An adsorbent for selectively adsorbing organic esters in industrial wastewater and its preparation method

Abstract

This invention relates to the field of adsorption separation technology, specifically to an adsorbent for selectively adsorbing organic esters from industrial wastewater and its preparation method. The adsorbent contains polar functional groups capable of adsorbing organic esters and does not contain hydroxyl or carboxyl groups; the adsorbent's adsorption capacity for organic esters is not less than 12% of its total weight, and the density of the adsorbent is 0.5-1.2 g·cm³. ‑3 The adsorbent of this invention contains abundant polar functional groups, exhibiting strong selectivity for organic esters. This effectively avoids competitive adsorption of other molecules in the solution at the active sites, thus improving the purity of the recovered product. Under high liquid hourly space velocity (HLH), the adsorbent of this invention can purify the concentration of organic esters in the solution to below 1000 ppm.

Description

Technical Field

[0001] This invention relates to the field of adsorption separation technology, specifically to an adsorbent for selectively adsorbing organic esters from industrial wastewater and its preparation method. Background Technology

[0002] The solvent recovery stage in antibiotic production processes generates large amounts of wastewater containing organic esters, which must be separated and recovered to meet subsequent purification requirements. Traditional organic ester separation and recovery relies on azeotropic distillation, which consumes a large amount of steam, resulting in high recovery costs and additional wastewater discharge, severely impacting the economic efficiency of wastewater treatment processes. Adsorption separation is a better choice due to its low energy consumption and continuous operation. Its principle involves using an adsorbent to adsorb organic esters from concentrated wastewater, followed by desorption and recovery of the organic esters through steam heating, and regeneration of the adsorbent. However, this technology has specific requirements for the adsorbent: it must have high mechanical strength, be reusable within a temperature range of 10–165°C, be highly corrosion-resistant, and adaptable to various acidic and alkaline environments; and it must have selective adsorption capacity for organic esters to avoid competition for active sites with other molecules, thereby improving adsorption efficiency and the purity of the recovered product.

[0003] Chinese invention patent application CN101066785A uses a double-network interpenetrating secondary cross-linked modified adsorption resin, and Chinese invention patent application CN1534012A uses a diene cross-linked fatty acid ester macroporous adsorption resin. Neither of these can achieve selective adsorption of butyl acetate, and both will simultaneously adsorb impurities such as butanol and proteins. The former requires acetone to be used to elute butanol during regeneration, while the latter requires a large amount of water to rinse the organic macromolecules in the resin pores before steam desorption, which increases equipment and operating costs. Summary of the Invention

[0004] The first aspect of this invention provides an adsorbent for selectively adsorbing organic esters from industrial wastewater, characterized in that the adsorbent contains polar functional groups capable of adsorbing organic esters, and does not contain hydroxyl or carboxyl groups; the adsorbent's adsorption capacity for organic esters is not less than 12% of its total weight, and the density of the adsorbent is 0.73 g·cm³. -3 .

[0005] Optionally, the organic ester includes at least one of butyl acetate, ethyl acetate, propyl acetate, ethyl butyrate, and ethyl valerate.

[0006] Optionally, the adsorbent has an adsorption capacity for organic esters of not less than 15% of its total weight.

[0007] The polar functional group is selected from at least one of -F, -Cl, -Br, -I, -CHO, -NH2, and -NO2.

[0008] The polar functional group is selected from at least two of -F, -Cl, -Br, -I, -CHO, -NH2, and -NO2.

[0009] Optionally, the polar functional groups include -F and -Br, wherein the atomic ratio of -F to -Br is (1-6):1.

[0010] Optionally, the polar functional groups include -F and -CHO, and the atomic ratio of -F and -CHO is (1-6):1.

[0011] The adsorbent has a hardness of 93A, a tensile strength of 60MPa, and a compressive strength of 90MPa.

[0012] The adsorbent can be desorbed and regenerated by steam heating, and the adsorption performance (adsorption capacity) of the regenerated adsorbent decreases by ≤1%.

[0013] The adsorbent is in granular or cylindrical form.

[0014] Optionally, the granules have a diameter of 2000µm, and the cylindrical shape has a bottom diameter of 3mm and a height of 5mm.

[0015] The raw materials for preparing the adsorbent include: a compound that provides an active group, phenylethanol, and an initiator.

[0016] Optionally, the weight ratio of the compound providing the active group to phenylethanol is (5-12):18.

[0017] The initiator includes at least one of sodium persulfate, benzoyl peroxide, di-tert-butyl peroxide, and azobisisobutyronitrile.

[0018] The compounds providing the active groups include at least one of HF, HBr, HI, HCl, HNO3, aliphatic aldehydes, and aliphatic primary amines.

[0019] Optionally, the fatty aldehyde includes at least one of formaldehyde, propionaldehyde, and butyraldehyde.

[0020] Optionally, the aliphatic primary amine includes at least one of methylamine, propylamine, and butylamine.

[0021] The second aspect of the present invention provides a method for preparing an adsorbent for selectively adsorbing organic esters in industrial wastewater, comprising the following steps: adding a compound providing an active group dropwise to phenylethanol to carry out a substitution reaction; purifying the reactants by distillation to separate an intermediate; adding an initiator to the intermediate to initiate a polymerization reaction; and obtaining an adsorbent containing polar functional groups through post-treatment.

[0022] Optionally, the substitution reaction is carried out at a temperature of 70-90°C for 1-3 hours. Attached Figure Description

[0023] Figure 1 The infrared spectrum of the adsorbent prepared in Example 1 is shown.

[0024] Beneficial effects 1. The adsorbent of this invention contains abundant polar functional groups and has a strong selectivity for organic esters, effectively avoiding competitive adsorption of other molecules in the solution at the active site, which is beneficial to improving the purity of the recovered product.

[0025] 2. The adsorbent of this invention can purify the concentration of organic esters in solution to below 1000 ppm under high liquid hourly velocity.

[0026] 3. The binding force between the adsorbent and the ester in this invention is relatively weak, and the desorption of the ester and the regeneration of the adsorbent can be completed by heating with steam.

[0027] 4. The adsorbent of the present invention has excellent mechanical properties, with a hardness of 50~100A, a tensile strength of 50~60MPa, and a compressive strength of 80~90MPa.

[0028] 5. The adsorbent of this invention can be reused repeatedly, and its adsorption performance did not show any decline after 10 cycles of regeneration.

[0029] 6. The adsorbent of this invention has an adsorption capacity of up to 15% of its total weight. Detailed Implementation

[0030] Example 1 An adsorbent for selectively adsorbing organic esters in industrial wastewater is prepared from the following raw materials: a compound providing active groups (HCl), phenethyl alcohol, a pH adjuster (NaOH), and an initiator (potassium persulfate).

[0031] An adsorbent for selectively adsorbing organic esters in industrial wastewater is prepared as follows: Using a compound providing the active group (99.9% purity) and phenethyl alcohol as raw materials, 180g of phenethyl alcohol is first placed in a flask and heated to 45°C. Then, 70g of the compound providing the active group is slowly added dropwise, and the mixture is heated to 80°C. This temperature is maintained while stirring the solution. After stirring for 2 hours, the solution is cooled to room temperature, poured into ice water, and NaOH is added to adjust the pH to neutral. After filtering out solid impurities, the remaining solution is heated and distilled in a flask, and the fraction collected at 180-190°C is collected. The collected fraction is reacted with potassium persulfate as an initiator at 220°C. After reacting for 1 hour, the solution is filtered, the solid product is collected, and dried at 60°C to obtain the adsorbent. The infrared spectrum of the product is shown below. Figure 1 As shown.

[0032] Example 2 The specific implementation method is the same as in Example 1; the difference is that the compound providing the active group is HF.

[0033] Example 3 The specific implementation method is the same as in Example 1; the difference is that the compound providing the active group is HBr.

[0034] Example 4 The specific implementation method is the same as in Example 1; the difference is that the compound providing the active group is HI.

[0035] Example 5 The specific implementation method is the same as in Example 1; the difference is that the compound providing the active group is CH3CHO.

[0036] Example 6 The specific implementation method is the same as in Example 1; the difference is that the compound providing the active group is CH3CH2NH2.

[0037] Example 7 The specific implementation method is the same as in Example 1; the difference is that the compound providing the active group is HNO3.

[0038] Example 8 An adsorbent for selectively adsorbing organic esters in industrial wastewater is prepared from the following raw materials: a compound providing active groups (20g HF and 80.9g HBr), phenethyl alcohol, a pH adjuster (NaOH), and an initiator (peroxide).

[0039] An adsorbent for selectively adsorbing organic esters in industrial wastewater is prepared as follows: Using a compound providing the active group (99.9% purity) and phenethyl alcohol as raw materials, 180g of phenethyl alcohol is first placed in a flask and heated to 45°C. Then, the compound providing the active group is slowly added dropwise, and the temperature is maintained while stirring the mixture. After stirring for 2 hours, the mixture is cooled to room temperature, ice water is added, and NaOH is added to adjust the pH to neutral. After filtering out solid impurities, the remaining solution is heated and distilled in a flask, and the fraction collected at 200-210°C is collected. The collected fraction is reacted with peroxide at 210°C. After reacting for 1 hour, the solution is filtered, the solid product is collected, and dried at 60°C to obtain the adsorbent. Example 9 The specific implementation method is the same as in Example 8; the difference is that the mass of HF is adjusted from 20g to 60g.

[0040] Example 10 An adsorbent for selectively adsorbing organic esters in industrial wastewater is prepared from the following raw materials: a compound providing active groups (20g HF and 44g CH3CHO), phenylethanol, a pH adjuster (NaOH), and an initiator (peroxide).

[0041] An adsorbent for selectively adsorbing organic esters in industrial wastewater is prepared as follows: Using a compound providing the active group (99.9% purity) and phenethyl alcohol as raw materials, 180g of phenethyl alcohol is first placed in a flask and heated to 45°C. Then, the compound providing the active group is slowly added dropwise, and the temperature is maintained while stirring the mixture. After stirring for 2 hours, the mixture is cooled to room temperature, ice water is added, and NaOH is added to adjust the pH to neutral. After filtering out solid impurities, the remaining solution is heated and distilled in a flask, and the fraction collected at 170-175°C is collected. The collected fraction is reacted with ammonium persulfate at 220°C. After reacting for 1 hour, the solution is filtered, the solid product is collected, and dried at 60°C to obtain the adsorbent.

[0042] Example 11 The specific implementation method is the same as in Example 10; the difference is that the mass of HF is adjusted from 20g to 120g.

[0043] Example 12 The specific implementation method is the same as in Example 10; the difference is that the mass of HF is adjusted from 20g to 40g.

[0044] Example 13 The specific implementation method is the same as in Example 3; the difference is that the mass of HBr is adjusted from 70g to 50g.

[0045] Comparative Example 1 An adsorbent for selectively adsorbing organic esters in industrial wastewater is prepared from the following raw materials: a compound providing active groups (CH3COOH), phenylethanol, a pH adjuster (NaOH), and an initiator (potassium persulfate).

[0046] An adsorbent for selectively adsorbing organic esters in industrial wastewater is prepared as follows: Using a compound providing active groups (99.9% purity) and phenethyl alcohol as raw materials, 160g of phenethyl alcohol is first placed in a flask and heated to 60°C. Then, 30g of the compound providing active groups is slowly added dropwise, and the mixture is heated to 80°C. This temperature is maintained while stirring the solution. After stirring for 1.5 hours, the solution is cooled to room temperature, poured into ice water, and NaOH is added to adjust the pH to neutral. After filtering out solid impurities, the remaining solution is heated and distilled in a flask, and the fraction collected at 160-170°C is collected. The collected fraction is reacted at 200°C with peroxide as an initiator. After reacting for 1 hour, the solution is filtered, the solid product is collected, and dried at 60°C to obtain the adsorbent.

[0047] Comparative Example 2 A method for preparing an adsorbent is as follows: 40 mL of styrene, 60 mL of toluene, and 0.15 g of azobisisobutyronitrile (initiator) are added sequentially to a three-necked flask, followed by heating and stirring. Nitrogen gas is introduced as a protective gas during stirring, and the temperature is raised to 75-80°C. The reaction is carried out at this temperature for approximately 4-6 hours, during which the solution gradually becomes viscous. After the reaction is complete, the reaction system is allowed to cool naturally to room temperature. The reaction solution is then slowly poured into a beaker containing 1 L of pure ethanol, resulting in the precipitation of a large amount of white solid. The solution is filtered through a funnel, and the obtained solid is dried in a 60°C oven to obtain the adsorbent.

[0048] Comparative Example 3 A method for preparing an adsorbent is as follows: 0.5 g of CuCl and 40 mL of pyridine are added to a three-necked flask and stirred. After stirring at room temperature for about 30 minutes, the temperature is raised to 25-30 °C, and this solution is used as a catalyst. 10 g of 2,6-dimethylphenol is dissolved in 20 mL of toluene to form a homogeneous solution, which is then slowly added dropwise to the prepared catalyst solution while air is introduced. After the addition is complete, the temperature is kept constant for 2-4 hours. After the reaction is complete, the reaction solution is poured into a beaker containing 150 mL of 1 mol / L NaOH solution and cooled with crushed ice. The polymer precipitates out in solid form. The reactants are filtered through a funnel, and the resulting solid is dried at 60 °C to obtain the adsorbent.

[0049] Comparative Example 4 A method for preparing an adsorbent is as follows: 200 mL of N-methylpyrrolidone is added to a reaction vessel as a solvent, followed by the sequential addition of 147 g of p-dichlorobenzene, 56 g of sodium hydrosulfide, and 10 mL of a 5%–10% NaOH solution, and then the mixture is stirred and heated. The reaction is first carried out at a relatively low temperature of 160–180 °C for 1–2 hours, and then the temperature is rapidly increased to 220–260 °C. The reaction is then stirred at this temperature for 3–6 hours. The reaction solution is poured into a beaker containing distilled water to allow the solid to precipitate. The solid is dried at 120–140 °C to obtain the adsorbent.

[0050] Comparative Example 5 The specific implementation method is the same as Comparative Example 1; the difference is that the mass of CH3COOH is adjusted to 60g.

[0051] Performance testing methods 1. Adsorbents prepared in Examples 1-11 and Comparative Example 1 were subjected to adsorption experiments on organic esters. The specific experimental method (acidic wastewater solution) was as follows: First, 10g of butyl acetate solution (purity 99.9%) was weighed by tareing in a beaker on a balance. 990g of purified water was poured into the beaker and stirred evenly. Then, a few drops of CH3COOH solution (purity 99.9%) were added to adjust the pH to below 5. The prepared adsorbents were poured into the prepared solutions and soaked for 10min. After soaking, they were taken out, dried, and weighed. The weight difference of the adsorbent before and after soaking was the amount of butyl acetate adsorbed. The results are shown in Table 1. The experimental results show that the adsorbents containing one polar functional group (-F, -Cl, -Br, -I, -CHO, -NH2, -NO2) all had an adsorption capacity greater than 1.4g. The adsorbents containing two polar functional groups could further increase the adsorption capacity to more than 1.5g. However, the adsorbents containing carboxyl groups did not adsorb butyl acetate.

[0052] 2. The adsorbent prepared in Example 5 was subjected to adsorption experiments in acidic, neutral and alkaline aqueous solutions containing organic esters. The total weight of the adsorbent used in the experiment was 10g, and the concentration (mass concentration) of organic esters in the aqueous solution was 1%. The test results are shown in Table 2.

[0053] Preparation method for acidic wastewater solution: Same as the preparation method in Test 1.

[0054] Preparation method for neutral wastewater solution: Same as the preparation method in Test 1, except that no subsequent pH adjustment is performed during the solution preparation process.

[0055] Preparation method of alkaline wastewater solution: Same as the preparation method in Test 1, except that the solution is adjusted to pH>9 using NaOH during the solution preparation process.

[0056] Experimental results show that the adsorbent has the highest adsorption capacity for organic esters in neutral solution.

[0057] 3. Take 10g of the adsorbent prepared in Example 7 and perform adsorption-water vapor (110℃) regeneration in an aqueous solution containing 1% (mass concentration) organic ester at pH≈3. Repeat the experiment 10 times. The amount of organic ester adsorbed each time is shown in Table 3. The experimental results show that the adsorbent has excellent regeneration performance and can meet the requirements for repeated use.

[0058] 4. The adsorbents prepared in Examples 10, 12, 13 and Comparative Examples 2-5 were subjected to adsorption experiments in neutral aqueous solutions containing organic esters. The total weight of the adsorbent material used in the experiments was 10 g, and the concentration (mass concentration) of the organic ester in the aqueous solution was 1%. The test results are shown in Table 4. The experimental results show that the adsorption performance of Comparative Example 2 (adsorbent with double bond functional group), Comparative Example 3 (adsorbent with ether bond functional group), and Comparative Example 4 (adsorbent with thioether functional group) was poor. Even with the increase of carboxyl group content (Comparative Example 5), the adsorption performance was still poor. Comparing Examples 10 and 12, it is shown that increasing the proportion of F atoms is beneficial to the adsorption of butyl acetate.

[0059] Performance test data Table 1

[0060] Table 2

[0061] Table 3

[0062] Table 4

Claims

1. An adsorbent for selectively adsorbing organic esters from industrial wastewater, characterized in that, The adsorbent contains polar functional groups that can adsorb organic esters and does not contain hydroxyl or carboxyl groups; the adsorbent's adsorption capacity for organic esters is not less than 12% of its total weight.

2. The adsorbent for selectively adsorbing organic esters in industrial wastewater according to claim 1, characterized in that, The polar functional group is selected from at least one of -F, -Cl, -Br, -I, -CHO, -NH2, and -NO2.

3. The adsorbent for selectively adsorbing organic esters in industrial wastewater according to claim 2, characterized in that, The polar functional group is selected from at least two of -F, -Cl, -Br, -I, -CHO, -NH2, and -NO2.

4. The adsorbent for selectively adsorbing organic esters in industrial wastewater according to claim 3, characterized in that, The adsorbent has a hardness of 50~100A, a tensile strength of 50~60MPa, and a compressive strength of 80~90MPa.

5. The adsorbent for selectively adsorbing organic esters in industrial wastewater according to claim 4, characterized in that, The adsorbent can be desorbed and regenerated by steam heating, and the adsorption performance of the regenerated adsorbent decreases by ≤1%.

6. The adsorbent for selectively adsorbing organic esters in industrial wastewater according to claim 1, characterized in that, The adsorbent is in granular or cylindrical form.

7. The adsorbent for selectively adsorbing organic esters in industrial wastewater according to claim 6, characterized in that, The granules have a diameter of 50~2000µm, and the cylindrical shape has a bottom diameter of 3~5mm and a height of 5~10mm.

8. The adsorbent for selectively adsorbing organic esters in industrial wastewater according to claim 1, characterized in that, The raw materials for preparing the adsorbent include: a compound that provides an active group, phenylethanol, and an initiator.

9. The adsorbent for selectively adsorbing organic esters in industrial wastewater according to claim 8, characterized in that, The compounds providing the active groups include at least one of HF, HBr, HI, HCl, HNO3, aliphatic aldehydes, and aliphatic primary amines.

10. A method for preparing an adsorbent for selectively adsorbing organic esters in industrial wastewater according to any one of claims 1-9, characterized in that, Includes the following steps: A compound providing the active group is added dropwise to phenethyl alcohol to carry out a substitution reaction. The reactants are purified by distillation to separate the intermediate. An initiator is added to the intermediate to initiate a polymerization reaction, and the adsorbent containing polar functional groups is obtained after post-treatment.

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