Method for removing sulfonamide antibiotics in environmental water body based on advanced oxidation system

Abstract

The invention belongs to the field of environmental chemistry, and particularly relates to a method for removing sulfonamide antibiotics in an environmental water body based on an advanced oxidation system. According to the method, antibiotics in environmental water are removed through an advanced oxidation process of a non-free radical way, the performance of the method is superior to that of other nonmetal carbon-based / PMS systems, interference of inorganic ions and natural organic matter can be tolerated, and high efficiency is shown. The advantages provide an efficient method for removing the sulfonamide antibiotics in the environmental water body.

Description

Technical Field

[0001] The present invention belongs to the field of environmental chemistry, and particularly relates to a method for removing sulfonamide antibiotics in environmental water bodies based on an advanced oxidation system, which is a method for removing sulfonamide antibiotics in environmental water bodies using a nano-graphite / peroxymonosulfate (NG / PMS) system. Background Art

[0002] With the development of society and the improvement of people's living standards, sulfonamide antibiotics are widely used in the treatment of diseases of humans and animals, or as feed additives to promote the growth of livestock. These sulfonamide antibiotics are not completely transformed and absorbed in the human and animal bodies, and up to 50%-70% of the dose is discharged out of the body in the form of the original drug or metabolic intermediates. Antibiotics in the natural environment not only have certain biological toxicity themselves, but also increase the resistance genes of organisms, thus bringing great harm to the entire ecosystem. Therefore, it is very necessary to remove antibiotics in the environment in a timely and effective manner.

[0003] At present, the advanced oxidation process is a main method for removing antibiotics in the environment. The advanced oxidation process mainly catalyzes / activates oxidants (such as hydrogen peroxide, ozone, persulfate, etc.) to generate reactive oxygen species, such as hydroxyl radicals (·OH), ozone (O3), superoxide radicals (·O2 - ), and then degrades organic pollutants into small molecules or even completely mineralizes them to achieve efficient removal of pollutants.

[0004] In order to obtain an advanced oxidation system with high oxidation performance, researchers usually choose heavy metals such as Fe, Co, Ni, etc. as catalysts / activators. Although the introduction of heavy metals can significantly improve the oxidation ability of the system, there is a risk of secondary environmental pollution; in addition, some oxidation systems require external energy (such as light energy, heat energy, electrical energy, etc.) to drive the reaction, which leads to disadvantages such as limited reaction conditions and narrow application range.

[0005] The patent with the publication number CN118681582A provides a method for preparing biochar-supported cobalt-modified carbon nitride and activating persulfate to degrade antibiotics. In the reaction system, although the removal efficiency of tetracycline reaches 80%, the leaching concentration of cobalt ions during the reaction is 1 mg / L, and there is a risk of heavy metal secondary environmental pollution.

[0006] The patent with the publication number CN113998758A provides a method for photocatalytic and electrocatalytic synergy of graphitic carbon nitride to activate persulfate for degrading antibiotics. This method uses graphitic carbon nitride to activate persulfate to generate reactive oxygen species for degrading antibiotics. During the implementation of this method, external energies such as visible light irradiation and electric fields are required to achieve the removal of antibiotics. Although this method can achieve efficient removal of tetracycline, oxytetracycline, levofloxacin, ciprofloxacin, or sulfamethoxazole, melamine, urea, or thiourea needs to be added during the preparation of graphitic carbon nitride, and these additives are prone to causing nitrogen pollution. Since this method not only requires external energy but also may cause secondary pollution, it is not a completely green approach for antibiotic removal.

[0007] In view of the limitations of the prior art, it is necessary to develop a more green and efficient catalytic / oxidation method for removing sulfonamide antibiotics in water. Summary of the Invention

[0008] In view of the problems commonly existing in the catalytic / oxidation means based on advanced oxidation processes in the prior art, such as the need for external energy and the risk of heavy metal leaching, the present invention has developed a method for removing sulfonamide antibiotics in environmental water bodies based on an advanced oxidation system. This method is a more green and efficient system based on nano-graphite (NG) / peroxymonosulfate (PMS), and it is a method for removing sulfonamide antibiotics in environmental water bodies through an advanced oxidation process via a non-free radical pathway.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A method for removing sulfonamide antibiotics in environmental water bodies based on an advanced oxidation system, wherein the advanced oxidation system uses nano-graphite (NG) as an activator and peroxymonosulfate (PMS) as an oxidant. It is an advanced oxidation system that does not require external energy, has a wide reaction pH range, and has no risk of heavy metal leaching, and is used to efficiently remove sulfonamide antibiotics in environmental water bodies.

[0011] It should be noted that the present invention proceeds spontaneously under normal temperature, normal pressure, and natural light conditions, and the constructed system can remove more than 90% of sulfathiazole (STZ) through a non-free radical pathway within the first twenty minutes after the reaction starts.

[0012] Furthermore, the advanced oxidation system established by the present invention mainly relies on the electron transfer between antibiotics (electron donors) and PMS (electron acceptors) on the surface of NG. Therefore, the removal efficiency of antibiotics in the present invention is not affected by anions and humic acid (HA) in water, and there is no need to particularly regulate the pH value of the reaction system.

[0013] The present invention is achieved through the following solutions:

[0014] Step (1): Weigh a certain amount of NG and mix it with ultrapure water. Put the mixture into an ultrasonic cleaner and ultrasonicate for 10 minutes to evenly disperse NG in water, maintaining the NG concentration at 20 mg / L or higher.

[0015] Step (2): Mix the NG homogeneous turbid solution obtained in step (1) with STZ, and then place it on a magnetic stirrer and stir for 30 minutes to achieve adsorption equilibrium of the NG / STZ mixed solution. At this time, the concentration of STZ in the solution is 10 mg / L.

[0016] Step (3): Rapidly add PMS to the solution after adsorption equilibrium in step (2) to initiate the oxidation reaction. At this time, the concentration of PMS in the system is 0.5 mmol / L or higher.

[0017] Step (4): At preset time intervals, use a syringe with a needle to take out 1 mL of the mixture in step (3), then remove the needle and replace it with a filter head with a 0.22 μm filter membrane to push out the mixture to obtain the reaction clear liquid. Take 900 μL of the reaction clear liquid into a liquid chromatography injection vial, add 100 μL of 0.1 mol / L Na2S2O3 to terminate the reaction, and make the whole sampling process as rapid as possible.

[0018] Step (5): Detect the residual STZ in the collected samples using high-performance liquid chromatography with an ultraviolet detector.

[0019] It should be noted that the method described in this case follows a proportional relationship between the amount of substances added and the efficiency of removing sulfonamide antibiotics from environmental water bodies.

[0020] In addition, through the above steps, nano-graphite (NG) can be used as an activator and peroxymonosulfate (PMS) as an oxidant to construct an advanced oxidation system that requires no external energy, has a wide reaction pH range, and no risk of heavy metal leaching, for the efficient removal of antibiotics from environmental water bodies.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] (1) The present invention requires no external energy, reducing the investment cost of the process;

[0023] (2) In the present invention, nano-graphite belongs to a non-metallic material and has no risk of heavy metal ion leaching;

[0024] (3) The present invention has a wide reaction pH range and can still achieve the efficient removal of sulfonamide antibiotics under conditions of high-concentration inorganic anions and humic acid.

[0025] (4) The present invention is simple to operate, green and efficient, and environmentally friendly;

[0026] (5) The reactants of the nano-graphite and persulfate system used in the present invention are both solids, which are convenient for transportation and application. Brief Description of the Drawings

[0027] 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 for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0028] Figure 1 It is the scanning electron microscope (SEM) morphology information diagram of NG of the present invention.

[0029] Figure 2 It is the transmission electron microscope (TEM) morphology information diagram of NG of the present invention.

[0030] Figure 3 It is the X-ray powder diffraction (XRD) crystal structure diagram of NG of the present invention.

[0031] Figure 4 It is the X-ray photoelectron spectroscopy (XPS) chemical state information diagram of NG of the present invention.

[0032] Figure 5 It is the comparison of the removal efficiency of STZ between the NG / PMS system and the PMS system of the present invention. C0 refers to the concentration of sulfathiazole at the zero point of the reaction, and C T refers to the concentration of sulfathiazole at a certain moment; C T / C0 being 0 means that the concentration of STZ is lower than the detection limit of the instrument at this time.

[0033] Figure 6 It is the removal efficiency of sulfonamide antibiotics by the NG / PMS system of the present invention. C0 refers to the concentration of sulfonamide antibiotics at the zero point of the reaction, and C T refers to the concentration of sulfonamide antibiotics at a certain moment; C T / C0 being 0 means that the concentration of sulfonamide antibiotics is lower than the detection limit of the instrument at this time.

[0034] Figure 7 It is the influence of inorganic ions and humic acid on the removal efficiency of STZ based on the NG / PMS system of the present invention. C0 refers to the concentration of STZ at the zero point of the reaction, and C T refers to the concentration of STZ at a certain moment; C T / C0 being 0 means that the concentration of STZ is lower than the detection limit of the instrument at this time. Detailed Embodiments

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] Here, the special term "embodiment", any embodiment described as "exemplary" does not have to be construed as superior to or better than other embodiments. For the performance index tests in the embodiments of this application, unless otherwise specified, the conventional test methods in the art are adopted. It should be understood that the terms described in this application are only used to describe specific embodiments and are not used to limit the content disclosed in this application.

[0037] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by those of ordinary skill in the technical field to which this application belongs; the test methods and technical means not specifically noted in other parts of this application refer to the experimental methods and technical means commonly adopted by those of ordinary skill in the art.

[0038] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "middle", "upper", "lower", "rise", "fall", "vertical", "plane", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0039] To better illustrate the content of this application, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that this application can still be implemented without some specific details. In the embodiments, some methods, means, instruments, devices, etc. well-known to those skilled in the art are not described in detail in order to highlight the gist of this application.

[0040] On the premise of no conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the obtained technical solutions belong to the content disclosed in the embodiments of this application.

[0041] The present invention discloses a method for removing sulfonamide antibiotics in environmental water bodies using a nano-graphite / persulfate (NG / PMS) system.

[0042] To better understand the present invention, the following embodiments are used to further specifically elaborate on the present invention, but it should not be construed as a limitation to the present invention. For those skilled in the art, some non-essential improvements and adjustments made according to the above-mentioned invention content are also considered to fall within the protection scope of the present invention.

[0043] Example 1

[0044] (1) Weigh 2.5 mg of NG and homogeneously disperse it in 44 mL of ultrapure water. This process is carried out in an ultrasonic cleaner with an ultrasonic duration of 10 minutes.

[0045] (2) Mix the homogeneously dispersed NG suspension with 5 mL of STZ with a concentration of 100 mg / L, and place it on a magnetic stirrer and stir for 30 minutes to achieve adsorption equilibrium of the solution.

[0046] (3) After the reaction solution in step (2) reaches adsorption equilibrium, add 1 mL of PMS with a concentration of 5 mmol / L to initiate the oxidation reaction.

[0047] (4) Set up another control experiment without adding graphite, and keep the rest of the reaction conditions exactly the same.

[0048] (5) The reaction is stirred evenly and reacted for 60 minutes under the conditions of normal temperature, normal pressure, and natural light, and samples are taken at preset time points; use high-performance liquid chromatography with an ultraviolet detector to detect STZ and determine its removal efficiency.

[0049] As Figure 1 , it can be seen from the SEM characterization results that the surface of NG is rough and uneven, which is beneficial to the adsorption of sulfonamide antibiotics and PMS. As Figure 2 , it can be seen from the TEM characterization results that NG is in a spherical or quasi-spherical structure and has a large specific surface area. As Figure 3 , it can be seen from the XRD spectrum that the crystal plane structure of NG has a high similarity to that of graphite. As Figure 4 , it can be seen from the XPS spectrum that the main component element of NG is carbon, and it has a certain amount of nitrogen and oxygen doping.

[0050] The relationship between the removal efficiency of the NG / PMS system for STZ and time is shown in Figure 5 , and the results show that NG can significantly improve the oxidation performance of PMS for STZ, and thus achieve the purpose of efficiently removing STZ.

[0051] Example 2

[0052] (1) Weigh seven groups of 2.5 mg of NG and homogeneously disperse them separately in 44 mL of ultrapure water. This process is carried out in an ultrasonic cleaner with an ultrasonic duration of 10 minutes.

[0053] (2) Mix the homogeneously dispersed NG suspension with 5 mL of STZ with a concentration of 100 mg / L, and add Cl - , SO4 2- , CO3 2- , HCO3 - , NO3 -, HPO4 2- , HA, where the concentration of inorganic ions is 5 mmol / L and the dosage of HA is 1 mg.

[0054] (3) Stir all these seven groups of reactions on a magnetic stirrer for 30 minutes to make the mixed solution reach the adsorption equilibrium.

[0055] (4) After the reaction solution in step (3) reaches the adsorption equilibrium, add 1 mL of PMS with a concentration of 5 mmol / L to initiate the oxidation reaction.

[0056] (5) Stir evenly for 60 minutes under the conditions of normal temperature, normal pressure and natural light, and use high performance liquid chromatography with an ultraviolet detector to detect STZ to determine its removal efficiency.

[0057] Based on the NG / PMS system - the influence of inorganic ions and humic acid on the removal efficiency of STZ is shown in Figure 7 . The results show that higher concentrations of inorganic ions and humic acid have little effect on the removal efficiency of STZ. This is attributed to the fact that the NG / PMS system is a non-radical oxidation process with PMS as the electron acceptor and STZ as the electron donor, and NG as the electron bridge. The whole process of STZ degradation is dominated by electron transfer, so the anions and natural organic matter commonly found in natural water environments do not scavenge the reactive oxygen species of this reaction. Therefore, this method can be applied to the removal of sulfonamide antibiotics in environmental water bodies.

[0058] Example 3

[0059] (1) Weigh four groups of 2.5 mg of NG and homogenize them separately and disperse them in 44 mL of ultrapure water. This process is carried out in an ultrasonic cleaner with an ultrasonic duration of 10 minutes.

[0060] (2) Mix the homogenized and dispersed NG suspension with 5 mL of sulfathiazole (STZ), sulfamethazine (SM2), sulfacetamide (SA), and sulfamethoxazole (SMZ) with a concentration of 100 mg / L, and stir on a magnetic stirrer for 30 minutes to make the mixed solution reach the adsorption equilibrium.

[0061] (3) After the reaction solution in (2) reaches the adsorption equilibrium, add 1 mL of PMS with a concentration of 5 mmol / L to initiate the oxidation reaction.

[0062] (4) Stir evenly for 60 minutes under the conditions of normal temperature, normal pressure and natural light, and use high performance liquid chromatography with an ultraviolet detector to detect different sulfonamide antibiotics to determine their removal efficiency.

[0063] The removal efficiency of the NG / PMS system for sulfonamide antibiotics is shown in Figure 6. The results showed that when only PMS was present, the reactive oxygen species generated by PMS had a certain degradation effect on sulfonamide antibiotics; when both NG and PMS were present, the degradation rate of sulfonamide antibiotics increased significantly, indicating that NG had a good activation effect on PMS. Therefore, the NG / PMS system can efficiently remove sulfonamide antibiotics from water.

[0064] Based on the above results, it can be seen that the present invention proposes a system based on nano-graphite (NG) / persulfate (PMS) for removing antibiotics from environmental water bodies through an advanced oxidation process via a non-free radical pathway. The performance of this method is superior to other non-metallic carbon-based / PMS systems, can tolerate the interference of inorganic ions and natural organic matter, and exhibits high efficiency. These advantages provide an efficient method for removing sulfonamide antibiotics from environmental water bodies.

[0065] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for removing sulfonamide antibiotics from environmental water bodies based on an advanced oxidation system, characterized in that The advanced oxidation system uses nano-graphite (NG) as an activator and peroxymonosulfate (PMS) as an oxidant. It is an advanced oxidation system that does not require external energy, has a wide reaction pH range, and has no risk of heavy metal leaching, and is used to efficiently remove sulfonamide antibiotics in environmental water bodies.

2. The method for removing sulfonamide antibiotics from environmental water based on the advanced oxidation system according to claim 1, wherein, The operation steps of the method are as follows: (1) Mix NG with ultrapure water and then ultrasonicate to obtain a homogeneous NG turbid solution for standby; (2) Mix the homogeneous NG turbid solution obtained in step (1) with STZ, and magnetically stir to make the NG / STZ mixed solution reach adsorption equilibrium; (3) Rapidly add PMS to the solution after adsorption equilibrium in step (2) to initiate the oxidation reaction; (4) At preset time intervals, use a syringe with a needle to take out 1 mL of the mixed solution in step (3), then remove the needle and replace it with a filter head with a 0.22 μm filter membrane to push out the mixed solution to obtain a reaction clear solution; Take 900 μL of the reaction clear solution into a liquid chromatography injection vial, add 100 μL of 0.1 mol / L Na2S2O3 to terminate the reaction, and the whole sampling process should be as rapid as possible; (5) Detect the residual STZ in the collected samples by high performance liquid chromatography with an ultraviolet detector.

3. The method for removing sulfonamide antibiotics in environmental water based on the advanced oxidation system according to claim 2, wherein The concentration of NG in the homogeneous NG turbid solution is 20 mg / L or more.

4. The method for removing sulfonamide antibiotics in environmental water based on the advanced oxidation system according to claim 2, characterized in that, The concentration of STZ in the NG / STZ mixed solution is 10 mg / L.

5. The method for removing sulfonamide antibiotics from environmental water based on the advanced oxidation system according to claim 2, wherein When initiating the oxidation reaction, the concentration of PMS in the system is 0.5 mmol / L or more.

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