Method for preparing high-cyclodextrin-content adsorption resin based on etherification polymerization reaction and application of high-cyclodextrin-content adsorption resin

Abstract

The invention relates to a method for preparing high-cyclodextrin-content adsorption resin based on etherification polymerization reaction and application of the high-cyclodextrin-content adsorption resin, which can simplify the synthesis steps of the cyclodextrin-containing adsorption resin, reduce the synthesis cost, improve the cyclodextrin content of the resin and the adsorption capacity of the resin, and realize the application of adsorbing aromatic organic small molecule pollutants from sewage. The method comprises the following steps: dissolving cyclodextrin with concentrated alkali liquor, heating and stirring to obtain a deprotonated cyclodextrin alkali solution A; dissolving dichloro methyl aromatic hydrocarbon with dioxane to obtain a solution B; dropwise adding the solution B into the solution A, carrying out etherification polymerization reaction, washing a product with a diluted hydrochloric acid solution until the product is neutral, washing with water, carrying out suction filtration, respectively carrying out Soxhlet extraction with absolute ethyl alcohol and deionized water, and carrying out vacuum drying to obtain a product. The preparation process is simple, the raw materials are cheap and easy to obtain, the raw material conversion path is direct, a series of environmental pollution caused by intermediate separation, purification and other technological processes in multi-step synthesis is avoided, and the method is energy-saving and environment-friendly and has practical popularization and application value.

Description

Technical Field

[0001] This invention relates to the fields of chemical engineering and environmental protection, and in particular to a method for preparing adsorption resins with high cyclodextrin content based on etherification polymerization and its application. Background Technology

[0002] In recent years, with the rapid development of industry and agriculture, large amounts of domestic sewage and industrial and agricultural wastewater have been directly or indirectly discharged into rivers, lakes, and seas. This wastewater contains a large number of organic pollutants, primarily phenols, organic amines, and various dyes, which, as protozoan poisons, can be toxic to living organisms. There are various methods for treating organic pollutants in wastewater, such as oxidation, biochemical methods, extraction, adsorption, and ion exchange. Among these, adsorption has advantages such as high efficiency, ease of treatment, easy elution and regeneration, energy saving, and environmental friendliness. Therefore, in recent years, adsorption has been widely adopted due to its simple operation, low investment, and high treatment efficiency. The key to adsorption lies in the adsorbent.

[0003] Currently, adsorption resins are among the most commonly used adsorbents. In research on the adsorption of organic pollutants by adsorption resins, cyclodextrin-modified adsorption resins have shown excellent adsorption effects on organic pollutants. These cyclodextrin-containing adsorbents can selectively adsorb organic pollutants. This is because the inner surface of cyclodextrin is a hydrophobic cavity, while the outer surface contains a large number of hydroxyl groups. The hydrophobic cavity can form an envelope with organic molecules of suitable size, thus exhibiting good stereoselectivity and recognition performance for many organic molecules. Modifying resins with cyclodextrin is the most common method for synthesizing cyclodextrin-containing adsorbent resins. However, the modification method has drawbacks: the synthesis steps are relatively cumbersome, and the cyclodextrin content in the modified resin is limited. Its absorption capacity for organic pollutants such as low-molecular-weight phenols, organic amines, and various dyes is significantly limited, and its synthesis and adsorption effects are not satisfactory. Therefore, developing an adsorbent resin that is cost-effective, has a high cyclodextrin content, and exhibits good adsorption performance for further application in the adsorption treatment of small-molecule organic pollutants, while also requiring high adsorption efficiency, simple synthesis steps, excellent regeneration performance, and environmental friendliness, has become an urgent technical problem to be solved. Summary of the Invention

[0004] In view of the above situation and to overcome the shortcomings of the existing technology, the purpose of this invention is to provide a method for preparing high cyclodextrin content adsorption resin based on etherification polymerization and its application. This method synthesizes a novel cyclodextrin-containing adsorption resin in one step through etherification, thereby improving the resin's adsorption capacity for small organic molecule pollutants. This simplifies the synthesis steps of the cyclodextrin-containing adsorption resin, reduces synthesis costs, increases the cyclodextrin content and adsorption capacity of the resin, and achieves the application of efficiently adsorbing aromatic small organic molecule pollutants from wastewater.

[0005] This invention discloses a method for preparing a high-cyclodextrin content adsorption resin based on etherification polymerization. The adsorption resin is prepared by etherification polymerization of cyclodextrin and dichloromethyl aromatic hydrocarbon, specifically including the following steps: S1. Dissolve cyclodextrin in concentrated alkaline solution, heat and stir to obtain deprotonated cyclodextrin alkaline solution A; S2. Dissolve dichloromethyl aromatic hydrocarbon in dioxane to obtain solution B; The dichloromethyl aromatic hydrocarbon is 1,4-dichloromethylbenzene or 4,4'-dichloromethylbiphenyl; S3. Add solution B dropwise to solution A to make the molar ratio of cyclodextrin to dichloromethyl aromatic hydrocarbon 1:6. Then, carry out an etherification polymerization reaction at 85-90℃ for 7-21 hours to obtain the reaction product. Then, wash the reactants with 0.1M dilute hydrochloric acid solution until the pH is neutral = 7. After washing with water and filtration, perform Soxhlet extraction with anhydrous ethanol and deionized water respectively. Dry under vacuum at 80-100℃ to obtain the final product.

[0006] The application of the high cyclodextrin content adsorption resin prepared by the above method in the adsorption of aromatic organic small molecule pollutants in wastewater.

[0007] The preparation process of this invention is simple, the raw materials are cheap and readily available, and the conversion path is direct. It avoids a series of environmental pollution caused by intermediate separation and purification processes in multi-step synthesis, meets the requirements of "atom economy" and "low environmental impact" in "green synthesis", and has a high cyclodextrin content in the adsorption resin, which has a good adsorption effect on small organic molecule pollutants. It is energy-saving and environmentally friendly, and has practical application value. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the synthesis route of the high cyclodextrin content adsorption resin of the present invention; Figure 2 The images show the Fourier transform infrared (FTIR) spectra of the high cyclodextrin content adsorption resins prepared in Examples 1, 2, and 3. Figure 3 This is a SEM image of the high cyclodextrin content adsorption resin prepared in Example 1; Figure 4 This is a SEM image of the high cyclodextrin content adsorption resin prepared in Example 2; Figure 5 Here is a SEM image of the high cyclodextrin content adsorption resin prepared in Example 3; Detailed Implementation

[0009] The specific embodiments of the present invention will be described in detail below with reference to examples.

[0010] The present invention can be described in the following embodiments. Example

[0011] This invention discloses a method for preparing a high cyclodextrin content adsorption resin based on etherification polymerization, comprising the following steps: S1. Dissolve 10g (8.82mmol) of β-cyclodextrin in 30.8mL of 30% NaOH solution and stir magnetically at 40~50℃ until completely dissolved to obtain deprotonated cyclodextrin alkaline solution A. S2. Dissolve 8.51 g of 1,4-dichloromethylbenzene (XDC) in dioxane to obtain solution B; S3. Add solution B dropwise to solution A to make the molar ratio of cyclodextrin to dichloromethyl aromatic hydrocarbon 1:6, and then carry out etherification polymerization at 90℃ for 7h to obtain the reaction product. Then wash the reactants with 0.1M dilute hydrochloric acid solution until neutral pH=7, wash with water and filter, and perform Soxhlet extraction with anhydrous ethanol and deionized water respectively. Dry under vacuum at 75℃ to obtain the finished product.

[0012] The method yielded 8.98 g of β-XDC cyclodextrin-containing adsorption resin, with each 0.1 g adsorbing 63.92 mg / g of phenol and 122.67 mg / g of bisphenol A in 25 mL of 600 mg / L solution. Example

[0013] This invention discloses a method for preparing a high cyclodextrin content adsorption resin based on etherification polymerization, comprising the following steps: S1. Dissolve 5.72 g (4.41 mmol) of γ-cyclodextrin in 15.4 mL of 30% NaOH solution and stir magnetically at 40-50 °C until completely dissolved to obtain deprotonated cyclodextrin alkaline solution A. S2. Dissolve 4.255g of 1,4-dichloromethylbenzene (XDC) in dioxane to obtain solution B; S3. Add solution B dropwise to solution A to make the molar ratio of cyclodextrin to dichloromethyl aromatic hydrocarbon 1:6, and then carry out etherification polymerization at 90℃ for 21h to obtain the reaction product. Then wash the reactants with 0.1M dilute hydrochloric acid solution until neutral pH=7, wash with water and filter, and perform Soxhlet extraction with anhydrous ethanol and deionized water respectively. Dry under vacuum at 75℃ to obtain the finished product.

[0014] The method yielded 6.5178 g of γ-XDC cyclodextrin-containing adsorption resin. 0.1 g of this resin adsorbed 66.72 mg / g of phenol and 122.01 mg / g of bisphenol A in 25 mL of 600 mg / L phenol.

[0015] Example 3 This invention discloses a method for preparing a high cyclodextrin content adsorption resin based on etherification polymerization, comprising the following steps: S1. Dissolve 5.72 g (4.41 mmol) of β-cyclodextrin in 15.4 mL of 30% NaOH solution and stir magnetically at 40-50 °C until completely dissolved to obtain deprotonated cyclodextrin alkaline solution A. S2. Dissolve 4.255g of 1,4-dichloromethylbiphenyl (BCMB) in dioxane to obtain solution B; S3. Add solution B dropwise to solution A to make the molar ratio of cyclodextrin to dichloromethyl aromatic hydrocarbon 1:6, and then carry out etherification polymerization at 90℃ for 21h to obtain the reaction product. Then wash the reactants with 0.1M dilute hydrochloric acid solution until neutral pH=7, wash with water and filter, and perform Soxhlet extraction with anhydrous ethanol and deionized water respectively. Dry under vacuum at 75℃ to obtain the finished product.

[0016] The method yielded 2.2987 g of β-BCMB cyclodextrin-containing adsorption resin. 0.1 g of this resin adsorbed 51.14 mg / g of phenol and 89.22 mg / g of bisphenol A in 25 mL of 600 mg / L phenol.

[0017] The application of the high cyclodextrin content adsorption resin prepared by the above method in the adsorption of aromatic organic small molecule pollutants in wastewater.

[0018] It should also be noted that the above embodiments are only used to describe the technical solutions of the present invention and not to limit them. Any other modifications or equivalent substitutions made by researchers and technicians in the art to the technical solutions of the present invention, as long as they do not depart from the scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

[0019] The preparation process of this invention is simple, the raw materials are inexpensive and readily available, and the raw material conversion path is direct. It avoids a series of environmental pollution caused by intermediate separation and purification processes in multi-step synthesis, meeting the requirements of "atom economy" and "low environmental impact" in "green synthesis". The adsorption resin has a high cyclodextrin content, which has a good adsorption effect on small organic molecule pollutants. It is energy-saving and environmentally friendly. It is the crystallization of the applicant's creative labor, and the good adsorption effect has been verified by experiments. The relevant experimental data are as follows: The FTIR spectra of the adsorption resins prepared in Examples 1, 2, and 3 are shown below. Figure 2 As shown in the infrared image, it is clear that the three resins differ at 1085.25 cm⁻¹. -1 There is strong absorption nearby, which is the absorption peak of the numerous ether bonds on the resin, at 3441.35 cm⁻¹. -1 A strong absorption peak of alcohol hydroxyl groups was generated nearby, which is the absorption peak of the large number of hydroxyl groups on the cyclodextrin. The large presence of cyclodextrin helps the resin adsorb small organic molecules.

[0020] Table 1. Adsorption performance of the adsorption resin of the present invention for phenol and bisphenol A Table 2. Specific surface area and pore size analysis results of the three adsorption resins resin <![CDATA[Specific surface area (m 2 / g)]]> Average pore size (nm) Resin color Example 1 18.85 4.10 White Example 2 64.86 3.26 White Example 3 60.09 3.52 White As can be seen from the above, the beneficial technical effects of the present invention are: (1) The present invention uses inexpensive cyclodextrin and dichloromethyl aromatic hydrocarbon as the main raw materials to prepare an adsorption resin containing cyclodextrin with good adsorption performance through etherification crosslinking reaction. The adsorption resin has a good adsorption effect on small organic molecules.

[0021] (2) The cyclodextrin-containing adsorption resin prepared by the method of the present invention has many advantages such as high cyclodextrin content, low synthesis cost, simple synthesis steps, and strong adsorption capacity.

[0022] Compared with existing technologies, the adsorption resin preparation process of this invention is simple, uses inexpensive and readily available raw materials, and has a direct conversion path. It avoids a series of environmental pollution issues caused by intermediate separation and purification processes in multi-step synthesis, meeting the requirements of "atom economy" and "low environmental impact" in "green synthesis." The solvent system is green, using an alkaline aqueous solution and dioxane as the basic solvent. Compared to the highly toxic and difficult-to-recover organic solvents that may be used in traditional synthesis (such as certain halogenated hydrocarbons, nitrobenzenes, and high-boiling-point aromatics), this system has lower toxicity and better biodegradability. Furthermore, the introduction of the aqueous solution significantly reduces the amount of organic solvent, minimizing environmental emissions and health risks from solvent volatilization. The operation is low-threshold and controllable, with fewer reaction steps, requiring no complex equipment or harsh reaction conditions (such as high temperature, high pressure, inert gas protection), facilitating continuous industrial production and reducing the risk of product quality instability due to fluctuations in multi-step operations. The resulting product has a high cyclodextrin content; it exhibits excellent adsorption performance for aromatic small-molecule pollutants such as phenol and bisphenol A, representing a major innovation in wastewater treatment and possessing practical application value.

Claims

1. A method for preparing an adsorbent resin with high cyclodextrin content based on etherification polymerization, wherein the adsorbent resin is prepared by etherification polymerization of cyclodextrin and dichloromethyl aromatic hydrocarbon, specifically comprising the following steps: S1. Dissolve cyclodextrin in concentrated alkaline solution, heat and stir to obtain deprotonated cyclodextrin alkaline solution A; S2. Dissolve dichloromethyl aromatic hydrocarbon in dioxane to obtain solution B; The dichloromethyl aromatic hydrocarbon is 1,4-dichloromethylbenzene or 4,4'-dichloromethylbiphenyl; S3. Add solution B dropwise to solution A to make the molar ratio of cyclodextrin to dichloromethyl aromatic hydrocarbon 1:

6. Then, carry out an etherification polymerization reaction at 85-90℃ for 7-21 hours to obtain the reaction product. Then, wash the reactants with 0.1M dilute hydrochloric acid solution until the pH is neutral = 7. After washing with water and filtration, perform Soxhlet extraction with anhydrous ethanol and deionized water respectively. Dry under vacuum at 80-100℃ to obtain the final product.

2. The method for preparing a high cyclodextrin content adsorption resin based on etherification polymerization according to claim 1, characterized in that, Includes the following steps: S1. Dissolve 10g (8.82mmol) of β-cyclodextrin in 30.8mL of 30% NaOH solution and stir magnetically at 40~50℃ until completely dissolved to obtain deprotonated cyclodextrin alkaline solution A. S2. Dissolve 8.51 g of 1,4-dichloromethylbenzene in dioxane to obtain solution B; S3. Add solution B dropwise to solution A to make the molar ratio of cyclodextrin to dichloromethyl aromatic hydrocarbon 1:6, and then carry out etherification polymerization at 90℃ for 7h to obtain the reaction product. Then wash the reactants with 0.1M dilute hydrochloric acid solution until neutral pH=7, wash with water and filter, and perform Soxhlet extraction with anhydrous ethanol and deionized water respectively. Dry under vacuum at 75℃ to obtain the finished product.

3. The method for preparing a high cyclodextrin content adsorption resin based on etherification polymerization according to claim 1, characterized in that, Includes the following steps: S1. Dissolve 5.72 g (4.41 mmol) of γ-cyclodextrin in 15.4 mL of 30% NaOH solution and stir magnetically at 40-50 °C until completely dissolved to obtain deprotonated cyclodextrin alkaline solution A. S2. Dissolve 4.255g of 1,4-dichloromethylbenzene in dioxane to obtain solution B; S3. Add solution B dropwise to solution A to make the molar ratio of cyclodextrin to dichloromethyl aromatic hydrocarbon 1:6, and then carry out etherification polymerization at 90℃ for 21h to obtain the reaction product. Then wash the reactants with 0.1M dilute hydrochloric acid solution until neutral pH=7, wash with water and filter, and perform Soxhlet extraction with anhydrous ethanol and deionized water respectively. Dry under vacuum at 75℃ to obtain the finished product.

4. The method for preparing a high cyclodextrin content adsorption resin based on etherification polymerization according to claim 1, characterized in that, Includes the following steps: S1. Dissolve 5.72 g (4.41 mmol) of β-cyclodextrin in 15.4 mL of 30% NaOH solution and stir magnetically at 40-50 °C until completely dissolved to obtain deprotonated cyclodextrin alkaline solution A. S2. Dissolve 4.255g of 1,4-dichloromethylbiphenyl in dioxane to obtain solution B; S3. Add solution B dropwise to solution A to make the molar ratio of cyclodextrin to dichloromethyl aromatic hydrocarbon 1:6, and then carry out etherification polymerization at 90℃ for 21h to obtain the reaction product. Then wash the reactants with 0.1M dilute hydrochloric acid solution until neutral pH=7, wash with water and filter, and perform Soxhlet extraction with anhydrous ethanol and deionized water respectively. Dry under vacuum at 75℃ to obtain the finished product.

5. The application of the high cyclodextrin content adsorption resin prepared by the method according to any one of claims 1-4 in the adsorption of aromatic organic small molecule pollutants in wastewater.

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