Sulfobetaine-modified montmorillonite composite material, method for preparing same, and use thereof

Abstract

The application discloses a sulfobetaine-modified montmorillonite composite material and a preparation method and application thereof, and the preparation method comprises the following steps: acidizing montmorillonite, and reacting the obtained acidized montmorillonite with a sulfobetaine dispersion solution, wherein the sulfobetaine contained in the sulfobetaine dispersion solution comprises at least one of sulfobetaine 8, sulfobetaine 10, dodecyldimethylsulfopropyl betaine, 3-sulfopropyl tetradecyl dimethyl betaine and 3-sulfopropyl hexadecyl dimethyl betaine. The sulfobetaine-modified montmorillonite composite material prepared by the application has the advantages of low cost, high adsorption capacity, high adsorption efficiency, strong anti-interference ability, good dispersibility, easy separation, green environmental protection and the like, is a novel adsorbent with excellent adsorption performance, and can be widely used for treating organic pollutant wastewater, can quickly adsorb and remove organic pollutants in the wastewater under the premise of less dosage, has high use value and good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of environmentally friendly adsorption materials technology, and relates to a sulfobetaine-modified montmorillonite composite material, its preparation method and application. Background Technology

[0002] With the rapid development of technology, various chemicals are constantly being produced and used, leading to a continuous influx of emerging organic pollutants into the environment and creating new environmental risks. These pollutants are characterized by their high degree of concealment, difficulty in degradation, carcinogenicity, and reproductive toxicity. Taking antibiotics as an example, doxycycline, as a new pollutant, poses a potential threat to both human health and the environment. Doxycycline has a wide range of sources, entering water bodies through domestic sewage, aquaculture wastewater, pharmaceutical wastewater, and medical wastewater, where it migrates and transforms within the environment. On the one hand, doxycycline inhibits the growth of beneficial microorganisms in water bodies, leading to the proliferation of drug-resistant microorganisms and disrupting the microbial balance of the aquatic ecosystem. It also has toxic effects on other aquatic organisms, such as freshwater algae and zooplankton, affecting the species richness of aquatic life. On the other hand, because doxycycline readily forms chelates with calcium and magnesium ions in the environment, it is difficult to detect in the aqueous phase. This means that water treatment processes may not completely remove this antibiotic, leading to the risk of long-term low-dose antibiotic intake. This long-term exposure may cause bacteria in the human body to develop drug resistance, potentially causing serious environmental and health problems. Therefore, removing new pollutants from the environment is urgently needed.

[0003] Currently, methods commonly used to treat new pollutants include biodegradation, advanced oxidation, photodegradation, electrolysis, and adsorption. Among these, adsorption has received widespread attention due to its advantages such as simple and intuitive operation, diverse types, high treatment efficiency, and good effluent quality. However, it also has disadvantages such as limited adsorption capacity, complex regeneration, and potential secondary pollution. Therefore, it is necessary to develop more environmentally friendly, green, and efficient adsorbent materials.

[0004] Montmorillonite is widely used as an adsorbent due to its excellent adsorption properties, abundant natural resources, and low cost. In particular, its adsorption performance can be improved through various modification methods, expanding its application in the treatment of new pollutants. However, several drawbacks need to be overcome to make it effective in daily life: Firstly, the adsorption process of montmorillonite requires a long time to reach equilibrium, and its adsorption kinetics are relatively slow, making it difficult to cope with sudden water pollution events, thus limiting its application. Secondly, the adsorption process of montmorillonite is affected by the content of impurities in the water. These impurities may compete with pollutants for adsorption sites or change the charge properties of the montmorillonite surface, thereby affecting its adsorption of target pollutants. These drawbacks not only affect water treatment efficiency but also increase water treatment costs, greatly limiting the practical application of montmorillonite adsorbents in water treatment. For example, some researchers have proposed a method to modify montmorillonite using surfactants (dodecyl betaine or dodecyl sulfobetaine). However, the modified montmorillonite adsorbent obtained in this way still suffers from drawbacks such as susceptibility to water quality, poor adsorption efficiency, and easy aggregation. Furthermore, the excessive use of surfactants in the preparation process not only hinders cost reduction but also easily leads to secondary pollution. Additionally, some researchers have proposed a method to modify sodium-based montmorillonite using hydroxymethyl chitosan. However, the resulting carboxymethyl chitosan-modified montmorillonite still suffers from poor adsorption capacity and low adsorption efficiency, making it difficult to achieve efficient adsorption of pollutants with lower dosages. Therefore, obtaining a low-cost, high-capacity, high-efficiency, highly resistant to interference, well-dispersed, easily separable, and environmentally friendly modified montmorillonite adsorbent is of great significance for the effective removal of antibiotics from wastewater. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a sulfobetaine-modified montmorillonite composite material with low cost, high adsorption capacity, high adsorption efficiency, strong anti-interference ability, good dispersion and easy separation, and green environmental protection, as well as its preparation method and application.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A method for preparing a sulfobetaine-modified montmorillonite composite material includes the following steps:

[0008] S1. Acidification of montmorillonite yields acidified montmorillonite;

[0009] S2. The acidified montmorillonite obtained in step S1 is mixed with a sulfobetaine dispersion and reacted to obtain a sulfobetaine-modified montmorillonite composite material; the sulfobetaine dispersion contains at least one of thiobetaine 8, thiobetaine 10, dodecyl dimethyl sulfopropyl betaine, 3-sulfopropyl tetradecyl dimethyl betaine, and 3-sulfopropyl hexadecyl dimethyl betaine.

[0010] In a further improvement to the above preparation method, in step S2, the mass ratio of sulfobetaine in the sulfobetaine dispersion to the acidified montmorillonite is 0.05 to 0.4:1.

[0011] In a further improvement to the above preparation method, in step S2, the sulfobetaine dispersion is prepared by the following method: sulfobetaine is mixed with a solvent and ultrasonically dispersed at a temperature of 25℃~35℃ for 10min~30min to obtain the sulfobetaine dispersion; the concentration of the sulfobetaine dispersion is 0.5g / L~4g / L; and the solvent is ultrapure water.

[0012] In a further improvement to the above preparation method, in step S2, the reaction is carried out under stirring conditions; the reaction temperature is 30℃~70℃; the stirring speed is 300rpm~500rpm; the stirring time is 18h~30h; after the reaction is completed, the following treatment is also included: the product obtained after the reaction is centrifuged, washed, and dried at a temperature of 70℃ for 18h~30h to obtain sulfobetaine-modified montmorillonite composite material.

[0013] In a further improvement to the above preparation method, in step S1, montmorillonite is acidified with an acid solution; the mass-to-volume ratio of montmorillonite to acid solution is 1 g: 10 mL; the concentration of the acid solution is 1 mol / L to 2 mol / L; the acid solution is a sulfuric acid solution; the montmorillonite is montmorillonite K-10; the montmorillonite is further treated before use by drying at 50℃ to 80℃ for 18 h to 30 h; the acidification is carried out at a temperature of 40℃ to 70℃ for 18 h to 30 h; after the acidification is completed, the following treatment is further carried out: the product obtained after acidification is centrifuged, washed, and dried at a temperature of 70℃ for 18 h to 30 h to obtain acidified montmorillonite.

[0014] As a general technical concept, the present invention also provides a sulfobetaine-modified montmorillonite composite material, which is prepared by the preparation method described above.

[0015] The above-mentioned sulfobetaine-modified montmorillonite composite material is further improved in that the sulfobetaine-modified montmorillonite composite material includes sulfobetaine and montmorillonite; the sulfobetaine is loaded on the montmorillonite.

[0016] As a general technical concept, the present invention also provides an application of the above-mentioned sulfobetaine-modified montmorillonite composite material in the treatment of antibiotic wastewater.

[0017] Further improvements to the above application include the following steps: mixing the sulfobetaine-modified montmorillonite composite material with antibiotic wastewater for adsorption treatment to complete the treatment of antibiotic wastewater; the amount of the sulfobetaine-modified montmorillonite composite material added is 0.05g to 0.25g per liter of antibiotic wastewater.

[0018] In a further improvement to the above application, the concentration of antibiotics in the antibiotic wastewater is 5 mg / L to 25 mg / L; the antibiotic is at least one of doxycycline, tetracycline, ciprofloxacin, and ofloxacin; the pH value of the antibiotic wastewater is 4 to 8; the adsorption treatment is carried out under stirring conditions at a speed of 300 rpm to 500 rpm; the temperature of the adsorption treatment is 15℃ to 35℃; and the time of the adsorption treatment is 20 min to 200 min.

[0019] Compared with the prior art, the advantages of the present invention are as follows:

[0020] (1) In view of the shortcomings of existing modified montmorillonite adsorbents, such as poor adsorption capacity, strong anti-interference ability, and easy agglomeration, as well as the resulting defects such as high dosage, low adsorption efficiency, and poor adaptability, this invention creatively proposes a method for preparing sulfobetaine-modified montmorillonite composite material. First, the montmorillonite is acidified, which not only improves the morphology and structure of montmorillonite and provides more favorable spatial conditions for sulfobetaine molecules to enter the interlayer of montmorillonite, but also changes the charge distribution and properties on the surface of montmorillonite, which is conducive to promoting the interaction between montmorillonite and sulfobetaine with zwitterionic structure. At the same time, it can also destroy the interlayer of montmorillonite particles. The aggregated structure is beneficial for improving the dispersibility of montmorillonite. Based on this, acidified montmorillonite is mixed with a sulfobetaine dispersion for reaction. This allows for the modification of acidified montmorillonite with sulfobetaine to prepare a high-performance sulfobetaine-modified montmorillonite composite material. Specifically, by improving the morphology and structure of montmorillonite, the pore size and interlayer spacing can be increased. This allows sulfobetaine to penetrate deeper into the interlayer structure of montmorillonite, achieving more complete modification and better leveraging the performance advantages of sulfobetaine, such as improving the hydrophilicity and antistatic properties of montmorillonite. While improving electrical properties, the increase in interlayer spacing of montmorillonite leads to the formation of small channels, resulting in smaller pore sizes, larger pore volumes, and a higher proportion of mesoporous structures. This, to some extent, increases the specific surface area, adds adsorption sites, and improves adsorption performance. Furthermore, by altering the charge distribution and properties of the montmorillonite surface, electrostatic attraction can facilitate the more effective attraction of sulfobetaine molecules. This promotes the rapid binding of acidified montmorillonite with sulfobetaine, enabling effective modification of montmorillonite with sulfobetaine even with lower sulfobetaine dosage, making the modification process easier, and enhancing the adsorption performance of montmorillonite with sulfobetaine. The stronger bond between sulfobetaine particles enhances the structural stability of the material. Third, by improving the dispersibility of montmorillonite, it promotes the absorption of more sulfobetaine, allowing montmorillonite particles to contact and react more evenly with sulfobetaine, preventing over- or under-modification in certain areas. This ensures the consistency and uniformity of the modification effect, improves the quality stability of the modified montmorillonite product, and, more importantly, enhances the adsorption effect of sulfobetaine on montmorillonite, promoting its uniform dispersion on the montmorillonite surface and forming a protective film. This protective film can then be used to prevent the aggregation of montmorillonite particles.Compared with conventional modified montmorillonite adsorbents, the sulfobetaine-modified montmorillonite composite material prepared in this invention has the following advantages: (a) Excellent adsorption performance. By improving the structural morphology of montmorillonite and introducing sulfobetaine, not only can the specific surface area and the number of adsorption sites of the composite material be increased, but the affinity of the composite material for organic pollutants (such as antibiotics) can also be enhanced, thereby making the sulfobetaine-modified montmorillonite composite material have a higher adsorption capacity and higher adsorption efficiency, and enabling more efficient adsorption of organic pollutants under conditions of lower dosage; (b) Strong anti-interference ability. Introducing sulfobetaine onto the surface of montmorillonite allows for the utilization of its surface functional groups, enabling the sulfobetaine-modified montmorillonite composite material to possess multiple adsorption mechanisms, such as physical and chemical adsorption. This not only allows the surface functional groups of sulfobetaine to adjust the pH value of the system, enabling the composite material to adapt to different pH conditions, but also allows the surface functional groups of sulfobetaine to interact with functional groups in organic pollutants, forming specific binding bonds. This reduces interference from cations and anions in the system, allowing the composite material to adapt to various pH conditions. (c) It has good dispersibility and is easy to separate. Acidification can improve the dispersibility of montmorillonite, and by forming a sulfobetaine protective film on the surface of montmorillonite, it can prevent the aggregation of montmorillonite particles. Therefore, the sulfobetaine-modified montmorillonite composite material can maintain a good dispersion state in the solution, which is conducive to its long-term adsorption in the solution. Solid-liquid separation can be achieved simply by standing, which is convenient for the recovery of the adsorbent; (d) It is low-cost and environmentally friendly. The montmorillonite used is abundant in nature and widely distributed. The acquisition cost is relatively low, and it is environmentally friendly. The environmental impact is relatively small, and the adsorbed montmorillonite can be disposed of through landfill or other methods. It exhibits good stability and is a low-cost, environmentally friendly material. Furthermore, the sulfobetaine used, as an important amphoteric surfactant, possesses excellent surface activity, maintaining good surface activity and solubility even in high-salt solutions. It is not prone to electrolysis or phase separation, remains stable over a wide pH range, and can undergo hydrolysis under certain conditions, exhibiting biodegradability and high environmental friendliness. Therefore, it can be used as a corrosion inhibitor and scale inhibitor, forming stable complexes with calcium and magnesium ions in water. In addition, the preparation method of this invention allows for the preparation of high-performance sulfobetaine-modified montmorillonite composite materials with a smaller amount of sulfobetaine, which helps reduce preparation costs. The sulfobetaine-modified montmorillonite composite material prepared by this invention has the advantages of low cost, high adsorption capacity, high adsorption efficiency, strong anti-interference ability, good dispersion and easy separation, and green environmental protection. It is a new type of adsorbent with excellent adsorption performance and can be widely used to treat organic pollutant wastewater. It can quickly adsorb and remove organic pollutants in wastewater with less dosage, and has high use value and good application prospects.

[0021] (2) In the preparation method of the present invention, sulfuric acid solution is used as acid solution to acidify montmorillonite. The chemical environment of the surface and interlayer of the prepared acidified montmorillonite is more conducive to subsequent modification treatment. At the same time, it can also facilitate further reaction with organic reagents, etc., to achieve further optimization and customization of montmorillonite performance to meet the special needs of different application fields. This is something that other acid solutions do not have.

[0022] (3) The present invention also provides an application of sulfobetaine-modified montmorillonite composite material in the treatment of antibiotic wastewater. Specifically, the sulfobetaine-modified montmorillonite composite material is mixed with antibiotic wastewater for adsorption treatment. The adsorption of antibiotics in the wastewater can be achieved by stirring. It has the advantages of good adsorption effect, high adsorption efficiency, simple operation, low cost, and easy separation after adsorption. It can effectively remove antibiotics from wastewater and is of great significance for the effective purification of antibiotic wastewater. Attached Figure Description

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0024] Figure 1 The images show scanning electron microscope (SEM) images of the thiobetaine 8-modified montmorillonite composite material (AM8) and the original montmorillonite (CK) prepared in Example 1 of this invention.

[0025] Figure 2 Fourier transform infrared spectra of the sulfobetaine-modified montmorillonite composite materials (AM8, AM10, AM12, AM14, AM16) prepared in Example 1 of this invention.

[0026] Figure 3 This is a comparison chart showing the adsorption effect of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline under different KCl ion strengths in Example 2 of the present invention.

[0027] Figure 4 This is a comparison chart showing the adsorption effect of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline under different NaCl ion strengths in Example 2 of the present invention.

[0028] Figure 5 This is a comparison of the adsorption effects of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline under different pH conditions in Example 3 of the present invention.

[0029] Figure 6 This is a graph showing the adsorption effect of the thiobetaine 8-modified montmorillonite composite material (AM8) on different types of antibiotics in Example 4 of the present invention.

[0030] Figure 7 This is a comparison chart of the adsorption effects of sulfobetaine-modified montmorillonite composite materials (AM8, AM10, AM12, AM14, AM16) and sulfobetaine-montmorillonite composite materials (M8, M10, M12, M14, M16) on doxycycline in Example 5 of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0032] In the following embodiments of the present invention, unless otherwise specified, the materials and instruments used are commercially available, the equipment used is conventional equipment, and the data obtained are the average values ​​of more than three repeated experiments.

[0033] Example 1

[0034] A method for preparing a sulfobetaine-modified montmorillonite composite material, specifically comprising: modifying acidified montmorillonite with thiobetaine 8, including the following steps:

[0035] (1) Place K-10 montmorillonite in an oven and dry it at 70℃ for 24 hours to obtain dried montmorillonite, denoted as CK.

[0036] (2) Place 10g of dried montmorillonite into 100mL of 1mol / L sulfuric acid solution and stir mechanically at 40℃ for 24h. Then centrifuge, wash, discard the supernatant, put the precipitate into an oven and dry at 70℃ for 24h, collect and store to obtain acidified montmorillonite.

[0037] (3) Disperse 0.1g of thiobetaine 8 in 100mL of ultrapure water by ultrasonication and sonicate at 25℃ for 10min to obtain thiobetaine 8 dispersion.

[0038] (4) 1g of the acidified montmorillonite obtained in step (2) was placed into the thiobetaine 8 dispersion obtained in step (3), and mechanically stirred for 24h at 40℃ and 500rpm. After centrifugation, the supernatant was washed with deionized water and ethanol until it became clear. The supernatant was dried at 70℃ for 24h to obtain the thiobetaine 8-modified montmorillonite composite material, denoted as AM8.

[0039] In this embodiment, different types of sulfobetaine were also used to prepare sulfobetaine-modified montmorillonite composite materials, which were basically the same as in Example 1, except that thiobetaine 10, dodecyl dimethyl sulfopropyl betaine, 3-sulfopropyl tetradecyl dimethyl betaine, and 3-sulfopropyl hexadecyl dimethyl betaine were used instead of thiobetaine 8. When the sulfobetaine was thiobetaine 10, dodecyl dimethyl sulfopropyl betaine, 3-sulfopropyl tetradecyl dimethyl betaine, or 3-sulfopropyl hexadecyl dimethyl betaine, the results were thiobetaine 10 modified montmorillonite composite material, dodecyl dimethyl sulfopropyl betaine-modified montmorillonite composite material, 3-sulfopropyl tetradecyl dimethyl betaine-modified montmorillonite composite material, and 3-sulfopropyl hexadecyl dimethyl betaine-modified montmorillonite composite material, respectively, and were denoted as AM10, AM12, AM14, and AM16.

[0040] In this embodiment, different types of sulfobetaine were also used to prepare sulfobetaine-montmorillonite composite materials, which were basically the same as in Example 1, except that: thiobetaine 8, thiobetaine 10, dodecyl dimethyl sulfopropyl betaine, 3-sulfopropyl tetradecyl dimethyl betaine, and 3-sulfopropyl hexadecyl dimethyl betaine were used as sulfobetaine, and dry montmorillonite (unacidified) was used instead of acidified montmorillonite. Specifically, when the sulfobetaine was thiobetaine 8, thiobetaine 10, dodecyl dimethyl sulfopropyl betaine, etc., the sulfobetaine-montmorillonite composite material was prepared. When methyl sulfopropyl betaine, 3-sulfopropyltetradecyl dimethyl betaine, and 3-sulfopropylhexadecyl dimethyl betaine are used, they are respectively thiobetaine-8-montmorillonite composite material, thiobetaine-10-montmorillonite composite material, dodecyl dimethyl sulfopropyl betaine-montmorillonite composite material, 3-sulfopropyltetradecyl dimethyl betaine-montmorillonite composite material, and 3-sulfopropylhexadecyl dimethyl betaine-montmorillonite composite material, and are respectively denoted as M8, M10, M12, M14, and M16.

[0041] Figure 1 The images show scanning electron microscope (SEM) images of the thiobetaine 8-modified montmorillonite composite material (AM8) and the original montmorillonite (CK) prepared in Example 1 of this invention. Figure 1 In the diagram, (a) and (b) represent CK, and (c) and (d) represent AM8. (From...) Figure 1 As shown in (a) and (b), the unmodified montmorillonite has a flat surface structure, a smooth surface, and a clear layered structure. Figure 1 (c) It can be seen that after modification with thiobetaine 8, the montmorillonite crystal layer exhibits obvious curling; Figure 1 (d) It can be seen that after acid activation and surfactant modification, montmorillonite is composed of a large number of broken crystalline layers, in a loose sheet-like aggregate state, with irregular curling or wrinkling structures on the surface.

[0042] To verify whether the introduction of sulfobetaine improves the dispersibility of montmorillonite, the N2 adsorption-desorption isotherms of thiobetaine 8-acidified montmorillonite and dried montmorillonite were measured. The specific surface area, pore size, pore volume, and other parameters of thiobetaine 8-acidified montmorillonite and dried montmorillonite were calculated using the Barrete-Joynere-Halenda model, as shown in Table 1. Table 1 shows that the specific surface area of ​​thiobetaine 8-acidified montmorillonite is increased compared to dried montmorillonite, indicating that the addition of sulfobetaine can improve the aggregation of montmorillonite and expand its specific surface area.

[0043] Table 1. Specific surface area, pore size, and pore volume of thiobetaine-modified montmorillonite and virgin montmorillonite.

[0044] <![CDATA[BET specific surface area (m 2 / g)]]> <![CDATA[Pore volume (cm 3 / g)]]> Aperture (nm) AM8 90.8061 0.154440 6.5727 CK 51.8665 0.125500 8.6214

[0045] Figure 2 The Fourier transform infrared spectra of the sulfobetaine-modified montmorillonite composite materials (AM8, AM10, AM12, AM14, AM16) prepared in Example 1 of this invention are shown below. Figure 2 It can be seen that, compared with unmodified montmorillonite, the sulfobetaine-modified montmorillonite composite material prepared in this invention has more peaks related to sulfobetaine, indicating that sulfobetaine is loaded onto montmorillonite.

[0046] Example 2

[0047] The anti-interference ability of sulfobetaine-modified montmorillonite composite material in treating antibiotic wastewater was investigated. Specifically, the sulfobetaine-modified montmorillonite composite material was used to adsorb and treat doxycycline wastewater, including the following steps:

[0048] Group 1: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a solution with a KCl concentration of 5 mg / L and a doxycycline concentration of 5 mg / L (the volume of the solution is 100 mL, and the pH value is 6.8), and place it under mechanical stirring at 25℃ and 400 rpm for 2 h to complete the treatment of doxycycline wastewater.

[0049] Group 2: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a solution with a KCl concentration of 10 mg / L and a doxycycline concentration of 5 mg / L (the volume of the solution is 100 mL, and the pH value is 6.8), and place it under mechanical stirring at 25℃ and 400 rpm for 2 h to complete the treatment of doxycycline wastewater.

[0050] Group 3: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a solution with a KCl concentration of 15 mg / L and a doxycycline concentration of 5 mg / L (the volume of the solution is 100 mL, and the pH value is 6.8), and place it under mechanical stirring at 25℃ and 400 rpm for 2 h to complete the treatment of doxycycline wastewater.

[0051] Group 4: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a solution with a KCl concentration of 20 mg / L and a doxycycline concentration of 5 mg / L (the volume of the solution is 100 mL, and the pH value is 6.8), and place it under mechanical stirring at 25℃ and 400 rpm for 2 h to complete the treatment of doxycycline wastewater.

[0052] Group 5: 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1 was added to a solution with a KCl concentration of 25 mg / L and a doxycycline concentration of 5 mg / L (the volume of the solution was 100 mL, and the pH was 6.8). The solution was mechanically stirred at 25°C and 400 rpm for 2 hours to complete the treatment of doxycycline wastewater.

[0053] After mechanical stirring and adsorption are complete, 1 mL of the treated solution is taken and the doxycycline content is determined by high performance liquid chromatography.

[0054] Figure 3 This is a comparison chart showing the adsorption effect of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline under different KCl ionic strengths in Example 2 of this invention. Figure 3 It was found that the removal rates of doxycycline were 97.76%, 98.26%, 98.47%, 97.42%, and 98.08% respectively when potassium chloride concentrations of 5 mg / L, 10 mg / L, 15 mg / L, 20 mg / L, and 25 mg / L were added to the wastewater. This indicates that adding potassium chloride to the wastewater does not affect the adsorption effect of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline. Furthermore, the adsorption effect of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline remained good with increasing KCl concentration, showing no significant change. This phenomenon confirms that the adsorption of doxycycline by thiobetaine 8-modified montmorillonite composite material (AM8) involves chemisorption, where the adsorption sites react with specific functional groups on the doxycycline molecule. KCl does not interfere with this specific chemical binding, and the KCl concentration does not have a significant effect on adsorption.

[0055] In this embodiment, the adsorption effect of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline under different KCl ionic strengths was also investigated. The results were basically the same as in Example 2, except that KCl was used instead of NaCl.

[0056] Figure 4 This is a comparison chart showing the adsorption effect of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline under different NaCl ionic strengths in Example 2 of this invention. Figure 4 It can be seen that adding sodium chloride to wastewater does not affect the adsorption effect of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline. Furthermore, with increasing NaCl concentration, the adsorption effect of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline remains good without significant change. This result is consistent with... Figure 3 Similar. Additionally, by Figure 4 It can be seen that when the addition amount of thiobetaine 8-modified montmorillonite composite material (AM8) is 10 mg / 100 mL, the removal rates of doxycycline in doxycycline wastewater with sodium chloride concentrations of 5 mg / L, 10 mg / L, 15 mg / L, 20 mg / L, and 25 mg / L after 20 min of adsorption treatment are 80.06%, 84.05%, 86.28%, 92.35%, and 79.24%, respectively. Therefore, the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in this invention can efficiently remove antibiotics from antibiotic wastewater with a smaller dosage.

[0057] Depend on Figure 3 and Figure 4 The results show that the sulfobetaine-modified montmorillonite composite material prepared in this invention exhibits excellent anti-interference ability.

[0058] Example 3

[0059] The adaptability of sulfobetaine-modified montmorillonite composite material in treating antibiotic wastewater with different pH values ​​was investigated. Specifically, the sulfobetaine-modified montmorillonite composite material was used to adsorb and treat doxycycline wastewater with different pH values, including the following steps:

[0060] Group 1: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a doxycycline solution with a pH of 3 and a concentration of 5 mg / L (the volume of the solution is 100 mL), and place it under mechanical stirring at 25 °C and 400 rpm for 2 h to complete the treatment of doxycycline wastewater.

[0061] Group 2: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a doxycycline solution with a pH of 5 and a concentration of 5 mg / L (the volume of the solution is 100 mL), and place it under mechanical stirring at 25 °C and 400 rpm for 2 h to complete the treatment of doxycycline wastewater.

[0062] Group 3: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a doxycycline solution with a pH of 7 and a concentration of 5 mg / L (the volume of the solution is 100 mL), and place it under mechanical stirring at 25 °C and 400 rpm for 2 h to complete the treatment of doxycycline wastewater.

[0063] Group 4: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a doxycycline solution with a pH of 9 and a concentration of 5 mg / L (the volume of the solution is 100 mL), and place it under mechanical stirring at 25 °C and 400 rpm for 2 h to complete the treatment of doxycycline wastewater.

[0064] Group 5: 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1 was added to a doxycycline solution (pH 11, concentration 5 mg / L, volume 100 mL). The solution was mechanically stirred at 25°C and 400 rpm for 2 hours to complete the treatment of doxycycline wastewater.

[0065] After mechanical stirring and adsorption are complete, 1 mL of the treated solution is taken and the doxycycline content is determined by high performance liquid chromatography.

[0066] Figure 5 Figure 5 shows a comparison of the adsorption effect of thiobetaine 8-modified montmorillonite composite material (AM8) on doxycycline under different pH conditions in Example 3 of this invention. As shown in Figure 5, thiobetaine 8-modified montmorillonite maintained a high adsorption rate for doxycycline at pH values ​​from 3 to 9. In an acidic environment, the amino group on doxycycline undergoes protonation and becomes positively charged, while the surface of the thiobetaine 8-modified montmorillonite composite material (AM8) is negatively charged, thus improving adsorption efficiency through electrostatic attraction. However, as the pH increases, the negative charge on the surface of the thiobetaine 8-modified montmorillonite composite material (AM8) increases, and the doxycycline molecule also becomes negatively charged, leading to a decrease in adsorption efficiency. It is evident that the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in this invention exhibits a strong electrostatic attraction with doxycycline. Furthermore, when the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in this invention is used to treat antibiotic wastewater, it demonstrates excellent adsorption capacity for antibiotic wastewater with pH values ​​ranging from 3 to 9, and shows good adaptability to water bodies with different pH values.

[0067] Example 4

[0068] An application of a sulfobetaine-modified montmorillonite composite material in the treatment of antibiotic wastewater specifically involves using the sulfobetaine-modified montmorillonite composite material to adsorb and treat doxycycline (DCH) wastewater, tetracycline (TC) wastewater, ofloxacin (OF) wastewater, ciprofloxacin (CIP) wastewater, and norfloxacin (NOR) wastewater, respectively, including the following steps:

[0069] Group 1: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a doxycycline (DCH) solution with a concentration of 5 mg / L (the volume of the solution is 100 mL, and the pH value is 6.8), and place it under mechanical stirring at 25℃ and 400 rpm for 2 h to complete the treatment of wastewater.

[0070] Group 2: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a tetracycline (TC) solution with a concentration of 5 mg / L (the volume of the solution is 100 mL, and the pH value is 6.4), and place it under mechanical stirring at 25℃ and 400 rpm for 2 h to complete the treatment of wastewater.

[0071] Group 3: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to an ofloxacin (OF) solution with a concentration of 5 mg / L (the volume of the solution is 100 mL, and the pH value is 6.7), and place it under mechanical stirring at 25℃ and 400 rpm for 2 h to complete the treatment of wastewater.

[0072] Group 4: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a 5 mg / L ciprofloxacin (CIP) solution (the volume of the solution is 100 mL, and the pH value is 7.1), and place it under mechanical stirring at 25℃ and 400 rpm for 2 h to complete the treatment of wastewater.

[0073] Group 5: Take 10 mg of the thiobetaine 8-modified montmorillonite composite material (AM8) prepared in Example 1, add it to a 5 mg / L norfloxacin (NOR) solution (the volume of the solution is 100 mL, and the pH value is 5.9), and place it under mechanical stirring at 25℃ and 400 rpm for 2 h to complete the treatment of wastewater.

[0074] After mechanical stirring and adsorption are completed, 1 mL of the treated solution is taken and the antibiotic content in the wastewater is determined by high performance liquid chromatography.

[0075] Figure 6 Figure 6 shows the adsorption effect of the thiobetaine 8-modified montmorillonite composite material (AM8) on different types of antibiotics in Example 4 of this invention. As can be seen from Figure 6, after 2 hours of treatment, the removal rates of doxycycline (DCH), tetracycline (TC), ofloxacin (OF), ciprofloxacin (CIP), and norfloxacin (NOR) in wastewater prepared by the thiobetaine 8-modified montmorillonite composite material (AM8) of this invention are 98.47%, 98.85%, 96.65%, 98.03%, and 97.35%, respectively. It is evident that the thiobetaine-modified montmorillonite composite material prepared by this invention has good adsorption effects on different types of antibiotics and can effectively remove antibiotics from water bodies, thereby achieving effective purification of antibiotic wastewater. This indicates that the thiobetaine-modified montmorillonite composite material of this invention can be widely used in the purification of different water bodies such as rivers, lakes, and groundwater, with high application value and promising prospects. It is of great significance for improving water quality and protecting aquatic ecosystems.

[0076] Example 5

[0077] An application of a sulfobetaine-modified montmorillonite composite material in the treatment of antibiotic wastewater, specifically, the adsorption treatment of doxycycline (DCH) wastewater using the sulfobetaine-modified montmorillonite composite material, including the following steps:

[0078] Group 1: Take 5 mg of the sulfobetaine-modified montmorillonite composite materials (AM8, AM10, AM12, AM14, AM16) prepared in Example 1, and add them to a 10 mg / L doxycycline (DCH) solution (100 mL in volume, pH 6.8). The solution is then mechanically stirred at 25 °C and 400 rpm for 2 h to adsorb the wastewater.

[0079] Group 2: Take 5 mg of the sulfobetaine-montmorillonite composite materials (M8, M10, M12, M14, M16) prepared in Example 1, and add them to a 10 mg / L doxycycline (DCH) solution (100 mL in volume, pH 6.8). The solution is then mechanically stirred at 25 °C and 400 rpm for 2 h to adsorb the wastewater.

[0080] After mechanical stirring and adsorption are complete, 1 mL of the treated solution is taken and the doxycycline content is determined by high performance liquid chromatography.

[0081] Figure 7 This is a comparison of the adsorption effects of sulfobetaine-modified montmorillonite composite materials (AM8, AM10, AM12, AM14, AM16) and sulfobetaine-montmorillonite composite materials (M8, M10, M12, M14, M16) on doxycycline in Example 5 of this invention. Figure 7 It can be seen that the removal rates of doxycycline by sulfobetaine-modified montmorillonite composite materials (AM8, AM10, AM12, AM14, AM16) after 2 hours of stirring and adsorption were 70.02%, 63.74%, 67.81%, 59.91%, and 44.33%, respectively. Under the same conditions, the removal rates of doxycycline by sulfobetaine-montmorillonite composite materials (M8, M10, M12, M14, M16) were 44.37%, 29.68%, 44.40%, 22.94%, and 34.73%, respectively. Therefore, acidification of montmorillonite beforehand is beneficial for improving the adsorption performance of sulfobetaine-modified montmorillonite composites. This is likely because: firstly, acidification introduces hydrogen ions, altering the surface charge of montmorillonite and enhancing its adsorption of polar molecules or ions; secondly, appropriate acidification can enlarge the pore size of montmorillonite, allowing it to accommodate larger molecules and thus improving its adsorption capacity for macromolecular pollutants such as organic matter. Furthermore, acidification reduces particle agglomeration, thereby improving its dispersion stability within the system and enhancing the composite material's performance.

[0082] The results above show that, compared with conventional modified montmorillonite adsorbents, the sulfobetaine-modified montmorillonite composite material prepared in this invention has the following advantages: (a) Excellent adsorption performance. By improving the structural morphology of montmorillonite and introducing sulfobetaine, not only can the specific surface area and the number of adsorption sites of the composite material be increased, but the affinity of the composite material for organic pollutants (such as antibiotics) can also be enhanced, thereby making the sulfobetaine-modified montmorillonite composite material have higher adsorption capacity and higher adsorption efficiency, and enabling more efficient adsorption of organic pollutants under conditions of lower dosage; (b) Anti-interference. With strong adsorption capacity, by introducing sulfobetaine onto the surface of montmorillonite, the surface functional groups of sulfobetaine can be utilized to enable the sulfobetaine-modified montmorillonite composite material to possess multiple adsorption mechanisms, such as physical adsorption and chemical adsorption. Not only can the surface functional groups of sulfobetaine adjust the pH value of the system, allowing the composite material to adapt to different pH conditions, but the surface functional groups of sulfobetaine can also interact with the functional groups of organic pollutants, forming specific bindings. This reduces the interference from cations and anions present in the system, enabling the composite material to... (c) It is adaptable to wastewater containing a large number of coexisting ions; (d) It has good dispersibility and is easy to separate. Acidification can improve the dispersibility of montmorillonite, and by forming a sulfobetaine protective film on the surface of montmorillonite, it can prevent the aggregation of montmorillonite particles. Therefore, the sulfobetaine-modified montmorillonite composite material can maintain a good dispersion state in the solution, which is conducive to its long-term adsorption effect in the solution. Solid-liquid separation can be achieved simply by standing, which is convenient for the recovery of the adsorbent; (e) It is low in cost and environmentally friendly. The montmorillonite used is abundant in nature and widely distributed, and the acquisition cost is relatively low. The material exhibits minimal environmental impact, and the adsorbed montmorillonite can be disposed of through landfilling. It demonstrates good stability and is a low-cost, environmentally friendly material. Furthermore, the sulfobetaine used, as an important amphoteric surfactant, possesses excellent surface activity, maintaining good surface activity and solubility even in high-salt solutions. It is not prone to electrolysis or phase separation, remains stable over a wide pH range, and can undergo hydrolysis under certain conditions, exhibiting biodegradability and high environmental friendliness. Therefore, it can be used as a corrosion inhibitor and scale inhibitor, forming stable complexes with calcium and magnesium ions in water. Additionally, the preparation method of this invention allows for the preparation of high-performance sulfobetaine-modified montmorillonite composite materials with a smaller amount of sulfobetaine, which helps reduce preparation costs. Therefore, the sulfobetaine-modified montmorillonite composite material prepared by this invention has the advantages of low cost, high adsorption capacity, high adsorption efficiency, strong anti-interference ability, good dispersion and easy separation, and green environmental protection. It is a new type of adsorbent with excellent adsorption performance and can be widely used to treat organic pollutant wastewater. It can quickly adsorb and remove organic pollutants in wastewater with less dosage, and has high use value and good application prospects.

[0083] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. The application of a sulfobetaine-modified montmorillonite composite material in the treatment of antibiotic wastewater, characterized in that, Includes the following steps: The antibiotic wastewater is treated by mixing a sulfobetaine-modified montmorillonite composite material with the wastewater for adsorption. The amount of the sulfobetaine-modified montmorillonite composite material added is 0.05g to 0.25g per liter of antibiotic wastewater. The sulfobetaine-modified montmorillonite composite material comprises sulfobetaine and montmorillonite. The sulfobetaine is loaded onto the montmorillonite. The preparation method of the sulfobetaine-modified montmorillonite composite material includes the following steps: S1. Acidification of montmorillonite yields acidified montmorillonite; S2. The acidified montmorillonite obtained in step S1 is mixed with a sulfobetaine dispersion and reacted to obtain a sulfobetaine-modified montmorillonite composite material; the sulfobetaine dispersion contains at least one of thiobetaine 8 and thiobetaine 10; the mass ratio of the sulfobetaine in the sulfobetaine dispersion to the acidified montmorillonite is 0.05 to 0.4:

1.

2. The application according to claim 1, characterized in that, In step S2, the sulfobetaine dispersion is prepared by the following method: sulfobetaine is mixed with a solvent and ultrasonically dispersed at a temperature of 25℃~35℃ for 10 min~30 min to obtain the sulfobetaine dispersion; the concentration of the sulfobetaine dispersion is 0.5g / L~4g / L; the solvent is ultrapure water.

3. The application according to claim 1, characterized in that, In step S2, the reaction is carried out under stirring conditions; the reaction temperature is 30℃~70℃; the stirring speed is 300 rpm~500 rpm; the stirring time is 18h~30h; after the reaction is completed, the following treatment is also included: the product obtained after the reaction is centrifuged, washed, and dried at a temperature of 70℃ for 18h~30h to obtain sulfobetaine-modified montmorillonite composite material.

4. The application according to any one of claims 1 to 3, characterized in that, In step S1, montmorillonite is acidified using an acid solution; the mass-to-volume ratio of montmorillonite to acid solution is 1 g: 10 mL; the concentration of the acid solution is 1 mol / L to 2 mol / L; the acid solution is sulfuric acid solution; the montmorillonite is montmorillonite K-10; the montmorillonite is further treated before use by drying at 50℃ to 80℃ for 18h to 30h; the acidification is carried out at a temperature of 40℃ to 70℃ for 18h to 30h; after the acidification is completed, the following treatment is further carried out: the product obtained after acidification is centrifuged, washed, and dried at 70℃ for 18h to 30h to obtain acidified montmorillonite.

5. The application according to claim 1, characterized in that, The concentration of antibiotics in the antibiotic wastewater is 5 mg / L to 25 mg / L; the antibiotic is at least one of doxycycline, tetracycline, ciprofloxacin, and ofloxacin; the pH value of the antibiotic wastewater is 4 to 8; the adsorption treatment is carried out under stirring conditions at a speed of 300 rpm to 500 rpm; the temperature of the adsorption treatment is 15℃ to 35℃; and the time of the adsorption treatment is 20 min to 200 min.

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