A method for preparing a sulfonated magnetic cyclodextrin composite adsorbent and its application.

Abstract

This invention discloses a method for preparing a sulfonated magnetic cyclodextrin composite adsorbent and its application, comprising the following steps: Step 1: Coating Fe3O4 nanoparticles with β-cyclodextrin to obtain β-CD@Fe3O4 magnetic microparticles; Step 2: Introducing allyl groups onto the surface of the β-CD@Fe3O4 magnetic microparticles obtained in Step 1 to obtain magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4; Step 3: Grafting 2-acryloylamino-2-methyl-1-propanesulfonic acid onto the surface of the magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 obtained in Step 2 to obtain the sulfonated magnetic cyclodextrin composite adsorbent; wherein, the mass ratio of the magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 to 2-acryloylamino-2-methyl-1-propanesulfonic acid is 1:(1~2.5), and the reaction is carried out at 40~60℃ for 2~4h.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a method for preparing a sulfonated magnetic cyclodextrin composite adsorbent and its application. Background Technology

[0002] With the rapid development of the livestock and poultry farming industry, pollution of water bodies by heavy metals and antibiotics is becoming increasingly serious. During livestock and poultry farming, heavy metals are often added to animal feed due to their growth-promoting effects. With the continuous discharge of farm wastewater, heavy metal ions inevitably enter natural water bodies. Heavy metal pollution is insidious, persistently toxic, and not only is it non-biodegradable, but it also accumulates through the food chain and food web, ultimately threatening the health of plants, animals, and humans. Antibiotics are commonly used to prevent and treat animal diseases, but they are difficult for organisms to metabolize and absorb. Antibiotics discharged into the aquatic environment not only inhibit microbial growth and affect the survival of aquatic plants and animals, but also induce the production of drug-resistant bacteria or drug-resistant genes, disrupting the ecological balance of aquatic bodies and even threatening the safety of drinking water. Both antibiotics and heavy metals are typical environmental pollutants that can enter the environment through various pathways. Therefore, the phenomenon of combined antibiotic and heavy metal pollution in water bodies is widespread. Due to the significant differences in their physicochemical properties and environmental behaviors, and the fact that their interactions can form complexes with variable structures and toxicities, the control and treatment of combined antibiotic and heavy metal pollution in water faces significant challenges. Therefore, it is urgent to completely eliminate or minimize the content of antibiotics and heavy metal ions before discharging aquaculture wastewater into receiving water bodies.

[0003] Adsorption is currently the most widely used method for treating wastewater contaminated with both antibiotics and heavy metals. It boasts advantages such as strong adsorption capacity, low cost, wide availability of adsorbent materials, simple operation, and effectiveness in removing various antibiotics and heavy metals. Compared to traditional adsorbents, magnetic nanomaterials offer faster adsorption rates, higher adsorption efficiency, lower preparation costs, and efficient recycling, leading to their increasingly widespread application in wastewater treatment. Iron-based magnetic materials, in particular, exhibit high activity, enabling more efficient adsorption of pollutants from wastewater. Furthermore, the availability and low cost of iron make them more suitable for practical applications. Therefore, using iron-based magnetic materials for wastewater adsorption offers significant advantages. Functionalized Fe3O4 composites can improve the performance of adsorbents in adsorbing heavy metal ions, thus attracting increasing attention. However, current functionalized Fe3O4 composites still suffer from limitations such as limited adsorption capacity, poor adsorption specificity, structural stability, and poor biocompatibility. Since different types of pollutants in water often compete for adsorption sites on the adsorbent surface, limited adsorption capacity leads to a decrease in the removal rate of individual pollutants. Poor adsorption specificity makes it difficult for adsorbents to selectively remove specific pollutants. In addition, the interaction of various functional groups of different types of pollutants can produce different complexes, which can change the adsorption behavior of the adsorbent and make it difficult for the adsorbent to meet the requirements of simultaneously removing multiple coexisting mixed pollutants. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the existing technology, the purpose of this invention is to provide a method for preparing sulfonated magnetic cyclodextrin composite adsorbent and its application, so as to solve the problems of limited adsorption capacity, poor adsorption specificity, difficulty in adsorbent separation, and low removal efficiency of antibiotics and heavy metals in composite wastewater in the existing technology.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for preparing a sulfonated magnetic cyclodextrin composite adsorbent includes the following steps:

[0007] Step 1: Coating Fe3O4 nanoparticles with β-cyclodextrin to obtain β-CD@Fe3O4 magnetic microparticles;

[0008] Step 2: Allyl groups are introduced onto the surface of the β-CD@Fe3O4 magnetic microparticles obtained in Step 1 to obtain magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4;

[0009] Step 3: Graft 2-acrylamido-2-methyl-1-propanesulfonic acid onto the surface of the magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 obtained in Step 2 to obtain the sulfonated magnetic cyclodextrin composite adsorbent; wherein the mass ratio of the magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 to 2-acrylamido-2-methyl-1-propanesulfonic acid is 1:(1~2.5), and the reaction is carried out at 40~60℃ for 2~4h.

[0010] Preferably, in step 1, β-CD@Fe3O4 magnetic microparticles are prepared by coating Fe3O4 nanoparticles with β-cyclodextrin using reverse emulsion polymerization.

[0011] Preferably, the specific steps of the reverse emulsion polymerization method are as follows:

[0012] At 50℃, β-cyclodextrin was dissolved in a 20% sodium hydroxide solution until a transparent paste was formed. After cooling to room temperature, Fe3O4 nanoparticles were added and stirred continuously until a uniform black paste-like β-CD@Fe3O4 mixture was obtained. This mixture was then added to a mixture of liquid paraffin and Span-80. After heating to 35℃, liquid epichlorohydrin was added. The mixture was stirred for 8–12 h to form a water-in-oil emulsion. The emulsion was broken with anhydrous ethanol and allowed to stand. Solid-liquid magnetic separation was performed. The mixture was washed several times with anhydrous ethanol and pure water, dried, and ground to obtain β-CD@Fe3O4 magnetic microparticles. The mass ratio of Fe3O4 to β-cyclodextrin was 1:(2–4); the volume ratio of Span-80 to liquid paraffin was 1:(50–100); and 2.8–3.5 mL of liquid epichlorohydrin was added per 100 mL of the reaction system solution.

[0013] Preferably, Fe3O4 nanoparticles and β-cyclodextrin are mixed and stirred at room temperature for 45 min at a stirring speed of 300 rpm; liquid paraffin and Span-80 are mixed and stirred at 30°C for 30 min at a stirring speed of 800 rpm.

[0014] Preferably, in step 2, the allyl group is introduced through the following steps:

[0015] The β-CD@Fe3O4 magnetic microparticles obtained in step 1 were dissolved in anhydrous N,N-dimethylformamide / anhydrous dimethyl sulfoxide at a volume ratio of 1:1. After the reaction was fully completed by stirring continuously at 800 rpm for 1 h at 30 °C, sodium hydroxide solid was added and stirring was continued for another 1 h. The temperature was adjusted to 20 °C, and liquid propylene bromide was slowly added under nitrogen protection. The reaction was stirred at 1000 rpm for 12–24 h and then allowed to stand. Solid-liquid magnetic separation was performed, and the microparticles were washed repeatedly with anhydrous ethanol and pure water. After drying and grinding, magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 were obtained. The mass ratio of β-CD@Fe3O4 magnetic microparticles to liquid propylene bromide was 1:1.

[0016] Preferably, in step 3, potassium persulfate is added as an initiator, and the concentration of potassium persulfate is 0.05 g / mL.

[0017] This invention also provides an application of a sulfonated magnetic cyclodextrin composite adsorbent. The sulfonated magnetic cyclodextrin composite adsorbent prepared by the above method can be used to remove moxifloxacin and / or copper ions from wastewater. The composite adsorbent prepared by this invention can adsorb and treat moxifloxacin or copper ions in wastewater individually, and can also treat binary composite wastewater containing both moxifloxacin and copper ions, simultaneously removing both moxifloxacin and copper ions.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The sulfonated magnetic cyclodextrin composite adsorbent prepared by the method of the present invention can react with moxifloxacin and copper ions simultaneously in complex wastewater systems. This is achieved through the active sulfonic acid groups (-SO3) on its structure. - It overcomes the shortcomings of insufficient selectivity in the adsorption of heavy metal ions. At the same time, after the adsorbent adsorbs moxifloxacin, the moxifloxacin contains carboxyl, carbonyl or piperazine groups, which can act as potential electron donors to coordinate heavy metals and undergo complexation reactions to form antibiotic-metal ion complexes, thus synergistically enhancing the selective adsorption of copper ions in heavy metal wastewater.

[0020] 2. The sulfonated magnetic cyclodextrin composite adsorbent prepared by the method of the present invention can achieve rapid magnetic separation of moxifloxacin and copper ions by adding an external magnetic field after adsorption. After separation, it can be desorbed by 0.1 mol / L hydrochloric acid solution at pH 1.0 to achieve concentration of pollutants and regeneration of adsorbent. After regeneration, it is easy to recover and the recovery cost is low. The adsorption capacity of the adsorbent is minimally lost after regeneration.

[0021] 3. The method described in this invention is simple to operate, requires no harsh reaction conditions, is easy to control, and uses abundant and inexpensive raw materials, making it suitable for industrial production. Attached Figure Description

[0022] Figure 1 The infrared spectrum of the intermediate product in the preparation of the sulfonated magnetic cyclodextrin composite adsorbent in Example 1 is shown.

[0023] Figure 2 The image shows the magnetic saturation curve of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1.

[0024] Figure 3 The image shows the X-ray diffraction pattern of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1.

[0025] Figure 4 The images show the X-ray photoelectron spectra of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 and the adsorbent after adsorbing pollutants. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the present invention are within the scope of protection of the present invention.

[0027] Unless otherwise specified in the specific context, the numerical ranges listed herein include upper and lower limits, as well as all integers and fractions within that range, but are not limited to the specific values ​​listed when the range is defined. The term "and / or" as used herein is inclusive; for example, "A and / or B" means either only A, or only B, or both A and B.

[0028] I. Preparation method of sulfonated magnetic cyclodextrin composite adsorbent

[0029] Step 1: Coating Fe3O4 nanoparticles with β-cyclodextrin to obtain β-CD@Fe3O4 magnetic microparticles; In Step 1, β-CD@Fe3O4 magnetic microparticles are prepared by coating Fe3O4 nanoparticles with β-cyclodextrin using reverse emulsion polymerization.

[0030] The specific steps are as follows:

[0031] At 50℃, β-cyclodextrin was dissolved in a 20% sodium hydroxide solution until a transparent paste was formed. After cooling to room temperature, Fe3O4 nanoparticles were added and the mixture was stirred continuously until a uniform black paste-like β-CD@Fe3O4 mixture was obtained. This mixture was then added to a mixture of liquid paraffin and Span-80. The mixture was heated to 35℃ and liquid epichlorohydrin was added. After stirring for 8–12 hours, a water-in-oil emulsion was formed. The emulsion was broken with anhydrous ethanol, allowed to stand, and subjected to solid-liquid magnetic separation. The emulsion was washed several times with anhydrous ethanol and pure water, dried, and ground to obtain β-cyclodextrin. CD@Fe3O4 magnetic microparticles; wherein, the mass ratio of Fe3O4 to β-cyclodextrin is 1:(2~4); the volume ratio of span-80 to liquid paraffin is 1:(50~100); the amount of epichlorohydrin added is 2.8~3.5mL of liquid epichlorohydrin per 100mL of reaction system solution; Fe3O4 nanoparticles and β-cyclodextrin are mixed and stirred at room temperature for 45min at a stirring speed of 300rpm; liquid paraffin and span-80 are mixed and stirred at 30℃ for 30min at a stirring speed of 800rpm.

[0032] Step 2: Allyl groups are introduced onto the surface of the β-CD@Fe3O4 magnetic microparticles obtained in Step 1 to obtain magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4; in Step 2, allyl groups are introduced through the following steps:

[0033] The β-CD@Fe3O4 magnetic microparticles obtained in step 1 were dissolved in anhydrous N,N-dimethylformamide / anhydrous dimethyl sulfoxide at a volume ratio of 1:1. After the reaction was fully completed by stirring continuously at 800 rpm for 1 h at 30 °C, sodium hydroxide solid was added and stirring was continued for another 1 h. The temperature was adjusted to 20 °C, and liquid propylene bromide was slowly added under nitrogen protection. The reaction was stirred at 1000 rpm for 12–24 h and then allowed to stand. Solid-liquid magnetic separation was performed, and the microparticles were washed repeatedly with anhydrous ethanol and pure water. After drying and grinding, magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 were obtained. The mass ratio of β-CD@Fe3O4 magnetic microparticles to liquid propylene bromide was 1:1.

[0034] Step 3: Graft 2-acrylamido-2-methyl-1-propanesulfonic acid onto the surface of the magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 obtained in Step 2 to obtain the sulfonated magnetic cyclodextrin composite adsorbent; wherein the mass ratio of the magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 to 2-acrylamido-2-methyl-1-propanesulfonic acid is 1:(1~2.5), and the reaction is carried out at 40~60℃ for 2~4h. Potassium persulfate is added as an initiator, and the amount of potassium persulfate added is 0.05g / mL.

[0035] This invention has found that although grafting active sulfonic acid groups onto adsorbents can overcome the drawback of insufficient selectivity for heavy metal ions, not all compounds containing sulfonic acid groups can achieve this technical effect. For example, during the research, this invention found that although sodium styrene sulfonate also has a strongly anionic, water-soluble sulfonic acid group and can also undergo electrostatic adsorption with moxifloxacin, its adsorption effect is significantly different from that of 2-acrylamido-2-methyl-1-propanesulfonic acid. The adsorbent grafted with sodium styrene sulfonate has a lower adsorption capacity for moxifloxacin than the adsorbent prepared in this invention. In addition, the amount of 2-acrylamido-2-methyl-1-propanesulfonic acid grafted also affects the adsorption effect of the adsorbent. The adsorbent with a mass ratio of magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 and 2-acrylamido-2-methyl-1-propanesulfonic acid grafted at 1:2 has the best adsorption effect.

[0036] II. Examples and Comparative Examples

[0037] Example 1

[0038] 1) Preparation of β-CD@Fe3O4 magnetic microparticles

[0039] β-CD@Fe3O4 magnetic microparticles were prepared by coating Fe3O4 nanoparticles with β-cyclodextrin using a reverse emulsion polymerization method. This method not only suppressed the aggregation tendency of Fe3O4 nanoparticles, but also increased the surface effect of Fe3O4 nanoparticles due to the presence of β-cyclodextrin. First, 8g of β-cyclodextrin powder was accurately weighed and dissolved in 10mL of 20% sodium hydroxide solution. The solution was magnetically stirred at 50℃ for 45min until the β-cyclodextrin was completely dissolved into a transparent paste. Then, 2g of Fe3O4 nanoparticles were weighed and added to the β-cyclodextrin-sodium hydroxide mixture. The mixture was mechanically stirred at 300rpm for 45min at room temperature to ensure uniform dispersion of the Fe3O4 nanoparticles, resulting in a black, viscous paste-like mixture. Simultaneously, a 250mL three-necked flask containing 100mL of liquid paraffin and 2mL of SPAN-80 mixture was placed in a 30℃ water bath. The mechanical stirrer was set to 800rpm and stirred for 30min to obtain a homogeneous mixture. A homogeneous mixture of β-cyclodextrin, sodium hydroxide, and Fe3O4 was rapidly added to the flask in a thin stream using a syringe, causing it to quickly disperse into small particles within the paraffin-Span-80 mixture. After the water bath reached 35°C, 2.8 mL of liquid epichlorohydrin was added dropwise to the flask, and stirring was continued for 8 hours until the reaction was complete. The flask was then removed from the water bath, and anhydrous ethanol was added to break the emulsion. After standing, solid-liquid magnetic separation was achieved using an external magnetic field. The resulting black solid was washed several times alternately with anhydrous ethanol and pure water, dried, and ground to obtain β-CD@Fe3O4 magnetic microparticles.

[0040] 2) Preparation of magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4

[0041] Accurately weigh 3.5g of the β-CD@Fe3O4 magnetic particles prepared in step 1) and disperse them in a 250ml three-necked flask containing 80mL of anhydrous N,N-dimethylformamide / anhydrous dimethyl sulfoxide at a volume ratio of 1:1. Place the three-necked flask in a 35℃ water bath and use a JJ-1 precision booster timer mechanical stirrer to continuously stir at 800rpm for 1h to ensure sufficient reaction. Then add 0.6g of sodium hydroxide solid and continue stirring for 1h. Next, adjust the water bath temperature to 20℃ and slowly add 3.5mL of liquid bromopropylene under nitrogen protection. Then adjust the stirrer speed to 1000rpm and stir for 12h. After the reaction is complete, let it stand and achieve solid-liquid magnetic separation under the action of an external magnetic field. Wash several times with anhydrous ethanol and pure water alternately, dry and grind to obtain magnetic allyl β-cyclodextrin composite particles (Allyl@β-CD@Fe3O4).

[0042] 3) Preparation of sulfonated magnetic cyclodextrin composite adsorbent

[0043] 0.4 g of magnetic allyl β-cyclodextrin composite microparticles were dispersed in a reaction flask containing 25 mL of pure water. Nitrogen gas was continuously purged for 10 min to remove oxygen while stirring the suspension. Then, 1 mL of 0.05 g / mL potassium persulfate solution (prepared and dissolved rapidly at 50 °C) was added for initiation. After reacting under nitrogen for 10 min, 0.8 g of 2-acrylamido-2-methyl-1-propanesulfonic acid solution (AMPS) dissolved in 5 mL of pure water was added. Nitrogen gas was purged for another 5 min, and the reaction flask was quickly capped. The mixture was shaken thoroughly and placed in a 50 °C water bath for 3 h. During this period, the reaction flask was shaken every half hour to ensure uniform mixing of the reaction system. After the reaction was completed, the mixture was allowed to stand, and solid-liquid separation was achieved using an external magnetic field. The resulting product was washed several times alternately with anhydrous ethanol and pure water, dried, and ground to obtain the final sulfonated magnetic cyclodextrin composite adsorbent (AMPS@Allyl@β-CD@Fe3O4).

[0044] Example 2

[0045] 1) Preparation of β-CD@Fe3O4 magnetic particles: (same as step 1 in Example 1)

[0046] 2) Preparation of magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4: (Same as step 2 in Example 1)

[0047] 3) Preparation of sulfonated magnetic cyclodextrin composite adsorbent

[0048] 0.4 g of magnetic allyl β-cyclodextrin composite microparticles were dispersed in a reaction flask containing 25 mL of pure water. Nitrogen gas was continuously purged for 10 min to remove oxygen while stirring the suspension. Then, 1 mL of 0.05 g / mL potassium persulfate solution (prepared and dissolved rapidly at 50 °C) was added for initiation. After reacting under nitrogen for 10 min, 0.4 g of 2-acrylamido-2-methyl-1-propanesulfonic acid solution (AMPS) dissolved in 5 mL of pure water was added. Nitrogen gas was purged for another 5 min, and the reaction flask was quickly capped. The mixture was shaken thoroughly and placed in a 50 °C water bath for 3 h. During this period, the reaction flask was shaken every half hour to ensure uniform mixing of the reaction system. After the reaction was completed, the mixture was allowed to stand, and solid-liquid separation was achieved using an external magnetic field. The resulting product was washed several times alternately with anhydrous ethanol and pure water, dried, and ground to obtain the final sulfonated magnetic cyclodextrin composite adsorbent (AMPS@Allyl@β-CD@Fe3O4).

[0049] Example 3

[0050] 1) Preparation of β-CD@Fe3O4 magnetic particles: (same as step 1 in Example 1)

[0051] 2) Preparation of magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4: (Same as step 2 in Example 1)

[0052] 3) Preparation of sulfonated magnetic cyclodextrin composite adsorbent

[0053] 0.4 g of magnetic allyl β-cyclodextrin composite microparticles were weighed and dispersed in a reaction flask containing 25 mL of pure water. Nitrogen gas was continuously purged for 10 min to remove oxygen while stirring the suspension. Then, 1 mL of 0.05 g / mL potassium persulfate solution (prepared and dissolved rapidly at 50 °C) was added for initiation. After reacting under nitrogen for 10 min, 0.6 g of 2-acrylamido-2-methyl-1-propanesulfonic acid solution (AMPS) dissolved in 5 mL of pure water was added. Nitrogen gas was purged for another 5 min, and the reaction flask was quickly capped. The mixture was shaken thoroughly and placed in a 50 °C water bath for 3 h. During this period, the reaction flask was shaken every half hour to ensure uniform mixing of the reaction system. After the reaction was completed, the mixture was allowed to stand, and solid-liquid separation was achieved using an external magnetic field. The resulting product was washed several times alternately with anhydrous ethanol and pure water, dried, and ground to obtain the final sulfonated magnetic cyclodextrin composite adsorbent (AMPS@Allyl@β-CD@Fe3O4).

[0054] Example 4

[0055] 1) Preparation of β-CD@Fe3O4 magnetic particles: (same as step 1 in Example 1)

[0056] 2) Preparation of magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4: (Same as step 2 in Example 1)

[0057] 3) Preparation of sulfonated magnetic cyclodextrin composite adsorbent

[0058] 0.4 g of magnetic allyl β-cyclodextrin composite microparticles were weighed and dispersed in a reaction flask containing 25 mL of pure water. Nitrogen gas was continuously purged for 10 min to remove oxygen while stirring the suspension. Then, 1 mL of 0.05 g / mL potassium persulfate solution (prepared and dissolved rapidly at 50 °C) was added for initiation. After reacting under nitrogen for 10 min, 1.0 g of 2-acrylamido-2-methyl-1-propanesulfonic acid solution (AMPS) dissolved in 5 mL of pure water was added. Nitrogen gas was purged for another 5 min, and the reaction flask was quickly capped. The mixture was shaken thoroughly and placed in a 50 °C water bath for 3 h. During this period, the reaction flask was shaken every half hour to ensure uniform mixing of the reaction system. After the reaction was completed, the mixture was allowed to stand, and solid-liquid separation was achieved using an external magnetic field. The resulting product was washed several times alternately with anhydrous ethanol and pure water, dried, and ground to obtain the final sulfonated magnetic cyclodextrin composite adsorbent (AMPS@Allyl@β-CD@Fe3O4).

[0059] Compare with Example 1

[0060] 1) Preparation of β-CD@Fe3O4 magnetic particles: (same as step 1 in Example 1)

[0061] Compare with Example 2

[0062] 1) Preparation of β-CD@Fe3O4 magnetic particles: (same as step 1 in Example 1)

[0063] 2) Preparation of magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4: (Same as step 2 in Example 1)

[0064] Compare with Example 3

[0065] 1) Preparation of β-CD@Fe3O4 magnetic particles: (same as step 1 in Example 1)

[0066] 2) Preparation of magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4: (Same as step 2 in Example 1)

[0067] 3) Preparation of sulfonated magnetic cyclodextrin composite adsorbent

[0068] 0.4 g of magnetic allyl β-cyclodextrin composite microparticles were weighed and dispersed in a reaction flask containing 25 mL of pure water. Nitrogen gas was continuously purged for 10 min to remove oxygen while stirring the suspension. Then, 1 mL of 0.05 g / mL potassium persulfate solution (prepared and dissolved rapidly at 50 °C) was added for initiation. After reacting under nitrogen for 10 min, 0.4 g of sodium p-styrene sulfonate solution (SSS) dissolved in 5 mL of pure water was added. Nitrogen gas was purged for another 5 min, and the reaction flask was quickly capped. The mixture was shaken thoroughly and placed in a 50 °C water bath for 3 h. During this period, the reaction flask was shaken every half hour to ensure uniform mixing of the reaction system. After the reaction was completed, the mixture was allowed to stand, and solid-liquid separation was achieved using an external magnetic field. The resulting product was washed several times alternately with anhydrous ethanol and pure water, dried, and ground to obtain the final sulfonated magnetic cyclodextrin composite adsorbent (SSS@Allyl@β-CD@Fe3O4).

[0069] III. Performance Study on Removal of Moxifloxacin (MOX)

[0070] (1) The sulfonated magnetic cyclodextrin composite adsorbents prepared in Examples 1-4 and Control Example 3 were used to treat moxifloxacin (MOX) contaminated wastewater. The specific steps are as follows:

[0071] The adsorption performance of the sulfonated magnetic cyclodextrin composite adsorbents prepared in Examples 1-4 and Control Example 3 on a moxifloxacin solution with an initial concentration of 10 mg / L was investigated. Several 5 mg portions of the sulfonated magnetic cyclodextrin composite adsorbents prepared in Examples 1-4 and Control Example 3 were accurately weighed and placed in 20 mL small brown bottles. 20 mL of a moxifloxacin solution with an initial concentration of 10 mg / L was added to each bottle. These small brown bottles were then placed in a constant temperature water bath shaker and shaken at 25°C and 180 rpm for 12 h. After the reaction, an external magnetic field was applied to perform solid-liquid separation of the adsorbent. The supernatant was aspirated with a syringe, filtered through a 0.45 μm filter membrane, and the concentration of moxifloxacin in the filtrate was determined using a UV-5100 ultraviolet-visible spectrophotometer. The results are shown in Table 1.

[0072] The magnetic adsorbent prepared in this invention has an adsorption capacity (q) for antibiotics or metal ions. e The removal rate (mg / g) is calculated using formula (1); the removal rate (%) of antibiotics or metal ions is calculated using formula (2).

[0073]

[0074]

[0075] In the formula: C0 and C e , respectively, represent the mass concentrations of antibiotics or metal ions in the aqueous solution before adsorption and at adsorption equilibrium, in mg / L; m is the mass of the adsorbent, in g; V is the volume containing antibiotics or metal ions, in L.

[0076] Table 1. Comparison of adsorption effects of moxifloxacin on adsorbents prepared with different magnetic allyl β-cyclodextrin composite microparticles to AMPS mass ratios and grafted SSS.

[0077]

[0078] As shown in Table 1, the sulfonated magnetic cyclodextrin composite adsorbents prepared in Examples 1-4 and Control Example 3 all showed a removal effect on moxifloxacin. However, Examples 1-4 exhibited higher removal rates and larger adsorption capacities for moxifloxacin compared to Control Example 3. Structurally, this may be because both 2-acrylamido-2-methyl-1-propanesulfonic acid and sodium p-styrene sulfonate possess active double bonds with addition polymerization properties, allowing them to copolymerize with magnetic allyl β-cyclodextrin particles. Both also possess strongly anionic, water-soluble sulfonic acid groups that can electrostatically adsorb moxifloxacin. The difference lies in the amide groups contained in 2-acrylamido-2-methyl-1-propanesulfonic acid, which endow the sulfonated magnetic cyclodextrin composite adsorbent with excellent hydrolytic stability, acid, alkali, and thermal stability, thereby increasing its adsorption capacity for moxifloxacin. This also indicates that not all organic compounds containing sulfonic acid groups grafted onto magnetic allyl β-cyclodextrin particles exhibit excellent adsorption effects for moxifloxacin.

[0079] Furthermore, from the perspective of raw materials used in the preparation, it can be seen that the AMPS added in the preparation of the target adsorbents in Examples 1-4 were 0.8g, 0.4g, 0.6g, and 1.0g, respectively. Even in Example 2, where the AMPS dosage was only 0.4g, a removal rate of over 80% for moxifloxacin was achieved, which is significantly better than the control example. Further analysis of Table 1 shows that the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 exhibited the best removal effect for moxifloxacin. Therefore, from an economic perspective, the preparation condition of adding 0.8g of AMPS (i.e., Example 1) is more beneficial for both environmental protection and economic efficiency.

[0080] (2) The sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 was used for adsorption experiments on moxifloxacin (MOX) polluted wastewater under different acidic conditions. The specific steps are as follows:

[0081] The effect of solutions with different pH values ​​on the removal of moxifloxacin in a monoprotic pollutant system was investigated at 25℃. Several 5mg portions of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 were accurately weighed and placed in 20mL small brown bottles. 20mL of moxifloxacin solution with an initial concentration of 50mg / L and pH values ​​of 3.0-11.0 were added to each bottle, and the mixture was continuously shaken in a constant-temperature water bath at 180rpm for 12h. When adsorption reached equilibrium, the solid magnetic adsorbent was rapidly separated from the aqueous solution using an external magnetic field. The supernatant was aspirated with a syringe, filtered through a 0.45μm filter membrane, and the concentration of moxifloxacin in solutions at various pH values ​​after the adsorption reaction was determined using a UV-5100 ultraviolet-visible spectrophotometer. The adsorption capacity of the adsorbent prepared in Example 1 for moxifloxacin was calculated using formula (1). The results are shown in Table 2.

[0082] Table 2. Study on the removal of moxifloxacin by sulfonated magnetic cyclodextrin composite adsorbent under different acidic conditions.

[0083]

[0084] As shown in Table 2, the adsorption capacity of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 for moxifloxacin initially increased and then decreased with increasing pH from 3.0 to 11.0. The adsorption capacity increased significantly as the pH increased from 3.0 to 7.0, particularly from 3.0 to 4.0. Then, with further increases in pH, the adsorption capacity gradually increased, reaching its maximum at pH 7.0. However, with continued increases in pH, the adsorption capacity for moxifloxacin began to decrease. This may be because at pH < 7.0, the deprotonation of the sulfonic acid groups on the adsorbent surface intensifies with increasing pH, releasing numerous active adsorption sites previously occupied by hydrogen ions to adsorb moxifloxacin from the solution. Additionally, the adsorbent surface gradually becomes negatively charged, increasing the electrostatic attraction between moxifloxacin and the adsorbent, leading to a gradual increase in the adsorption efficiency for moxifloxacin. When pH > 7.0, the electrostatic repulsion between the negatively charged adsorbent and moxifloxacin in anionic form increases, and this strong electrostatic repulsion leads to a gradual decrease in the adsorption efficiency of the adsorbent for moxifloxacin. Therefore, when the pH is controlled within the range of 5–10, the adsorbent exhibits good adsorption performance for moxifloxacin.

[0085] (3) The sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 was used to treat wastewater containing moxifloxacin (MOX) and different ions to investigate the effect of coexisting ions on the adsorption efficiency of moxifloxacin. The specific steps are as follows:

[0086] First, prepare a 100 mg / L moxifloxacin solution. Then, prepare 100 mmol / L aqueous solutions of anions and cations (including KCl, CaCl2, MgCl2, Na2CO3, NaNO3, and Na2SO4), adjusting their pH to 7.0. Accurately weigh several 5 mg portions of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 into 20 mL small brown bottles. Then, add 10 mL of the prepared moxifloxacin solution, followed by the corresponding volumes of the prepared anion and cation solutions and pure water at pH 7.0, so that the concentration of moxifloxacin in the small brown bottle is 50 mg / L, and the concentrations of the anions and cations are 0, 0.1, 10, and 50 mmol / L, respectively. Place the small brown bottle in a constant temperature water bath shaker and continuously shake for 12 h at 25°C and 180 rpm. When adsorption reaches equilibrium, the solid magnetic adsorbent is rapidly separated from the aqueous solution by an external magnetic field. The supernatant is drawn up with a syringe, filtered through a 0.45 μm filter membrane, and the concentration of moxifloxacin in each solution after the adsorption reaction is completed is determined using a UV-5100 ultraviolet-visible spectrophotometer. The adsorption capacity of the adsorbent prepared in Example 1 for moxifloxacin is calculated using formula (1). The results are shown in Table 3.

[0087] Table 3. Effects of different concentrations of anions and cations on the adsorption of moxifloxacin by the sulfonated magnetic cyclodextrin composite adsorbent.

[0088]

[0089] Table 3 shows that the added anions and cations all inhibited the removal of moxifloxacin by the adsorbent to varying degrees, and the adsorption capacity of the adsorbent for moxifloxacin gradually decreased as the concentration of anions and cations increased from 0 to 50 mmol / L. The presence of cations may, on the one hand, compete with moxifloxacin for adsorption sites on the adsorbent, occupying some sites and thus reducing the adsorption capacity for moxifloxacin. On the other hand, some cations may undergo complexation reactions with moxifloxacin, significantly reducing the adsorbent's absorption of moxifloxacin. The influence of cations, in descending order, is: Mg 2+ >Ca 2+ >K + Moxifloxacin may coordinate with coexisting anions to form moxifloxacin-anion complexes. The formation of these complexes increases the radius of moxifloxacin, altering its charge properties and making it difficult for adsorbents to adsorb it. Furthermore, the weak acid anion CO32-... 2- The slight increase in solution pH, possibly due to hydrolysis, may affect the adsorption of moxifloxacin by the adsorbent, compared to NO3. - and SO4 2- The value is relatively small. Especially when CO3... 2-At concentrations of 10 mmol / L and 50 mmol / L, the adsorption capacity of the adsorbent for moxifloxacin did not change significantly. Therefore, the order of inhibition of the adsorbent's adsorption of moxifloxacin is as follows: SO42-. 2- >NO3 - >CO3 2- .

[0090] IV. Performance Study on Removal of Copper Ions Cu(II)

[0091] (1) The sulfonated magnetic cyclodextrin composite adsorbents prepared in Example 1 and Comparative Examples 1-3 were used to treat Cu(II) polluted wastewater. The specific steps are as follows:

[0092] Systems Cu(II)-2, Cu(II)-5, Cu(II)-10, and Cu(II)-50 (with initial Cu(II) concentrations of 2, 5, 10, and 50 mg / L, respectively) were set up to investigate the adsorption performance of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 and Control Examples 1-3 for Cu(II) in these four different systems. Several 5 mg portions of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 and Control Examples 1-3 were accurately weighed and placed in 20 mL small brown bottles. 20 mL of the liquid from each of the four systems was added to each bottle. These small brown bottles were then placed in a constant-temperature water bath shaker and shaken at 25°C and 180 rpm for 12 h. After the reaction, an external magnetic field was applied to separate the adsorbent into solid and liquid components. The supernatant was drawn up with a syringe and filtered through a 0.45 μm filter membrane. The concentration of Cu(II) in the filtrate was determined using a UV-5100 ultraviolet-visible spectrophotometer. The adsorption capacity of the adsorbents prepared in Example 1 and Control Examples 1-3 for Cu(II) was calculated using formula (1). The results are shown in Table 4.

[0093] Table 4 Comparison of the adsorption effects of the adsorbents prepared in Example 1 and Comparative Examples 1-3 on Cu(II) at different initial concentrations.

[0094]

[0095] As shown in Table 4, the adsorption capacity of the sulfonated magnetic cyclodextrin composite adsorbents prepared in Example 1 and Comparative Examples 1-3 for Cu(II) gradually increased. With increasing initial concentration, the equilibrium adsorption capacity of Cu(II) gradually increased, indicating that increasing the initial concentration is beneficial to improving the utilization rate of active sites in the adsorbent. This may be related to the increased adsorption driving force generated by the concentration difference in the solution, promoting the migration of Cu(II) to the adsorbent, and the increased probability of collision and adsorption due to the higher concentration of Cu(II) in the solution. The adsorption capacity of Comparative Example 1 for Cu(II) was greater than that of Comparative Example 2, indicating that the introduction of allyl groups successfully broke the hydrogen bond network within the β-CD@Fe3O4 molecule, resulting in a decrease in the adsorption capacity of Comparative Example 2 for Cu(II). However, the introduction of double bonds with addition polymerization properties provides the possibility of improving the topological properties of the adsorbent and expanding its application areas. Adsorption capacity for Cu(II): Example 1 > Comparative Example 3 > Comparative Example 2, demonstrating that grafting AMPS and SSS introduces a strongly anionic, water-soluble sulfonic acid group, increasing the variety of functional groups in the molecular structure and successfully improving the adsorption capacity of the adsorbent for Cu(II). When the Cu(II) concentration was low, the adsorption capacity of Control Example 1 for Cu(II) was actually greater than that of Control Example 3. When the Cu(II) concentration was high, the adsorption capacity of Control Example 1 for Cu(II) was less than that of Control Example 3. Control Example 1, which did not graft SSS, adsorbed Cu(II) through its intramolecular hydrogen bond network. Therefore, as the Cu(II) concentration gradually increased, the adsorption capacity of Control Example 1 for Cu(II) gradually became saturated. However, the adsorption effect of Control Example 3, which was grafted with SSS, was not good when the Cu(II) concentration was low. This is because the grafted SSS would hinder the effect of its intramolecular hydrogen bond network to adsorb Cu(II) at low Cu(II) concentrations, resulting in a lower adsorption capacity than Control Example 1 at low Cu(II) concentrations. Even compared with Example 2 of the present invention, which had the same amount of grafting, the adsorption effect of Control Example 3 for Cu(II) was not as good as that of Example 2. The adsorbent grafted with SSS required a higher Cu(II) concentration to exert its adsorption effect through the introduced sulfonic acid group.

[0096] (2) The sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 was used for adsorption experiments on Cu(II) polluted wastewater under different acidic conditions. The specific steps are as follows:

[0097] The effect of solutions with different pH values ​​on the removal of Cu(II) in a monoprotic pollutant system was investigated at 25℃. Several 5 mg portions of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 were accurately weighed and placed in 20 mL small brown bottles. 20 mL of Cu(II) solution with an initial concentration of 50 mg / L and a pH value of 2.0-6.0 was added to each bottle, and the mixture was continuously shaken in a constant temperature water bath shaker at 180 rpm for 12 h. When adsorption reached equilibrium, the solid magnetic adsorbent was rapidly separated from the aqueous solution by an external magnetic field. The supernatant was aspirated with a syringe, filtered through a 0.45 μm filter membrane, and the concentration of Cu(II) in the solutions at each pH value after the adsorption reaction was determined using a UV-5100 ultraviolet-visible spectrophotometer. The adsorption capacity of the adsorbent prepared in Example 1 for Cu(II) was calculated using formula (1). The results are shown in Table 2.

[0098] Table 5. Study on the removal of Cu(II) by sulfonated magnetic cyclodextrin composite adsorbent under different acidic conditions.

[0099]

[0100] As shown in Table 5, overall, the effect of pH changes on the adsorption capacity of the adsorbent for Cu(II) is not particularly large. The fluctuation in the adsorption capacity of the adsorbent for Cu(II) at different pH values ​​is relatively small compared to that of moxifloxacin. This indicates that the adsorbent has a relatively stable adsorption effect within the pH range of 2.5–6, while this adsorption effect begins to weaken significantly above pH 6. The adsorption capacity of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 for Cu(II) shows a trend of first increasing and then decreasing with increasing pH from 2.0 to 6.0. When the pH increases from 2.0 to 3.0, the adsorption capacity of the adsorbent for Cu(II) increases significantly, reaching its maximum adsorption capacity at pH 3.0. With further increases in pH, the adsorption capacity of the adsorbent for Cu(II) gradually decreases. At pH = 2, the strong electrostatic repulsion between the adsorbent surface and Cu(II) and H3O... + The competitive effect of ions leads to a low adsorption capacity of Cu(II), but the adsorption capacity gradually increases with increasing pH. This is partly due to the increasing pH in the solution, which causes the hydroxyl and amide groups on the adsorbent surface to gradually deprotonate, changing the surface charge from positive to negative, thus enhancing electrostatic attraction and promoting Cu(II) adsorption. On the other hand, the presence of H3O in the solution... + The competition for adsorption sites between Cu(II) and Cu(II) decreases. When pH > 3, the adsorption efficiency of Cu(II) gradually decreases, possibly because Cu(II) uses its M(OH) group as the adsorption site. +The presence of Cu(II) in the adsorbent increases, as does the precipitation on the adsorbent surface. Therefore, for the adsorption of Cu(II), the adsorbent exhibits the best adsorption effect when the pH is controlled between 3.0 and 5.0.

[0101] (3) The sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 was used to treat wastewater containing Cu(II) and different ions to investigate the effect of coexisting ions on the adsorption efficiency of Cu(II). The specific steps are as follows:

[0102] First, prepare a 100 mg / L Cu(II) solution. Then, prepare 100 mmol / L aqueous solutions of anions and cations (including KCl, CaCl2, MgCl2, Na2CO3, NaNO3, and Na2SO4), adjusting their pH to 5.0. Accurately weigh several 5 mg portions of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 into 20 mL small brown bottles. Then, add 10 mL of the prepared Cu(II) solution, followed by the corresponding volumes of the prepared anion and cation solutions and pure water at pH 5.0, so that the concentration of Cu(II) in the small brown bottle is 50 mg / L, and the concentrations of each anion and cation are 0, 0.1, 10, and 50 mmol / L, respectively. Place the small brown bottle in a constant temperature water bath shaker and continuously shake for 12 h at 25°C and 180 rpm. When adsorption reaches equilibrium, the solid magnetic adsorbent is rapidly separated from the aqueous solution by an external magnetic field. The supernatant is drawn up with a syringe, filtered through a 0.45 μm filter membrane, and the concentration of Cu(II) in each solution after the adsorption reaction is completed is determined using a UV-5100 ultraviolet-visible spectrophotometer. The adsorption capacity of the adsorbent prepared in Example 1 for Cu(II) is calculated using formula (1). The results are shown in Table 6.

[0103] Table 6. Effects of different concentrations of anions and cations on the adsorption of Cu(II) by the sulfonated magnetic cyclodextrin composite adsorbent.

[0104]

[0105] Table 6 shows that the added anions and cations all inhibited the removal of Cu(II) by the adsorbent to varying degrees. As the concentration of anions and cations increased from 0 to 50 mmol / L, the adsorption capacity of the adsorbent for Cu(II) gradually decreased. Coexisting cations in the solution compete with Cu(II) for the limited adsorption sites on the adsorbent surface, reducing Cu(II) adsorption. The influence of cations, in descending order, is: Mg... 2+ >Ca 2+ >K + Because the larger the charge number of the competing cation, the greater the inhibitory effect on Cu(II) adsorption. Furthermore, Mg... 2+The higher covalent nature of Cu(II) makes it more prone to hydration, which in turn reduces the binding of Cu(II) to the active sites on the adsorbent surface. The order of anion inhibition of Cu(II) adsorption is: SO42-. 2- >NO3 - >CO3 2- Because Cu(II) may coordinate with coexisting anions to form Cu(II)-anion complexes, the formation of these complexes alters the charge properties of Cu(II), making it difficult for Cu(II) to be adsorbed by the adsorbent. The smaller the radius of the coexisting anion, the less steric hindrance it has, making it easier to form complexes and occupy more active adsorption sites. Therefore, CO32-... 2- The effect of the adsorption effect on the adsorbent is minimal when adsorbing moxifloxacin or Cu(II).

[0106] V. Study on the Removal of Moxifloxacin (MOX) and Copper Ions (Cu(II)) by a Binary Pollutant System

[0107] To investigate the simultaneous removal performance of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 for both MOX and Cu(II) in MOX-Cu(II) and Cu(II)-MOX binary systems, and to explore whether there is a competitive effect between MOX and Cu(II), adsorption experiments were conducted in a mixed solution of MOX and Cu(II). The specific steps are as follows:

[0108] To analyze the competitive adsorption effect between antibiotics or metal ions in a binary system, the adsorption capacity ratio (R) was calculated using equation (3). q ):

[0109]

[0110] In the formula, q b (mg / g) and q s (mg / g) represents the adsorption capacity of antibiotics or metal ions in binary and single systems, respectively, under the same adsorption conditions.

[0111] Twenty-four different systems were established, including MOX-0Cu(II), MOX-5Cu(II), MOX-10Cu(II), and MOX-20Cu(II) systems (with coexisting Cu(II) concentrations of 0, 5, 10, and 20 mg / L, and initial MOX concentrations of 10, 30, and 50 mg / L, respectively), as well as Cu(II)-0MOX, Cu(II)-5MOX, Cu(II)-10MOX, and Cu(II)-20MOX systems (with coexisting MOX concentrations of 0, 5, 10, and 20 mg / L, and initial Cu(II) concentrations of 10, 30, and 50 mg / L, respectively). The effects of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 on the adsorption of Cu(II) on MOX and the adsorption of Cu(II) by MOX in these twenty-four different systems were investigated. Accurately weigh several 5 mg portions of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 into 20 mL small brown bottles. Add 20 mL of the above twenty-four systems with pH 5 respectively. Place the small brown bottles in a constant temperature water bath shaker and shake continuously for 12 h at 25 °C and 180 rpm. When the adsorption reaches equilibrium, the solid magnetic adsorbent is quickly separated from the aqueous solution by an external magnetic field. The supernatant is drawn with a syringe and filtered through a 0.45 μm filter membrane. The concentrations of MOX and Cu(II) in each solution after the adsorption reaction are determined by a UV-5100 ultraviolet-visible spectrophotometer. The adsorption capacity of the adsorbent prepared in Example 1 for MOX and Cu(II) is calculated using formula (1), and the adsorption capacity ratio of MOX and Cu(II) in the binary system and the single system is calculated using formula (3). The results are shown in Table 7.

[0112] Table 7. Effects of Cu(II) on MOX and MOX on Cu(II) adsorption in binary composite systems.

[0113]

[0114] The adsorption capacity ratio (Rq) of pollutants in binary and monopolymeric systems can be used to determine the type of interaction between different pollutants: antagonistic (Rq<1), non-interaction (Rq=1), and synergistic (Rq>1). In the presence of Cu(II) at pH 5.0, the Rq value for moxifloxacin adsorption is less than 1, and at a constant initial moxifloxacin concentration, Rq decreases with increasing Cu(II) concentration. This is because the competitive adsorption of Cu(II) consumes some available adsorption sites for moxifloxacin on the adsorbent. At a constant initial Cu(II) concentration, Rq increases as the initial moxifloxacin concentration gradually increases from low to high. This is because the increased concentration difference enhances the adsorption driving force, thus promoting moxifloxacin adsorption and reducing the influence of coexisting Cu(II).

[0115] In the presence of moxifloxacin, during the adsorption of Cu(II) by the adsorbent, at low initial Cu(II) concentrations, the adsorbent possesses reserve adsorption sites for moxifloxacin, leading to antagonism between Cu(II) and the coexisting moxifloxacin. However, due to the smaller molecular size of Cu(II), Cu(II) is more readily adsorbed than moxifloxacin, thus the competitive effect is not severe. With increasing initial Cu(II) concentration, the concentration gradient increases, further promoting Cu(II) adsorption and reducing the antagonistic effect of the coexisting moxifloxacin. Specifically, at an initial Cu(II) concentration of 30 mg / L, antagonism occurs at low coexisting moxifloxacin concentrations, followed by a weak synergistic effect as the coexisting moxifloxacin concentration increases. The synergistic effect gradually strengthens with increasing initial Cu(II) concentration. Possibly due to the increased probability of collision and adsorption at high initial Cu(II) concentrations, after the adsorbent adsorbs moxifloxacin, the moxifloxacin contains carboxyl, carbonyl, or piperazine groups, which can act as potential electron donors to coordinate Cu(II), forming a ternary complex (adsorbent-MOX-Cu(II)), synergistically enhancing the selective adsorption of Cu(II). Therefore, in a solution system where Cu(II) and MOX coexist, when the Cu(II) concentration is above 50 mg / L and the MOX concentration is above 20 mg / L, the adsorbent can simultaneously adsorb Cu(II) and MOX. Furthermore, in a solution system where Cu(II) and MOX coexist, the coexistence of Cu(II) and MOX synergistically enhances the selective adsorption of Cu(II) by the adsorbent described in this invention.

[0116] VI. Analysis and Explanation of the Effects of the Attached Drawings

[0117] Figure 1 The infrared spectra of the intermediate products in the preparation of the sulfonated magnetic cyclodextrin composite adsorbent in Example 1 are shown below. Among them, (a) is the infrared spectrum of β-CD@Fe3O4 magnetic particles, (b) is the infrared spectrum of Allyl@β-CD@Fe3O4, and (c) is the infrared spectrum of the prepared sulfonated magnetic cyclodextrin composite adsorbent AMPS@Allyl@β-CD@Fe3O4.

[0118] In the FTIR of β-CD@Fe3O4 magnetic particles, the characteristic absorption peak of the stretching vibration of the Fe-O bond is at 584 cm⁻¹. -1 The position around 1033 cm⁻¹ indicates the successful embedding of the magnetic core Fe₃O₄ nanoparticles. -1 There is strong CO tensile vibration at this location and at 3400 cm. -1The characteristic peak of the -OH group at 1695 cm⁻¹ indicates the spectral characteristics of intact β-cyclodextrin, proving that β-cyclodextrin was successfully coated onto the magnetic core Fe₃O₄ nanoparticles. In the spectra of Allyl@β-CD@Fe₃O₄ and AMPS@Allyl@β-CD@Fe₃O₄, the peak at 1695 cm⁻¹ indicates the characteristic spectral characteristics of intact β-cyclodextrin, proving that β-cyclodextrin was successfully coated onto the magnetic core Fe₃O₄ nanoparticles. -1 The stretching vibration absorption peak of the C=C bond at the β-CD@Fe3O4 magnetic particles indicates the successful introduction of allyl groups onto the surface of the magnetic particles. The absorption peak at 1555 cm⁻¹ on the sulfonated modified adsorbent AMPS@Allyl@β-CD@Fe3O4 further confirms this. -1 The (secondary amide II band) at 1354 cm⁻¹ is a new peak generated by the combined absorption of NH bending vibration and CN stretching vibration. -1 The S=O stretching vibration peak indicates that 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) was successfully grafted onto the surface of the adsorbent, thus preparing a sulfonated adsorbent.

[0119] Figure 2 The magnetic saturation curve is shown for the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1.

[0120] The magnetic properties of AMPS@Allyl@β-CD@Fe3O4 were analyzed using a vibrating sample magnetometer in a magnetic field ranging from -20000 to 20000 Oe. The results are as follows: Figure 2 As shown in the figure, the curves are symmetrically distributed and there is no obvious hysteresis, indicating that the sample has superparamagnetism. The saturation magnetization of AMPS@Allyl@β-CD@Fe3O4 is 57.54 emu / g. Compared with the saturation magnetization of 84.7 emu / g of Fe3O4 nanoparticles in relevant data, the magnetic properties of the adsorbent decreased after β-cyclodextrin coating, allyl grafting, and sulfonation modification due to the increased content of non-ferromagnetic polymers covering the magnetic core surface. However, the prepared adsorbent can still perform good magnetic separation under the guidance of an external magnetic field.

[0121] Figure 3 The X-ray diffraction pattern is shown for the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1; where (a) is the diffraction peak of the PDF#99-0073 crystal plane of Fe3O4, and (b) is the X-ray diffraction curve of AMPS@Allyl@β-CD@Fe3O4.

[0122] To investigate the crystal structure of the synthesized material, the XRD pattern of AMPS@Allyl@β-CD@Fe3O4 was analyzed and measured. The test results are as follows: Figure 3As shown. The diffraction peaks of Fe3O4 at 18.29, 30.08, 35.43, 43.05, 53.41, 56.94, 62.52, 73.96 and 86.70 on PDF#99-0073 (111), (220), (311), (400), (422), (511), (440), (533) and (642) are highly consistent with the characteristic peaks of the magnetic adsorbent AMPS@Allyl@β-CD@Fe3O4, indicating that the addition of β-cyclodextrin, allyl and 2-acrylamido-2-methyl-1-propanesulfonic acid has almost no effect on the crystal structure of the nanoparticles.

[0123] Figure 4 The images show the X-ray photoelectron spectra of the sulfonated magnetic cyclodextrin composite adsorbent prepared in Example 1 and the adsorbent after adsorbing pollutants; where (a) is the X-ray photoelectron spectra of AMPS@Allyl@β-CD@Fe3O4, (b) is the X-ray photoelectron spectra of AMPS@Allyl@β-CD@Fe3O4 after adsorbing moxifloxacin, and (c) is the X-ray photoelectron spectra of AMPS@Allyl@β-CD@Fe3O4 after adsorbing Cu(II).

[0124] XPS analysis can further determine the elemental composition of the prepared adsorbent and whether it successfully adsorbed pollutants. The results are as follows: Figure 4 As shown. The Fe 2p peak appearing on AMPS@Allyl@β-CD@Fe3O4 indicates that β-cyclodextrin was successfully coated on the surface of Fe3O4 nanoparticles. Furthermore, the appearance of the S2p and N1s peaks indicates successful grafting of 2-acrylamido-2-methyl-1-propanesulfonic acid, consistent with the results of FTIR analysis. The F1s and Cu peaks appearing on MOX+AMPS@Allyl@β-CD@Fe3O4... 2+ The presence of Cu 2p on +AMPS@Allyl@β-CD@Fe3O4 indicates that the prepared adsorbent successfully adsorbed the pollutants moxifloxacin and Cu(II).

[0125] VII. Adsorbent Regeneration

[0126] The reusability of adsorbents is considered a key economic indicator for practical applications. Using a 0.1 mol / L hydrochloric acid solution at pH 1.0 as the desorbent, five adsorption-desorption cycle experiments were conducted to evaluate the reusability of AMPS@Allyl@β-CD@Fe3O4. The specific steps are as follows:

[0127] 55 mg of sulfonated magnetic cyclodextrin composite adsorbent (AMPS@Allyl@β-CD@Fe3O4) was added to 220 mL of moxifloxacin solution (pH 7.0) with an initial concentration of 50 mg / L and Cu(II) solution (pH 5.0), respectively, and the reaction was mechanically stirred for 6 h. After the reaction, AMPS@Allyl@β-CD@Fe3O4 after adsorbing moxifloxacin and Cu(II) was recovered by magnetic separation, respectively. Then, they were added to 110 mL of desorption buffer (0.1 mol / L hydrochloric acid solution (pH 1.0)) and stirred for another 3 h to ensure complete desorption of both materials, thereby regenerating the adsorbent (the volume ratio of pollutant solution to desorption buffer was 2:1, which can concentrate the pollutants moxifloxacin and Cu(II)). After the reaction, the regenerated adsorbent was repeatedly washed with ultrapure water, dried, and used for the next adsorption experiment. The adsorption-desorption cycle was repeated 5 times under the same experimental conditions to investigate the cyclic regeneration effect of the adsorbent AMPS@Allyl@β-CD@Fe3O4.

[0128] The desorption experiments showed that the adsorption capacity of AMPS@Allyl@β-CD@Fe3O4 for moxifloxacin decreased with increasing cycle number, from an initial 86.37 mg / g to 58.24 mg / g in the fifth cycle. The adsorption capacity for Cu(II) also decreased with increasing cycle number, from an initial 19.99 mg / g to 12.26 mg / g in the fifth cycle. The main reason is likely that the adsorption sites on the adsorbent are not completely desorbed during the desorption process, resulting in partial loss of active sites. Furthermore, the adsorbent is also lost during the adsorption-desorption cycle washing steps, leading to a decrease in overall adsorption capacity.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a sulfonated magnetic cyclodextrin composite adsorbent, characterized in that, Includes the following steps: Step 1: Coating Fe3O4 nanoparticles with β-cyclodextrin to obtain β-CD@Fe3O4 magnetic microparticles; Step 2: Allyl groups are introduced onto the surface of the β-CD@Fe3O4 magnetic microparticles obtained in Step 1 to obtain magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4; Step 3: Graft 2-acrylamido-2-methyl-1-propanesulfonic acid onto the surface of the magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 obtained in Step 2 to obtain the sulfonated magnetic cyclodextrin composite adsorbent; wherein the mass ratio of the magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 to 2-acrylamido-2-methyl-1-propanesulfonic acid is 1:(1~2.5), and the grafting reaction is carried out at 40~60 °C for 2~4 h.

2. The preparation method of the sulfonated magnetic cyclodextrin composite adsorbent according to claim 1, characterized in that, In step 1, β-CD@Fe3O4 magnetic microparticles were prepared by coating Fe3O4 nanoparticles with β-cyclodextrin using reverse emulsion polymerization.

3. The preparation method of the sulfonated magnetic cyclodextrin composite adsorbent according to claim 2, characterized in that, The specific steps of the reverse emulsion polymerization method are as follows: At 50 °C, β-cyclodextrin was dissolved in a 20% sodium hydroxide solution until a transparent paste was formed. After cooling to room temperature, Fe3O4 nanoparticles were added and the mixture was stirred continuously until a uniform black paste-like β-CD@Fe3O4 mixture was obtained. This mixture was then added to a mixture of liquid paraffin and Span-80. After heating to 35 °C, liquid epichlorohydrin was added. The mixture was stirred for 8-12 h to form a water-in-oil emulsion. The emulsion was broken with anhydrous ethanol and allowed to stand. Solid-liquid magnetic separation was performed. The mixture was washed several times with anhydrous ethanol and pure water, dried, and ground to obtain β-CD@Fe3O4 magnetic microparticles. The mass ratio of Fe3O4 to β-cyclodextrin was 1:(2-4); the volume ratio of Span-80 to liquid paraffin was 1:(50-100); and 2.8-3.5 mL of liquid epichlorohydrin was added per 100 mL of the reaction system solution.

4. The preparation method of the sulfonated magnetic cyclodextrin composite adsorbent according to claim 3, characterized in that, Fe3O4 nanoparticles and β-cyclodextrin were mixed and stirred at room temperature for 45 min at a stirring speed of 300 rpm; liquid paraffin and Span-80 were mixed and stirred at 30 °C for 30 min at a stirring speed of 800 rpm.

5. The preparation method of the sulfonated magnetic cyclodextrin composite adsorbent according to claim 1, characterized in that, In step 2, the allyl group is introduced through the following steps: The β-CD@Fe3O4 magnetic microparticles obtained in step 1 were dissolved in anhydrous N,N-dimethylformamide / anhydrous dimethyl sulfoxide at a volume ratio of 1:

1. After the reaction was fully completed by stirring continuously at 800 rpm for 1 h at 30 ℃, sodium hydroxide solid was added and stirring was continued for another 1 h. The temperature was adjusted to 20 ℃, and liquid propylene bromide was slowly added under nitrogen protection. The mixture was stirred at 1000 rpm for 12-24 h and then allowed to stand. Solid-liquid magnetic separation was performed, and the microparticles were washed repeatedly with anhydrous ethanol and pure water. After drying and grinding, magnetic allyl β-cyclodextrin composite microparticles Allyl@β-CD@Fe3O4 were obtained. The mass ratio of β-CD@Fe3O4 magnetic microparticles to liquid propylene bromide was 1:

1.

6. The preparation method of the sulfonated magnetic cyclodextrin composite adsorbent according to claim 1, characterized in that, In step 3, potassium persulfate is added as an initiator, and the concentration of potassium persulfate is 0.05 g / mL.

7. An application of a sulfonated magnetic cyclodextrin composite adsorbent, characterized in that, The sulfonated magnetic cyclodextrin composite adsorbent prepared by the preparation method according to any one of claims 1 to 6 can be used to remove moxifloxacin and / or copper ions from wastewater.

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