Activated carbon for reducing resistance genes in activated sludge, preparation method and application thereof

Abstract

The present invention relates to the field of environmental technology, and discloses an activated carbon for reducing resistance genes in activated sludge, a preparation method thereof, and an application thereof, wherein an amino functional group, C6-HSL, and 3-oxo-C6-HSL are connected to the surface of the activated carbon. The activated carbon in the present invention can physically adsorb the generated resistance genes on the basis of reducing the content of resistance genes in the activated sludge.

Description

Technical Field

[0001] The invention relates to the field of environmental technology, and in particular to activated carbon for reducing resistance genes in activated sludge, and a preparation method and application thereof. Background Art

[0002] In recent years, antibiotics have been widely used in human production and life, resulting in a gradual increase in the concentration of antibiotics in the environment. Antibiotics can cause survival pressure on bacteria in the environment, and induce or bioscreen the generation of antibiotic-resistant bacteria (ARB). ARBs carry antibiotic resistance genes (ARGs), which will hinder the use of antibiotics to treat human and animal pathogens, making it impossible to effectively eliminate infections, posing a serious threat to human health. There are two main ways to spread resistance genes: vertical transmission and horizontal transmission. Vertical transmission is from parents to offspring, passed down from generation to generation. Horizontal transmission is the transmission of resistance genes between bacterial cells through mobile genetic elements such as plasmids, transposons, integrons, and bacteriophages. There are three main ways: transformation, conjugation transfer, and transduction.

[0003] As the final collection place of various types of wastewater, sewage treatment plants are the main treatment sites for antibiotics. However, the removal of antibiotics by traditional sewage treatment processes is very limited. Therefore, under the long-term antibiotic selection pressure, the production of antibiotic resistance genes in sewage treatment plants is induced and promoted. The activated sludge method is one of the most commonly used processes in sewage treatment plants. There are very few existing methods for removing resistance genes in sewage treatment plants that target activated sludge. However, the resistance genes released by activated sludge into the environment in the form of microbial aerosols cannot be ignored, which will pose a serious threat to human health. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an activated carbon for reducing resistance genes in activated sludge, and a preparation method and application thereof. The activated carbon in the present invention can physically adsorb the produced resistance genes on the basis of reducing the content of resistance genes in activated sludge.

[0005] The invention provides activated carbon for reducing resistance genes in activated sludge. Amino functional groups, C6-HSL and 3-oxo-C6-HSL are connected to the surface of the activated carbon.

[0006] Furthermore, the molar ratio of C6-HSL to 3-oxo-C6-HSL is 1-3:1-3.

[0007] Furthermore, the molar ratio of C6-HSL to 3-oxo-C6-HSL is 1:1.

[0008] Furthermore, the activated carbon is coconut shell activated carbon.

[0009] The present invention also provides a method for preparing the activated carbon, which comprises:

[0010] Step S1: treating the activated carbon by plasma enhanced chemical vapor precipitation, introducing ammonia gas into the plasma enhanced chemical vapor precipitation method for treatment, and setting the ammonia gas flow rate, treatment power, current, and voltage during treatment;

[0011] Step S2: subjecting C6-HSL and 3-oxo-C6-HSL to substitution reaction with bromine;

[0012] Step S3: subjecting the products obtained in step S1 and step S2 to an alkylation reaction under heating conditions to obtain activated carbon.

[0013] Furthermore, in step S1, the ammonia flow rate, processing power, current and voltage during the treatment are set as follows:

[0014] The ammonia flow rate is 80mL / min-100mL / min, the processing power is 45W-55W; the current is not greater than 1A and greater than 0A; the voltage is not greater than 100KV and greater than 0KV.

[0015] Furthermore, in step S2, ferric chloride needs to be added during the substitution reaction.

[0016] Furthermore, the added mass of the ferric chloride is 0.5% of the total mass of the reactants participating in the substitution reaction.

[0017] Furthermore, in step S2, the substitution reaction temperature is 20°C-50°C, and the substitution reaction time is 20min-30min.

[0018] Furthermore, in step S2, the molar ratio of C6-HSL to bromine is 1:1; the molar ratio of 3-oxo-C6-HSL to bromine is 1:1.

[0019] Furthermore, during the alkylation treatment, the molar ratio of the substituted C6-HSL to the substituted 3-oxo-C6-HSL is 1-3:1-3.

[0020] Furthermore, during the alkylation treatment, the molar ratio of the substituted C6-HSL to the substituted 3-oxo-C6-HSL is 1:1.

[0021] Furthermore, in step S3, the heating temperature is 60°C-100°C, and the heating time is 1h-2h.

[0022] Furthermore, during the alkylation treatment, the mass ratio between the substituted C6-HSL and the product obtained in step S1 is 1:2.

[0023] The activated carbon obtained by the invention is used in reducing resistance genes in sewage treatment units.

[0024] Furthermore, the resistance gene includes tet(X) , sul2 , ErmF , adeF , OXA-129 , aadA3 , aadA16 , vanH gene in vanA cluster , msrE , mphE , qacJ , qacG .

[0025] The embodiments of the present invention have the following technical effects:

[0026] 1. The biological signal molecule C6-HSL and the biological signal molecule 3-oxo-C6-HSL connected to the activated carbon of the present invention can adjust the bacterial distribution and dominant bacterial community in the sewage pool through the quorum sensing system, which is beneficial to reduce the growth of the bacterial community containing resistance genes, thereby helping to reduce the generation of resistance genes; on this basis, the activated carbon first uses physical adsorption to fix the resistance genes to prevent them from flowing out of the sewage treatment pool, and secondly, the activated carbon, as the main body for loading C6-HSL and 3-oxo-C6-HSL, can reduce the loss of C6-HSL and 3-oxo-C6-HSL with the treated sewage, thereby ensuring the treatment effect of the sewage treatment unit.

[0027] 2. In the present invention, in order to further reduce the content of resistance genes in the sewage pool, the number of connections between C6-HSL and 3-oxo-C6-HSL on the surface of activated carbon, as well as the ratio between C6-HSL and 3-oxo-C6-HSL, are further designed; in addition, the amino functional groups on the surface of activated carbon can, on the one hand, enhance the adsorption capacity of activated carbon, and on the other hand, serve as a bridge connecting activated carbon with C6-HSL and 3-oxo-C6-HSL.

[0028] 3. The activated carbon obtained by the present invention can significantly reduce the activated sludge and sewage treatment units tet(X) , sul2 , ErmF , adeF , OXA-129 , aadA3 , aadA16 , vanH gene in vanA cluster , msrE , mphE , qacJ ,qacG Resistance genes. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 This is the synthesis route provided in Example 1 of the present invention, wherein the upper one is a route for synthesis using C6-HSL, and the lower one is a route for synthesis using 3-oxo-C6-HSL. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only 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 belong to the scope of protection of the present invention.

[0032] In a first aspect, some embodiments of the present invention provide an activated carbon for reducing resistance genes in activated sludge, wherein amino functional groups, C6-HSL and 3-oxo-C6-HSL are connected to the surface of the activated carbon.

[0033] In the present invention, C6-HSL and 3-oxo-C6-HSL can adjust the bacterial distribution and dominant bacterial population in the sewage pool through the quorum sensing system, which is beneficial to reduce the growth of the bacterial population that can produce resistance genes, thereby helping to reduce the production of resistance genes. On the one hand, the amino functional group can enhance the adsorption capacity of activated carbon, thereby facilitating the adsorption of resistance genes in sewage units and activated sludge. On the other hand, the amino functional group serves as a bridge connecting C6-HSL and 3-oxo-C6-HSL with activated carbon, thereby promoting a stable connection between C6-HSL and 3-oxo-C6-HSL and activated carbon.

[0034] In some embodiments, the molar ratio of C6-HSL to 3-oxo-C6-HSL is 1-3:1-3.

[0035] In some embodiments, the molar ratio of C6-HSL to 3-oxo-C6-HSL is 1:1.

[0036] In some embodiments, the activated carbon is coconut shell activated carbon.

[0037] In a second aspect, some embodiments of the present invention also provide a method for preparing the activated carbon, the method comprising:

[0038] Step S1: treating the activated carbon by plasma enhanced chemical vapor precipitation, introducing ammonia gas into the plasma enhanced chemical vapor precipitation method for treatment, and setting the ammonia gas flow rate, treatment power, current, and voltage during treatment;

[0039] Step S2: subjecting C6-HSL and 3-oxo-C6-HSL to substitution reaction with bromine;

[0040] Step S3: subjecting the products obtained in step S1 and step S2 to an alkylation reaction under heating conditions to obtain activated carbon.

[0041] In some embodiments, in step S1, the ammonia flow rate, processing power, current, and voltage during the treatment are set as follows:

[0042] The ammonia flow rate is 80mL / min-100mL / min, the processing power is 45W-55W; the current is not greater than 1A and greater than 0A; the voltage is not greater than 100KV and greater than 0KV.

[0043] In the present invention, by controlling the flow rate of ammonia, the content of amino functional groups on the surface of activated carbon can be regulated. The content of amino functional groups not only needs to be able to connect enough C6-HSL and 3-oxo-C6-HSL on the surface of activated carbon, but also needs to be able to further enhance the adsorption capacity of activated carbon.

[0044] In some embodiments, in step S2, ferric chloride needs to be added during the substitution reaction.

[0045] In some embodiments, the added mass of the ferric chloride is 0.5% of the total mass of the reactants involved in the substitution reaction.

[0046] In some embodiments, in step S2, the substitution reaction temperature is 20°C-50°C.

[0047] In some embodiments, in step S2, the molar ratio of C6-HSL to bromine is 1:1; the molar ratio of 3-oxo-C6-HSL to bromine is 1:1.

[0048] In some embodiments, during the alkylation treatment, the molar ratio of the substituted C6-HSL to the substituted 3-oxo-C6-HSL is 1-3:1-3.

[0049] In some embodiments, during the alkylation treatment, the molar ratio of the substituted C6-HSL to the substituted 3-oxo-C6-HSL is 1:1.

[0050] In some embodiments, in step S3, the heating temperature is 60° C.-100° C., and the heating time is 1 h-2 h.

[0051] In some embodiments, during the alkylation treatment, the mass ratio between the substituted C6-HSL and the product obtained in step S1 is 1:2.

[0052] In a third aspect, some embodiments of the present invention also provide the use of activated carbon in reducing resistance genes in sewage treatment units.

[0053] In some embodiments, the resistance gene comprises tet(X) , sul2 , ErmF , adeF , OXA-129 , aadA3 , aadA16 , vanH gene in vanA cluster , msrE , mphE , qacJ , qacG .

[0054] The following is described in conjunction with specific embodiments and comparative examples:

[0055] Embodiment 1:

[0056] Place 100g of coconut shell activated carbon in a plasma enhanced chemical deposition instrument, and install electrodes to generate plasma for treatment under vacuum conditions, so that the vacuum degree in the reaction chamber drops to 2Pa. Open the air inlet passage, and introduce ammonia gas at a flow rate of 90mL / min, and use a rotor flowmeter to control the flow rate to keep the gas pressure in the reaction chamber stable at 50Pa. Start the high-frequency power supply, and set the processing power plan to 50W; current (1A), voltage (50KV); processing time is 5min, and finally turn off the power and take out the activated carbon;

[0057] C6-HSL and 3-oxo-C6-HSL were subjected to substitution reaction with bromine element respectively, the molar ratio of C6-HSL to bromine element was 1:1, and the molar ratio of 3-oxo-C6-HSL to bromine element was 1:1; when C6-HSL was subjected to substitution reaction with bromine element, 0.5% of ferric chloride of the total mass of C6-HSL and bromine element was added; when 3-oxo-C6-HSL was subjected to substitution reaction with bromine element, 0.5% of ferric chloride of the total mass of 3-oxo-C6-HSL and bromine element was added; the temperature of substitution reaction was 35°C, and the time of substitution reaction was 25min;

[0058] The molar ratio of the substituted C6-HSL and the substituted 3-oxo-C6-HSL is 1:1, and the mass ratio between the substituted C6-HSL and the product obtained after plasma enhanced chemical deposition treatment is 1:2; an alkylation reaction is carried out; the temperature of the alkylation reaction is 70° C. and the time is 1 hour.

[0059] Embodiment 2:

[0060] The method of Example 2 is the same as that of Example 1, but the molar ratio of the substituted C6-HSL and the substituted 3-oxo-C6-HSL in Example 2 is 3:1, and the other methods are the same as those of Example 1.

[0061] Embodiment 3:

[0062] The method of Example 3 is the same as that of Example 1, except that the molar ratio of the substituted C6-HSL and the substituted 3-oxo-C6-HSL in Example 2 is 1:3, and the other methods are the same as those of Example 1.

[0063] Comparative Example 1:

[0064] Coconut shell activated carbon.

[0065] Comparative Example 2:

[0066] Place 100g of coconut shell activated carbon in a plasma enhanced chemical deposition instrument, and install electrodes to generate plasma for treatment under vacuum conditions, so that the vacuum degree in the reaction chamber drops to 2Pa. Open the air inlet passage, and introduce ammonia gas at a flow rate of 90mL / min, and use a rotor flowmeter to control the flow rate to keep the gas pressure in the reaction chamber stable at 50Pa. Start the high-frequency power supply, and set the processing power plan to 50W; current (1A), voltage (50KV); processing time is 5min, and finally turn off the power and take out the activated carbon;

[0067] C6-HSL is subjected to substitution reaction with bromine, and the molar ratio of C6-HSL to bromine is 1:1; when C6-HSL and bromine undergo substitution reaction, 0.5% of ferric chloride based on the total mass of C6-HSL and bromine is added; the temperature of the substitution reaction is 35°C, and the time of the substitution reaction is 25 minutes;

[0068] The mass ratio between the substituted C6-HSL and the product obtained after plasma enhanced chemical deposition treatment is 1:2; an alkylation reaction is performed; the temperature of the alkylation reaction is 70° C. and the time is 1 hour.

[0069] Comparative Example 3:

[0070] Place 100g of coconut shell activated carbon in a plasma enhanced chemical deposition instrument, and install electrodes to generate plasma for treatment under vacuum conditions, so that the vacuum degree in the reaction chamber drops to 2Pa. Open the air inlet passage, and introduce ammonia gas at a flow rate of 90mL / min, and use a rotor flowmeter to control the flow rate to keep the gas pressure in the reaction chamber stable at 50Pa. Start the high-frequency power supply, and set the processing power plan to 50W; current (1A), voltage (50KV); processing time is 5min, and finally turn off the power and take out the activated carbon;

[0071] 3-oxo-C6-HSL and bromine are subjected to substitution reaction, and the molar ratio of 3-oxo-C6-HSL to bromine is 1:1; when 3-oxo-C6-HSL and bromine undergo substitution reaction, 0.5% of ferric chloride based on the total mass of 3-oxo-C6-HSL and bromine is added; the temperature of the substitution reaction is 35°C, and the time of the substitution reaction is 25 minutes;

[0072] The mass ratio between the substituted 3-oxo-C6-HSL and the product obtained after plasma enhanced chemical deposition treatment is 1:2; an alkylation reaction is performed; the temperature of the alkylation reaction is 70° C. and the time is 1 hour.

[0073] The present invention also obtains embodiments and comparative examples for comparative testing:

[0074] Test of the number of resistance genes: The activated sludge was subjected to metagenomic sequencing, and then sewage containing antibiotics was added (the antibiotic was sulfamethoxazole, and its content was 500 μg / L), and the examples and comparative examples were respectively placed in the activated sludge with antibiotics added, and the system was run for 20 days, and then the activated sludge and the discharged sewage were subjected to metagenomic sequencing, and the added mass of the examples and comparative examples in the sludge was 5 mg / 100 mg. The activated sludge with antibiotics added was used as the control group.

[0075] Results and analysis:

[0076] Table 1 Results before and after treatment of the embodiment

[0077]

[0078] Table 2 Results before and after treatment of the examples and comparative examples

[0079]

[0080] Table 3 Content of resistance genes in the treated water discharged from the examples and comparative examples

[0081]

[0082] according to Figure 1The activated carbon of the present invention was synthesized according to the preparation process, and the examples and comparative examples were applied to sewage containing activated sludge to treat resistance genes. The results are shown in Tables 1 to 3. It can be found from Tables 1 and 2 that the generation of resistance genes in the examples is reduced compared with the comparative examples after the addition of the activated carbon of the present invention. It can be seen that by regulating the distribution of the flora and the dominant flora in the sewage treatment unit by the biological signal C6-HSL and the biological signal 3-oxo-C6-HSL, it is beneficial to reduce the growth of the flora that can produce resistance genes, thereby helping to reduce the generation of resistance genes. It can be found from Table 3 that the resistance gene content in the discharged sewage after being treated with the activated carbon of the present invention is further reduced. It can be seen that the activated carbon loaded with amino functional groups uses physical adsorption to fix the resistance genes to prevent them from flowing out of the sewage treatment tank, thereby significantly reducing the resistance gene content in the wastewater.

[0083] It should be understood by those skilled in the art that the biological signal affects the distribution of microorganisms in the activated sludge, and therefore, the selection and concentration of the biological signal will directly affect the distribution of microorganisms in the activated sludge, thereby affecting the generation of resistance genes. Compared with Examples 1 to 3, Example 1 has less resistance gene generation at the corresponding concentration, and therefore, it is further preferred that the molar ratio of the biological signal C6-HSL to the biological signal 3-oxo-C6-HSL is 1:1.

[0084] In summary, the activated carbon obtained by the present invention can not only reduce the generation of resistance genes, but also is beneficial to the fixation of resistance genes.

[0085] It should be noted that the terms used in the present invention are only for describing specific embodiments, rather than limiting the scope of the present application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular, but may also include the plural. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of more restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method or device including the elements.

[0086] It should also be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0087] 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 by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. An activated carbon for reducing resistance genes in activated sludge, characterized in that: The activated carbon surface is connected with amino functional groups, C6-HSL and 3-oxo-C6-HSL; The preparation method of the activated carbon comprises: Step S1: treating the activated carbon by plasma enhanced chemical vapor precipitation, introducing ammonia gas into the plasma enhanced chemical vapor precipitation method for treatment, and setting the ammonia gas flow rate, treatment power, current, and voltage during the treatment; Step S2: subjecting C6-HSL and 3-oxo-C6-HSL to substitution reaction with bromine; Step S3: subjecting the products obtained in step S1 and step S2 to an alkylation reaction under heating conditions to obtain activated carbon.

2. The activated carbon according to claim 1, characterized in that The molar ratio of C6-HSL to 3-oxo-C6-HSL is 1-3:1-3; The activated carbon is coconut shell activated carbon.

3. The method for preparing activated carbon according to any one of claims 1 to 2, characterized in that: The preparation method comprises: Step S1: treating the activated carbon by plasma enhanced chemical vapor precipitation, introducing ammonia gas into the plasma enhanced chemical vapor precipitation method for treatment, and setting the ammonia gas flow rate, treatment power, current, and voltage during the treatment; Step S2: subjecting C6-HSL and 3-oxo-C6-HSL to substitution reaction with bromine; Step S3: subjecting the products obtained in step S1 and step S2 to an alkylation reaction under heating conditions to obtain activated carbon.

4. The preparation method according to claim 3, characterized in that: In step S1, the ammonia flow rate, processing power, current and voltage during the treatment are set as follows: The ammonia flow rate is 80mL / min-100mL / min, the processing power is 45W-55W; the current is not greater than 1A and greater than 0A; the voltage is not greater than 100KV and greater than 0KV.

5. The preparation method according to claim 3, characterized in that: In the step S2, ferric chloride needs to be added during the substitution reaction; The added mass of the ferric chloride is 0.5% of the total mass of the reactants involved in the substitution reaction.

6. The preparation method according to claim 3, characterized in that: In step S2, the substitution reaction temperature is 20°C-50°C, and the substitution reaction time is 20min-30min; In the step S2, the molar ratio of C6-HSL to bromine is 1:1; the molar ratio of 3-oxo-C6-HSL to bromine is 1:

1.

7. The preparation method according to claim 3, characterized in that: During the alkylation treatment, the molar ratio of the substituted C6-HSL to the substituted 3-oxo-C6-HSL is 1-3:1-3; During the alkylation treatment, the mass ratio between the substituted C6-HSL and the product obtained in step S1 is 1:

2.

8. The preparation method according to claim 3, characterized in that: In step S3, the heating temperature is 60° C.-100° C., and the heating time is 1 h-2 h.

9. Use of the activated carbon according to any one of claims 1 to 2 in reducing resistance genes in sewage treatment units.

10. The use according to claim 9, characterized in that: The resistance genes include tet(X) , sul2 , FWf , F , OXA-129 , aadA3 , aadA16 , vanH gene in vanA cluster , mxD , mphE , QUR as well as QUR .

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