Magnetic composite hydrogel for tetracycline hydrochloride adsorption as well as preparation method and application of magnetic composite hydrogel

Abstract

The invention provides magnetic composite hydrogel for tetracycline hydrochloride adsorption as well as a preparation method and application of the magnetic composite hydrogel, and belongs to the technical field of water pollution treatment. The preparation method of the magnetic composite hydrogel comprises the following steps: neutralizing acrylic acid with sodium hydroxide to obtain a reaction solution 1; adding sodium 4-styrene sulfonate and sodium lignin sulfonate into the reaction liquid 1, uniformly mixing, then adding ferroferric oxide, a cross-linking agent and an initiator into a reaction system, and carrying out polymerization reaction under the protection of an inert atmosphere to obtain the magnetic composite hydrogel. The magnetic composite hydrogel adsorbent prepared by the method has high adsorption capacity on tetracycline hydrochloride, the removal rate of 50mg / L tetracycline hydrochloride solution within 3h is 96% or above, and the magnetic composite hydrogel adsorbent not only has extremely high adsorption performance and removal efficiency, but also has relatively high adsorption rate.

Description

Technical Field

[0001] The present invention relates to the technical field of water pollution treatment, and particularly relates to a magnetic composite hydrogel for adsorbing tetracycline hydrochloride, a preparation method thereof, and an application thereof. Background Art

[0002] Tetracycline hydrochloride is a broad-spectrum antibiotic that has been widely used in human medicine and the poultry farming industry to prevent or treat bacterial infections and promote animal growth. After entering the organism, tetracycline hydrochloride cannot be completely absorbed, and most of it will be released into the environment through feces or urine. Moreover, its chemical composition is stable and difficult to degrade. Therefore, the residue and long-term existence of tetracycline hydrochloride in the environment will have continuous harmful effects, such as inhibiting the growth of aquatic organisms and seriously endangering human health (such as endocrine disorders, joint diseases, central nervous system defects, etc.). More importantly, it will lead to the emergence of antibiotic-resistant bacteria and antibiotic-resistant genes. Traditional water treatment processes are difficult to effectively remove drug residues in water bodies. Therefore, finding efficient, economical, and environmentally friendly technologies to remove drug residues in water bodies is one of the hotspots of global research today. The adsorption method is widely used because of its high removal efficiency and good economic benefits, and it is an ideal method for treating water pollutants. Currently, the commonly used adsorbents have problems such as low adsorption capacity and difficult recovery. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a magnetic composite hydrogel for adsorbing tetracycline hydrochloride, a preparation method thereof, and an application thereof. The magnetic composite hydrogel provided by the present invention has a strong adsorption capacity and a fast adsorption rate for tetracycline hydrochloride, and is easy to recover and reprocess.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] One of the technical solutions of the present invention is a preparation method of a magnetic composite hydrogel for adsorbing tetracycline hydrochloride, comprising the following steps:

[0006] Step 1. Neutralize acrylic acid with sodium hydroxide to obtain reaction solution 1;

[0007] Step 2. Add sodium 4-styrenesulfonate and sodium lignosulfonate to the reaction solution 1, mix evenly, and then add magnetite, a cross-linking agent, and an initiator to the reaction system, and carry out a polymerization reaction under the protection of an inert atmosphere to obtain the magnetic composite hydrogel.

[0008] Another technical solution of the present invention is a magnetic composite hydrogel prepared by the above preparation method.

[0009] Another technical solution of the present invention is an application of the above magnetic composite hydrogel in adsorbing tetracycline hydrochloride in water.

[0010] The fourth technical solution of the present invention is a method for removing tetracycline hydrochloride from water. Under acidic conditions, a water sample is mixed with the above-mentioned magnetic composite hydrogel for adsorbing tetracycline hydrochloride in the water sample.

[0011] The present invention discloses the following technical effects:

[0012] The magnetic composite hydrogel adsorbent prepared by the present invention has a high adsorption capacity for tetracycline hydrochloride (up to 488.62 mg / g), and the removal rate of a 50 mg / L tetracycline hydrochloride solution is above 96% within 3 h. Compared with common tetracycline hydrochloride adsorption materials on the market, it not only has extremely high adsorption performance and removal efficiency, but also has a fast adsorption rate. Description of the Drawings

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0014] Figure 1 Infrared spectrum diagram of the magnetite prepared in step (1) of Example 1;

[0015] Figure 2 XRD of the magnetite prepared in step (1) of Example 1;

[0016] Figure 3 Scanning electron microscope image of the magnetic composite hydrogel prepared in Example 1. Detailed Embodiments

[0017] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0018] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0019] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the said documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0020] Without departing from the scope or spirit of this invention, various modifications and variations can be made to the specific embodiments of the description of this invention, which are obvious to those skilled in the art. Other embodiments obtained from the description of this invention are obvious to those skilled in the art. The description and examples of this invention are merely exemplary.

[0021] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0022] Iron oxide (Fe3O4), commonly known as magnetite, is an important iron oxide with unique physical and chemical properties. It appears black, is magnetic, and is a semiconductor, which makes it extremely important in many applications. The crystal structure of iron oxide can be a spinel structure, usually composed of Fe2+ and Fe3+ ions, endowing it with magnetism. In addition, it also has high thermal stability and chemical stability, and has good tolerance to acidity and alkalinity. In the application of hydrogel adsorbents, the magnetism and hydrophilicity of iron oxide make it an ideal functional material. Hydrogels are widely used in biomedical, environmental governance, food industry and other fields due to their good water absorption and biocompatibility. Incorporating iron oxide into hydrogels can endow them with new functions, such as enhanced adsorption capacity and controlled release characteristics. The high specific surface area and magnetism of iron oxide enable it to effectively adsorb pollutants in water, such as heavy metal ions and organic pollutants. By adjusting the composition and structure of the hydrogel, the selective adsorption performance for specific pollutants can be further improved. In addition, the magnetic properties of iron oxide enable the gel material after adsorption saturation to be rapidly separated by applying an external magnetic field, facilitating subsequent regeneration or disposal.

[0023] Sodium lignosulfonate (SL) is a natural polymer with abundant functional groups. Its structure contains a large number of benzene rings, alcohol hydroxyl groups and side chains with sulfonic acid groups, which endow it with good hydrophilicity and dispersibility, and have good adsorption capacity for various pollutants (such as heavy metal ions, organic dyes, etc.), and can effectively remove pollutants in water.

[0024] The first aspect of the present invention provides a method for preparing a magnetic composite hydrogel for adsorbing tetracycline hydrochloride, which comprises the following steps:

[0025] Step 1. Neutralize acrylic acid (AA) with sodium hydroxide to obtain reaction solution 1;

[0026] Step 2. Add sodium 4-styrenesulfonate and sodium lignosulfonate to the reaction solution 1, mix evenly, and then add iron tetroxide, a crosslinking agent and an initiator to the reaction system, and carry out a polymerization reaction under the protection of an inert atmosphere to obtain the magnetic composite hydrogel.

[0027] In a preferred embodiment of the present invention, the dosage of the sodium hydroxide is: controlling the neutralization degree of acrylic acid to be 0% to 30%.

[0028] More preferably, the dosage of the sodium hydroxide is: controlling the neutralization degree of acrylic acid to be 0% to 10%.

[0029] Even more preferably, the dosage of the sodium hydroxide is: controlling the neutralization degree of acrylic acid to be 5%.

[0030] In a preferred embodiment of the present invention, the molar ratio of acrylic acid to sodium 4-styrenesulfonate is 5:1 to 13:1; the dosage of sodium lignosulfonate is 0.06% to 0.2% of the total mass of acrylic acid and sodium 4-styrenesulfonate; the dosage of iron tetroxide is 0.1% to 0.5% of the total mass of acrylic acid and sodium 4-styrenesulfonate.

[0031] More preferably, the molar ratio of acrylic acid to sodium 4-styrenesulfonate is 8:1 to 10:1; the dosage of sodium lignosulfonate is 0.06% to 0.15% of the total mass of acrylic acid and sodium 4-styrenesulfonate; the dosage of iron tetroxide is 0.2% to 0.4% of the total mass of acrylic acid and sodium 4-styrenesulfonate.

[0032] Even more preferably, the molar ratio of acrylic acid to sodium 4-styrenesulfonate is 9:1; the dosage of sodium lignosulfonate is 0.09% to 0.1% of the total mass of acrylic acid and sodium 4-styrenesulfonate; the dosage of iron tetroxide is 0.2% to 0.3% of the total mass of acrylic acid and sodium 4-styrenesulfonate.

[0033] In a preferred embodiment of the present invention, the crosslinking agent is N,N'-methylenebisacrylamide; the dosage of the crosslinking agent is 0.2% to 0.9% of the total molar amount of acrylic acid and sodium 4-styrenesulfonate.

[0034] More preferably, the dosage of the crosslinking agent is 0.6% to 0.7% of the total molar amount of acrylic acid and sodium 4-styrenesulfonate.

[0035] In a preferred embodiment of the present invention, the initiator is ammonium persulfate; the dosage of the initiator is 0.03-0.15% of the total molar amount of acrylic acid and sodium 4-styrenesulfonate.

[0036] More preferably, the dosage of the initiator is 0.05-0.06% of the total molar amount of acrylic acid and sodium 4-styrenesulfonate.

[0037] The present invention regulates the adsorption performance of the obtained hydrogel by controlling the neutralization degree of acrylic acid, the dosage ratio of sodium lignosulfonate, sodium 4-styrenesulfonate, iron tetroxide and acrylic acid. When the dosage ratio of the neutralization degree of acrylic acid, sodium lignosulfonate, sodium 4-styrenesulfonate, iron tetroxide and acrylic acid is not within the above parameter range, the adsorption performance of the obtained hydrogel for tetracycline hydrochloride will be reduced.

[0038] The present invention regulates the rate of the polymerization reaction by controlling the dosages of the initiator and the crosslinking agent. The rate of the polymerization reaction will affect the adsorption performance of the obtained hydrogel for tetracycline hydrochloride. When the dosages of the initiator and the crosslinking agent are not within the above parameter ranges, the adsorption performance of the obtained hydrogel for tetracycline hydrochloride will be reduced.

[0039] The hydrogel adsorbent prepared by the present invention contains a large number of carboxyl groups and sulfonic acid groups, which produce hydrogen bond interactions and electrostatic interactions with pollutant molecules. After the addition of iron tetroxide to the polymer network, the electrostatic interaction with pollutants can be enhanced, which is beneficial to recycling.

[0040] In a preferred embodiment of the present invention, the temperature of the polymerization reaction is 70-80 °C and the time is 10-20 min.

[0041] The second aspect of the present invention provides a magnetic composite hydrogel prepared by the above preparation method.

[0042] The third aspect of the present invention provides an application of the above magnetic composite hydrogel in adsorbing tetracycline hydrochloride in water bodies.

[0043] The fourth aspect of the present invention provides a method for removing tetracycline hydrochloride in water bodies. Under acidic conditions, the water sample and the above magnetic composite hydrogel are mixed to carry out the adsorption of tetracycline hydrochloride in the water sample.

[0044] In a preferred embodiment of the present invention, the acidic condition is pH = 3; the dosage of the magnetic composite hydrogel is 0.625 mg / mL.

[0045] In the present invention, iron tetroxide can be obtained through commercial channels or prepared by a preparation method well-known to those skilled in the art. For example: the chemical co-precipitation method: it is prepared by adding ammonia water to ferric chloride hexahydrate and ferrous chloride tetrahydrate under a nitrogen atmosphere at 85 °C.

[0046] The technical solutions described in the present invention are conventional solutions in the art unless otherwise specified. The reagents or raw materials used are purchased from commercial channels or are publicly available unless otherwise specified.

[0047] To better understand the present invention, the content of the present invention will be further clarified below in conjunction with embodiments. However, the content of the present invention is not limited to the following embodiments.

[0048] Example 1

[0049] (1) Preparation of magnetite: 2.35 g of ferric chloride hexahydrate and 0.86 g of ferrous chloride tetrahydrate were added to 40 ml of deionized water. After mixing, the mixture was transferred to a three-necked flask, nitrogen was introduced, and the mixture was stirred at a speed of 300 r / min at 85 °C for 60 min. Then 15 mL of ammonia water was added, and the obtained product was centrifuged 3 times and dried at 75 °C for later use. As shown in the infrared spectrum, the characteristic peaks of magnetite are obvious, and its successful synthesis can also be clearly seen from the XRD spectrum ( Figure 1 ). The addition of magnetite can significantly enhance the adsorption performance of the polymer for tetracycline hydrochloride. Figure 2 )

[0050] (2) Preparation of magnetic composite hydrogel: 0.1746 g of sodium hydroxide was dissolved in 5 mL of deionized water, mixed evenly with 6.29 mL of AA for a neutralization reaction, then 2 g of sodium 4-styrenesulfonate and 0.01 g of sodium lignosulfonate were added, and the obtained mixed solution was placed in a three-necked flask and stirred; nitrogen was introduced into the system; after stirring at room temperature for 10 min, 0.0249 g of magnetite was added, and stirring and heating were continued. When the temperature reached 75 °C, first 0.0897 g of N,N'-methylenebisacrylamide was added and stirred for 5 min, and finally 0.0332 g of ammonium persulfate was added. The polymerization reaction time was 10 - 20 min. After the reaction, the obtained product was washed with absolute ethanol, dried and crushed at 55 °C to obtain adsorbent particles with a particle size of 20 - 40 mesh (i.e., magnetic composite hydrogel).

[0051] Adsorption performance test: Under the condition that the pH is equal to 3, 25 mg of the adsorbent was used for the test in 20 ml of tetracycline hydrochloride solution (50 mg / L). At 3 h, the adsorption of the adsorbent for tetracycline hydrochloride had reached basic stability, and the drug removal rate at this time was measured. The results showed that the maximum adsorption capacity of the obtained adsorbent for tetracycline hydrochloride was 488.62 mg / g, and the removal rate of tetracycline hydrochloride was above 96%.

[0052] Example 2

[0053] The difference from Example 1 is only that the mass of N,N'-methylenebisacrylamide is adjusted from "0.0897 g" to "0.0448 g", and other steps and parameters are the same as those in Example 1.

[0054] The adsorbent obtained in this example was subjected to the same adsorption performance test as in Example 1. The results showed that the maximum adsorption capacity of the obtained adsorbent for tetracycline hydrochloride was 433.1976 mg / g, and the removal rate of the tetracycline hydrochloride solution was above 93.7%.

[0055] Example 3

[0056] The difference from Example 1 was only that the mass of ammonium persulfate was adjusted from "0.0332 g" to "0.0664 g", and other steps and parameters were the same as those in Example 1.

[0057] The adsorbent obtained in this example was subjected to the same adsorption performance test as in Example 1. The results showed that the maximum adsorption capacity of the obtained adsorbent for tetracycline hydrochloride was 405.4958 mg / g, and the removal rate of the tetracycline hydrochloride solution was above 92.1%.

[0058] Example 4

[0059] The difference from Example 1 was only that the molar ratio of sodium 4-styrenesulfonate to acrylic acid was adjusted from "9:1" to "13:1", and other steps and parameters were the same as those in Example 1.

[0060] The adsorbent obtained in this example was subjected to the same adsorption performance test as in Example 1. The results showed that the maximum adsorption capacity of the obtained adsorbent for tetracycline hydrochloride was 394.4582 mg / g, and the removal rate of the tetracycline hydrochloride solution was above 90.5%.

[0061] It can be seen from the above examples that the adsorbent prepared by the present invention has high adsorption performance and fast adsorption rate, and has broad application prospects.

[0062] Comparative Example 1

[0063] The difference from Example 1 was only that the addition of sodium 4-styrenesulfonate was omitted, and other steps and parameters were the same as those in Example 1.

[0064] The adsorbent obtained in this comparative example was subjected to the same adsorption performance test as in Example 1. The results showed that the maximum adsorption capacity of the obtained adsorbent for tetracycline hydrochloride was 312.43 mg / g, and the removal rate of the tetracycline hydrochloride solution was above 83.16%.

[0065] Comparative Example 2

[0066] The difference from Example 1 was only that the mass of sodium lignosulfonate was adjusted from "0.01 g" to 0.05 g, and other steps and parameters were the same as those in Example 1.

[0067] The adsorbent obtained in this comparative example was subjected to the same adsorption performance test as in Example 1. The results showed that the maximum adsorption capacity of the obtained adsorbent for tetracycline hydrochloride was 301.53 mg / g. The removal rate of the tetracycline hydrochloride solution was above 81.07%.

[0068] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a magnetic composite hydrogel for tetracycline hydrochloride adsorption, characterized in that: The following steps are involved: Step 1. neutralizing acrylic acid with sodium hydroxide to obtain a reaction solution 1; Step 2. Add sodium 4-styrene sulfonate and sodium lignin sulfonate to the reaction solution 1 and mix them evenly. Then, add ferrosoferric oxide, a crosslinking agent and an initiator to the reaction system, and perform a polymerization reaction under the protection of an inert atmosphere to obtain the magnetic composite hydrogel.

2. The preparation method according to claim 1, characterized in that: The dosage of the sodium hydroxide is to control the neutralization degree of acrylic acid to be 0% to 30%.

3. The preparation method according to claim 1, characterized in that: The molar ratio of acrylic acid to sodium 4-styrene sulfonate is 5:1-13:1; the amount of sodium lignin sulfonate is 0.06-0.2% of the total mass of acrylic acid and sodium 4-styrene sulfonate; the amount of ferrosoferric oxide is 0.1-0.5% of the total mass of acrylic acid and sodium 4-styrene sulfonate.

4. The preparation method according to claim 1, characterized in that: The cross-linking agent is N, N-methylenebisacrylamide; the amount of the cross-linking agent is 0.2% to 0.9% of the total molar amount of acrylic acid and sodium 4-styrene sulfonate.

5. The preparation method according to claim 1, characterized in that: The initiator is ammonium persulfate; the amount of the initiator used is 0.03-0.15% of the total molar amount of acrylic acid and sodium 4-styrene sulfonate.

6. The preparation method according to claim 1, characterized in that: The polymerization reaction temperature is 70-80°C and the reaction time is 10-20 minutes.

7. A magnetic composite hydrogel prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the magnetic composite hydrogel according to claim 7 in adsorbing tetracycline hydrochloride in water.

9. A method for removing tetracycline hydrochloride from water, characterized in that: Under acidic conditions, a water sample and the magnetic composite hydrogel according to claim 7 are mixed to adsorb tetracycline hydrochloride in the water sample.

10. The method for removing tetracycline hydrochloride in water according to claim 9, characterized in that: The acidic condition is pH=3; the dosage of the magnetic composite hydrogel is 0.625 mg / mL.

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