Multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergistic effect

Abstract

The invention belongs to the field of wastewater treatment, and provides a multi-dimensional pollution control method for complex organic wastewater based on a nano-millimeter cross-scale synergistic effect. The method comprises the following steps: dissolving an oxidizing agent in complex organic wastewater containing organic pollutants and resistance genes to obtain wastewater containing the oxidizing agent, and contacting the wastewater containing the oxidizing agent with a catalyst for wastewater treatment, the catalyst catalyzes the oxidizing agent to generate active oxygen species to degrade organic pollutants in the complex organic wastewater and remove resistance genes in the complex organic wastewater; the catalyst is chitosan particles loaded with nano CoMn2O4 in situ. According to the method disclosed by the invention, the antibiotic resistance genes in the wastewater can be removed while the organic pollutants in the wastewater are degraded, and the long-term operation stability of the wastewater treatment method is improved.

Description

Technical Field

[0001] The present invention belongs to the field of wastewater treatment and relates to a multi-dimensional pollution control method for complex organic wastewater based on the synergistic effect of nano-millimeter cross-scale. Background Art

[0002] In the livestock industry, the prophylactic use of antibiotics has accelerated the evolution of environmental microbial drug resistance, while the routine supplementation of antibiotics through feed has promoted the enrichment of drug-resistant strains. Microorganisms carrying antibiotic resistance genes (ARGs) in the animal intestine are discharged into the environment with feces, and the ARGs in the environment can be transmitted between different microorganisms through horizontal gene transfer. The continuous high-dose application of antibiotics in hospitals has also caused similar problems. Currently, a variety of ARGs have been detected in water sources, posing a major public health safety hazard.

[0003] Livestock and poultry breeding wastewater, as a key object in the field of environmental governance, contains both conventional pollutants and new pollutants such as ARGs, showing dual pollution characteristics. Livestock and poultry breeding wastewater is not only a typical high-resistance gene transmission carrier, but also its inherent low carbon-nitrogen ratio characteristics greatly increase the difficulty of biological treatment. For example, such wastewater can cause problems such as strong carbon source dependence and microbial community metabolic imbalance in the biological treatment system. Current mainstream treatment processes, such as constructed wetlands, membrane filtration, and reverse osmosis, although they can remove some dissolved pollutants in this type of wastewater, face limitations such as long treatment cycles, low treatment efficiency, and high operating costs. Advanced oxidation technologies (AOPs) based on multiple reactive species mechanisms can solve the problems of low treatment efficiency and high operating costs faced by the above treatment processes. AOPs generate reactive oxygen species including sulfate radicals (SO4 ·- ), hydroxyl radicals ( · OH), organic radicals (RO · ), superoxide radicals (O2 ·- ), singlet oxygen ( 1 O2), etc. through the catalysis of oxidants by catalysts, and can convert organic pollutants into low-toxic or non-toxic biodegradable small molecule products, having unique advantages in the treatment of refractory organic pollutants in water. Although there have been many studies and applications of AOPs in the degradation of organic pollutants, there is currently a lack of systematic research on the simultaneous degradation of pollutants and removal of ARGs in livestock and poultry breeding wastewater with complex matrix characteristics and dual pollutant characteristics. The treatment of such wastewater still faces problems such as high treatment difficulty and poor treatment effect.

[0004] Among the numerous catalytic materials used to catalyze oxidants to produce reactive oxygen species, nanocatalytic materials have the characteristics of high specific surface area and adjustable electronic structure, which are conducive to exposing abundant active sites and improving their catalytic performance, showing significant advantages in improving catalytic reaction efficiency and targeted regulation. However, the large-scale application of nanocatalytic materials in wastewater treatment is restricted by factors such as difficulty in separation and recycling, easy agglomeration and inactivation, poor long-term performance, high process cost and difficulty in large-scale production.

[0005] Therefore, for complex organic wastewater such as livestock and poultry breeding wastewater that contains both organic pollutants and new pollutants such as ARGs, if we can combine the advantages of high activity of nanocatalytic materials and non-agglomeration of micron materials, design catalytic materials with nano-millimeter cross-scale synergistic effects to enhance the long-term stability of nanocatalytic materials, and on this basis develop a multidimensional pollution control method for complex organic wastewater that can operate stably and for a long time, and achieve the simultaneous removal of organic pollutants and ARGs in complex organic wastewater, it will have important positive significance for reducing the environmental risks of complex organic wastewater. Summary of the invention

[0006] In view of the problem that the existing technology is difficult to treat complex organic wastewater containing both organic pollutants and new pollutants such as ARGs and has poor treatment effect, the present invention provides a multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy, so as to remove ARGs while degrading organic pollutants in the wastewater, and improve the long-term operation stability of the wastewater treatment method.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0008] The multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy includes the following steps:

[0009] dissolving an oxidant in complex organic wastewater containing organic pollutants and resistance genes to obtain wastewater containing the oxidant, contacting the wastewater containing the oxidant with a catalyst for wastewater treatment, wherein during the wastewater treatment process, the catalyst catalyzes the oxidant to produce active oxygen species to degrade organic pollutants in the complex organic wastewater and remove resistance genes in the complex organic wastewater;

[0010] The catalyst is chitosan particles loaded with nano CoMn2O4 in situ, and is composed of porous chitosan particles and nano CoMn2O4 loaded in situ on the porous chitosan particles.

[0011] In the above technical solution, the size of the catalyst is in the millimeter level, for example, the size (diameter) of the catalyst may be between 3 and 8 mm.

[0012] In the above technical solution, the content of nano-CoMn2O4 in the catalyst is 30 wt% to 50 wt%.

[0013] In the above technical solution, a chemical bond is formed between the nano-CoMn2O4 and the porous chitosan particles in the catalyst, thereby realizing the stable composite of the two phases of nano-CoMn2O4 and the porous chitosan particles.

[0014] In the above technical solution, the preparation method of the catalyst is as follows:

[0015] (1) Dissolve chitosan in a formic acid aqueous solution with a volume concentration of 1% to 2% to obtain a chitosan solution; dissolve Co(NO3)2·6H2O and MnCl2·4H2O in water to obtain a metal salt mixed solution with a molar ratio of Co to Mn of 1:2.

[0016] (2) Add the metal salt mixed solution to the chitosan solution under stirring, stir and mix well, and ultrasonically remove the bubbles in the solution to obtain a precursor solution; in this precursor solution, the concentration of chitosan is 18 to 30 g / L, and the concentration of cobalt ions is 0.03 to 0.1 mol / L.

[0017] (3) Drop the precursor solution into a NaOH solution with a temperature of 80 to 100 °C and a concentration of 1 to 2 mol / L, react at 80 to 100 °C for 2 to 4 h, cool to room temperature, separate the obtained solid phase, wash it thoroughly with water, and freeze-dry to obtain the product.

[0018] Further, when preparing the catalyst in the above technical solution, in step (1), the concentration of the chitosan solution is preferably 20 to 35 g / L, and the concentration of cobalt ions in the metal salt mixed solution is preferably 0.8 to 2.4 mol / L.

[0019] Further, when preparing the catalyst in the above technical solution, in step (3), it is preferred to drop the precursor solution into the NaOH solution at a constant speed. For example, a peristaltic pump can be used to drop the precursor solution into the NaOH solution. By controlling the inner diameter of the pipe connected to the outlet of the peristaltic pump and the dropping speed of the precursor solution, the size of the prepared catalyst can be controlled. For example, the inner diameter of the pipe connected to the outlet of the peristaltic pump can be controlled to be 1.6 to 9.6 mm, and the dropping speed of the precursor solution can be controlled to be 40 to 80 drops / min.

[0020] In the above technical solution, the concentration of the oxidant in the wastewater containing the oxidant is controlled to be 1 to 2 mmol / L.

[0021] In the above technical solution, the oxidant is peracetic acid, monopersulfate, dipersulfate or hydrogen peroxide.

[0022] In the above technical solution, the active oxygen species produced by the catalyst catalyzing the oxidant are related to the type of oxidant used. For example, when the oxidant used is peracetic acid, the active oxygen species produced include organic free radicals, singlet oxygen, and hydroxyl free radicals.

[0023] In the above technical solution, the wastewater containing the oxidant can be brought into contact with the catalyst for wastewater treatment by adding the catalyst to the wastewater containing the oxidant. Preferably, the dosage of the catalyst in the wastewater is controlled to be 1200 - 2000 mg / L. When the wastewater containing the oxidant is brought into contact with the catalyst in this way for wastewater treatment, after the treatment of a batch of wastewater is completed, the catalyst in the wastewater is separated and then recycled.

[0024] In the above technical solution, preferably, the catalyst is added to a fixed-bed continuous flow device, and the wastewater containing the oxidant is introduced into the fixed-bed continuous flow device to bring the wastewater containing the oxidant into contact with the catalyst for wastewater treatment. In practical applications, the residence time of the wastewater containing the oxidant in the fixed-bed continuous flow device can be determined according to the water quality of the wastewater, the size of the fixed-bed continuous flow device, the loading amount of the catalyst in the fixed-bed continuous flow device, etc. Generally, the hydraulic residence time of the wastewater containing the oxidant in the fixed-bed continuous flow device should enable the removal rate of organic pollutants or / and resistance genes in the wastewater to reach equilibrium or meet the actual application requirements. Generally speaking, the hydraulic residence time of the wastewater containing the oxidant in the fixed-bed continuous flow device can be controlled to be 30 - 60 min. Usually, the wastewater containing the oxidant is introduced into the fixed-bed continuous flow device from the lower part of the fixed-bed continuous flow device, and the wastewater containing the oxidant is discharged from the upper part of the fixed-bed continuous flow device.

[0025] In the technical solution of the above method, the pH value of the complex organic wastewater is controlled to be 3 - 9. When the oxidant used is peracetic acid, peroxymonosulfate, or peroxydisulfate, preferably, the pH value of the complex organic wastewater is controlled to be 6 - 9. When the oxidant used is hydrogen peroxide, preferably, the pH value of the complex organic wastewater is controlled to be 3 - 5.

[0026] In the technical solution of the above method, the resistance gene is an antibiotic resistance gene.

[0027] In the technical solution of the above method, the complex organic wastewater includes livestock and poultry breeding wastewater.

[0028] In the above technical solution, the complex organic wastewater contains organic substances including antibiotics.

[0029] Compared with the prior art, the technical solution provided by the present invention has the following beneficial technical effects:

[0030] 1. The present invention provides a multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy. The operation of this method is as follows: Dissolve an oxidant in complex organic wastewater containing organic pollutants and resistance genes to obtain wastewater containing the oxidant, and bring the wastewater containing the oxidant into contact with a catalyst for wastewater treatment. During the wastewater treatment process, the catalyst catalyzes the oxidant to generate reactive oxygen species to degrade the organic pollutants in the complex organic wastewater and remove the resistance genes in the complex organic wastewater. The method of the present invention uses chitosan particles in-situ loaded with nano-CoMn2O4 as a catalyst to activate the oxidant to generate reactive oxygen species to achieve the removal of organic pollutants and resistance genes in the complex organic wastewater. On the one hand, the method of the present invention can reduce the risk of horizontal transfer of resistance genes (especially ARGs) while degrading organic pollutants in the wastewater, realizing multi-dimensional pollution control of complex organic wastewater, and solving the problems of difficult treatment and poor treatment effect faced by complex wastewater with complex matrix characteristics and dual pollutant characteristics (such as livestock and poultry breeding wastewater). On the other hand, using chitosan particles in-situ loaded with nano-CoMn2O4 as a catalyst endows the method of the present invention with excellent long-term operation stability, can solve the problem of poor operation stability of the existing treatment methods using nano-catalytic materials as catalysts to catalyze oxidants to generate reactive oxygen species, and is beneficial to reducing the treatment cost of complex organic wastewater and realizing engineering application.

[0031] 2. The present invention has experimentally confirmed that the catalyst used in the method of the present invention has good catalytic effects on oxidants including peracetic acid, peroxymonosulfate, persulfate, and hydrogen peroxide, can catalyze these oxidants to generate reactive oxygen species, and then produce good removal effects on organic pollutants and resistance genes. It has the advantage of wide applicability to oxidants, which is beneficial to selecting appropriate oxidants for treatment according to the water quality of the wastewater in practical applications, and increases the flexible applicability of the wastewater treatment method.

[0032] 3. The present invention is verified through experiments that there are significant differences in the effects of the millimeter-scale catalyst CMO@CS prepared in Example 1 and the nano-CoMn2O4 (CMO) prepared in Comparative Example 2 on the degradation of bisphenol A (BPA) in simulated wastewater by peracetic acid (PAA) in a continuous flow experiment. As the continuous operation time of the fixed-bed device gradually increases, the removal rate of BPA by the CMO / PAA system gradually decreases, while the removal rate of BPA by the CMO@CS / PAA system remains basically stable. When the fixed-bed device is continuously operated for 85 h, the removal rate of BPA by the CMO / PAA system decreases from the initial level of 90% to about 50%, while the removal rate of BPA by the CMO@CS / system remains at about 90% all the time; the average removal rate of BPA by the CMO / PAA system is 66.1%, while the average removal rate of BPA by the CMO@CS / system is as high as 90.1%. This shows that the in-situ method of loading nano-CoMn2O4 on the chitosan carrier in the present invention can effectively avoid the problem that the activity of nano-CoMn2O4 is easily reduced during wastewater treatment, which is beneficial to maintaining the catalytic activity of nano-CoMn2O4 in the long term, and is very beneficial for the engineering and large-scale application of the method described in the present invention.

[0033] 4. The method described in the present invention is particularly suitable for treating complex organic wastewater (such as livestock and poultry breeding wastewater) containing both organic pollutants and new pollutants such as ARGs. The present invention is verified through experiments that when using livestock and poultry breeding wastewater as the treatment object, the method described in the present invention can effectively reduce the chromaticity, COD value, TOC value, TN value and biotoxicity of livestock and poultry breeding wastewater; at the same time, the method described in the present invention can remove or convert macromolecular dissolved organic matter (DOM) and other substances in livestock and poultry breeding wastewater into small-molecule DOM; the method described in the present invention can effectively remove most of the organic matter in livestock and poultry breeding wastewater, and can also effectively reduce the abundances of ARGs including tetracycline resistance genes, sulfonamide resistance genes, glycopeptide resistance genes and aminoglycoside resistance genes. That is, the method described in the present invention can not only achieve the removal of organic pollutants during conventional wastewater treatment, but also has a unique role in destroying the genetic stability of ARGs, providing an effective solution for simultaneously controlling gene pollution and the pollution of toxic and harmful chemical substances in environmental media. Description of the Drawings

[0034] Figure 1 Figure (a) is a photograph of CMO@CS, CS and CMO / CS, Figure 1 Figure (b) is an SEM image of CMO@CS, CS and CMO / CS, Figure 1 Figure (c) is a TEM image of CMO@CS, CS and CMO / CS, Figure 1 Figure (d) is an EDS spectrum of CMO@CS, Figure 1(e) is the SEM image of CMO@CS, Figure 1 (f) is the infrared spectra of CMO@CS, CS, CMO / CS, and CMO, Figure 1 (g) is the XRD patterns of CMO@CS, CS, CMO / CS, and CMO.

[0035] Figure 2 (a) is the removal rate of BPA during the degradation of BPA by CS, CMO / CS, and CMO@CS catalyzing PAA; Figure 2 (b) is the removal rate of BPA during the degradation of BPA by CMO@CS catalyzing PAA, PMS, PDS, and H2O2.

[0036] Figure 3 is the influence of different quenchers on the degradation of BPA in the CMO / PAA system.

[0037] Figure 4 is the schematic diagram of the fixed-bed device. In the figure, 1 - catalyst, 2 - cylinder, 3 - cotton, 4 - support frame, 5 - peristaltic pump, 6 - water inlet beaker, 7 - water outlet beaker.

[0038] Figure 5 is the removal rate of BPA during the degradation of BPA by CMO@CS and CMO catalyzing PAA in the continuous-flow experiment.

[0039] Figure 6 is the effluent photos after the fixed-bed device has been continuously operated for 0 h, 12 h, 48 h, and 96 h.

[0040] Figure 7 (a) and (b) are the COD values and COD removal rates of the effluent during the continuous operation of the fixed-bed device, Figure 7 (c) and (d) are the TOC values and TOC removal rates of the effluent during the continuous operation of the fixed-bed device, Figure 7 (e) and (f) are the TN values and TN removal rates of the effluent during the continuous operation of the fixed-bed device.

[0041] Figure 8 (a) is the removal rate of various organic matters in the livestock and poultry breeding wastewater after the fixed-bed device has been continuously operated for 96 h in Example 7, Figure 8 (b) is the removal rate of antibiotics in the livestock and poultry breeding wastewater after the fixed-bed device has been continuously operated for 96 h in Example 7.

[0042] Figure 9It is the Van Krevelen diagram of DOM in the original livestock and poultry breeding wastewater and the treated effluent in Example 8. Among them, Figure (a) is the Van Krevelen diagram of DOM in the original livestock and poultry breeding wastewater, Figure (b) is the Van Krevelen diagram of DOM that has been completely removed after treatment, and Figure (c) is the Van Krevelen diagram of DOM that has been partially removed after treatment. Figure 8 Figure (d) is the Van Krevelen diagram of DOM that has not changed after treatment.

[0043] Figure 10 Figure (a) is the LEfSe phylogenetic cladogram of groups G1 - G2. Figure 10 Figure (b) is the LEfSe phylogenetic cladogram of groups G1, G3, and G4.

[0044] Figure 11 Figure (a) is the circos diagram of the CARD database of the top 10 genes in terms of abundance in the water samples of groups G1 - G4. Figure 11 Figure (b) is the heatmap of the clustering of the abundances of drug - resistant genes in the water samples of groups G1 - G4. Detailed implementation manners

[0045] The following further illustrates the multi - dimensional pollution control method for complex organic wastewater based on nano - millimeter cross - scale synergy provided by the present invention through examples. It should be noted that the following examples are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention. Those skilled in the art make some non - essential improvements and adjustments to the present invention according to the above - mentioned invention content for specific implementation, which still fall within the protection scope of the present invention.

[0046] Example 1

[0047] In this example, the catalyst, chitosan particles with in - situ loaded nano - CoMn2O4, is prepared by the in - situ method, and the steps are as follows:

[0048] (1) Chitosan (CS) is added to a formic acid aqueous solution with a volume concentration of 1%, and stirred for 12 h. At this time, CS is completely dissolved to obtain a CS solution with a CS concentration of 20 g / L.

[0049] Co(NO3)2·6H2O and MnCl2·4H2O are dissolved in deionized water to obtain a metal salt mixed solution with a molar ratio of Co to Mn of 1:2. In this metal salt mixed solution, the concentration of cobalt ions is 0.8 mol / L and the concentration of manganese ions is 1.6 mol / L.

[0050] (2) Slowly add the metal salt mixed solution to the CS solution under stirring, continue stirring for 30 min to achieve sufficient mixing, and then ultrasonicate for 30 min to remove the bubbles in the obtained mixed solution, obtaining a precursor solution; in this precursor solution, the concentration of CS is 19 g / L, the concentration of cobalt ions is 0.0381 mol / L, and the concentration of manganese ions is 0.0762 mol / L.

[0051] (3) Use a peristaltic pump to drip the precursor solution through a silica gel tube with an inner diameter of 4.8 mm at a dropping rate of 50 drops / min into a NaOH solution with a temperature of 90 °C and a concentration of 1.25 mol / L. After the dropping is completed, react at 90 °C for 2 h. During this process, the cobalt ions and manganese ions in the precursor solution droplets undergo an in-situ coprecipitation reaction to form nano-CoMn2O4 and are loaded on the CS microspheres. Cool to room temperature, filter and separate the obtained solid phase, wash with deionized water, and freeze-dry to obtain the catalyst prepared by the in-situ method, denoted as CMO@CS. In CMO@CS, the content of CoMn2O4 is 32 wt% (theoretical loading amount).

[0052] Comparative Example 1

[0053] In this comparative example, the preparation of freeze-dried chitosan particles is as follows:

[0054] (1) Add CS to a 1% formic acid aqueous solution by volume, stir for 12 h, and at this time CS is completely dissolved to obtain a CS solution with a CS concentration of 20 g / L.

[0055] (3) Use a peristaltic pump to drip the CS solution through a silica gel tube with an inner diameter of 4.8 mm at a dropping rate of 50 drops / min into a NaOH solution with a temperature of 90 °C and a concentration of 1.25 mol / L. After the dropping is completed, react at 90 °C for 2 h, cool to room temperature, filter and separate the obtained solid phase, wash with deionized water, and freeze-dry to obtain freeze-dried chitosan particles, denoted as CS.

[0056] Comparative Example 2

[0057] In this comparative example, the catalyst - chitosan particles with nano-CoMn2O4 heterogeneously loaded are prepared by the heterogeneous method, and the steps are as follows:

[0058] (1) Add CS to a 1% formic acid aqueous solution by volume, stir for 12 h, and at this time CS is completely dissolved to obtain a chitosan solution with a CS concentration of 20 g / L.

[0059] Dissolve Co(NO3)2·6H2O and MnCl2·4H2O in deionized water to obtain a metal salt mixed solution with a molar ratio of Co to Mn of 1:2. In this metal salt mixed solution, the concentration of cobalt ions is 0.8 mol / L and the concentration of manganese ions is 1.6 mol / L.

[0060] (2) Add the mixed metal salt solution to the NaOH solution at a temperature of 90 °C and a concentration of 1.25 mol / L, and stir at 90 °C

[0061] for 2 h. During this process, cobalt ions and manganese ions undergo an in-situ coprecipitation reaction to form nano-CoMn2O4. Cool to room temperature, filter to separate the solid phase, wash with deionized water, and dry in vacuum. Denote it as CMO.

[0062] (3) Slowly add CMO to the CS solution under stirring, continue stirring for 30 min to achieve full mixing, and then sonicate for 30 min to remove the bubbles in the obtained mixed solution to obtain a precursor solution; in this precursor solution, the concentration of CS is 19 g / L and the concentration of CMO is 0.0381 mol / L.

[0063] (4) Use a peristaltic pump to drop the precursor solution into the NaOH solution at a temperature of 90 °C and a concentration of 1.25 mol / L through a silica gel tube with an inner diameter of 4.8 mm at a dropping rate of 50 drops / min. After dropping, react at 90 °C for 2 h, cool to room temperature, separate the obtained solid phase, wash with deionized water, and freeze-dry to obtain a catalyst prepared by the ex-situ method, denoted as CMO / CS. In CMO / CS, the content of CoMn2O4 is 32 wt% (theoretical loading).

[0064] Example 2

[0065] In this example, CMO@CS, CS, and CMO / CS prepared in Example 1 and Comparative Examples 1-2 were characterized.

[0066] The photos of CMO@CS, CS, and CMO / CS are as shown in Figure 1 Figure (a). CS is white particles, CMO@CS and CMO / CS are black particles, and the color of CMO@CS is darker than that of CMO / CS. Further, CMO@CS, CS, and CMO / CS were tested by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM images and TEM images are as shown in Figure 1 Figures (b) and (c). CoMn2O4 is in the form of nano-sheets, the surface of CS has a network-like fiber structure, the surface of CMO@CS is uniformly loaded with CoMn2O4 nano-sheets, realizing the composite of the organic phase and the inorganic phase. CMO / CS retains the wall structure of the individual CS, and at the same time, the addition of CoMn2O4 nano-sheets increases its surface roughness. In addition, the average diameter of CMO@CS, CS, and CMO / CS is about 4 mm.

[0067] CMO@CS was tested by EDS and SEM. The results are as shown in Figure 1 Figures (d) and (e). Among them, Figure 1The EDS-mapping results shown in Figure (d) confirm the uniform distribution of C, N, O, Co, and Mn on the surface of CMO@CS, and the atomic ratio of Co to Mn is maintained at 1:2. Combining Figure 1 Figures (c) and (e), it can also be seen that CMO@CS has a rich porous structure.

[0068] Infrared spectroscopy tests were performed on CMO@CS, CS, CMO / CS, and CMO. The results are as Figure 1 shown in Figure (f). The broad absorption band at 3500 - 3200 cm -1 corresponds to the stretching vibrations of O-H and N-H, and the absorption band at 1570 cm -1 is attributed to the N-H bending vibration of the -NH2 group in chitosan. Compared with CMO / CS, CMO@CS shows an obvious characteristic peak of metal-oxygen bonds around 500 cm -1 . This means that compared with CMO / CS, the anchoring effect of CoMn2O4 nanosheets on CS in CMO@CS is better, and the combination between CoMn2O4 nanosheets and CS is more stable.

[0069] X-ray diffraction tests were performed on CMO@CS, CS, CMO / CS, and CMO. The results are as Figure 1 shown in Figure (g). CS shows a semi-crystalline broad peak at 2θ = 20.9°, and the diffraction peaks of CoMn2O4 nanosheets in CMO@CS become broader, which also indicates that an effective composite occurs between the two phases of CS and CoMn2O4 nanosheets in CMO@CS.

[0070] Example 3

[0071] In this example, the ability of CMO@CS, CS, and CMO / CS prepared in Example 1 and Comparative Examples 1 - 2 to catalyze the degradation of peracetic acid (PAA) for typical emerging pollutants was investigated.

[0072] Using bisphenol A (BPA) as a typical emerging pollutant, BPA was dissolved in deionized water to form a solution with a BPA concentration of 10 μmol / L, and the pH value of this solution was 6.3. This solution was used as the simulated wastewater.

[0073] PAA was added to the simulated wastewater, and then the catalyst (CMO@CS, CS, or CMO / CS) was added to degrade BPA in the simulated wastewater. The dosage of PAA was controlled at 0.2 mmol / L, and the dosage of the catalyst was 0.3 mg / L. Timing started after the addition of the catalyst. After treating the wastewater for 20 min, the sample was filtered through a membrane filter and sodium thiosulfate was added to terminate the reaction. The concentration of BPA was determined by high-performance liquid chromatography (HPLC) and denoted as [BPA]. The initial concentration of BPA in the simulated wastewater was denoted as [BPA]0, and [BPA] / [BPA]0 was calculated. The results are as Figure 2 shown in Figure (a) of

[0074] As can be seen from Figure 2 Figure (a) of

[0075] Example 4

[0076] In this example, the ability of CMO@CS prepared in Example 1 to catalyze different oxidants to degrade typical emerging pollutants was investigated. The oxidants used included PAA, persulfate (PDS), peroxymonosulfate (PMS), and hydrogen peroxide (H2O2).

[0077] Taking BPA as a typical emerging pollutant, BPA was dissolved in deionized water to form a solution with a BPA concentration of 10 μmol / L. The pH value of this solution was 6.3. When PAA, PDS, or PMS was used as the oxidant, the BPA solution with a pH value of 6.3 was used as the simulated wastewater. When H2O2 was used as the oxidant, the pH value of the BPA solution was adjusted to 4, and the BPA solution with a pH value of 4 was used as the simulated wastewater.

[0078] The oxidant (PAA, PDS, PMS, or H2O2) was added to the simulated wastewater, and then CMO@CS was added to degrade BPA in the simulated wastewater. The dosage of the oxidant was controlled at 0.2 mmol / L, and the dosage of CMO@CS was 0.3 mg / L. Timing started after the addition of CMO@CS. After treating the wastewater for 20 min, the sample was filtered through a membrane filter and sodium thiosulfate was added to terminate the reaction. The concentration of BPA was determined by HPLC and denoted as [BPA]. The initial concentration of BPA in the simulated wastewater was denoted as [BPA]0, and [BPA] / [BPA]0 was calculated. The results are as Figure 2 shown in Figure (b) of

[0079] As can be seen from Figure 2As can be seen from Figure (b), when CMO@CS is used to catalyze the degradation of BPA in simulated wastewater with PAA, PMS, PDS, and H2O2, the removal rates of BPA after 20 minutes of degradation are 90%, 95%, 81%, and 41%, respectively. This indicates that CMO@CS is applicable to different oxidants including PAA, PMS, PDS, and H2O2, and can catalyze these oxidants to produce good organic pollutant removal effects.

[0080] Example 5

[0081] In this example, the types of reactive oxygen species generated by nano-CoMn2O4 (CMO), which plays a major catalytic role in CMO@CS, during the catalysis of PAA were investigated. A variety of quenchers were used to explore the types of reactive oxygen species generated in the CMO / PAA system during the degradation of pollutants. Methanol (MeOH), tert-butanol (TBA), 2,4-hexadiene (2,4-HD), and furfuryl alcohol (FFA) were used as quenchers respectively. MeOH and 2,4-HD can quench both hydroxyl radicals (·OH) and organic radicals (RO·) simultaneously, TBA can only quench ·OH, and FFA can quench singlet oxygen ( 1 1O2).

[0082] BPA was dissolved in deionized water to form a solution with a BPA concentration of 10 μmol / L, and the pH value of this solution was 6.3. This solution was used as the simulated wastewater. PAA and CMO prepared in Comparative Example 2 were added to the simulated wastewater, and the simulated wastewater was treated for 20 minutes at room temperature and under stirring conditions. The dosage of CMO was controlled at 0.3 mg / L, and the dosage of PAA was 0.2 mmol / L. Different concentrations and different types of quenchers were added to the simulated wastewater before the reaction started, specifically as follows:

[0083] Control group: No quencher was added;

[0084] MeOH group: MeOH was added to the simulated wastewater to a concentration of 10 mmol / L and 200 mmol / L;

[0085] TBA group: TBA was added to the simulated wastewater to a concentration of 10 mmol / L and 200 mmol / L;

[0086] 2,4-HD group: 2,4-HD was added to the simulated wastewater to a concentration of 10 mmol / L and 20 mmol / L respectively;

[0087] FFA group: FFA was added to the simulated wastewater to a concentration of 10 mmol / L and 20 mmol / L respectively.

[0088] During the simulated wastewater treatment process, samples were taken every 1 - 5 minutes, filtered through a filter membrane, sodium thiosulfate was added to terminate the reaction, and the BPA concentration was determined by HPLC, denoted as [BPA]. The initial concentration of BPA was denoted as [BPA]0, and [BPA] / [BPA]0 was calculated. The results are as Figure 3 shown.

[0089] After adding the corresponding quenching agents, the higher the degree of inhibition of BPA degradation, the greater the contribution of the active species quenched by the corresponding quenching agents to pollutant degradation. Figure 3 Figures (a) - (d) represent the effects of the quenching agents MeOH, TBA, 2,4 - HD, and FFA on the degradation of BPA in the CMO / PAA system. It can be seen from this figure that when 10 mmol / L and 20 mmol / L of FFA were added, the degradation of BPA was inhibited to a large extent; when 200 mmol / L of TBA was added, the degradation of BPA was inhibited to a certain extent; when 10 mmol / L and 20 mmol / L of 2,4 - HD were added, and when 20 mmol / L of MeOH was added, the degradation of BPA was also inhibited to a large extent. Combining the above experimental results, the main reactive oxygen species during the degradation of BPA by CMO - activated PAA is RO · , 1 O2 and · OH also made certain contributions to the degradation of BPA.

[0090] Example 6

[0091] In this example, the ability of the CMO@CS prepared in Example 1 and the CMO prepared in Comparative Example 2 to catalyze the degradation of typical emerging pollutants by PAA was investigated through a continuous - flow experiment.

[0092] Taking BPA as a typical emerging pollutant, BPA was dissolved in deionized water to form a solution with a BPA concentration of 10 μmol / L. The pH value of this solution was 6.3, and this solution was used as simulated wastewater. PAA was added to the simulated wastewater to form an oxidant - containing wastewater with a PAA concentration of 1 mmol / L.

[0093] The fixed - bed devices for the experimental group and the control group were set up according to the following operations:

[0094] As Figure 4As shown in the figure, a fixed-bed device was set up. Catalyst 1 was loaded into a round tube 2 made of acrylic. Cotton 3 was filled above Catalyst 1. The round tube 2 was longitudinally arranged with its axis perpendicular to the horizontal plane by the support of a support frame 4. The bottom of the cylinder 2 was provided with a water inlet, and the top of the round tube 2 was provided with a water outlet. The inner diameter of the round tube 2 was 50 mm, and the filling height of Catalyst 1 in the round tube was 17 cm. The water inlet of the round tube was connected to an inlet beaker 6 for containing the wastewater to be treated through a pipe fitting by a peristaltic pump 5, and the water outlet of the round tube 2 was connected to an outlet beaker 7 for containing the treated wastewater through a pipe fitting. The catalyst filled in the round tube of the experimental group's fixed-bed device was CMO@CS prepared in Example 1, and the catalyst filled in the round tube of the control group's fixed-bed device was CMO prepared in Comparative Example 2.

[0095] The oxidant-containing wastewater was filled into the inlet beaker, and the oxidant-containing wastewater was continuously pumped into the round tube from the water inlet of the cylinder of the fixed-bed device of the experimental group or the control group at a flow rate of 10 mL / min through a peristaltic pump. Then, the treated wastewater flowing out from the water outlet of the round tube was collected by an outlet beaker. The fixed-bed device was continuously operated for 85 h. During this period, samples were taken every 0.5 - 5 h to measure the BPA concentration and calculate the BPA removal rate. The results are as Figure 5 shown.

[0096] It can be seen from Figure 5 this that the difference in the effect of CMO@CS and CMO in catalyzing the degradation of BPA in simulated wastewater in the continuous-flow experiment is very significant. As the continuous operation time of the fixed-bed device gradually increases, the removal rate of BPA by the CMO / PAA system gradually decreases. For example, when the fixed-bed device is continuously operated for 10 h, the removal rate of BPA decreases from the initial level of 90% to about 70%. When the fixed-bed device is continuously operated for 65 h, the removal rate of BPA decreases to about 60%. When the fixed-bed device is continuously operated for 85 h, the removal rate of BPA decreases to about 50%. The main reason for the decrease in the removal rate of BPA by the CMO / PAA system with the increase in the continuous operation time of the fixed-bed device is that nano-scale CMO is prone to caking during the wastewater treatment process, resulting in a decrease in its catalytic activity. The removal rate of BPA by the CMO@CS / PAA system remains basically stable, with only slight fluctuations. When the fixed-bed device is continuously operated for 85 h, the removal rate of BPA still remains at about 90%. When the experimental group and the control group's fixed-bed devices are continuously operated for 85 h, the average removal rate of BPA by the CMO / PAA system is 66.1%, while the average removal rate of BPA by the CMO@CS system is as high as 90.1%. This shows that the in-situ method of loading nano-CoMn2O4 on chitosan particles in the present invention can effectively avoid the problem of the decrease in the activity of CMO during the wastewater treatment process, which is beneficial to maintaining the catalytic activity of CMO in the long term and is very beneficial for the engineering application of the method described in the present invention.

[0097] Example 7

[0098] In this example, the ability of the CMO@CS prepared in Example 1 to catalyze the degradation of livestock and poultry breeding wastewater by PAA was investigated.

[0099] As Figure 4 shown, a fixed-bed device was set up. The catalyst 1 (CMO@CS prepared in Example 1) was loaded into the acrylic round tube 2. Cotton 3 was filled above the catalyst 1. The round tube 2 was longitudinally arranged with its axis perpendicular to the horizontal plane by the support of the support frame 4. The bottom of the cylinder 2 was provided with a water inlet, and the top of the round tube 2 was provided with a water outlet. The inner diameter of the round tube 2 was 50 mm, and the loading height of the catalyst 1 in the round tube was 17 cm. The water inlet of the round tube was connected to the inlet beaker 6 for containing the wastewater to be treated through a pipe and a peristaltic pump 5, and the water outlet of the round tube 2 was connected to the outlet beaker 7 for containing the treated wastewater through a pipe.

[0100] The total organic carbon content (TOC value) of the livestock and poultry breeding wastewater used in this example was 42.27 mg / L, the chemical oxygen demand (COD value) was 134.96 mg / L, the total nitrogen content (TN value) was 126.50 mg / L, and the pH value was 6.5.

[0101] PAA was added to the livestock and poultry breeding wastewater until the concentration of PAA reached 1 mmol / L. The obtained livestock and poultry breeding wastewater containing PAA was loaded into the inlet beaker. The livestock and poultry breeding wastewater containing PAA was continuously pumped into the round tube through the water inlet of the fixed-bed device at a flow rate of 10 mL / min by the peristaltic pump. Then, the treated wastewater flowing out of the water outlet of the round tube was collected with the outlet beaker. When the livestock and poultry breeding wastewater containing PAA flowed through the round tube and contacted the CMO@CS therein, the CMO@CS catalyzed PAA to generate reactive oxygen species to degrade the organic pollutants in the livestock and poultry breeding wastewater. The fixed-bed device was continuously operated for 96 h. During this period, sampling was carried out every 3 - 12 h to measure the chromaticity of the effluent and calculate the chromaticity removal rate, measure the COD value of the effluent and calculate the COD removal rate, measure the TOC value of the effluent and calculate the TOC removal rate, and measure the TN value of the effluent and calculate the TN removal rate.

[0102] Figure 6The photos of the effluent after the continuous operation of the fixed-bed device for 0 h, 12 h, 48 h, and 96 h are shown. The colority of the effluent was measured according to the "Determination of Water Quality Colority - Dilution Multiple Method" (HJ 1182 - 2021). The results show that the initial colority of the livestock and poultry breeding wastewater was 1800 times. After the continuous operation of the fixed-bed device for 12 h, 48 h, and 96 h, the colority of the effluent was 20 times, 10 times, and 10 times respectively, and the corresponding colority removal rates were 98.89%, 99.44%, and 99.44% respectively. This indicates that using CMO@CS to catalyze PAA in the fixed-bed device can stably and efficiently reduce the colority of livestock and poultry breeding wastewater.

[0103] Figure 7 Figures (a) and (b) show the COD value and COD removal rate of the effluent during the continuous operation of the fixed-bed device. As can be seen from the figure, after the continuous operation of the fixed-bed device for 96 h, the COD value of the livestock and poultry breeding wastewater decreased from the initial 134.96 mg / L to 65.2 mg / L, and the average COD removal rate reached 47.01%. Figure 7 Figures (c) and (d) show the TOC value and TOC removal rate of the effluent during the continuous operation of the fixed-bed device. As can be seen from the figure, after the continuous operation of the fixed-bed device for 96 h, the TOC value of the livestock and poultry breeding wastewater decreased from the initial 42.27 mg / L to 19.08 mg / L, and the average TOC removal rate reached 38.67%. This indicates that using CMO@CS to catalyze PAA in the fixed-bed device has a relatively high mineralization rate for livestock and poultry breeding wastewater, which is mainly attributed to the synergistic oxidation effect of CMO@CS catalyzing PAA to generate reactive oxygen species.

[0104] Figure 7 Figures (e) and (f) show the TN value and TN removal rate of the effluent during the continuous operation of the fixed-bed device. As can be seen from the figure, after the continuous operation of the fixed-bed device for 96 h, the TN value of the livestock and poultry breeding wastewater decreased from the initial 126.50 mg / L to 13.04 mg / L, and the average TN removal rate was 8.81%. This indicates that during the wastewater treatment process, some organic matter in the livestock and poultry breeding wastewater was converted into nitrogen gas, while the others were internal conversions of organic nitrogen.

[0105] Example 8

[0106] In this example, the removal effects of various organic matters in the livestock and poultry breeding wastewater in Example 7 were further explored.

[0107] Take the raw livestock and poultry breeding wastewater in Example 7 and the effluent after the fixed-bed device operates continuously for 96 h, and test the content of organic matter in the water sample by high performance liquid chromatography-electrostatic field orbitrap high resolution mass spectrometry, and calculate the removal rate of each organic matter. Retrieve the reference examples in the database (primary mass spectrometry database and secondary mass spectrometry database) according to the mass-to-charge ratio of the detected substances to determine the molecular structure. 1516 characteristic compounds were systematically matched and identified in the livestock and poultry breeding wastewater, which can be divided into four categories: hormones, antibiotics, mycotoxins, and acids. Figure 8 Figure (a) of Figure 8 shows the removal rates of various organic matters in the livestock and poultry breeding wastewater after the fixed-bed device in Example 7 operates continuously for 96 h. The longer the bar in the figure, the higher the removal rate of the corresponding organic matter, and the shorter the bar in the figure, the lower the removal rate of the corresponding organic matter. The longest bar indicates that the removal rate of the corresponding organic matter is 100%. Figure 8 Figure (b) of Figure 8 further shows the removal rates of various antibiotics in the livestock and poultry breeding wastewater after the fixed-bed device in Example 7 operates continuously for 96 h. The longer the bar in the figure, the higher the removal rate of the corresponding antibiotic, and the shorter the bar in the figure, the lower the removal rate of the corresponding antibiotic. The longest bar indicates that the removal rate of the corresponding antibiotic is 100%. Combining Figure 8 Figure (b) of Figure 8 for further analysis, it is found that the average removal rate of antibiotics in the livestock and poultry breeding wastewater after the fixed-bed device in Example 7 operates continuously for 96 h is 85.6%.

[0108] Furthermore, by focusing on analyzing the removal of 331 typical compounds in the livestock and poultry breeding wastewater, the results show that after the fixed-bed device in Example 7 operates continuously for 96 h, the removal effects of acids and antibiotics are relatively better than the other two categories. Generally speaking, after the fixed-bed device in Example 7 operates continuously for 96 h, the removal rate of 78.9% of the organic compounds in the livestock and poultry breeding wastewater is more than 50%.

[0109] The experimental results of this example show that using CMO@CS to catalyze PAA in the fixed-bed device can degrade the organic matter in the livestock and poultry breeding wastewater in a long-term and stable manner.

[0110] Example 9

[0111] In this example, further explore the transformation characteristics of dissolved organic matter (DOM) in the livestock and poultry breeding wastewater at the molecular level in Example 7.

[0112] Take the original livestock and poultry breeding wastewater in Example 7 and the effluent after the continuous operation of the fixed-bed device for 96 h, and determine the molecular composition of DOM in the water sample by Q-Exactive Orbitrap Plus high-resolution mass spectrometry. In the molecular formula analysis of DOM, based on the elemental composition of organic matter, DOM in livestock and poultry breeding wastewater is divided into eight categories: nitrogen-containing organic matter (CHON), sulfur-containing organic matter (CHOS), phosphorus-containing organic matter (CHOP), carbon, hydrogen and oxygen compounds (CHO), nitrogen and phosphorus-containing organic matter (CHONP), nitrogen and sulfur-containing organic matter (CHONS), nitrogen, sulfur and phosphorus-containing organic matter (CHONSP), and sulfur and phosphorus-containing organic matter (CHOSP). And DOM in livestock and poultry breeding wastewater is further divided into nine functional categories through the Van Krenvlen diagram (this diagram can provide the atomic ratio of compounds and display compounds with different compositions through different points) combined with the O / C and H / C atomic ratios, including lipid, protein-like, amino acid (AS), carbohydrate-like (Carb), unsaturated hydrocarbon (UH), lignin-like (Lignins), tannin-like (Tannins), condensed aromatic structure compound (CA), and saturated compound (SAT). The size of the circle in the Van Krenvlen diagram is proportional to the molecular weight of DOM.

[0113] Figure 9 Figure is the Van Krenvlen diagram of DOM in the original livestock and poultry breeding wastewater in Example 7 and the effluent after the continuous operation of the fixed-bed device for 96 h. Among them, Figure (a) is the Van Krenvlen diagram of DOM in the original livestock and poultry breeding wastewater, Figure (b) is the Van Krenvlen diagram of DOM that has been completely removed after the continuous operation of the fixed-bed device for 96 h, and Figure (c) is the Van Krenvlen diagram of DOM that has been partially removed after the continuous operation of the fixed-bed device for 96 h. Figure 9Figure (d) is the VanKrenvlen diagram of DOM that remained unchanged after the continuous operation of the fixed-bed device for 96 h. It can be seen from this figure that in the original livestock and poultry breeding wastewater, the molecular weights of lipids, saturated compounds (SAT), and tannins are between 400 and 1000 Da, with the characteristics of an obvious macromolecular structure, and they are the main macromolecular components of DOM in the water sample. The molecular weights of amino acids (AS) and carbohydrates (Carb) are between 200 and 400 Da, showing low molecular weight characteristics, while the molecular weight span of condensed aromatic structure compounds (CA), saturated compounds (SAT), and unsaturated hydrocarbons (UH) is the largest. After continuously operating the fixed-bed device for 96 h in Example 7, most of the DOM was removed, and only a small amount of macromolecular lipids and proteins remained. The highly toxic unsaturated hydrocarbons (UH) and condensed aromatic structure compounds (CA) have been basically removed, which is of great significance for reducing environmental risks.

[0114] The experimental results of this example show that using CMO@CS to catalyze PAA in the fixed-bed device can remove or convert macromolecular substances in livestock and poultry breeding wastewater into small-molecule DOM.

[0115] Example 10

[0116] In this example, metagenomic sequencing technology was used to analyze the changes in dominant microbial groups and resistance genes during the treatment of livestock and poultry breeding wastewater. A total of 4 experimental groups were set up as follows in this example:

[0117] Raw water group (Group G1): The livestock and poultry breeding wastewater in Example 7, without any treatment.

[0118] PAA single treatment for 96 h group (Group G2): Take the livestock and poultry breeding wastewater in Example 7, add PAA to it for wastewater treatment for 96 h, and the concentration of PAA in the livestock and poultry breeding wastewater is 1 mmol / L.

[0119] CMO@CS / PAA treatment for 12 h group (Group G3): According to the operation in Example 7, continuously operate the fixed-bed device for 12 h.

[0120] CMO@CS / PAA treatment for 96 h group (Group G4): According to the operation in Example 7, continuously operate the fixed-bed device for 96 h.

[0121] Take the water samples of Group G1 and the water samples after treatment of Groups G2 - G4, and use metagenomic sequencing technology to analyze the dominant species of microorganisms in the water samples. When sampling, 3 biological replicates were set for each group. The 3 biological replicates of Group G1 were denoted as A1 - A3, the 3 biological replicates of Group G2 were denoted as B1 - B3, the 3 biological replicates of Group G3 were denoted as C1 - C3, and the 3 biological replicates of Group G4 were denoted as D1 - D3.

[0122] Figure 10 Figure (a) of is the LEfSe cladogram of Groups G1 - G2, and Figure (b) is the LEfSe cladogram of Groups G1, G3 and G4. The LEfSe cladogram shows the differential species at different species hierarchical levels obtained among different groups. The circles from the inside to the outside represent different taxonomic levels (kingdom, phylum, class, order, family, genus, species) in turn. In the water samples of Group G1, the dominant bacterial groups are Pseudomonadaceae, Methanocorpusculaceae, Unclassified Bacteroidota, Methanocorpusculum and Denitrificimonas caeni. In the water samples of Group G2, the dominant species are Methanothrix, Methanotrichales and Methanothrix soehngenii. In the water samples of Group G3, the dominant species are Unclassified Bacillota, Unclassified Mycoplasmatota and Unclassified Candidatus Cloacimonadota. In the water samples of Group G4, the dominant species are Unclassified Candidatus Parcubacteria, Unclassified Archaea and Unclassified Candidatus Cloacimonadota. From Figure 10 Figure (a) of shows that the number of dominant species in the water samples of Group G1 and Group G2 is approximately the same, indicating that the use of PAA alone has limited impact on the abundance of dominant species in livestock and poultry breeding wastewater. From Figure 10 Figure (b) of shows that there are obvious differences in the dominant species among the water samples of Group G1 and Groups G3 - G4. In the water samples of Group G1, the relative abundance of the dominant species is much higher than that of Groups G3 - G4. This shows that using the CMO@CS catalyst for PAA treatment of livestock and poultry breeding wastewater in a fixed - bed device can change the types of dominant species of microorganisms in livestock and poultry breeding wastewater, reduce the number of dominant species of microorganisms in livestock and poultry breeding wastewater and lower the abundance of dominant species of microorganisms in livestock and poultry breeding wastewater.

[0123] Figure 11 Figure (a) is a circos plot of the top 10 genes in terms of abundance in the water samples of groups G1 - G4 in the CARD database. From this figure, it can be seen that the top 10 AROs in the livestock and poultry breeding wastewater are vanT_gene_in_vanG_cluster, vanW_gene_in_vanI_cluster, tetM, tetO, tet36, qacEΔ1, vanY_gene_in_vanF_cluster, sul1, tetT, APH(3')-IIIa. The proportions of these 10 ARGs are 22.1%, 18.1%, 13.5%, 10.1%, 5.2%, 6.7%, 6.1%, 6.9%, 5.3% and 5.9% respectively. This is closely related to the resistance of antibiotics such as tetracyclines (tet series), glycopeptides (van series) and disinfectants (qacEΔ1). After continuously operating the fixed-bed device for 96 h (Group G4), the abundances of most tetracycline resistance genes, sulfonamide resistance genes, glycopeptide resistance genes and aminoglycoside resistance genes in the livestock and poultry breeding wastewater decreased significantly, indicating that the method described in the present invention can effectively remove the resistance genes in the livestock and poultry breeding wastewater by using CMO@CS to catalyze PAA in the fixed-bed device.

[0124] Through metagenomic sequencing and bioinformatics analysis, the gene sequences in the water samples of groups G1 - G4 were compared with the CARD database to obtain the functional annotations of each gene and the abundance data in each water sample. The top 35 functional genes in terms of abundance and their abundance information in each water sample were screened out to draw a heat map and perform cluster analysis from the level of functional differences between different experimental groups. The results are as Figure 11 shown in Figure (b). As can be seen from Figure 11 Figure (b), the effect of reducing the relative abundance of ARGs in the effluent treated with PAA alone is limited, while the use of CMO@CS / PAA treatment can effectively reduce the relative abundance of ARGs in the effluent. The relative abundance of ARGs decreases with the extension of the treatment time. Especially when the fixed-bed device operates continuously for 96 h, Figure 11 the red area in Figure (b) decreases sharply, indicating that the relative abundance of ARGs in the effluent decreases significantly. It shows that the method described in the present invention can effectively remove ARGs in the livestock and poultry breeding wastewater by using CMO@CS to catalyze PAA in the fixed-bed device, and the method described in the present invention has a unique role and advantage in destroying the genetic stability of drug resistance genes.

[0125] Example 11

[0126] In this embodiment, chitosan particles with in-situ loaded nano-CoMn2O4 are prepared and a wastewater treatment method is provided, and the steps are as follows:

[0127] (1) Add CS to an aqueous formic acid solution with a volume concentration of 1%, and stir for 12 h. At this time, CS is completely dissolved to obtain a CS solution with a CS concentration of 20 g / L.

[0128] Dissolve Co(NO3)2·6H2O and MnCl2·4H2O in deionized water to obtain a metal salt mixed solution with a molar ratio of Co to Mn of 1:2. In this metal salt mixed solution, the concentration of cobalt ions is 1.8 mol / L and the concentration of manganese ions is 3.6 mol / L.

[0129] (2) Slowly add the metal salt mixed solution to the chitosan solution under stirring, continue stirring for 30 min to achieve sufficient mixing, and then ultrasonicate for 30 min to remove the bubbles in the obtained mixed solution to obtain a precursor solution; in this precursor solution, the concentration of CS is 19.8 g / L, the concentration of cobalt ions is 0.085 mol / L, and the concentration of manganese ions is 0.170 mol / L.

[0130] (3) Use a peristaltic pump to drop the precursor solution through a silica gel tube with an inner diameter of 7.9 mm into a NaOH solution with a temperature of 100 °C and a concentration of 1.25 mol / L at a dropping rate of 40 drops / min. After the dropping is completed, react at 100 °C for 1 h. During this process, the cobalt ions and manganese ions in the precursor solution droplets undergo an in-situ coprecipitation reaction to form nano-CoMn2O4 and are loaded on the CS microspheres. Cool to room temperature, filter and separate the obtained solid phase, wash with deionized water, and freeze-dry to obtain a catalyst prepared by the in-situ method. In this catalyst, the content of CoMn2O4 is 49 wt% (theoretical loading amount).

[0131] (4) Use the catalyst prepared in this embodiment to catalyze the degradation of livestock and poultry breeding wastewater with the same water quality as that in Example 7. The specific operation is basically the same as that in Example 7, except that the CMO@CS in Example 7 is replaced with the catalyst prepared in this embodiment.

[0132] After the continuous operation of the fixed-bed device for 96 h, sampling was carried out every 3 - 12 h during this period to measure the chromaticity of the effluent and calculate the chromaticity removal rate, measure the COD value of the effluent and calculate the COD removal rate, measure the TOC value of the effluent and calculate the TOC removal rate, and measure the TN value of the effluent and calculate the TN removal rate. The results show that after the continuous operation of the fixed-bed device for 96 h in this example, the chromaticity removal rate of the livestock and poultry breeding wastewater is 99.52%. After the continuous operation of the fixed-bed device for 96 h in this example, the average COD removal rate of the livestock and poultry breeding wastewater is 49.54%, the average TOC removal rate of the livestock and poultry breeding wastewater reaches 40.87%, and the average TN removal rate of the livestock and poultry breeding wastewater is 9.96%. After the continuous operation of the fixed-bed device for 96 h, sampling was carried out, and the metagenomic sequencing technology was used to analyze the changes in resistance genes after the treatment of livestock and poultry breeding wastewater. The results show that the method of the present invention can effectively remove ARGs in the livestock and poultry breeding wastewater by using CMO@CS to catalyze PAA in the fixed-bed device.

Claims

1. A multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy, characterized in that, It includes the following steps: Dissolve an oxidant in a complex organic wastewater containing organic pollutants and resistance genes to obtain a wastewater containing the oxidant, and contact the wastewater containing the oxidant with a catalyst for wastewater treatment. During the wastewater treatment process, the catalyst catalyzes the oxidant to generate reactive oxygen species to degrade the organic pollutants in the complex organic wastewater and remove the resistance genes in the complex organic wastewater; The catalyst is a chitosan particle in-situ loaded with nano-CoMn2O4, which is composed of porous chitosan particles and nano-CoMn2O4 in-situ loaded on the porous chitosan particles.

2. The multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy according to claim 1, wherein The size of the catalyst is in the millimeter range, and the content of nano-CoMn2O4 in the catalyst is 30wt% - 50wt%.

3. The multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy according to claim 2, characterized in that The preparation method of the catalyst is as follows: (1) Dissolve chitosan in a formic acid aqueous solution with a volume concentration of 1% - 2% to obtain a chitosan solution; dissolve Co(NO3)2·6H2O and MnCl2·4H2O in water to obtain a metal salt mixed solution with a molar ratio of Co to Mn of 1:2; (2) Add the metal salt mixed solution to the chitosan solution under stirring, fully stir and mix, and ultrasonically remove the bubbles in the solution to obtain a precursor solution; in this precursor solution, the concentration of chitosan is 18 - 30g / L, and the concentration of cobalt ions is 0.03 - 0.1mol / L; (3) Drop the precursor solution into a NaOH solution with a temperature of 80 - 100°C and a concentration of 1 - 2mol / L, react at 80 - 100°C for 2 - 4h, cool to room temperature, separate the obtained solid phase, wash it thoroughly with water, and freeze-dry to obtain the product.

4. The multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy according to any one of claims 1 to 3, characterized in that, Control the concentration of the oxidant in the wastewater containing the oxidant to be 1 - 2mmol / L.

5. The multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy according to claim 4, wherein The oxidant is peracetic acid, peroxymonosulfate, peroxydisulfate or hydrogen peroxide.

6. The multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy according to any one of claims 1 to 3, characterized in that, Add the catalyst to a fixed-bed continuous flow device, and pass the wastewater containing the oxidant into the fixed-bed continuous flow device to contact the wastewater containing the oxidant with the catalyst for wastewater treatment.

7. The multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy according to claim 6, characterized in that Control the hydraulic retention time of the wastewater containing the oxidant in the fixed-bed continuous flow device to be 30 - 60min.

8. The multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy according to any one of claims 1 to 3, characterized in that Control the pH value of the complex organic wastewater to be 3 - 9.

9. The multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy according to any one of claims 1 to 3, characterized in that, The resistance gene is an antibiotic resistance gene.

10. The multi-dimensional pollution control method for complex organic wastewater based on nano-millimeter cross-scale synergy according to any one of claims 1 to 3, characterized in that, The complex organic wastewater includes livestock and poultry breeding wastewater.

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