Humic acid mediated light-microbial electro-Fenton method for degrading pollutants in sludge

Abstract

The invention discloses a humic acid mediated light-microbial electro-Fenton method for degrading pollutants in sludge. The method comprises the following steps: constructing a double-chamber microbial fuel cell; a biological reaction raw material is added into the anode chamber of the double-chamber microbial fuel cell, and the biological reaction raw material can generate biological reaction to release electrons; adding sludge containing pollutants, humic acid and ferrous ions into a cathode chamber of the double-chamber microbial fuel cell; the anode and the cathode of the microbial fuel cell are connected under the illumination condition, so that a reaction is carried out in the cathode chamber, and pollutants in the sludge are degraded. According to the method, the pollutants in the sludge are degraded by adopting a humic acid mediated light-microbial electro-Fenton method, so that on one hand, a Fenton reaction is promoted to generate a large number of free radicals with relatively strong oxidizing capacity to promote degradation, and on the other hand, growth and metabolism of hosts of the pollutants in the sludge are inhibited to reduce abundance of the pollutants; the synergistic effect of the two can effectively improve the degradation effect.

Description

Technical Field

[0001] The invention relates to the technical field of environmental engineering, and in particular to a humic acid-mediated light-microorganism electro-Fenton method for degrading pollutants in sludge. Background Art

[0002] With the surge in the use of antibiotics worldwide, pollutants such as antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) have been generated and spread, which pose potential environmental and public health risks. In the environment, sewage treatment plants have always been considered to be important accumulation sites for ARGs. Among them, excess sludge is identified as one of the rich areas of ARGs. The composition of excess sludge is complex, mainly including microbial flocs, organic matter, inorganic suspended particles and colloidal substances. In addition, excess sludge also contains pollutants such as pathogens, viruses, antibiotics and ARGs transferred from sewage. Excess sludge contains high-density and diverse microbial communities, which can promote the horizontal transfer of ARGs between microorganisms through MGEs. If a large number of ARGs in sludge cannot be effectively treated and removed, they will enter the environment with the discharge of sludge, causing ARGs to spread in the environment. For example, when sludge is used as farmland fertilizer or landfill, the ARGs contained in it can be transmitted to humans and animals through horizontal gene transfer and other pathways, affecting human health.

[0003] Residual sludge is a by-product produced during the biological wastewater treatment process. Its composition structure includes microorganisms and extracellular micropolymers. Microorganisms are further subdivided into extracellular polymers (EPS) and bacterial cells. EPS is a complex polymer mixture existing outside the cells of microbial aggregates. It is composed of a variety of organic macromolecules such as proteins, polysaccharides, humus, nucleic acids, lipids and uronic acid, which are aggregated in the form of dispersion forces, electrostatic forces, hydrogen bonds, hydrophobic effects, etc. Therefore, the organic matter in the sludge is mainly distributed in EPS, and it is of various types, complex components, high molecular weight, and difficult to degrade. Organic pollutants such as antibiotics, dyes, and phenol are all pure substances or simple mixtures with fixed and simple molecular structures, and cannot be directly linked to the complex structure of sludge organic matter.

[0004] Currently, when treating sludge, there is still a problem of insufficient degradation effect on ARGs pollutants. Summary of the invention

[0005] The invention provides a humic acid-mediated light-microorganism electro-Fenton method for degrading pollutants in sludge, which is used to solve the problem that the degradation effect of the existing process on pollutants in sludge is insufficient.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] A humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge comprises the following steps:

[0008] Construction of a dual-chamber microbial fuel cell;

[0009] Adding a biological reaction raw material to the anode chamber of the dual-chamber microbial fuel cell, wherein the biological reaction raw material can undergo a biological reaction to release electrons;

[0010] Adding pollutant-containing sludge, humic acid and ferrous ions into the cathode chamber of the dual-chamber microbial fuel cell;

[0011] The anode and cathode of the microbial fuel cell are connected under light conditions to allow a reaction to occur in the cathode chamber to degrade the pollutants.

[0012] Furthermore, the method further comprises: during the reaction in the cathode chamber, continuously aerating the cathode chamber.

[0013] Furthermore, the lighting condition is to use a xenon lamp light source with a power of 200-600W; preferably, the lighting condition is to use a xenon lamp light source with a power of 300W.

[0014] Furthermore, the method further comprises: adjusting the initial pH value of the reaction system in the cathode chamber to ≤4; preferably, adjusting the initial pH value of the reaction system in the cathode chamber to 3.

[0015] Furthermore, the reaction time in the cathode chamber is ≥120 min; preferably, the reaction time in the cathode chamber is 120-360 min; more preferably, the reaction time in the cathode chamber is 240 min.

[0016] Further, the temperature at which the reaction occurs in the cathode chamber is 20-30°C; preferably, the temperature at which the reaction occurs in the cathode chamber is 23-27°C; more preferably, the temperature at which the reaction occurs in the cathode chamber is 25°C.

[0017] Furthermore, the humic acid concentration of the reaction system in the cathode chamber is 18-120 mg / L; preferably, the humic acid concentration of the reaction system in the cathode chamber is 36-120 mg / L; more preferably, the humic acid concentration of the reaction system in the cathode chamber is 60 mg / L.

[0018] Furthermore, the ferrous ion concentration of the reaction system in the cathode chamber is 50-1000 μM; preferably, the ferrous ion concentration of the reaction system in the cathode chamber is 1000 μM.

[0019] Furthermore, the step of constructing a dual-chamber microbial fuel cell includes: selecting organic glass material to make a reactor, and using a cation exchange membrane to separate the interior of the reactor into an anode chamber and a cathode chamber, using carbon brushes as the anode and the cathode, and placing the anode and the cathode in the anode chamber and the cathode chamber respectively, and using titanium wire to connect the anode, the cathode and an external resistor to form a loop to obtain a dual-chamber microbial fuel cell.

[0020] Further, the pollutants include antibiotic resistance genes and / or mobile genetic elements; preferably, the antibiotic resistance genes include at least one of sulfonamide antibiotic resistance genes, aminoglycoside antibiotic resistance genes, MLSB antibiotic resistance genes, tetracycline antibiotic resistance genes and β-lactam resistance genes.

[0021] In summary, the present invention has at least the following beneficial effects:

[0022] The present invention uses humic acid mediated light-microorganism electro-Fenton method to degrade pollutants in sludge. On the one hand, humic acid, as a typical electron shuttle and metal chelator, has rich redox active functional groups, which is conducive to improving the efficiency of electron transfer. Adding humic acid to the Fenton reaction can provide more iron binding sites and convert Fe 3+ Reduction to Fe 2 + , promoting the generation of ·OH in the Fenton reaction. In addition, humic acid is a natural light-absorbing substance with abundant photosensitive functional groups such as aromatic carbonyl and hydroxyl groups, which can transform from the ground state to the excited state under light conditions, thereby continuing to react with dissolved oxygen to generate ·OH, superoxide anions (·O2 - ) and H2O2, which are conducive to the Fenton reaction, and thus help to improve the degradation effect of pollutants such as ARGs in sludge. On the other hand, the present invention can effectively inhibit the growth and metabolism of ARGs hosts in sludge by improving the sludge treatment process, so that the abundance of ARGs hosts such as Gp10, Gp17, Ilumatobacter, Terimonas, Aquihabitans, etc. is reduced, thereby reducing the abundance of ARGs and MGEs. Therefore, the present invention improves the conditions of the Fenton reaction to promote the production of strong oxidative free radicals such as ·OH and the inhibition of the host of pollutants in the sludge. The synergistic effect of the two can further improve the degradation effect of pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 It is a schematic diagram of the degradation mechanism of the humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge provided in an embodiment of the present invention.

[0025] Figure 2 HA and HA-Fe of Example 1 of the present invention 2+ SEM images of the complex (a and b are HA magnified 2000 times and 10000 times, respectively; c and d are HA-Fe 2+ Complex magnified 2000x and 10000x).

[0026] Figure 3 (a) is Fe 2+ Chronoamperometric curves of the mediated electrochemical redox system; Figure 3 (b) is HA-Fe of Example 1 2 + Chronoamperometric curves of coupled-mediated electrochemical redox system.

[0027] Figure 4 The Fe generated in the reaction system of Example 1 and its control group 3+ / Fe 2+ concentration changes.

[0028] Figure 5 The reaction system of Example 1 and its control group captures OH and 1 EPR spectrum of O2.

[0029] Figure 6 (a) is a graph showing the change of ·OH content generated by HA solution at different concentrations with illumination time; Figure 6

[0030] (b) is the content of ·OH under different coupling systems.

[0031] Figure 7 It is the absolute abundance diagram of pollutants under different treatment methods.

[0032] Figure 8 It is a distribution map of resistance mechanisms of pollutants under different treatment methods.

[0033] Fig. 9 is the absolute abundance diagram of pollutants after treatment at different pH values.

[0034] Fig.10 It is the absolute abundance diagram of pollutants after treatment at different reaction times.

[0035] Fig.11 Is different HA and Fe 2+ Absolute abundance plot of pollutants after treatment at concentrations.

[0036] Fig.12 It is the dominant bacterial community composition of each treatment group at the phylum level.

[0037] Fig.13 It is the dominant bacterial community composition at the genus level in each treatment group.

[0038] Fig.14 This is the network analysis diagram of ARGs, MGEs pollutants and bacterial genera. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Sludge refers to the muddy flocs formed after sewage is treated by biological methods. As a product after sewage treatment, sludge is not only significantly different from sewage in morphology, but also contains pollutants in different forms from sewage. Specifically, the resistance genes in sewage exist in the genetic material in the cells of pathogens. To crack the resistance genes in sewage, it is only necessary to crack the cell structure of the pathogens and further destroy the internal genetic material DNA and the resistance genes on it. The resistance genes in sludge exist in large quantities in extracellular polymers (EPS). EPS wraps ARGs to form a high-molecular polymer structure that is difficult to degrade. The removal of this part of ARGs is the core and difficulty of sludge ARGs removal and degradation. For the resistance genes in sludge, it is only possible to further degrade the intracellular resistance genes after thoroughly destroying the high-molecular extracellular polymer structure and the resistance genes therein. It can be seen that the idea of ​​treating pollutants in sludge is completely different from that of treating sewage, and it is more difficult to treat.

[0041] The embodiment of the present invention provides a humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge, comprising the following steps S1 to S4:

[0042] S1. Construct a dual-chamber microbial fuel cell.

[0043] In a further embodiment, the steps of constructing a dual-chamber microbial fuel cell include: selecting organic glass material to make a reactor, and using a cation exchange membrane to separate the interior of the reactor into an anode chamber and a cathode chamber, using carbon brushes as anodes and cathodes, placing the anodes and cathodes in the anode chamber and cathode chamber respectively, and using titanium wire to connect the anodes, cathodes and external resistors to form a loop to obtain a dual-chamber microbial fuel cell. The obtained dual-chamber microbial fuel cell can provide a reaction site for degrading pollutants in sludge, and achieve effective degradation of pollutants in sludge.

[0044] Exemplarily, in some embodiments, the size of each single chamber of the anode chamber and the cathode chamber of the dual-chamber microbial fuel cell is 4cm×6cm×6cm, the effective volume is 250mL, and a channel with an inner diameter of 1cm is opened on the reactor for adding and pouring the reaction solution. The anode and cathode materials are pretreated carbon brushes, and electroactive microorganisms such as electroactive bacteria are attached and grown on the surface of the anode. The anode, cathode and an external resistor of 1000Ω are connected to form a loop using titanium wire.

[0045] S2. Adding biological reaction raw materials into the anode chamber of the dual-chamber microbial fuel cell, wherein the biological reaction raw materials can undergo biological reactions to release electrons.

[0046] For example, in some embodiments, the biological reaction raw material can be anaerobic sludge from a sewage treatment plant. The organic matter contained in the sludge will be oxidized by the electroactive bacteria on the anode surface, releasing electrons and protons, which will migrate to the cathode through the titanium wire and the cation exchange membrane respectively, to facilitate the degradation reaction in the cathode chamber.

[0047] S3, adding pollutant-containing sludge, humic acid (HA) and ferrous ions (Fe 2+ ).

[0048] Illustratively, in some embodiments, the pollutant-containing sludge may be anaerobic sludge from a sewage treatment plant.

[0049] In further embodiments, the contaminants include antibiotic resistance genes (ARGs) and / or mobile genetic elements (MGEs); wherein MGEs are a type of DNA fragment that transmits genes among bacteria, archaea, and eukaryotes.

[0050] In a further embodiment, the antibiotic resistance gene includes at least one of a sulfonamide resistance gene, an aminoglycoside resistance gene, an MLSB resistance gene, a tetracycline resistance gene, and a beta-lactam resistance gene. The humic acid-mediated light-microorganism electro-Fenton method of the embodiment of the present application can effectively degrade the above-mentioned pollutants in the sludge.

[0051] In a further embodiment, the humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge further includes: during the reaction in the cathode chamber, continuously aerating the cathode chamber. Exemplarily, in some embodiments, the cathode chamber can be continuously aerated by an aeration pump. Thus, in the cathode chamber, the oxygen electrons adsorbed on the cathode surface are reduced to H2O2 through a two-electron reduction pathway to supplement the H2O2 raw material required for degradation.

[0052] In a further embodiment, the humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge also includes: adjusting the initial pH value of the reaction system in the cathode chamber to ≤4; illustratively, in some embodiments, the initial pH value of the reaction system in the cathode chamber can be adjusted to 1, 2, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4 or any value ≤4.

[0053] In a further embodiment, the initial pH value of the reaction system in the cathode chamber is adjusted to 3, at which time the degradation effect is better.

[0054] In a further embodiment, the reaction time in the cathode chamber is ≥120 min; illustratively, in some embodiments, the reaction time in the cathode chamber can be 120 min, 150 min, 180 min, 210 min, 240 min, 270 min, 300 min, 330 min, 360 min, 390 min, 400 min or any value ≥120 min.

[0055] In a further embodiment, the reaction time in the cathode chamber is 120-360 minutes; at this time, the degradation effect is better.

[0056] In a further embodiment, the reaction time in the cathode chamber is 240 minutes, which is beneficial to further improve the degradation effect.

[0057] In a further embodiment, the temperature of the reaction in the cathode chamber is 20-30°C; illustratively, in some embodiments, the temperature of the reaction in the cathode chamber can be 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C or any value between 20-30°C.

[0058] In a further embodiment, the temperature at which the reaction occurs in the cathode chamber is 23-27° C., at which the degradation effect is better.

[0059] In a further embodiment, the temperature at which the reaction occurs in the cathode chamber is 25° C., which is beneficial for further improving the degradation effect.

[0060] In a further embodiment, the humic acid concentration of the reaction system in the cathode chamber is 18-120 mg / L; illustratively, in some embodiments, the humic acid concentration of the reaction system in the cathode chamber can be 18 mg / L, 27 mg / L, 36 mg / L, 45 mg / L, 60 mg / L, 70 mg / L, 80 mg / L, 90 mg / L, 100 mg / L, 110 mg / L, 120 mg / L or any value between 18-120 mg / L.

[0061] In a further embodiment, the humic acid concentration of the reaction system in the cathode chamber is 36-120 mg / L, at which time the degradation effect is better.

[0062] In a further embodiment, the humic acid concentration of the reaction system in the cathode chamber is 60 mg / L, which is beneficial to further improve the degradation effect.

[0063] In a further embodiment, the ferrous ion concentration of the reaction system in the cathode chamber is 50-1000 μM; illustratively, in some embodiments, the ferrous ion concentration of the reaction system in the cathode chamber can be 50 μM, 100 μM, 200 μM, 300 μM, 400 μM, 500 μM, 600 μM, 700 μM, 800 μM, 900 μM, 1000 μM or any value between 50-1000 μM.

[0064] In a further embodiment, the ferrous ion concentration of the reaction system in the cathode chamber is 1000 μM, at which time the degradation effect is better.

[0065] In the embodiment of the present invention, by controlling the reaction conditions in the cathode chamber within the above-mentioned appropriate range, the cathode chamber can fully react and the reaction efficiency is high, which is beneficial to improving the H2O2 yield and promoting the generation of strong oxidizing free radicals in the reaction system, thereby facilitating the efficient degradation of pollutants in the sludge.

[0066] S4. Connect the anode and cathode of the microbial fuel cell under light conditions to allow a reaction to occur in the cathode chamber, thereby degrading pollutants in the sludge.

[0067] In a further embodiment, the illumination condition uses a xenon lamp light source with a power of 200-600W; in some embodiments, the power of the xenon lamp light source used in the illumination condition can be 200W, 250W, 300W, 350W, 400W, 450W, 500W, 550W, 600W or any value between 200-600W.

[0068] In a further embodiment, the illumination condition is to use a xenon lamp light source with a power of 300W, and the degradation effect is better at this time.

[0069] In order to understand the technical solution of the present invention more clearly, Figure 1 The degradation principle of pollutants in sludge by the embodiment of the present invention is exemplarily shown in FIG.

[0070] On the one hand, the degradation of pollutants in sludge by the embodiments of the present invention is to enhance the degradation effect by promoting the Fenton reaction to generate a large number of free radicals with strong oxidizing ability (such as hydroxyl radicals (·OH)). Figure 1 As shown, electroactive bacteria oxidize organic matter in the anode chamber, releasing electrons and protons (as shown in Formula 1 below), and the electrons and protons migrate to the cathode through the external titanium wire and the cation exchange membrane respectively. In the cathode chamber, the electrons of oxygen adsorbed on the cathode surface are reduced to H2O2 through a two-electron reduction pathway (as shown in Formula 2 below). Fe 2+ The Fenton reaction with H2O2 generates a large amount of ·OH (as shown in Equation 3). ·OH can oxidize pollutants such as ARGs into simpler oxidation products (as shown in Equation 4). 2+ In the reaction system, Fe 3+ Directly obtain electrons and reduce to Fe 2+ (As shown in Formula 5), ​​HA to Fe 3+ The electron ligand transfer will also occur gradually, generating Fe 2+ Realize Fe 2+ / Fe 3+ Redox cycle (as shown in Equation 6 below).

[0071] C x H y O z +(2x-z)H2O→xCO2+(y+4x-2z)H + +(y+4x-2z)e - (1)

[0072] O2+2H + +2e - →H2O2 (2)

[0073] Fe 2+ +H2O2→Fe 3+ + OH+OH - (3)

[0074] OH+RH→R+H2O (4)

[0075] Fe 3+ +e - →Fe 2+ (5)

[0076]

[0077] In addition, HA and Fe 2+ The complex will also undergo photochemical reactions under light conditions to produce active species such as ·OH, thereby oxidizing ARGs and microorganisms. The series of photochemical reactions that occur in this process are first due to the fact that after HA absorbs light, its photosensitive functional groups, such as aromatic carbonyl and hydroxyl groups, become excited states ( 1 HA * , 3 HA * and HA·) (as shown in Formula 7), 3 HA * and HA·will react with dissolved oxygen to generate OH, 1 O2 and H2O2 (as shown in the following formulas 8, 9, and 10). Thus, under the action of light, HA chelates Fe 2+ The treatment enhanced the Fenton oxidation capacity, that is, the microbial electro-Fenton oxidation of pollutants was more effective with the assistance of light and HA.

[0078]

[0079] HA · +O2+2H + →HA ·+ +2·OH (8)

[0080] 3 HA * +O2+2H + →H2O2+ 1 HA * (9)

[0081] 3 HA * +O2→ 1 O2+ 1 HA *(10) Moreover, the excess H 2 O 2 in the HA-mediated light-microbial electro-Fenton system can also be decomposed into ·OH through illumination or directly (as shown in Equations 11 and 12), which further facilitates the generation of ·OH.

[0082] H2O2+e - → OH+HO - (11)

[0083]

[0084] On the other hand, the degradation of pollutants in sludge by the embodiments of the present invention is improved by inhibiting the growth and metabolism of the host of pollutants in sludge. Specifically, the HA-mediated light-microbial electro-Fenton system caused the abundance of ARGs hosts such as Gp10, Gp17, Ilumatobacter, Terimonas, Aquihabitans to decrease, inhibited their growth and metabolism, and inhibited or killed the growth of these ARGs hosts, causing a decrease in the abundance of ARGs and MGEs.

[0085] Based on the humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge provided by the above exemplary embodiments, the method has at least the following advantages:

[0086] 1) After the process treatment of the embodiment of the present application, the electron transfer capacity in the cathode reaction system is enhanced, and the synergistic effect of light and HA can ensure that the reaction system obtains a higher Fe 2+ The reduction rate can promote the Fenton reaction, thereby improving the degradation effect of pollutants.

[0087] 2) After the process of the present application embodiment, OH and 1 The enhanced electron paramagnetic resonance spectroscopy (EPR) signal of O2 free radicals indicates that the generation of strong oxidizing free radicals in the reaction system is promoted, resulting in a better degradation effect.

[0088] 3) The HA-mediated light-microbial electro-Fenton system triggered a decrease in the abundance of ARGs hosts such as Gp10, Gp17, Ilumatobacter, Terimonas, and Aquihabitans, inhibited their growth metabolism, and caused the growth of these ARGs hosts to be inhibited or killed, triggering a decrease in the abundance of ARGs and MGEs.

[0089] 4) After the process treatment of the embodiment of the present application, by improving the conditions of the Fenton reaction to promote the production of strong oxidative free radicals such as OH and the inhibition of the host of pollutants in the sludge, the synergistic effect of the two can effectively improve the degradation effect. Referring to the following examples, the degradation rates of Sulfonamide, Aminoglycoside and MLSB resistance genes in the sludge can reach 45.49%, 61.17% and 74.83%, and the removal rate of MGEs can reach 87.43%, which effectively inhibits the further spread of ARGs in the environment and reduces the risk of pollution spread of pollutants.

[0090] 5) Referring to the following examples, it can be seen that when the initial pH value is 3, the removal effect of ARGs and MGEs is more significant.

[0091] 6) Referring to the following examples, it can be seen that under the concentration conditions of HA (60 mg / L) + Fe (1000 μM), MLSB, Sulfonamide resistance genes and MGEs were significantly reduced (p<0.05), and other ARGs also showed different degrees of reduction. The removal of ARGs was more effective under this initial concentration condition.

[0092] The following examples describe the disclosure of the present application in more detail, and these examples are merely illustrative, as it will be apparent to those skilled in the art that various modifications and variations are made within the scope of the disclosure of the present application. Unless otherwise stated, all reagents and raw materials used in the following examples are commercially available or synthesized according to conventional methods, and the instruments used in the examples are commercially available.

[0093] The data testing methods of the following embodiments and comparative examples are as follows:

[0094] The changes in the electrochemical activity of HA were analyzed using an electrochemical workstation with a three-electrode cell.

[0095] Determination of Fe using o-phenanthroline spectrophotometry 2+ / Fe 3+ concentration.

[0096] Electron paramagnetic resonance spectroscopy (EPR) was used to determine the ·OH and 1 O2.

[0097] After the reaction, the total DNA of each sample was extracted using the FastDNA SPIN Kit for soil.

[0098] Using Qubit TM 4. Detect the concentration of extracted DNA using Fluorometer.

[0099] Ultra-high-throughput fluorescence quantitative PCR was used to detect antibiotic resistance genes in samples.

[0100] Example 1

[0101] This embodiment provides a humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge, comprising the following steps:

[0102] S1. A fixed bed reactor with an effective volume of 250 mL was selected. The reactor material was organic glass. The inside of the reactor was divided into an anode chamber and a cathode chamber by a cation exchange membrane. The size of each single chamber was 4 cm × 6 cm × 6 cm. A hole was opened at the top of the reactor with an inner diameter of 1 cm for adding and pouring the reaction raw materials. The anode and cathode materials were carbon brushes pretreated with acetone. A 100Ω external resistor was used as an external load. The anode, cathode and external resistor were combined with titanium wire to form a closed loop to obtain a dual-chamber microbial fuel cell.

[0103] S2. Fill the anode chamber of the reactor with anaerobic activated sludge from the sewage treatment plant and replace the sludge every 5 days.

[0104] S3. Fill the cathode chamber of the reactor with a mixed solution of 0.1 mol / L potassium ferrocyanide and 0.1 mol / L potassium dihydrogen phosphate, and keep replacing the mixed solution every 2 days. When the reactor voltage stabilizes at a certain value (≥300mV), it indicates that the biofilm has been successfully domesticated and the reactor is ready to start. After the reactor is started, replace the cathode electrolyte with sludge, inject a certain dose of HA and Fe 2+ The HA and Fe 2+ The concentrations were 60 mg / L and 100 μM, respectively. The initial pH value was adjusted to 3, and the cathode chamber was continuously aerated.

[0105] S4. Place the reactor in a xenon lamp box with a 300W irradiation light source, and use a magnetic stirrer (speed 500r / min) to keep the cathode chamber homogeneous under illumination conditions. Circulating cooling water at 15°C is introduced into the reactor from a low-temperature thermostatic bath to prevent the reactor from overheating due to irradiation. The reactor is operated at room temperature (25±2°C) for 360 minutes.

[0106] Test and result analysis

[0107] (1) Efficiency of HA-mediated photo-microbial electro-Fenton degradation of ARGs and other pollutants contained in sludge

[0108] Reference Figure 2, which shows the original microstructure of HA and the microstructure of the complex formed by HA and Fe obtained by the HA-mediated light-microbial electro-Fenton (Light-HA-Fe-BES) treatment process of Example 1. It can be seen that by observing HA in SEM images of different magnifications, it can be found that HA presents a block structure, the particle size varies, and aggregate clusters are formed. The surface has a certain degree of roughness and there are pores of different sizes. In contrast, the complex formed by HA and Fe presents a lamellar crystal structure, the surface is relatively rough, sharp particles are attached, and irregular protruding microstructures are formed on the surface. By comparing and analyzing the changes in the apparent morphology, it can be determined that this crystalline rough cluster structure is a larger floc formed by the combination of HA and Fe, thereby verifying the HA-Fe 2+ Formation of composite structures.

[0109] Figure 3 (a) shows Fe 2+ The chronoamperometric curve of the medium electrochemical redox system, the corresponding treatment process is different from that of Example 1 in that no HA is added; Figure 3 (b) shows the HA-Fe 2+ Chronoamperometric curve of coupled-mediated electrochemical redox system. Figure 3 When the electron transfer capacity was quantified by chronoamperometry, the signal intensities of the system's EAC (electron accepting capacity) and EDC (electron donating capacity) were both improved after the addition of HA. The increase in EDC is mainly attributed to the redox activity of HA, which mainly comes from the mutual conversion between phenolic groups and quinone groups. Due to the action of accepting electrons, some quinone oxidizable groups are reduced, resulting in an increase in EDC. The change in EAC may be due to the formation of new functional structures by the functional groups of HA during the reaction, especially the possible appearance of more oxidizable functional groups. These changes increase the system's electron accepting capacity, thereby significantly improving the system's EAC and EDC, indicating that HA mediates Fe 2+ The electron transfer capacity is significantly enhanced.

[0110] Reference Figure 4 To further prove that the presence of HA has an effect on Fe 2+ In order to generate a catalytic effect, two control groups different from Example 1 were set up. The treatment processes of the two control groups were Light-Fe-BES and HA-Fe-BES, respectively. The difference between the treatment processes of the two control groups and Example 1 was that HA was not added and no light source was used for irradiation. The irradiation time was controlled within 0.5h, 4h and 8h to investigate the Fe 2+ As shown in the figure, in the system without adding HA, Fe 2+The photoreduction rate of Fe 2+ The photoreduction rate of Fe remained at a low level within 8 hours and gradually decreased. 2+ The concentration of Fe 3+ / Fe 2+ The ratio fluctuates within a certain range, Fe 2+ The concentration was maintained at about 40%. The comparison of the three groups of experiments showed that the synergistic effect of light and HA can ensure that the Light-HA-Fe-BES system of Example 1 can obtain a higher Fe 2+ Reduction rate.

[0111] Reference Figure 5 The two key free radicals ·OH and ·OH produced in the solution under three conditions were determined by EPR: blank solution (the difference from Example 1 is that no HA is added, denoted as Light in the figure), dark HA solution (the difference from Example 1 is that no light source is used for irradiation, denoted as HA in the figure) and illuminated HA solution (Example 1, denoted as Light-HA). 1 O2 signal, Figure 5 (a) shows the ·OH capture EPR spectrum, Figure 5 (b) shows 1 O2 captures EPR spectra. Figure 5 As shown in (a), no obvious ·OH signal peak was observed between dark HA and illuminated blank, and there was no significant difference in response intensity. In illuminated HA, a 1:2:2:1 quartet peak was observed, and the response value was higher than that of dark HA and illuminated blank. This indicates that more ·OH can be produced during the illumination of HA. Similarly, Figure 5 (b) shows that the HA 1 The O2 response intensity was higher than that of dark HA and light blank. 1 O2 is an active oxygen species that attacks the double bond structure in organic pollutants. 1 The generation of O2 is closely related to the effect of light HA. 1 The results of the spectral signal of O2 show that the induction pathways of the two free radicals are enhanced due to the presence of light, which is consistent with the results of the study on soluble organic matter that promotes the formation of free radicals, further proving that the treatment process of the embodiment of the present invention is beneficial to improving the degradation effect.

[0112] Based on the determination of free radicals, it can be determined that HA will generate more ·OH under light conditions. 1Compared with O2, the production of ·OH can more effectively illustrate the photochemical activity of HA in transforming pollutants, because the quenching effect of ·OH is the strongest and the degradation effect on pollutants is the most significant.

[0113] In subsequent analysis and research, the inventors used two different concentrations of HA, 18 mg / L and 90 mg / L, to conduct quantitative experiments on ·OH, in order to explore the specific situation of HA producing ·OH under light conditions.

[0114] Reference Figure 6 , Figure 6 (a) is a graph showing the change of ·OH content generated by HA solutions at different concentrations as a function of illumination time. By comparing the ·OH concentrations generated by HA solutions of different concentrations after illumination, it can be seen that the ·OH concentration gradually increases with time. The ·OH concentration of 18 mg / L HA after illumination for 4-8 hours is approximately 1.2-1.6×10 -3 mM, while the ·OH concentration of 90 mg / L HA after 4-8 h of illumination is about 3.3-4.3×10 -3 mM. As the reaction time exceeded 4h, the growth of ·OH concentration slowed down. The reason may be that some components in HA quenched the ·OH produced by themselves during the photochemical reaction, resulting in a decrease in the yield of ·OH. In addition, although the generation efficiency of ·OH increased with the increase of HA concentration, the increase of ·OH concentration did not show a significant correlation with the increase of HA concentration. It is inferred that the photochemical activity of HA may be affected by the HA structure and the carbon-carbon bonds of humic acid molecules. In addition, it may also be because the chromaticity of natural organic matter affects the homogeneous state of the photoreaction system to a certain extent.

[0115] The embodiment of the present invention is mainly used to treat new pollutants ARGs and MGEs in sludge. After the treated sludge, ARGs and MGEs are effectively degraded. After measuring more than 40 types of ARGs, 34 significant and stable types of ARGs and MGEs were detected in the raw sludge (RS), including 28 ARGs and 6 MGEs. Specifically, the 28 ARGs include sulfonamide antibiotics (Sulfonamide) resistance genes, aminoglycoside antibiotics (Aminoglycoside) resistance genes, MLSB antibiotics resistance genes, tetracycline antibiotics (Tetracycline) resistance genes and β-lactam (BetaLactamase) resistance genes. Among them, sulfonamide, MLSB and aminoglycoside resistance genes account for about 91.54% of the absolute abundance of total ARGs, showing a high abundance.

[0116] Reference Figure 7After RS ​​was treated with different systems, except for the light-HA-BES condition, the absolute abundance of ARGs and MGEs increased. In other systems, the absolute abundance of most ARGs and MGEs in sludge decreased to varying degrees. Especially after the Light-HA-Fe-BES treatment, the absolute abundance of sulfonamide, aminoglycoside and MLSB resistance genes, which accounted for the highest proportion in RS, decreased from 9.87×10 6 copies / g, 2.73×10 6 copies / g and 4.37×10 6 The copies / g was reduced to 5.38×10 6 copies / g, 1.06×10 6 copies / g and 1.10×10 6 copies / g, and the degradation rates reached 45.49%, 61.17% and 74.83%, respectively. The absolute abundance of sulfonamide, MLSB resistance genes and MGEs decreased significantly (p<0.05). In addition, the removal rate of Tetracycline resistance genes exceeded 60%, and the removal rate of Beta-Lactamase resistance genes even reached more than 90%. In RS detection, MGEs accounted for about 30% of the total genetic material. After treatment with Light-HA-Fe-BES, the removal rate of MGEs reached 87.43%. This result shows the efficient removal ability of Light-HA-Fe-BES treatment on MGEs. MGEs are a type of DNA fragments that transmit genes in bacteria, archaea and eukaryotes, and they play an important role in the spread of antibiotic resistance genes. Therefore, the effective removal of MGEs is of great significance for slowing the development of antibiotic resistance.

[0117] Comparing the treatments of Light-HA-Fe-BES and Light-Fe-BES, the addition of HA further removed ARGs, especially Sulfonamide and MGEs, whose absolute abundances were significantly reduced (p<0.05). At the same time, light also plays an important role in the treatment. By comparing the conditions of Light-HA-Fe-BES and HA-Fe-BES, it can be seen that under dark conditions, the removal effect of ARGs in the HA-Fe-BES system is almost the same as that of Light-Fe-BES, which means that in the absence of light, the addition of HA does not have a positive effect on the further removal of ARGs in the system. Therefore, in the presence of HA, solar radiation is likely to stimulate HA to produce more strong oxidative free radicals to remove ARGs.

[0118] Reference Figure 8There is a close connection between resistance mechanisms and ARGs, as antibiotic resistance is often due to bacteria carrying specific genes that encode specific resistance-related mechanisms that allow bacteria to resist the effects of antibiotics. Figure 8 As shown in the figure, under different treatments, the distribution of ARGs resistance mechanisms includes: Antibiotic Deativate, Cellular Protection, Integrase, Transposase and Efflux Pump, among which Antibiotic Deativate, Cellular Protection and Integrase are the main resistance mechanisms. These three resistance mechanisms are often considered to be encoded by ARGs.

[0119] The antibiotic inactivation mechanism decreased after Light-HA-Fe-BES and Light-Fe-BES treatment compared with RS, and the cell protection mechanism also decreased to a certain extent after Light-Fe-BES treatment. The antibiotic inactivation, cell protection and integrase mechanisms were significantly enriched after Light-HA-BES treatment. After ARGs were treated with Light-HA-BES, the abundance of Beta-Lactamase and Aminoglycoside resistance genes also showed similar enrichment. Studies have found that bacteria carrying the Beta-Lactamase resistance gene can produce an enzyme that can hydrolyze β-lactams and inactivate antibiotics. The Aminoglycoside resistance gene encodes an aminoglycoside transferase that can chemically modify aminoglycoside antibiotics and reduce their effectiveness against bacteria. Therefore, it is inferred that the increase in the abundance of Beta-Lactamase and Aminoglycoside resistance genes after Light-HA-BES treatment may be the cause of the change in resistance mechanism.

[0120] (2) Effect of pH value

[0121] Reference Fig. 9 , which shows the absolute abundance of pollutants at different pH values. Specifically, the difference from Example 1 (pH=3) is that the original sludge is adjusted to different pH values ​​(pH=4, 5, 6 and 7).

[0122] like Fig. 9As shown in the figure, when the initial pH value is 3, more ARGs and MGEs are removed, especially sulfonamide resistance genes and MGEs are significantly reduced (p<0.05), and the degradation effect is better at this time. This is because strong acidification destroys the extracellular EPS and cell membrane, promotes the release of ARGs and MGEs from the host body, and as ·OH is gradually released, the outer membrane of bacteria is degraded, the permeability increases, and the intracellular oxidation reaction is induced, which eventually destroys the sludge microbial cells and achieves the removal of ARGs and MGEs.

[0123] As the pH value increased, the amount of gene copy removal decreased. At the initial pH value of 4, the relative abundance of aminoglycoside, MLSB and sulfonamide resistance genes did not change significantly, while the abundance of beta-lactamase resistance genes and MGEs decreased. At pH values ​​of 5-6, except for MLSB and sulfonamide resistance genes, which still showed a downward trend, the abundance of other ARGs increased. At pH 7, the gene copy number of MLSB and MGEs increased significantly (p<0.05), and other gene types also showed an upward trend.

[0124] (3) Impact of reaction time

[0125] Reference Fig.10 , which shows the absolute abundance of pollutants at different reaction times. Specifically, the difference from Example 1 (reaction time 360 ​​min) is that the reaction times are adjusted to 15, 30, 60, 120, and 240 min.

[0126] like Fig.10 As shown in the figure, in the time from 0 to 60 min, except for Beta-Lactamase resistance genes and MGEs, the absolute abundance of the other four types of ARGs increased, which may be due to the fact that in the first 60 min, ·OH non-selectively removed organic matter in the sludge, inhibiting the removal of ARGs. In the time from 60 to 120 min, the absolute abundance of ARGs and MGEs was reduced to varying degrees. Among them, the abundance of Sulfonamide, MLSB resistance genes and MGEs decreased significantly (p<0.05). In the time from 120 to 240 min, although the absolute abundance of most ARGs and MGEs decreased to a certain extent, the further reduction of ARGs and MGEs in the sludge did not change significantly. However, when the reaction time reached 360 min, the abundance of most ARGs and MGEs showed an upward trend. It can be seen that Light-HA-Fe-BES has a good removal performance for ARGs and MGEs in the early stage of the reaction (0-120 min), while the abundance of ARGs and MGEs showed a rebound trend after 240 min.

[0127] (4)HA and Fe 2+ Effect of concentration

[0128] Reference Fig.11 , where different HA and Fe 2+ The absolute abundance of pollutants at different concentrations. Specifically, the difference from Example 1 is that different HA (36-120 mg / L) and Fe 2+ (50-1000μM) concentration reaction, reaction time is 120min.

[0129] like Fig.11 As shown, with the increase of HA and Fe 2+ With the increase of HA(36mg / L)+Fe 2+ (50μM) and HA (60mg / L) + Fe 2+ At low concentrations (50 μM), only sulfonamide resistance genes and MGEs showed significant decreases (p < 0.05). 2+ The concentration increased, in HA (60mg / L) + Fe 2+ (100 μM), MLSB, Sulfonamide resistance genes and MGEs were significantly reduced (p < 0.05), and other ARGs also decreased to varying degrees. 2+ The increase in dosage promotes Fe 2+ React with H2O2 to generate more ·OH. This also reasonably explains the 2+ Under the condition of 1000 μM, the absolute abundance of various genes was at the lowest level. However, as the HA concentration continued to increase, the absolute abundance of ARGs and MGEs increased. It can be seen that only under the appropriate concentration range selected in the embodiment of the present application can a better degradation effect be achieved.

[0130] Based on the above, according to the humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge provided in the embodiment of the present application, a dual-chamber microbial fuel cell is constructed, and electroactive bacteria are used to oxidize organic matter in the anode chamber to release electrons and protons, which migrate to the cathode through an external titanium wire and a cation exchange membrane, respectively. In the cathode chamber, the oxygen electrons adsorbed on the cathode surface are reduced to H2O2 through a two-electron reduction pathway. When HA and Fe are added, the electrons are reduced to H2O2. 2+ In the reaction system, Fe 3 + Directly obtain electrons and reduce to Fe 2+ , HA to Fe 3+ The electron ligand transfer will also occur gradually, generating Fe 2+ Realize Fe2+ / Fe 3+ Redox cycle. Fe 2+ The Fenton reaction with H2O2 generates a large amount of ·OH. In addition, HA and Fe 2+ The complex will also undergo photochemical reactions under light conditions to produce active species such as ·OH, thereby oxidizing pollutants such as ARGs and microorganisms. The series of photochemical reactions that occur in this process firstly cause HA to absorb light and become excited ( 1 HA * , 3 HA * and HA · ), 3 HA * and HA · It will react with dissolved oxygen in the solution to generate OH, 1 O2 and H2O2. Due to the excited state 3 HA * In the cathode, it can receive electrons and be converted into highly reducing HA · , while HA · It is easy to react with dissolved oxygen to generate ·OH with strong oxidizing properties. ·OH can oxidize cathode ARGs into simpler oxidation products, thereby effectively degrading and inhibiting the spread and transfer of pollutants such as ARGs.

[0131] (5) Effects of HA-mediated photo-microbial electro-Fenton on microbial communities

[0132] Reference Fig.12At the phylum level, the relative abundance of Proteobacteria, Bacteroidetes, Actinobacteria, Acidobacteria, Chloroflexi and Firmicutes was high, accounting for about 80% of the microorganisms, of which Bacteroidetes and Proteobacteria accounted for 50% of the microorganisms. Proteobacteria had the highest relative abundance in this study. After RS ​​was treated with different methods, the microbial community changed to a certain extent. Among all the treatments, Light-HA-Fe-BES treatment had a more obvious inhibitory effect on Bacteroidetes. It decreased from the initial 25% to 18%, and it also had a certain inhibitory effect on Actinobacteria and Acidobacteria. Comparing the ARGs removal results, it means that Bacteroidetes, Actinobacteria and Acidobacteria are likely to be potential hosts of the removed ARGs. In addition, after the Light-HA-Fe-BES treatment, Firmicutes increased from 5% to 16%. The reason why Firmicutes increased in Light-HAFe-BES may be that Firmicutes can produce spores to resist dehydration and extreme environments (high oxidative stress caused by Fenton). In addition, the cell wall of Firmicutes contains about 50%-80% peptidoglycan and the cell wall thickness is 10-50nm, so the specific structure of the cell wall may be another reason. These characteristics may help Firmicutes to withstand Fenton treatment and then survive. With the death of other bacterial phyla, the survival of Firmicutes has significantly increased the relative percentage of Firmicutes. In addition to the characteristics of Firmicutes themselves, we also speculate that Firmicutes may also be the main host of the remaining ARGs. Compared with the treatment without HA addition, the main changes in the microbial community after Light-Fe-BES treatment were that Bacteroidetes decreased from the initial 25% to 21%, and Proteobacteria increased from the initial 26% to 36%. Of course, whether it is Light-HA-Fe-BES or Light-Fe-BES treatment, in general, these two treatments have little effect on Chloroflexi, Acidobacteria, Actinobacteria and most other bacterial phyla. However, adding HA to the LightFe-BES system can significantly inhibit the relative abundance of Proteobacteria.

[0133] Reference Fig.13 At the genus level, RS samples showed a diverse distribution of microorganisms, with no single genus overly dominant. Aquihabitans, often referred to as a genus of aquatic microorganisms in biological classification, had the highest relative abundance in RS. The relative abundance of Aquihabitans decreased slightly after Light-HA-Fe-BES treatment. The relative abundances of Gp10, Gp17, Terrimonas, Ilumatobacter, and Gemmatimonas decreased. The abundance of Romboutsia increased significantly and replaced Aquihabitans as the dominant genus in the sample. The shift in dominant populations suggests that Light-HA-Fe-BES treatment may inhibit some bacteria such as Aquihabitans, Terrimonas, and Ilumatobacter more effectively than other bacteria, resulting in a decrease in their relative abundance. The increased abundance of Romboutsia also suggests that Romboutsia may be able to better exploit the conditions created by the LightHA-Fe-BES system, allowing them to outcompete other microorganisms and increase in relative abundance.

[0134] (6) Potential hosts of ARGs

[0135] Reference Fig.14 According to the co-occurrence results of ARGs, MGEs and bacterial genera, 7 bacterial genera are potential hosts of 23 ARGs subtypes. For example, Gp10 is a possible host of 4 ARGs subtypes, namely ereB, ermB, ermX and aadA5. The similar Gp17 is predicted to carry only a single ARGs subtype aadA2-1. By comparing the changes in the relative abundance of ARGs and microorganisms, we found that after Light-HA-Fe-BES treatment, in addition to the decrease in ARGs abundance, the relative abundance of Gp10 genus microorganisms also decreased. The co-occurrence of ARGs and microorganisms once again confirmed this result. In addition to Gp10, Terrimonas may carry two ARGs subtypes, ereA and tetX. Ilumatobacter may be associated with more than 9 ARGs (ereA, ermB, aadA2-1, blaOXY-2, tnpa7, blaTEM, aac(6')-Ib, intl1, strB, mphA, etc.).

[0136] (7) Complete Mechanism

[0137] Electroactive bacteria oxidize organic matter in the anode chamber, releasing electrons and protons (Formula (1)). The electrons and protons migrate to the cathode through the external titanium wire and the cation exchange membrane, respectively. In the cathode chamber of the system, the electrons of oxygen adsorbed on the cathode surface are reduced to H2O2 through a two-electron reduction pathway (Formula (2)). 2+ In the reaction system, Fe 3+ Directly obtain electrons and reduce to Fe 2+ (Formula (5)), HA to Fe 3+ The electron ligand transfer will also occur gradually, generating Fe 2+ Realize Fe 2+ / Fe 3+ Redox cycle (Equation (6)). Fe 2+ The Fenton reaction with H2O2 generates a large amount of ·OH (Formula (3)). The highly oxidizing H2O2 and ·OH gradually oxidize and decompose the ARGs in the extracellular polymers and intracellular genetic materials of the sludge from the outside to the inside.

[0138] Fe 2+ The concentration of ·OH produced by the reaction with H2O2 affects the removal of ARGs in the cathode. The production of ·OH is only considered as a general reaction. 2+ The complex will also undergo photochemical reactions under light conditions to produce active species such as ·OH, thereby oxidizing ARGs and microorganisms. The series of photochemical reactions that occur in this process are first due to HA absorbing light to become excited (1HA*, 3HA* and HA·) (Equation (7)), 3HA* and HA· will react with dissolved oxygen in the solution to generate ·OH, 1 O2 and H2O2 (Equations (8), (9), (10)). Since the excited state 3HA* can receive electrons in the cathode and be converted into the highly reducing HA·, and HA· easily reacts with dissolved oxygen to generate the highly oxidizing ·OH. Therefore, ·OH is crucial for the HA-mediated light-microbial electro-Fenton degradation of pollutants in sludge. However, the HA-mediated light-microbial electro-Fenton system involves multiple ·OH production pathways, and excess H2O2 can also be generated by light or direct decomposition to generate ·OH (Equations (11), (12)). This process will alleviate the rate limitation problem of the microbial electro-Fenton reaction.

[0139] In addition, the HA-mediated light-microbial electro-Fenton system inhibited the growth of ARGs hosts such as Gp10, Gp17, Ilumatobacter, Terimonas, and Aquihabitans, blocked their growth metabolism, reduced their abundance, inhibited the growth of these ARGs hosts or killed them, and caused a decrease in the abundance of ARGs and MGEs. For example, Gp10 is the host of four ARGs, aadA5, ereB, ermB, and ermX. After treatment with the humic acid-mediated light-microbial electro-Fenton system, the relative abundance of Gp10 microorganisms decreased by 43.89%, and the relative abundance of aadA5, ereB, ermB, and ermX also decreased, which were reduced by 55.58%, 88.41%, 44.85%, and 70.96%, respectively, compared with the original sludge. Gp17 carried aadA2-1, and the relative abundance of Gp17 decreased by 38.28% after system treatment, while the relative abundance of aadA2-1 decreased by 51.83%. Terrimonas carried both ereA and tetX, and the relative abundance of Terrimonas decreased by 51.49% after system treatment, while the relative abundance of ereA and tetX decreased by 96.32% and 57.57%, respectively. Ilumatobacter carried ARGs such as ereA, ermB, aadA2-1, blaOXY-2, tnpa7, blaTEM, aac(6')-Ib, intl1, strB, and mphA, and the relative abundance of Ilumatobacter decreased by 41.57% after system treatment, while the relative abundance of several ARGs it carried also decreased by 17.18%-100.00%.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge, characterized in that: The following steps are involved: Construction of a dual-chamber microbial fuel cell; Adding a biological reaction raw material to the anode chamber of the dual-chamber microbial fuel cell, wherein the biological reaction raw material can undergo a biological reaction to release electrons; Adding pollutant-containing sludge, humic acid and ferrous ions into the cathode chamber of the dual-chamber microbial fuel cell; The anode and cathode of the microbial fuel cell are connected under light conditions to allow a reaction to occur in the cathode chamber to degrade the pollutants.

2. The humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge according to claim 1, characterized in that: The method further comprises: During the reaction in the cathode chamber, aeration is continuously applied to the cathode chamber.

3. The humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge according to claim 1, characterized in that: The illumination condition is to use a xenon lamp light source with a power of 200-600W; Preferably, the lighting condition is to use a xenon lamp light source with a power of 300W.

4. The humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge according to claim 1, characterized in that: The method further comprises: Adjusting the initial pH value of the reaction system in the cathode chamber to be ≤4; Preferably, the initial pH value of the reaction system in the cathode chamber is adjusted to 3.

5. The humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge according to claim 1, characterized in that: The time for the reaction to occur in the cathode chamber is ≥120 min; Preferably, the reaction time in the cathode chamber is 120-360 min; More preferably, the reaction time in the cathode chamber is 240 minutes.

6. The humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge according to claim 1, characterized in that: The temperature of the reaction in the cathode chamber is 20-30°C; Preferably, the temperature at which the reaction occurs in the cathode chamber is 23-27°C; More preferably, the temperature at which the reaction occurs in the cathode chamber is 25°C.

7. The humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge according to claim 1, characterized in that: The humic acid concentration of the reaction system in the cathode chamber is 18-120 mg / L; Preferably, the humic acid concentration of the reaction system in the cathode chamber is 36-120 mg / L; More preferably, the humic acid concentration of the reaction system in the cathode chamber is 60 mg / L.

8. The humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge according to claim 1, characterized in that: The ferrous ion concentration of the reaction system in the cathode chamber is 50-1000 μM; Preferably, the ferrous ion concentration of the reaction system in the cathode chamber is 1000 μM.

9. The humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge according to claim 1, characterized in that: The steps of constructing a dual-chamber microbial fuel cell include: A reactor is made of organic glass, and the interior of the reactor is divided into an anode chamber and a cathode chamber by a cation exchange membrane. Carbon brushes are used as the anode and the cathode. The anode and the cathode are placed in the anode chamber and the cathode chamber respectively. Titanium wire is used to connect the anode, the cathode and an external resistor to form a loop, thereby obtaining a dual-chamber microbial fuel cell.

10. The humic acid-mediated light-microbial electro-Fenton method for degrading pollutants in sludge according to any one of claims 1 to 9, characterized in that: The contaminants include antibiotic resistance genes and / or mobile genetic elements; Preferably, the antibiotic resistance gene comprises at least one of a sulfonamide antibiotic resistance gene, an aminoglycoside antibiotic resistance gene, an MLSB antibiotic resistance gene, a tetracycline antibiotic resistance gene and a β-lactam resistance gene.

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