A magnetic composite hydrogel for adsorbing tetracycline hydrochloride and a preparation method and application thereof

Abstract

The application provides a kind of for tetracycline hydrochloride adsorption magnetic composite hydrogel and its preparation method and application, belong to water pollution treatment technical field.The preparation method of the magnetic composite hydrogel includes the following steps: acrylic acid is neutralized with sodium hydroxide to obtain reaction liquid 1;4-styrene sulfonic acid sodium and sodium lignosulfonate are added to the reaction liquid 1, mixed uniformly, then ferric oxide is added to the reaction system, crosslinking agent and initiator, polymerization is carried out under the protection of inert atmosphere, to obtain the magnetic composite hydrogel.The magnetic composite hydrogel adsorbent prepared by the application has high adsorption capacity for tetracycline hydrochloride, and the removal rate of 50mg / L tetracycline hydrochloride solution within 3h is more than 96%, not only has very high adsorption performance and removal efficiency, but also has a faster adsorption rate.

Description

Technical Field

[0001] This invention relates to the field of water pollution treatment technology, and in particular to a magnetic composite hydrogel for the adsorption of tetracycline hydrochloride, its preparation method and application. Background Technology

[0002] Tetracycline hydrochloride is a broad-spectrum antibiotic widely used in human medicine and poultry farming to prevent or treat bacterial infections and promote animal growth. Once inside an organism, tetracycline hydrochloride is not completely absorbed; most of it is released into the environment through feces or urine. Its chemical composition is stable and difficult to degrade, therefore, the persistence and long-term presence of tetracycline hydrochloride in the environment can have continuous harmful effects, such as inhibiting the growth of aquatic organisms, seriously endangering human health (e.g., endocrine disorders, joint diseases, central nervous system defects), and, more importantly, leading to the emergence of antibiotic-resistant bacteria and antibiotic resistance genes. Traditional water treatment processes are ineffective in removing drug residues from water bodies; therefore, finding efficient, economical, and environmentally friendly technologies to remove drug residues from water bodies is one of the current global research hotspots. Adsorption methods are widely used due to their high removal efficiency and economic benefits, making them an ideal method for treating water pollutants. However, commonly used adsorbents currently suffer from problems such as low adsorption capacity and difficulty in recovery. Summary of the Invention

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

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] One of the technical solutions of this invention is a method for preparing a magnetic composite hydrogel for tetracycline hydrochloride adsorption, comprising the following steps:

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

[0007] Step 2. Add sodium 4-styrene sulfonate and sodium lignin sulfonate to the reaction solution 1, mix well, then add iron oxide, crosslinking agent and initiator to the reaction system, and carry out polymerization reaction under inert atmosphere to obtain the magnetic composite hydrogel.

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

[0009] The third technical solution of the present invention is the application of the above-mentioned magnetic composite hydrogel in the adsorption of 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, the water sample is mixed with the above-mentioned magnetic composite hydrogel to adsorb tetracycline hydrochloride from the water sample.

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

[0012] The magnetic composite hydrogel adsorbent prepared by this invention has a high adsorption capacity for tetracycline hydrochloride (up to 488.62 mg / g), and the removal rate of 50 mg / L tetracycline hydrochloride solution is over 96% within 3 hours. Compared with commonly available tetracycline hydrochloride adsorbents, it not only has extremely high adsorption performance and removal efficiency, but also has a faster adsorption rate. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 The infrared spectrum of the iron(III) oxide prepared in step (1) of Example 1;

[0015] Figure 2 XRD pattern of the iron(III) oxide prepared in step (1) of Example 1;

[0016] Figure 3 This is a scanning electron microscope image of the magnetic composite hydrogel prepared in Example 1. Detailed Implementation

[0017] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0018] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0019] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0020] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0021] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0022] Ferric oxide (Fe3O4), commonly known as magnetite, is an important iron oxide with unique physicochemical properties. It is black, magnetic, and a semiconductor, making it extremely important in many applications. Ferric oxide has a spinel crystal structure, typically composed of Fe2+ and Fe3+ ions, which imparts its magnetism. Furthermore, it exhibits high thermal and chemical stability and good tolerance to acids and alkalis. In hydrogel adsorbent applications, the magnetic properties and hydrophilicity of ferric oxide make it an ideal functional material. Hydrogels are widely used in biomedicine, environmental remediation, and the food industry due to their excellent water absorption and biocompatibility. Incorporating ferric 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 ferric 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, its selective adsorption performance for specific pollutants can be further improved. In addition, the magnetic properties of iron oxide allow the saturated gel material to be quickly separated by an external magnetic field, facilitating subsequent regeneration or disposal.

[0023] Sodium lignosulfonate (SL) is a natural polymer rich in functional groups. Its structure contains numerous benzene rings, alcohol hydroxyl groups, and side chains with sulfonic acid groups. These characteristics give it excellent hydrophilicity and dispersibility, and it exhibits good adsorption capacity for various pollutants (such as heavy metal ions and organic dyes), effectively removing pollutants from water.

[0024] The first aspect of this invention provides a method for preparing a magnetic composite hydrogel for tetracycline hydrochloride adsorption, comprising the following steps:

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

[0026] Step 2. Add sodium 4-styrene sulfonate and sodium lignin sulfonate to the reaction solution 1, mix well, then add iron oxide, crosslinking agent and initiator to the reaction system, and carry out polymerization reaction under inert atmosphere to obtain the magnetic composite hydrogel.

[0027] In a preferred embodiment of the present invention, the amount of sodium hydroxide used is such that the degree of neutralization of acrylic acid is controlled to be 0% to 30%.

[0028] More preferably, the amount of sodium hydroxide used is such that the degree of neutralization of acrylic acid is controlled to be 0% to 10%.

[0029] More preferably, the amount of sodium hydroxide used is such that the degree of neutralization of acrylic acid is controlled at 5%.

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

[0031] More preferably, the molar ratio of acrylic acid and sodium 4-styrene sulfonate is 8:1 to 10:1; the amount of sodium lignin sulfonate is 0.06 to 0.15% of the total mass of acrylic acid and sodium 4-styrene sulfonate; and the amount of iron oxide is 0.2 to 0.4% of the total mass of acrylic acid and sodium 4-styrene sulfonate.

[0032] More preferably, the molar ratio of acrylic acid to sodium 4-styrene sulfonate is 9:1; the amount of sodium lignin sulfonate is 0.09 to 0.1% of the total mass of acrylic acid and sodium 4-styrene sulfonate; and the amount of iron oxide is 0.2 to 0.3% of the total mass of acrylic acid and sodium 4-styrene sulfonate.

[0033] In a preferred embodiment of the present invention, the crosslinking agent is N,N-methylenebisacrylamide; the amount 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 amount of the crosslinking agent is 0.6% to 0.7% of the total molar amount of acrylic acid and sodium 4-styrene sulfonate.

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

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

[0037] This invention regulates the adsorption performance of the resulting hydrogel by controlling the degree of neutralization of acrylic acid and the ratio of sodium lignosulfonate, sodium 4-styrenesulfonate, iron oxide, and acrylic acid. When the degree of neutralization of acrylic acid and the ratio of sodium lignosulfonate, sodium 4-styrenesulfonate, iron oxide, and acrylic acid are not within the above parameter range, the adsorption performance of the resulting hydrogel for tetracycline hydrochloride will be reduced.

[0038] This invention regulates the polymerization rate by controlling the amount of initiator and crosslinker. The polymerization rate affects the adsorption performance of the resulting hydrogel on tetracycline hydrochloride. When the amount of initiator and crosslinker is outside the above parameter range, the adsorption performance of the resulting hydrogel on tetracycline hydrochloride will be reduced.

[0039] The hydrogel adsorbent prepared in this invention contains a large number of carboxyl and sulfonic acid groups, which form hydrogen bonds and electrostatic interactions with pollutant molecules. The addition of iron(III) oxide to the polymer network enhances the electrostatic interaction with pollutants and facilitates recycling.

[0040] In a preferred embodiment of the present invention, the polymerization reaction is carried out at a temperature of 70-80°C for a time of 10-20 minutes.

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

[0042] A third aspect of the present invention provides an application of the above-mentioned magnetic composite hydrogel in the adsorption of tetracycline hydrochloride in water.

[0043] The fourth aspect of the present invention provides a method for removing tetracycline hydrochloride from water, wherein a water sample is mixed with the above-mentioned magnetic composite hydrogel under acidic conditions to adsorb tetracycline hydrochloride from the water sample.

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

[0045] In this invention, ferric oxide can be obtained from commercial sources or prepared by methods well known to those skilled in the art, such as chemical coprecipitation: ferric chloride hexahydrate and ferrous chloride tetrahydrate are prepared by adding ammonia water under a nitrogen atmosphere at 85°C.

[0046] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0047] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0048] Example 1

[0049] (1) Preparation of ferric oxide: 2.35 g of ferric chloride hexahydrate and 0.86 g of ferrous chloride tetrahydrate were added to 40 ml of deionized water, mixed, and transferred to a three-necked flask. Nitrogen gas was introduced, and the mixture was stirred at 300 r / min for 60 min at 85 °C. 15 mL of ammonia water was then added. The resulting product was centrifuged three times and dried at 75 °C for later use. Figure 1 As shown in the infrared spectrum, the characteristic peaks of iron(III) oxide are obvious, indicating its successful synthesis. The XRD spectrum (...) Figure 2 It is also evident that the addition of ferric oxide can significantly enhance the polymer's adsorption performance for tetracycline hydrochloride.

[0050] (2) Preparation of magnetic composite hydrogel: 0.1746 g of sodium hydroxide was dissolved in 5 mL of deionized water and mixed with 6.29 mL of AA for neutralization reaction. Then, 2 g of sodium 4-styrene sulfonate and 0.01 g of sodium lignosulfonate were added. The resulting solution was placed in a three-necked flask and stirred. Nitrogen gas was introduced into the system. After stirring at room temperature for 10 min, 0.0249 g of iron(III) oxide was added, and stirring and heating continued. When the temperature reached 75 °C, 0.0897 g of N,N-methylenebisacrylamide was added and stirred for 5 min. Finally, 0.0332 g of ammonium persulfate was added. The polymerization reaction time was 10-20 min. After the reaction, the product was washed with anhydrous ethanol, dried at 55 °C and pulverized to obtain 20-40 mesh adsorbent particles (i.e., magnetic composite hydrogel).

[0051] Adsorption performance test: Under pH 3 conditions, 25 mg of adsorbent was used in 20 ml of tetracycline hydrochloride solution (50 mg / L). After 3 hours, the adsorption of tetracycline hydrochloride by the adsorbent reached a basic stable state, and the drug removal rate was measured at this point. 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 only difference from Example 1 is that the mass of N,N-methylenebisacrylamide is adjusted from "0.0897g" to "0.0448g". All other steps and parameters are the same as in Example 1.

[0054] The adsorbent obtained in this embodiment 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. The removal rate of tetracycline hydrochloride solution was above 93.7%.

[0055] Example 3

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

[0057] The adsorbent obtained in this embodiment 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. The removal rate of tetracycline hydrochloride solution was above 92.1%.

[0058] Example 4

[0059] The only difference from Example 1 is that the molar ratio of sodium 4-styrenesulfonate to acrylic acid is changed from "9:1" to "13:1". All other steps and parameters are the same as in Example 1.

[0060] The adsorbent obtained in this embodiment 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. The removal rate of tetracycline hydrochloride solution was above 90.5%.

[0061] As can be seen from the above examples, 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 only difference from Example 1 is that the addition of sodium 4-styrenesulfonate is omitted; all other steps and parameters are the same as 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. The removal rate of tetracycline hydrochloride solution was over 83.16%.

[0065] Comparative Example 2

[0066] The only difference from Example 1 is that the mass of sodium lignosulfonate is adjusted from "0.01g" to 0.05g, while the other steps and parameters are the same as 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 tetracycline hydrochloride solution was above 81.07%.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a magnetic composite hydrogel for the adsorption of tetracycline hydrochloride, characterized in that, Includes the following steps: Step 1. Neutralize acrylic acid with sodium hydroxide to obtain reaction solution 1; Step 2. Add sodium 4-styrene sulfonate and sodium lignin sulfonate to the reaction solution 1, mix well, then add iron oxide, crosslinking agent and initiator to the reaction system, and carry out polymerization reaction under inert atmosphere to obtain the magnetic composite hydrogel. The molar ratio of acrylic acid to sodium 4-styrene sulfonate is 5:1 to 13:1; the amount of sodium lignin sulfonate used is 0.06 to 0.2% of the total mass of acrylic acid and sodium 4-styrene sulfonate. The amount of sodium hydroxide used is such that the degree of neutralization of acrylic acid is controlled to be 0%~30%.

2. The preparation method according to claim 1, characterized in that, The amount of iron oxide used is 0.1 to 0.5% of the total mass of acrylic acid and sodium 4-styrenesulfonate.

3. The preparation method according to claim 1, characterized in that, The crosslinking agent is N,N-methylenebisacrylamide; the amount of the crosslinking agent is 0.2% to 0.9% of the total molar amount of acrylic acid and sodium 4-styrenesulfonate.

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

5. The preparation method according to claim 1, characterized in that, The polymerization reaction is carried out at a temperature of 70-80℃ for 10-20 minutes.

6. A magnetic composite hydrogel prepared by the preparation method according to any one of claims 1-5.

7. The application of the magnetic composite hydrogel according to claim 6 in the adsorption of tetracycline hydrochloride in water.

8. A method for removing tetracycline hydrochloride from water, characterized in that, Under acidic conditions, the water sample and the magnetic composite hydrogel of claim 6 are mixed to adsorb tetracycline hydrochloride from the water sample.

9. The method for removing tetracycline hydrochloride from water according to claim 8, characterized in that, The acidic condition is pH=3; the amount of the magnetic composite hydrogel used is 0.625 mg / mL.

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