastewater treatment process for the production of p-aminophenol includes the following steps:

[0007] S1. Graphene oxide was prepared by the Hummers method. The obtained graphene oxide was poured into an ethanol solution (mass fraction of 3%) and ultrasonically dispersed in an ice-water bath at a power of 300-500w for 50-90min. Then hyperbranched polyetheramine was added and the mixture was stirred in an oil bath at 85-95℃ for 6-8h. After cooling, washing 5-8 times, and drying, hyperbranched polyetheramine-grafted graphene oxide was obtained.

[0008] Hyperbranched polyetheramine-grafted graphene oxide was ground and placed in acetone, then ultrasonically dispersed in an ice bath at a power of 300-500W for 3-4 hours. The mixture was then poured into a pretreated anion exchange resin and stirred at 55-65℃ for 10-20 hours. After cooling to 20-35℃, the mixture was dried in a vacuum oven to obtain the adsorbent material.

[0009] S2. Adjust the pH of the wastewater used in the production of p-aminophenol to 8-9 using a 15wt% sodium hydroxide solution. Add 10g of adsorbent material to each liter of wastewater used in the production of p-aminophenol. After standing for 1-2 hours, filter the wastewater through a 0.45μm filter membrane to obtain primary wastewater.

[0010] S3. The obtained primary wastewater is adjusted to pH 2-3 with 1 mol / L sulfuric acid solution and then fed into the primary Fenton reactor. Ferrous sulfate is added for the first time at 20-35℃, followed by hydrogen peroxide. The reaction is carried out for 3-6 hours to obtain secondary wastewater. The secondary wastewater is then fed into the second Fenton reactor. Ferrous sulfate is added for the second time at 20-35℃ and the reaction is carried out for 1-3 hours. The pH is then adjusted to 8-9 with 15% sodium hydroxide solution to allow precipitation. The filtrate is then filtered through a ceramic membrane to complete the wastewater treatment process for p-aminophenol production.

[0011] Furthermore, the mass ratio of graphene oxide to hyperbranched polyetheramine is 1:25-40.

[0012] Furthermore, the mass ratio of hyperbranched polyetheramine-grafted graphene to pretreated anion exchange resin is 1:3-5.

[0013] Furthermore, the anion exchange resin includes any one or more of KIP209, NG-6, and KIP210.

[0014] Furthermore, the molar ratio of ferrous sulfate added in the first and second additions to hydrogen peroxide is 0.2:0.8:1.2-2, and the dosage ratio of primary wastewater to hydrogen peroxide is 1L:0.5g.

[0015] Further, the preparation method of the pretreated anion exchange resin is as follows: the anion exchange resin is soaked in distilled water for 20-36 hours, then soaked in hydrochloric acid solution (mass fraction of 4%) and sodium hydroxide solution (mass fraction of 2%) for 20-36 hours respectively, washed until neutral, and filtered to obtain the pretreated anion exchange resin.

[0016] Furthermore, the ceramic membrane has a pore size of 40-80 nm, a membrane surface flow rate of 3-4.6 m / s, and a wastewater temperature of 8-12 °C during filtration.

[0017] Furthermore, hyperbranched polyetheramines are prepared by the following steps:

[0018] Polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and 2,4-diaminobutyric acid were added to anhydrous ethanol and stirred at 58-70°C for 9-12 hours. The mixture was then distilled under reduced pressure, washed in an organic solvent, and dried under vacuum for 12-18 hours to obtain hyperbranched polyetheramine.

[0019] Furthermore, the molar ratio of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and 2,4-diaminobutyric acid is 0.8-1.2:0.8-1.2:1, and the number-average molecular weight of polypropylene glycol diglycidyl ether is 640.

[0020] Furthermore, the organic solvent includes any one or more of cyclohexane, n-hexane, and n-heptane.

[0021] The beneficial effects of this invention are:

[0022] 1. This invention provides a wastewater treatment process for the production of p-aminophenol. First, an adsorbent material is prepared using graphene, anion exchange resin, and polyetheramine as raw materials to treat the wastewater in the first step, reducing the content of TOC and metal ions. Then, a second step of treatment is performed using the Fenton process, which causes hydrogen peroxide and ferrous ions to react and generate highly oxidizing hydroxyl radicals to attack the chemical bonds of recalcitrant organic compounds, thereby reducing COD in the wastewater and minimizing environmental harm. Finally, the wastewater is filtered through a ceramic membrane. Ceramic membranes exhibit excellent performance in wastewater treatment, and through cross-flow filtration, they can achieve long-term stable separation in wastewater, thus completing the wastewater treatment process for p-aminophenol production.

[0023] 2. In this invention, polyetheramines containing amino, hydroxyl, and carboxyl groups are grafted onto the surface of graphene oxide, which helps to improve the dispersibility of graphene oxide in resin. When treating wastewater, the large specific surface area and high conductivity of graphene can provide more active sites and electron transport channels for ion exchange, thereby improving the reaction rate and adsorption capacity of the composite material in the ion exchange process. The π-π electron conjugation effect on the hyperbranched polyetheramine grafted graphene oxide can achieve efficient adsorption of phenol, while the anion exchange resin can further remove phenol ions from the solution through ion exchange, resulting in a synergistic effect when combined.

[0024] 3. In this invention, the epoxy groups of polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether and the amino group of 2,4-diaminobutyric acid undergo a ring-opening reaction to form a hyperbranched polymer. The three-dimensional network-like hyperbranched polyetheramine is grafted onto the graphene surface to form a uniform coating layer, which effectively separates the graphene sheets and more effectively adsorbs pollutants in wastewater. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] 10g of KIP209 resin was soaked in 50mL of distilled water for 20h, then soaked in 100mL of hydrochloric acid solution (4wt%) and 100mL of sodium hydroxide solution (2wt%) for 20h respectively. After washing until neutral, the resin was filtered to obtain pretreated KIP209 exchange resin.

[0028] Example 2

[0029] 10g of KIP209 resin was soaked in 50mL of distilled water for 36h, then soaked in 150mL of hydrochloric acid solution (4wt%) and 150mL of sodium hydroxide solution (2wt%) for 36h respectively, washed until neutral, and filtered to obtain pretreated KIP209 exchange resin.

[0030] Example 3

[0031] Hyperbranched polyetheramines are prepared by the following steps:

[0032] 1.6 mol of polyethylene glycol diglycidyl ether, 1.6 mol of polypropylene glycol diglycidyl ether, and 2 mol of 2,4-diaminobutyric acid were added to 50 mL of anhydrous ethanol and stirred at 58 °C for 9 h. The mixture was then distilled under reduced pressure, washed in 100 mL of n-hexane, and dried under vacuum for 12 h to obtain hyperbranched polyetheramine.

[0033] Example 4

[0034] Hyperbranched polyetheramines are prepared by the following steps:

[0035] 2.4 mol of polyethylene glycol diglycidyl ether, 2.4 mol of polypropylene glycol diglycidyl ether, and 2 mol of 2,4-diaminobutyric acid were added to 50 mL of anhydrous ethanol and stirred at 70 °C for 12 h. The mixture was then distilled under reduced pressure, washed in 100 mL of n-hexane, and dried under vacuum for 18 h to obtain hyperbranched polyetheramine.

[0036] Example 5

[0037] Hyperbranched polyetheramines are prepared by the following steps:

[0038] 1.8 mol of polyethylene glycol diglycidyl ether, 2.2 mol of polypropylene glycol diglycidyl ether and 2 mol of 2,4-diaminobutyric acid were added to 50 mL of anhydrous ethanol and stirred at 68 °C for 10 h. The mixture was then distilled under reduced pressure, washed in 100 mL of n-hexane, and dried under vacuum for 15 h to obtain hyperbranched polyetheramine.

[0039] Example 6

[0040] A wastewater treatment process for the production of p-aminophenol includes the following steps:

[0041] S1. Graphene oxide was prepared by the Hummers method. 0.2 g of the obtained graphene oxide was poured into 2 L of ethanol solution (3 wt%) and ultrasonically dispersed in an ice-water bath at a power of 300 W for 50 min. Then, 5 g of hyperbranched polyetheramine from Example 4 was added and the mixture was stirred and reacted in an oil bath at 85 °C for 6 h. After cooling, washing 5 times, and drying, hyperbranched polyetheramine-grafted graphene oxide was obtained.

[0042] 2.4g of hyperbranched polyetheramine-grafted graphene oxide was ground and placed in 5mL of acetone, and then ultrasonically dispersed in an ice bath at a power of 300W for 3h. 7.2g of KIP209 resin pretreated in Example 2 was stirred at 55℃ for 10h, cooled to 20℃, and dried in a vacuum oven to obtain the adsorbent material.

[0043] S2. Adjust the pH of the wastewater from the production of p-aminophenol to 8 using a 15wt% sodium hydroxide solution. Add 10g of adsorbent material to each liter of wastewater from the production of p-aminophenol. After standing for 1 hour, filter the wastewater through a 0.45μm filter membrane to obtain primary wastewater.

[0044] S3. The obtained primary wastewater is adjusted to pH 2 with 1 mol / L H2SO4 solution and then fed into a primary Fenton reactor. Ferrous sulfate is added for the first time at 20°C, followed by hydrogen peroxide. The reaction is carried out for 3 hours to obtain secondary wastewater. The secondary wastewater is then fed into a second Fenton reactor. Ferrous sulfate is added for the second time at 20°C. The molar ratio of ferrous sulfate added for the first and second times to hydrogen peroxide is controlled at 0.2:0.8:1.2, and the ratio of primary wastewater to hydrogen peroxide is 1L:0.5g. The reaction is carried out for 1 hour, and the pH is adjusted to 8 with 15wt% sodium hydroxide solution to allow precipitation. The filtrate is then filtered through a ceramic membrane with a pore size of 40nm. The flow rate at the membrane surface is 3m / s, and the wastewater temperature during filtration is 8°C. This completes the wastewater treatment process for p-aminophenol production.

[0045] Example 7

[0046] A wastewater treatment process for the production of p-aminophenol includes the following steps:

[0047] Graphene oxide was prepared using the Hummers method. 0.2 g of the obtained graphene oxide was poured into 2 L of ethanol solution (3 wt%) and ultrasonically dispersed in an ice-water bath at a power of 500 W for 90 min. Then, 8 g of hyperbranched polyetheramine from Example 5 was added and the mixture was stirred and reacted in an oil bath at 95 °C for 8 h. After cooling, washing 8 times, and drying, hyperbranched polyetheramine-grafted graphene oxide was obtained.

[0048] 2.4g of hyperbranched polyetheramine-grafted graphene oxide was ground and placed in 5mL of acetone solvent. It was then ultrasonically dispersed in an ice bath at a power of 500W for 4h. 12g of KIP209 resin pretreated in Example 1 was stirred at 65℃ for 20h, cooled to 35℃, and dried in a vacuum oven to obtain the adsorbent material.

[0049] S2. Adjust the pH of the wastewater used in the production of p-aminophenol to 9 using a 15wt% sodium hydroxide solution. Add 10g of adsorbent material to each liter of wastewater used in the production of p-aminophenol. After standing for 2 hours, filter the wastewater through a 0.45μm filter membrane to obtain primary wastewater.

[0050] S3. The obtained primary wastewater is adjusted to pH 3 with 1 mol / L sulfuric acid solution and then fed into a primary Fenton reactor. Ferrous sulfate is added for the first time at 35°C, followed by hydrogen peroxide. The reaction is carried out for 6 hours to obtain secondary wastewater. The secondary wastewater is then fed into a second Fenton reactor. Ferrous sulfate is added for the second time at 35°C. The molar ratio of ferrous sulfate added for the first and second times to hydrogen peroxide is controlled at 0.2:0.8:2, and the ratio of primary wastewater to hydrogen peroxide is 1L:0.5g. The reaction is carried out for 3 hours, and the pH is adjusted to 9 with 15wt% sodium hydroxide solution to allow precipitation. The filtrate is then filtered through a ceramic membrane with a pore size of 80nm. The flow rate at the membrane surface is 4.6m / s, and the wastewater temperature during filtration is 12°C. This completes the wastewater treatment process for p-aminophenol production.

[0051] Example 8

[0052] A wastewater treatment process for the production of p-aminophenol includes the following steps:

[0053] Graphene oxide was prepared using the Hummers method. 0.2 g of the obtained graphene oxide was poured into 2 L of ethanol solution (mass fraction of 3%) and ultrasonically dispersed in an ice-water bath at a power of 400 W for 80 min. Then, 6 g of hyperbranched polyetheramine from Example 3 was added, and the mixture was stirred and reacted in a 90 °C oil bath for 7 h. After cooling, washing 6 times, and drying, hyperbranched polyetheramine-grafted graphene oxide was obtained.

[0054] 2.4 g of hyperbranched polyetheramine-grafted graphene oxide was ground and placed in 5 mL of acetone solvent. It was then ultrasonically dispersed in an ice bath at a power of 400 W for 3.5 h. 8.6 g of pretreated KIP209 resin was stirred at 60 °C for 12 h, cooled to 32 °C, and dried in a vacuum oven to obtain the adsorbent material.

[0055] S2. Adjust the pH of the wastewater used in the production of p-aminophenol to 8.6 using a 15wt% sodium hydroxide solution. Add 10g of adsorbent material to each liter of wastewater used in the production of p-aminophenol. After standing for 1.5h, filter the wastewater through a 0.45μm filter membrane to obtain primary wastewater.

[0056] S3. The obtained primary wastewater is adjusted to pH 2.4 with 1 mol / L sulfuric acid solution and then fed into a primary Fenton reactor. Ferrous sulfate is added for the first time at 30°C, followed by hydrogen peroxide. The reaction is carried out for 4 hours to obtain secondary wastewater. The secondary wastewater is then fed into a second Fenton reactor. Ferrous sulfate is added for the second time at 30°C. The molar ratio of ferrous sulfate added for the first and second times to hydrogen peroxide is controlled at 0.2:0.8:1.6, and the ratio of primary wastewater to hydrogen peroxide is 1L:0.5g. The reaction is carried out for 2 hours, and the pH is adjusted to 8.4 with 15wt% sodium hydroxide solution. Precipitation occurs, and the filtrate is filtered through a ceramic membrane with a pore size of 60nm. The flow rate at the membrane surface is 4m / s, and the wastewater temperature during filtration is 10°C. This completes the wastewater treatment process for p-aminophenol production.

[0057] Comparative Example 1

[0058] Based on Example 7, the hyperbranched polyetheramine in Example 7 was replaced with polyetheramine (from Aladdin Biochemical Technology Co., Ltd., with a relative molecular mass of 230), and the other raw materials and production processes were the same as in Example 7.

[0059] Comparative Example 2

[0060] Based on Example 7, the adsorbent material in Example 7 was replaced with the pretreated anion exchange resin in Example 1, and the remaining raw materials and production process were the same as in Example 7.

[0061] Comparative Example 3

[0062] Based on Example 7, hyperbranched polyetheramine-grafted graphene from Example 7 was used as the adsorbent material, while the remaining raw materials and production process were the same as in Example 7.

[0063] The wastewater from the production of p-aminophenol in a chemical plant in Yangzhou was treated using the treatment processes described in Examples 6-8 and Comparative Examples 1-3. The concentration of p-aminophenol in the original wastewater was 1413 mg / L, and the COD and TOC were 6170 mg / L and 1645 mg / L, respectively. The quality of the effluent was measured after treatment.

[0064] The TOC in the effluent was determined using a Torch combustion autosampler (Teledyne Tekmar, USA).

[0065] According to standard HJ / T399-2007, the COD value is measured, and the COD removal rate is calculated based on this: COD removed (chemical oxygen demand) / COD content in the original wastewater.

[0066] The calcium and magnesium ion contents in the raw wastewater and effluent were determined, and the removal rate was calculated as (raw wastewater content - effluent content) / raw wastewater content. The calcium ion removal rate was Q1, and the magnesium ion removal rate was Q2. The results are shown in Table 1.

[0067] Table 1

[0068] project Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Comparative Example 3 TOC (mg / L) 9.8 9.4 8.9 10.8 11.6 14.6 COD removal rate (%) 87.4 85.2 85.9 70.2 68.4 64.2 <![CDATA[Q1(%)]]> 98.8 99.2 99.5 76.2 55.4 94.2 <![CDATA[Q2(%)]]> 98.6 99.4 99.2 75.4 58.4 93.6

[0069] As shown in Table 1, compared with Comparative Examples 1-2, the TOC obtained in Examples 6-8 was 8.9-9.4 mg / L, and the COD removal rate was 85.2-87.4%. This indicates that the present invention not only has a lower TOC, but also a relatively better COD removal effect. The hyperbranched polyetheramine-grafted graphene can more effectively treat organic matter in wastewater. As for the removal rate of calcium and magnesium ions, the hyperbranched polyetheramine-grafted graphene is the main part for adsorbing metal ions. The hyperbranched structure in polyetheramine can chelate metal ions and can co-adsorb metal ions with graphene. Finally, after static sedimentation and separation, it can meet the treatment requirements of metal wastewater. Compared with Comparative Examples 2 and 3, the synergistic effect of hyperbranched graphene and anion exchange resin in Examples 6-8 can better remove pollutants in wastewater.

[0070] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

Claims

1. A wastewater treatment process for the production of p-aminophenol, characterized in that, Includes the following steps: S1. Pour graphene oxide into an ethanol solution, ultrasonically disperse it in an ice-water bath, add hyperbranched polyetheramine, stir at 85-95℃ for 6-8 hours, cool, wash, and dry to obtain hyperbranched polyetheramine-grafted graphene oxide. Hyperbranched polyetheramine-grafted graphene oxide was ground and placed in acetone, ultrasonically dispersed in an ice bath, poured into a pretreated anion exchange resin, stirred at 55-65℃ for 10-20 hours, cooled and dried to obtain the adsorbent material. S2. Adjust the pH of the wastewater used in the production of p-aminophenol to 8-9 with sodium hydroxide solution, add adsorption material, let stand for 1-2 hours, and then filter with a 0.45μm filter membrane to obtain primary wastewater. S3. The pH of the obtained primary wastewater is adjusted to 2-3 with sulfuric acid solution and then fed into the primary Fenton reactor. Ferrous sulfate is added for the first time at room temperature, followed by hydrogen peroxide. The reaction is carried out for 3-6 hours to obtain secondary wastewater. The secondary wastewater is fed into the second Fenton reactor. Ferrous sulfate is added for the second time at room temperature and the reaction is carried out for 1-3 hours. The pH is adjusted to 8-9 with sodium hydroxide solution to induce precipitation. The filtrate is then filtered through a ceramic membrane to complete the wastewater treatment process for p-aminophenol production. Preparation method of pretreated anion exchange resin: After soaking the anion exchange resin in distilled water for 20-36 hours, it is soaked in 4% hydrochloric acid solution and 2% sodium hydroxide solution for 20-36 hours respectively. After washing until neutral, it is filtered to obtain the pretreated anion exchange resin. The π-π electron conjugation effect on hyperbranched polyetheramine-grafted graphene oxide enables efficient adsorption of phenol, while anion exchange resin further removes phenol ions from the solution through ion exchange, resulting in a synergistic effect when combined.

2. The wastewater treatment process for p-aminophenol production according to claim 1, characterized in that, The mass ratio of graphene oxide to hyperbranched polyetheramine is 1:25-40.

3. The wastewater treatment process for p-aminophenol production according to claim 1, characterized in that, The mass ratio of hyperbranched polyetheramine-grafted graphene oxide to pretreated anion exchange resin is 1:3-5.

4. The wastewater treatment process for p-aminophenol production according to claim 1, characterized in that, Anion exchange resins include any one or more of KIP209, NG-6, and KIP210.

5. The wastewater treatment process for p-aminophenol production according to claim 1, characterized in that, The molar ratio of ferrous sulfate added for the first time, the molar ratio of ferrous sulfate added for the second time, and the molar ratio of hydrogen peroxide to primary wastewater is 0.2:0.8:1.2-2. The dosage ratio of primary wastewater to hydrogen peroxide is 1L:0.5g.

6. The wastewater treatment process for p-aminophenol production according to claim 1, characterized in that, The ceramic membrane has a pore size of 40-80nm, a membrane surface flow rate of 3-4.6m / s, and a wastewater temperature of 8-12℃ during filtration.

7. The wastewater treatment process for p-aminophenol production according to claim 1, characterized in that, Hyperbranched polyetheramines are prepared by the following steps: Polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and 2,4-diaminobutyric acid were added to anhydrous ethanol and stirred at 58-70°C for 9-12 hours. The mixture was then distilled under reduced pressure, washed in an organic solvent, and dried under vacuum for 12-18 hours to obtain hyperbranched polyetheramine.

8. The wastewater treatment process for p-aminophenol production according to claim 7, characterized in that, The molar ratio of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and 2,4-diaminobutyric acid is 0.8-1.2:0.8-1.2:1, and the number-average molecular weight of polypropylene glycol diglycidyl ether is 640.

9. The wastewater treatment process for p-aminophenol production according to claim 7, characterized in that, Organic solvents include any one or more of cyclohexane, n-hexane, and n-heptane.