Method for degrading macrolide antibiotic wastewater by activating persulfate with a biochar composite catalyst

Abstract

The application discloses a method for degrading macrolide antibiotic wastewater by using a biochar composite catalyst. ‑ Free radicals and SO4 ·‑ Free radicals, which can act on the lactone ring and glycosidic bond of the sugar group connected to the macrolide antibiotic, and then degrade the antibiotic. The degradation method for the macrolide antibiotic wastewater provided by the application can treat low-concentration antibiotic pharmaceutical wastewater, and has simple process and good degradation effect; the biochar composite catalyst has low corrosion and can adapt to complex water quality changes, is green and safe, and can be recycled multiple times, thereby providing a new method for degrading macrolide antibiotics in low-concentration antibiotic wastewater, realizing solid waste resource utilization, and having wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection, specifically relating to a method for activating persulfate-degraded macrolide antibiotic wastewater using a biochar composite catalyst PBC@PEI. Background Technology

[0002] Antibiotic wastewater mainly originates from the pharmaceutical industry, aquaculture, and medical institutions. It contains large amounts of undigested antibiotics, antibiotic metabolites, and antibiotic-resistant microorganisms. Therefore, the overuse of antibiotics leads to environmental problems. Antibiotics entering rivers and lakes cause severe oxygen depletion, inhibit cell proliferation in aquatic organisms, affect their physiology and morphology, leading to the extinction of aquatic animals, damaging ecosystems, and threatening human health. Most antibiotics are produced through microbial fermentation, which generates large amounts of antibiotic production wastewater. This wastewater has complex components, characterized by high concentration, high toxicity, and high salinity, making it difficult to treat using traditional physicochemical and biochemical methods. Furthermore, antibiotics themselves are toxic to microorganisms and have poor biodegradability, making it difficult to achieve stable and compliant discharge. Therefore, developing more efficient and economical methods and processes for treating antibiotic production wastewater to effectively reduce the antibiotic activity and antibacterial properties in the wastewater is an urgent need given the current severe environmental situation.

[0003] Common advanced treatment technologies for antibiotic wastewater include biological treatment, advanced oxidation technologies, membrane separation technologies, and other emerging technologies such as electrochemical oxidation and nanomaterial adsorption. Among these, biological treatment technologies are relatively sensitive to environmental factors and wastewater composition, and may be affected by factors such as temperature and pH. Membrane separation technologies require regular membrane replacement and cleaning, resulting in high maintenance costs. Current research indicates that advanced oxidation technologies based on persulfate monosulfate (PMS) and persulfate disulfate (PDS) can generate sulfate radicals (SO42-) with high redox potentials. ·- SO4 ·- It can not only directly oxidize and degrade pollutants, but also react with H2O and hydroxide ions (OH-). -Substances such as hydroxyl radicals, superoxide radicals, and singlet oxygen can generate other ROS through free radical chain reactions, thus forming a multi-component oxidation system and improving the universality of the degradation system. In existing research, heterogeneous catalysts are commonly used to activate persulfate, mainly including metal-based and non-metal-based catalysts. Metal-based catalysts suffer from drawbacks such as easy agglomeration and leaching of metal ions. Literature reports the synthesis of cobalt tetroxide (Co3O4) with a mesoporous structure using KIT-6 as a hard template for activating PMS to degrade chloramphenicol. When PMS = 1 mM, chloramphenicol can be completely degraded and removed under neutral conditions for 1 hour. However, cobalt is more toxic to humans, and the dissolution of cobalt ions and particle agglomeration limit its application. Non-metal-based catalysts suffer from drawbacks such as poor catalytic performance under neutral conditions, poor reusability, and low utilization efficiency of PMS activation. Studies have shown that when using granular activated carbon (GAC) as a PS activator to degrade metronidazole (MNZ), the MNZ removal rate increases from 60% to 80% as the GAC addition increases from 2.5 g / L to 5 g / L, but this requires a large amount of catalyst and has a low reusability rate. Therefore, to address the problems of poor reusability and low PMS activation efficiency of existing catalysts, this study focuses on enhancing electron transfer efficiency and utilizes inexpensive and readily available wood biochar to develop a carbon-based catalyst with high reusability and broad applicability. This catalyst can efficiently activate PMS to remove antibiotics from water. This catalyst can achieve the goal of solid waste resource recovery and also has promising application prospects in the field of water pollutant treatment technology. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies for treating low-concentration macrolide antibiotics in the advanced treatment stages of wastewater. It provides an application of a biochar composite catalyst to activate persulfate degradation of macrolide antibiotic wastewater, thus solving the problem of insufficient wastewater treatment capacity leading to the accumulation of large amounts of macrolide antibiotics in the environment, the proliferation of superbugs, and threats to the environment and human health.

[0005] To address the aforementioned technical problems, this invention provides a method for activating persulfate to degrade macrolide antibiotics in wastewater using a biochar composite catalyst. The method involves adding PBC@PEI to wastewater containing macrolide antibiotics to degrade the macrolide antibiotics in the wastewater.

[0006] The characteristic feature is that (i) the preparation method of the PBC@PEI catalyst is as follows:

[0007] (1) Dissolve 1.78g of K2FeO4 powder in 90mL of deionized water to form a K2FeO4 aqueous solution. Disperse 1g of sawdust biochar powder BC into the K2FeO4 aqueous solution and stir continuously for 8h;

[0008] (2) Place the mixed solution obtained in step (1) on filter paper, filter to remove excess water, transfer the solid mixture to a petri dish, and then put it in a forced-air drying oven to dry at 60°C for 12 hours.

[0009] (3) Grind the solid mixture obtained after drying in step (2) for 5 min to obtain a powder mixture. Transfer the powder mixture to a quartz boat and place the quartz boat in a tube furnace, then introduce nitrogen gas. Heat the powder mixture to 800℃ and hold for 2 h, with a temperature gradient of 5℃ / min. The obtained product is named PBC.

[0010] (4) Dissolve 0.02g of PEI in a beaker containing 10mL of deionized water. Take 0.1g of the product obtained in step (3) and place it in the above PEI aqueous solution. Then place the beaker in an ultrasonic oscillator and sonicate continuously for 1h, and let it stand for 12h.

[0011] (5) Transfer the solid-liquid mixture obtained in step (4) to a centrifuge tube, then place the centrifuge tube in a centrifuge and centrifuge for 10 minutes, then pour off the excess water; finally, place the centrifuge tube containing the mixture in a forced-air drying oven and dry it at 60°C for 12 hours, then take out the mixture in the tube and grind it for 5 minutes to obtain a powder mixture.

[0012] (6) Transfer the powder mixture obtained in step (5) into a quartz boat, place the quartz boat in a tube furnace, and introduce nitrogen gas. Heat the powder mixture to 500℃ and hold for 2 hours, with a temperature gradient of 5℃ / min. Remove the mixture from the tube and grind it for 5 minutes to obtain the final catalyst, named PBC@PEI.

[0013] The method for preparing the biochar composite material described in (ii) is characterized in that the PEI in step (4) is a 50% aqueous solution of 70,000 MW and the ultrasonic time does not exceed 1 h. In step (6), the calcination temperature of the powder mixture is 500℃ and it is maintained at 500℃ for 2 h, with a heating gradient of 5℃ / min.

[0014] The method for activating persulfate degradation of macrolide antibiotic wastewater using biochar composite catalyst as described in (iii) is characterized by the following steps:

[0015] (1) Dissolve 10 mg of macrolide standard in a small amount of deionized water in a 100 mL beaker, and then dilute to 1000 mL volumetric flask with deionized water to obtain a macrolide antibiotic solution with a concentration of 10 mg / L.

[0016] (2) Take 50 mL of the antibiotic from step (1) into a beaker, then add 0.005 g of the prepared PBC@PEI catalyst, and then add PMS to make the final concentration 15 mg / L. Perform two parallel tests for each group.

[0017] (3) The reaction system obtained in step (2) is continuously stirred at 25°C for 20 minutes at a stirring rate of 400 rpm. Every 1 to 5 minutes, a sample (about 1 mL) is collected using a syringe, filtered through a 0.22 μm aqueous membrane, and placed in a liquid chromatography vial for later use.

[0018] (4) Use high performance liquid chromatography to measure the changes in the concentration of macrolide antibiotics in the samples collected in step (3);

[0019] (5) Preferably, the macrolide antibiotic in step (1) is tylosin.

[0020] The method for degrading macrolide antibiotics in the wastewater system described in (iv) is characterized in that the macrolide antibiotics include one or more of erythromycin, roxithromycin, erythromycin, fluerythromycin, clarithromycin, pyruvicin, azithromycin, spiramycin, and tylosin.

[0021] The method for activating persulfate degradation of macrolide antibiotics in wastewater using the biochar composite catalyst described in (v) is characterized in that the biochar composite catalyst, when used in the treatment of wastewater containing low concentrations of macrolide antibiotics, can achieve a 100% removal rate of macrolide antibiotics, thereby removing recalcitrant organic pollutants.

[0022] The characteristic of (vi) is that the biochar composite catalyst activated PMS is of the type, wherein the persulfate can be one of sodium persulfate, potassium persulfate or ammonium persulfate, preferably potassium persulfate.

[0023] The method described in (vii) is characterized in that it can be applied to the deep treatment stage of wastewater treatment projects for macrolide antibiotic production, so as to completely degrade and eliminate its antibacterial properties.

[0024] The biochar composite catalyst-activated persulfate degradation oxidation method described in this invention is a novel method for the degradation of macrocyclic lactone antibiotics, and has the following advantages:

[0025] 1. The method of activating persulfate to degrade macrolide antibiotics in wastewater using biochar composite catalyst of the present invention can effectively decompose low concentrations of macrolide antibiotics in antibiotic production wastewater, leaving no antibiotic residues.

[0026] 2. The biochar composite catalyst prepared by this invention is inexpensive, readily available, green, and environmentally friendly. After use, it can be easily separated from the product for multiple recycling, reducing the secondary pollution of the environment caused by the catalyst itself, and is environmentally friendly.

[0027] 3. The hydrolysis treatment conditions in the process of treating macrolide antibiotic wastewater by the method of the present invention are mild. Due to the low temperature, the reaction operation is simple and the operating conditions are easy to control.

[0028] 4. The method of this invention can selectively hydrolyze and degrade macrolide antibiotics without interference from other coexisting substances in the wastewater. Therefore, this invention has excellent application prospects in the treatment of wastewater containing low concentrations of macrolide antibiotics.

[0029] 5. The method of this invention uses wood chip biochar as raw material to prepare a green and environmentally friendly material that can efficiently degrade macrolide antibiotics, thus realizing the resource utilization of solid waste. Attached Figure Description

[0030] Figure 1 The graph shows the efficiency of the PBC@PEI catalyst prepared in this invention in reducing tylosin at different PMS concentrations.

[0031] Figure 2 The diagram shows the efficiency of the PBC@PEI catalyst prepared in this invention in reducing tylosin at different dosages.

[0032] Figure 3 The graph shows the degradation efficiency of the PBC@PEI catalyst prepared in this invention at different concentrations of tylosin.

[0033] Figure 4 The graph shows the performance of the PBC@PEI catalyst prepared in this invention in degrading tylosin at different temperatures.

[0034] Figure 5 The diagram shows the efficiency of the PBC@PEI catalyst prepared in this invention in reducing tylosin under the influence of different anions.

[0035] Figure 6 The graph shows the performance of the PBC@PEI catalyst prepared in this invention in reducing tylosin in 5 cycles. Detailed Implementation

[0036] The present invention will be described in further detail with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0037] Example 1: A method for preparing a biochar composite catalyst, comprising the following steps:

[0038] (1) Dissolve 1.78g of K2FeO4 powder in 90mL of deionized water to form a K2FeO4 aqueous solution. Disperse 1g of wood biochar powder BC into the K2FeO4 aqueous solution and stir continuously for 8h. (2) Place the mixed solution obtained in step (1) on filter paper, filter to remove excess water, transfer the solid mixture to a petri dish, and then place it in a forced-air drying oven to dry at 60℃ for 12h. (3) Grind the solid mixture obtained after drying in step (2) for 5min to obtain a powder mixture, transfer the powder mixture to a quartz boat, place the quartz boat in a tube furnace, and introduce nitrogen gas. The powder mixture was heated to 800℃ and held for 2 hours with a temperature gradient of 5℃ / min. The obtained product was named PBC. (4) 0.02g of PEI was dissolved in a beaker containing 10mL of deionized water. 0.1g of the product obtained in step (3) was placed in the above PEI aqueous solution. The beaker was then placed in an ultrasonic oscillator and ultrasonicated continuously for 1 hour, followed by standing for 12 hours. (4) The solid-liquid mixture obtained in step (3) was transferred to a centrifuge tube. The centrifuge tube was then centrifuged for 10 minutes, and excess water was removed. Finally, the centrifuge tube containing the mixture was placed in a forced-air drying oven and dried at 60℃ for 12 hours. The mixture in the tube was then removed and ground for 5 minutes to obtain the powder mixture. (5) The powder mixture obtained in step (4) was transferred to a quartz boat and then placed in a tube furnace with nitrogen gas introduced. The powder mixture was heated to 500℃ and held for 2 hours with a temperature gradient of 5℃ / min. The final catalyst was obtained and named PBC@PEI.

[0039] Example 2: The biochar composite catalyst prepared in this invention activates different concentrations of PMS to degrade macrolide antibiotics.

[0040] Dissolve 10 mg of tylosin standard in a small amount of deionized water in a 100 mL beaker, then dilute to a 1000 mL volumetric flask with deionized water to obtain a 10 mg / L tylosin solution. Measure 50 mL of the prepared tylosin solution into a beaker, then add 5 mg of the prepared biochar composite acid catalyst. Add PMS to achieve final concentrations of 10 mg / L, 11 mg / L, 12 mg / L, 13 mg / L, 14 mg / L, 15 mg / L, and 16 mg / L. Stir continuously for 15 minutes at a speed of 400 rpm. Collect samples at regular time intervals using a 1 mL syringe, filter through a 0.22 μm aqueous membrane, and measure the tylosin degradation dynamics using high-performance liquid chromatography (HPLC).

[0041] Figure 1The results showed that the degradation efficiency of tylosin gradually increased with the increase of PMS concentration from 10 mg / L to 16 mg / L. When the PMS concentration increased to 15 mg / L and above, tylosin could be almost completely removed. This is because the catalyst can efficiently activate PMS to produce highly oxidizing SO4. ·- As the concentration of PMS increases, the generation of strong oxidizing free radicals also increases, thereby completely removing tylosin.

[0042] Example 3: The biochar composite catalyst prepared in this invention degrades macrolide antibiotics at different dosages.

[0043] Dissolve 10 mg of tylosin standard in a small amount of deionized water in a 100 mL beaker, then dilute to a 1000 mL volumetric flask with deionized water to obtain a 10 mg / L tylosin solution. Measure 50 mL of the prepared tylosin solution into a beaker, then add 0.0015 g, 0.0025 g, 0.004 g, 0.005 g, and 0.0075 g of biochar composite catalyst, respectively. Add PMS to bring the PMS concentration in the system to 15 mg / L. Turn on the stirrer and stir continuously for 15 minutes at a stirring rate of 400 rpm. Collect samples at regular time intervals using a 1 mL syringe, filter through a 0.22 μm aqueous membrane, and measure the tylosin degradation dynamics using high-performance liquid chromatography (HPLC).

[0044] Figure 2 The results showed that the hydrolysis efficiency of tylosin increased with increasing catalyst dosage, especially at a catalyst dosage of 0.1 g / L, where tylosin could be degraded within 10 minutes. However, it was observed that the increase in degradation efficiency was less significant when the composite catalyst dosage increased from 0.1 g / L to 0.15 g / L compared to the increase from 0.03 g / L to 0.1 g / L, indicating that under the condition of PMS = 15 mg / L, the PBC@PEI dosage gradually reached saturation, and further increasing the dosage was meaningless.

[0045] Example 4: The biochar composite catalyst prepared in this invention degrades macrolide antibiotics of different concentrations.

[0046] Dissolve 5 mg, 10 mg, 20 mg, 30 mg, and 40 mg of tylosin standards in a small amount of deionized water in 100 mL beakers, and then dilute to 1000 mL volumetric flasks with deionized water to obtain tylosin solutions with concentrations of 5 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, and 40 mg / L. Measure 50 mL of the prepared tylosin solution into a beaker, then add 0.005 g of biochar composite catalyst, followed by PMS. Turn on the stirrer and stir continuously for 15 minutes at a speed of 400 rpm. Collect samples at regular time intervals using a 1 mL syringe, filter through a 0.22 μm aqueous membrane, and measure the degradation dynamics of tylosin using high-performance liquid chromatography (HPLC).

[0047] Figure 3 The results show that under PMS concentration of 15 mg / L, when the initial concentration of tylosin is 5 mg / L, the catalyst can activate PMS and almost completely degrade tylosin within 7 minutes. When the initial concentration of tylosin is 10 mg / L, the catalyst can activate PMS and almost completely degrade tylosin within 10 minutes. As the concentration of tylosin increases, the degradation effect gradually decreases. This is because at lower PMS concentrations, the catalyst activates PMS, resulting in the release of SO4. ·- This was insufficient to degrade all tylosin. However, compared with studies conducted during the same period, PBC@PEI-activated PMS showed superior degradation of tylosin under low PMS concentration conditions of only 15 mg / L.

[0048] Example 5: The biochar composite catalyst prepared in this invention degrades macrolide antibiotics at different temperatures.

[0049] Dissolve 10 mg of tylosin standard in a small amount of deionized water in a 100 mL beaker, then dilute to a 1000 mL volumetric flask with deionized water to obtain a 10 mg / L tylosin solution. Measure 50 mL of the prepared tylosin solution into a beaker, and heat the beaker in a water bath to 25°C, 35°C, and 45°C respectively. After the temperature stabilizes, add 0.005 g of catalyst to the beaker, and finally add PMS. Turn on the stirrer and stir continuously for 15 minutes at a stirring rate of 400 rpm. Collect samples at regular time intervals using a 1 mL syringe, filter through a 0.22 μm aqueous membrane, and measure the tylosin degradation dynamics using high-performance liquid chromatography (HPLC).

[0050] Figure 4 This indicates that the degradation effect of TYL gradually increases with increasing temperature, consistent with the temperature pattern of conventional degradation. At all three temperatures, the removal rate of TYL reached over 99% within 15 minutes, demonstrating that TYL degradation can be completed in a very short time.

[0051] Example 6: The biochar composite catalyst prepared in this invention degrades macrolide antibiotics under the influence of different anions.

[0052] Dissolve 10 mg of tylosin standard in a small amount of deionized water in a 100 mL beaker, then dilute to a 1000 mL volumetric flask with deionized water to obtain a 10 mg / L tylosin solution. Measure 50 mL of the prepared tylosin solution into beakers, then add prepared NaCl, Na₂CO₃, NaHCO₃, and Na₂SO₄ solutions to each beaker to ensure the corresponding anion concentration is 1 mmol. Add 0.005 g of catalyst to each beaker, and finally add PMS. Turn on the stirrer and stir continuously for 15 minutes at a speed of 400 rpm. Collect samples at regular time intervals using a 1 mL syringe, filter through a 0.22 μm aqueous membrane, and measure the degradation dynamics of tylosin using high-performance liquid chromatography (HPLC).

[0053] Figure 5 This indicates that when the system contains Cl - SO4 2- CO3 2- Within a 15-minute reaction time, the degradation rate of TYL consistently reached over 95%. Even with different coexisting ions, PBC@PEI remained highly efficient in activating PMS to degrade TYL. Therefore, the PBC@PEI composite catalyst can adapt to complex water quality changes, overcoming the shortcomings of traditional catalysts whose catalytic efficiency is reduced by water quality variations.

[0054] Example 7: The biochar composite catalyst prepared in this invention degrades macrolide antibiotics in 5 cycles.

[0055] Dissolve 10 mg of tylosin standard in a small amount of deionized water in a 100 mL beaker, then dilute to a 1000 mL volumetric flask with deionized water to obtain a 10 mg / L tylosin solution. Measure 50 mL of the prepared tylosin solution into a beaker, place the beaker in a water bath and heat to 25°C. After the temperature stabilizes, add 0.005 g of catalyst, and finally add PMS. Turn on the stirrer and stir continuously for 15 minutes at a stirring rate of 400 rpm. Collect samples at regular time intervals using a 1 mL syringe, filter through a 0.22 μm aqueous membrane, and measure the tylosin degradation dynamics using high-performance liquid chromatography. Adsorb the biochar composite material with a strong magnet, wash repeatedly with distilled water, dry in a 60°C oven, and repeat the above reaction. The reaction process is repeated 5 times.

[0056] Figure 6The results show that the recycled biochar composite catalyst still achieves a tylosin degradation rate of over 99% within 15 minutes in the third reaction. The degradation rate of tylosin only decreased by about 5% in the fourth and fifth reactions. The biochar composite catalyst prepared in this invention has good recyclability and is an economical, efficient, and environmentally friendly functional material.

[0057] The specific embodiments described above are merely preferred embodiments of the present invention. However, other aspects and embodiments will be obvious to those skilled in the art. Without departing from the principle of the present invention, several modifications and improvements can be made, all of which fall within the protection scope of this application.

Claims

1. A method for degrading tylosin wastewater by using a biochar composite catalyst, characterized in that The application discloses a method for degrading tylosin by using a biochar composite product PBC@PEI as a catalyst, adding the catalyst and a certain amount of persulfate PMS into sewage containing tylosin, wherein the persulfate PMS is one of sodium persulfate, potassium hydrogen persulfate or ammonium persulfate; and the catalyst is prepared by the following steps: (1) 1.78g of K2FeO4 powder is dissolved in 90mL of deionized water to form a K2FeO4 aqueous solution; 1g of sawdust biochar powder BC is dispersed into the K2FeO4 aqueous solution, and continuous stirring is carried out for 8h; (2) the mixed solution obtained in the step (1) is placed on filter paper, and after the excessive water is removed by suction filtration, the solid mixture is transferred into a culture dish, and then is placed into a blast drying oven and dried at 60℃ for 12h; (3) the solid mixture obtained after drying in the step (2) is ground for 5min to obtain a powder mixture, the powder mixture is transferred into a quartz boat, and then the quartz boat is placed into a tube furnace, and nitrogen is introduced; the powder mixture is heated to 800℃ and kept for 2h, and the heating gradient is 5℃ / min; and the obtained product is named as PBC; (4) 0.02g of PEI is dissolved in a beaker containing 10mL of deionized water, 0.1g of the product obtained in the step (3) is placed into the PEI aqueous solution, and then the beaker is placed into an ultrasonic oscillator, and continuous ultrasonic oscillation is carried out for 1h, and then the beaker is placed for 12h; (5) the solid-liquid mixture obtained in the step (4) is transferred into a centrifuge tube, and then the centrifuge tube is placed into a centrifuge and centrifuged for 10min, and then the excessive water is poured out; finally, the centrifuge tube containing the mixture is placed into a blast drying oven and dried at 60℃ for 12h, the mixture in the tube is taken out and ground for 5min to obtain a powder mixture; (6) the powder mixture obtained in the step (5) is transferred into a quartz boat, and then the quartz boat is placed into a tube furnace, and nitrogen is introduced; the powder mixture is heated to 500℃ and kept for 2h, and the heating gradient is 5℃ / min; the mixture in the tube is taken out and ground for 5min to obtain the final catalyst, which is named as PBC@PEI.

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