Composition for synchronously removing organophosphorus pesticide and heavy metal combined pollution, preparation method and removal method

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to a composition for synchronously removing organophosphorus pesticide and heavy metal combined pollution, a preparation method and a removal method. The invention further provides an iron-carbon material and shewanella composite system, the composite system can enable thalli to be attached to the surface of the FeO / C material and grow into a biological membrane, and synchronous removal of composite pollution by the composite system is promoted; meanwhile, electron transfer is improved, so that heavy metal reduction and organophosphorus pesticide degradation are accelerated. Through verification, the compound system also effectively relieves the toxic effect of malathion and Cr (VI) compound pollution on cells. By applying the composite system disclosed by the invention, the composite pollution of malathion and Cr (VI) can be synchronously removed, and the removal rate of malathion and Cr (VI) is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and in particular relates to a composition for simultaneously removing compound pollution of organophosphorus pesticides and heavy metals, a preparation method and a removal method. Background Art

[0002] It is a common natural phenomenon that crops are damaged by pests, diseases, weeds and rodents. In actual production, pesticides are still one of the main means of preventing and controlling pests, diseases, weeds and rodents, which is crucial for protecting crops and reducing yield losses. The degradation treatment technology for various OPPs (organophosphorus farmicides) has made significant progress, providing strong support for the control of organophosphorus pollution. At present, the removal methods of organophosphorus pollution mainly include physical methods, chemical methods and biological methods.

[0003] According to the research of Al-Othman et al., inorganic pollutants are released into the environment in water-soluble and water-insoluble forms. Inorganic pollutants include various heavy metals such as chromium, copper, cadmium, lead, zinc, arsenic, etc. Wastewater containing Cr(VI) must be treated before being discharged into the environment. Researchers have tried a variety of technologies and methods to remove Cr(VI) from water. Common methods include: adsorption, ion exchange, membrane filtration, electrocoagulation and microbial remediation.

[0005] In recent years, relevant research has begun to focus on pollution control technology for complex pollutants. At present, there are relatively few studies on the simultaneous removal of organophosphorus pesticides and heavy metals by microbial remediation, and there is no report on microbial remediation methods for simultaneous removal of heavy metals and organophosphorus pesticide complex pollution in existing technologies. Summary of the invention

[0006] The purpose of the present invention is to provide a composition for simultaneously removing the composite pollution of organophosphorus pesticides and heavy metals, a preparation method and a removal method. The composite pollution of heavy metals and organophosphorus pesticides can be removed simultaneously by using the composition.

[0007] In order to solve the above technical problems, the following technical solutions are proposed:

[0008] The invention provides a composition for simultaneously removing compound pollution of organophosphorus pesticides and heavy metals, comprising iron-carbon material and Shewanella.

[0009] Preferably, the composition also includes an inorganic salt culture solution.

[0010] Preferably, the components in the composition are packaged or form a composite system; in the composite system, the Shewanella is loaded on the iron-carbon material; the loading method includes the Shewanella growing on the surface of the iron-carbon material to form a biofilm.

[0011] Preferably, the Shewanella includes Shewanella MR-1, with the strain number being ATCC 700550.

[0012] The present invention provides a method for preparing the composition described in the above technical solution, comprising:

[0013] The iron-carbon material suspension and the Shewanella suspension are mixed to obtain a composition.

[0014] Preferably, the preparation method of the composition comprises: mixing the iron-carbon material with a first portion of an inorganic salt culture solution to obtain an iron-carbon material suspension;

[0015] Mixing the iron-carbon material suspension, the Shewanella suspension and a second portion of the inorganic salt culture solution to obtain a composition;

[0016] The inoculation amount of the Shewanella suspension is 1% to 10% of the volume of the second part of the inorganic salt culture solution; based on the volume of the second part of the inorganic salt culture solution, the addition amount of the iron-carbon material suspension is 0.05 to 1 g / L.

[0017] Preferably, the first part of the inorganic salt culture solution and the second part of the inorganic salt culture solution respectively include: 0.5g / LKH2PO4, 0.5g / LK2HPO4, 2.5g / L(NH4)SO4, 1.0g / LNa2SO4, 0.1g / LCaCl2, 1.0g / LMgSO4, 10g / LNaCl, 3.36g / L sodium lactate and 1mL / L trace element solution;

[0018] The trace element liquid comprises: 0.1 g / L Na2SeO4·2H2O, 1.0 g / L FeSO4, 0.05 g / L ZnCl2, 0.01 g / L NiCl2·6H2O, 0.015 g / L CuSO4·5H2O and 0.001 g / L H2MoO4·2H2O.

[0019] The present invention provides a method for simultaneously removing compound pollution of organophosphorus pesticides and heavy metals, comprising: removing the composition by mixing with a to-be-degraded object; the to-be-degraded object contains compound pollution of organophosphorus pesticides and heavy metals;

[0020] The composition is the composition described in the above technical solution or the composition prepared by the preparation method described in the above technical solution.

[0021] Preferably, the organophosphorus pesticide includes malathion; the heavy metal includes heavy metal ions, and the heavy metal ions include Cr(VI); the mass concentration of malathion in the product to be degraded is 10 to 50 mg / L; the mass concentration of Cr(VI) in the product to be degraded is in the range of 5 to 40 mg / L.

[0022] Preferably, the removal method includes degradation; the degradation temperature is 35° C.; the degradation time is 12 to 96 hours; and the degradation pH value is 7.

[0023] Beneficial effects of the present invention: The present invention provides a composition for simultaneously removing organophosphorus pesticides and heavy metal composite pollution. Due to the addition of iron-carbon materials, the types of redox products in the composition are increased and the electron transfer resistance is reduced, which can improve electron transfer, thereby accelerating heavy metal reduction and degradation of organophosphorus pesticides; the iron-carbon material can also provide a suitable growth and reproduction space for Shewanella, and the bacteria of Shewanella adhere to the surface of the FeO / C material and grow into a biofilm, which effectively reduces the toxic effects of organophosphorus pesticides and heavy metal composite pollution on Shewanella cells, promotes the secretion of extracellular polymeric substances, and also enhances the permeability of cell membranes, promoting the composition to complex The invention can remove the pollution synchronously with high removal rate, and the iron-carbon material can also produce a certain adsorption effect on the pollutants. It has been verified that the Shewanella in the composition of the invention can realize the reduction of Cr(VI) and the degradation of malathion. The Shewanella bacteria adhere to the surface of the FeO / C material and grow into a biofilm, which effectively reduces the toxic effect of the combined pollution of malathion and Cr(VI) on the cells of Shewanella, accelerates the reduction of Cr(VI) and the degradation of malathion. The degradation rate of malathion by the composition of the invention is 93.98%, and the maximum reduction rate of Cr(VI) is 64.93%, which is 1.17 times and 1.47 times that of the single bacteria treatment. It can be seen that the composite system of the invention has good degradation performance in synergistically degrading malathion and Cr(VI), and has good application prospects in the field of microbial remediation technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 : are electron microscope images of Shewanella MR-1 and the iron-carbon material-cooperative Shewanella composite system, wherein a is an electron microscope image of Shewanella MR-1, and b is an electron microscope image of the iron-carbon material-cooperative Shewanella composite system;

[0025] Figure 2 CV curves of Shewanella, iron-carbon material and Shewanella composite system and composite system under different pollution systems;

[0026] Figure 3 Differential pulse voltammetry (DPV) of Shewanella, iron-carbon material-Shewanella composite system and composite system under different pollution systems;

[0027] Figure 4 The electrochemical impedance spectroscopy (EIS) of Shewanella, iron-carbon material and Shewanella composite system and composite system under different pollution systems;

[0028] Figure 5 This is the result diagram of the effect of FeO / C material dosage on Cr(VI) reduction rate;

[0029] Figure 6 This is the result graph showing the effect of FeO / C material dosage on malathion removal rate. DETAILED DESCRIPTION

[0030] The invention provides a composition for simultaneously removing compound pollution of organophosphorus pesticides and heavy metals. The composition comprises an iron-carbon material and Shewanella.

[0031] As an optional embodiment, the composition of the present invention also includes an inorganic salt culture solution. The inorganic salt culture solution of the present invention provides nutrients for the growth and reproduction of Shewanella, and promotes the growth of Shewanella to be loaded on the surface of the iron-carbon material. When the composition is in a packaged form or forms a composite system, the iron-carbon material and Shewanella are added to the degradable material respectively. While growing, Shewanella will also degrade malathion and Cr (VI) synchronously. While growing, Shewanella will form a biofilm on the surface. The formation of a biofilm is only more conducive to the degradation of organophosphorus pesticides and heavy metal composite pollution.

[0032] As an optional embodiment, when the components in the composition of the present invention are packaged separately, the iron-carbon material and Shewanella are packaged separately, and the iron-carbon material and Shewanella are added separately when used.

[0033] As another optional embodiment, the composition of the present invention forms a composite system, and the Shewanella in the composite system is loaded on the iron-carbon material. The loading method of the present invention includes the growth of the Shewanella on the surface of the iron-carbon material to form a biofilm. The culture solution is added during the loading of the present invention to promote the growth of Shewanella and load it on the surface of the iron-carbon material. Since the addition of the iron-carbon material leads to an increase in the types of redox substances in the composition and a decrease in the electron transfer resistance, the electron transfer speed can be increased, thereby accelerating the reduction of Cr(VI) and the degradation of malathion; the iron-carbon material can also provide bacteria with a suitable growth and reproduction space, and the Shewanella bacteria adhere to the surface of the iron-carbon material (recorded as FeO / C material) and grow into a biofilm, which effectively reduces the toxic effect of the combined pollution of malathion and Cr(VI) on the cells of Shewanella, promotes the secretion of extracellular polymeric substances, and also enhances the permeability of the cell membrane, promotes the simultaneous removal of the composite pollution by the composition, and has a high removal rate.

[0034] As an optional embodiment, the iron-carbon material of the present invention includes iron oxide and biochar; as another optional embodiment, the iron-carbon material of the present invention includes ferrous oxide and biochar: the preparation method of the iron-carbon material includes: first drying and cutting bamboo to obtain small pieces of bamboo; mixing the small pieces of bamboo with ammonia water and then boiling, washing and second drying in sequence to obtain treated small pieces of bamboo; mixing the treated small pieces of bamboo with ferric nitrate solution and then soaking; third drying and roasting the soaked bamboo, and grinding to obtain the iron-carbon material. As an optional embodiment, the bamboo of the present invention includes moso bamboo.

[0035] As an optional embodiment, the temperature of the first drying of the present invention can be 90-100°C, and can be 95°C. The insulation time can be 1-2d, and can be 1.5d. After the first drying of the present invention, the bamboo can be cut. In a specific embodiment of the present invention, the size of the cut bamboo can be 30mm×10mm×3mm.

[0036] As an optional embodiment, the volume concentration of the ammonia water of the present invention can be 4% to 6%, and can be 5%. As an optional embodiment, the temperature of the soaking of the present invention can be 95 to 100°C, and can be 100°C; the soaking time can be 5.5 to 6 hours, and can be 6 hours. The function of soaking is that soaking bamboo with ammonia water can soften the bamboo, increase the overall surface area of ​​the bamboo, and make it easier to load iron.

[0037] As an optional embodiment, after the soaking of the present invention, the bamboo obtained by soaking can be washed and dried for the second time to obtain small pieces of bamboo after treatment. As an optional embodiment, the washing water is ultrapure water. As an optional embodiment, the second drying is drying; the drying temperature is 70 to 80°C, and can be 80°C, and the drying time is 0.9 to 1 day, and can be 1 day. Drying after soaking can remove ammonia, dehydrate and dry, which is conducive to the preparation of subsequent materials.

[0038] As an optional embodiment, the present invention mixes the treated small pieces of bamboo with a ferric nitrate solution and then soaks them. The preparation method of the ferric nitrate solution of the present invention is: mixing ferric nitrate and an ethanol solution to obtain a ferric nitrate solution. The ethanol solution of the present invention includes ethanol and ultrapure water, and the volume ratio of the ethanol and ultrapure water is 1:1; the concentration of ferric nitrate in the ferric nitrate solution is 1.2 mol / L. The soaking temperature of the present invention is 55-65°C, and can be 60°C; the soaking can be carried out under water bath conditions; the soaking time is 4.5-5d, and can be 5d. The ferric nitrate solution of the present invention, as a precursor of iron-carbon material, can load iron ions on biochar.

[0039] As an optional embodiment, after the soaking described in the present invention, the bamboo obtained by soaking is subjected to a third drying and roasting; the third drying described in the present invention is oven drying; the drying temperature is 75-80°C, and can be 80°C, and the drying time is 18-24h, and can also be 21-24h, and can also be 24h.

[0040] As an optional embodiment, the roasting equipment of the present invention is a muffle furnace; the roasting temperature of the present invention is 595-600°C, and can be 600°C; the roasting time is 2.9-3h, and can be 3h.

[0041] As an optional embodiment, the present invention can grind and sieve the roasted product after cooling; the final temperature of the cooling can be room temperature; the target particle size of the grinding can be 2 to 3 mm, and can be 2.4 to 2.7 mm. The iron-carbon material is obtained after grinding in the present invention.

[0042] As an optional embodiment, an iron-carbon material is obtained. Since the iron-carbon material is a powder, it is not conducive to adding. Therefore, the iron-carbon material is fully hydrated, and the iron-carbon material is easy to add after being dissolved in water. As an optional embodiment, the hydrated medium is a culture solution. As an optional embodiment, the preparation method of the iron-carbon material suspension (i.e., FeO / C suspension) of the present invention may include: mixing the iron-carbon material with the culture solution to obtain the FeO / C suspension. The present invention does not specifically limit the volume ratio of the iron-carbon material to the culture solution, as long as the FeO / C suspension can be obtained, it is conducive to the addition of the iron-carbon material.

[0043] In the present invention, the culture solution may be an inorganic salt culture solution; the mass volume ratio of the iron-carbon material and the inorganic salt culture solution may be (0.9-1) g:100 mL. The inorganic salt culture solution of the present invention comprises: 0.5 g / L KH2PO4, 0.5 g / L K2HPO4, 2.5 g / L (NH4) SO4, 1.0 g / L Na2SO4, 0.1 g / L CaCl2, 1.0 g / LMgSO4, 10 g / L NaCl, 3.36 g / L sodium lactate and 1 mL / L trace element solution; the trace element solution comprises: 0.1 g / L Na2SeO4·2H2O, 1.0 g / L FeSO4, 0.05 g / L ZnCl2, 0.01 g / L NiCl2·6H2O, 0.015 g / L CuSO4·5H2O and 0.001 g / L H2MoO4·2H2O. The inorganic salt culture solution provides a growth environment and a required material basis for the Shewanella load.

[0044] As an optional embodiment, the mixing treatment of the iron-carbon material and the culture medium in the present invention can be performed by shaking and mixing, and the shaking treatment can include ultrasonic treatment and stirring in sequence; the ultrasonic treatment time can be 30 to 40 minutes, and can be 30 minutes; the ultrasonic temperature is room temperature, the ultrasonic power is 300w, and the ultrasonic frequency is 33khz; the stirring time is 24 to 36h, and can be 24h; there is no special limitation on the stirring speed parameters, and conventional parameters can be used.

[0045] The steps for obtaining the iron-carbon material suspension in the present invention are simpler and can be synthesized in large quantities without requiring expensive equipment and a large amount of labor and time, and is easier to promote.

[0046] The composite system of the present invention includes Shewanella. As an optional embodiment, the Shewanella of the present invention may include Shewanella MR-1, with the strain number of ATCC 700550; the Shewanella MR-1 of the present invention is purchased from the China Marine Microbial Culture Collection Center, and the Shewanella MR-1 is a Gram-negative bacterium that can achieve the simultaneous degradation of heavy metals and organophosphorus pesticides.

[0047] The present invention provides a method for preparing the composition described in the above technical solution, comprising:

[0048] The iron-carbon material suspension and the Shewanella suspension are mixed to obtain a composition.

[0049] As another optional embodiment, the preparation method of the composition of the present invention comprises: mixing the iron-carbon material with a first portion of an inorganic salt culture solution to obtain an iron-carbon material suspension; and mixing the iron-carbon material suspension, the Shewanella suspension, and a second portion of an inorganic salt culture solution to obtain a composition. The preparation method of the iron-carbon material suspension of the present invention has been discussed above and will not be repeated here.

[0050] As an optional embodiment, the preparation method of the Shewanella suspension of the present invention comprises: inoculating the Shewanella in a culture medium for culturing to obtain a culture solution; centrifuging the culture solution to obtain Shewanella cells; washing and resuspending the Shewanella cells to obtain a Shewanella suspension. The Shewanella of the present invention may be Shewanella MR-1. The technical features of the Shewanella MR-1 of the present invention have been discussed above and will not be repeated here.

[0051] As another optional embodiment, the present invention activates the frozen preservation solution of Shewanella to obtain a single colony; the present invention inoculates the single colony into a culture medium for culture to obtain a culture solution; the activation culture time of the present invention is 46 to 48 hours; the activation culture temperature is 30°C; the culture medium used for the activation culture includes LB solid culture medium; the composition of the LB solid culture medium includes 10.0 g / L tryptone, 5.0 g / L yeast extract powder, 10.0 g / L NaCl, and 15 to 20 g / L agar, the pH is adjusted to 7.0 to 7.2, and sterilized at 121°C for 30 minutes before use. The culture time of the present invention is 20 to 26 hours, and can further be 22 to 24 hours; the culture temperature is 28 to 32°C, and can further be 30 to 32°C; the culture speed is 150 to 180 r / min, and can also be 160 r / min. The culture medium used in the culture of the present invention is LB liquid culture medium. The LB liquid culture medium comprises 10.0 g / L tryptone, 5.0 g / L yeast extract and 10.0 g / L NaCl, the pH is adjusted to 7.0-7.2, and the medium is sterilized at 121° C. for 30 min before use.

[0052] The culture fluid is obtained, and the present invention centrifuges the culture fluid to obtain Shewanella cells; the Shewanella cells are washed and resuspended to obtain a Shewanella suspension. As another optional embodiment, the present invention has no special restrictions on the parameters of the centrifugation, washing and resuspension, and conventional methods can be used. In a specific embodiment of the present invention, the speed of the centrifugation is 6000 rpm and the time is 5 minutes. The solution used for washing and resuspension includes PBS buffer; the number of washing is 3 times.

[0053] As an optional embodiment, the present invention mixes the iron-carbon material suspension, the Shewanella MR-1 bacterial suspension and the second part of the inorganic salt culture solution to obtain a composition. The inoculation amount of the Shewanella MR-1 bacterial suspension of the present invention is 1% to 10% of the volume of the second part of the inorganic salt culture solution, or it can be 2% to 7%, or it can be 3% to 5%; based on the volume of the second part of the inorganic salt culture solution, the addition amount of the iron-carbon material suspension of the present invention is 0.05 to 1g / L, or it can be 0.1 to 0.5g / L, and it can be 0.1g / L. The composition of the inorganic salt culture solution has been discussed above and will not be repeated here.

[0054] As an optional embodiment, the present invention has no special limitation on the mixing parameters, and conventional methods can be used. After the iron-carbon material suspension, the Shewanella suspension and the inorganic salt culture solution are mixed, the Shewanella utilizes the culture solution to grow and reproduce, and forms a biofilm on the surface of the iron-carbon material.

[0055] The present invention provides a method for simultaneously removing compound pollution of organophosphorus pesticides and heavy metals, comprising: removing by mixing a composition with a to-be-degraded object; the to-be-degraded object contains compound pollution of organophosphorus pesticides and heavy metals; the composition is the composition described in the above technical solution or the composition prepared by the preparation method described in the above technical solution. As an optional embodiment, the organophosphorus pesticide of the present invention includes malathion; the heavy metal includes heavy metal ions, and the heavy metal ions include Cr(VI).

[0056] As an optional embodiment, the mass concentration of malathion in the material to be degraded of the present invention is 10 to 50 mg / L, or 20 to 40 mg / L.

[0057] As an optional implementation manner, the mass concentration of Cr(VI) in the material to be degraded of the present invention is 5 to 40 mg / L, or 10 to 30 mg / L.

[0058] As an optional embodiment, the removal method of the present invention may include degradation; the degradation temperature may be 30-40°C, or 35°C; the degradation time may be 12-96h, or 20-60h; in a specific embodiment of the present invention, the degradation time may be 12, 24, 28, 32, 44, 50, 68, 72, 78, 82, 88 or 92h. The pH value of the degradation of the present invention may be 7.

[0059] The present invention adds malathion and Cr(VI) to an inorganic salt culture solution to verify the degradation effect of the composition on malathion and Cr(VI). In a specific embodiment of the present invention, the inorganic salt culture solution contains malathion and Cr(VI), the inoculation amount of the Shewanella MR-1 bacterial suspension is 1% to 10% of the volume of the inorganic salt culture solution, can be 2% to 7%, and can also be 3% to 5%; the addition amount of the iron-carbon material suspension is 0.05 to 1 g / L, can be 0.1 to 0.2 g / L, and can also be 0.1 g / L.

[0060] The optimal removal rates of the composition of the present invention, i.e., the iron-carbon material and Shewanella composite system, for malathion and Cr(VI) are 93.98% and 64.93%, respectively, which are 1.17 times and 1.47 times that of single bacteria treatment.

[0061] In order to further illustrate the present invention, the technical solution provided by the present invention is described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0062] Example 1

[0063] 1. Preparation method of FeO / C suspension: First, the bamboo is dried at a temperature of 95°C for 1.5 days, and then cut into small pieces of bamboo with a size of 30 mm×10 mm×3 mm.

[0064] Then, the small piece of bamboo was soaked in ammonia water with a volume concentration of 5% and a soaking temperature of 100°C for 6 hours.

[0065] The bamboo obtained by soaking and boiling is washed and dried, the washing water is ultrapure water, the drying temperature is 80°C, and the time is 1 day.

[0066] The preparation method of the ferric nitrate solution is as follows: ferric nitrate and an ethanol-ultrapure water mixed solvent are mixed to obtain the ferric nitrate solution; the volume ratio of ethanol to ultrapure water in the ethanol-ultrapure water mixed solvent is 1:1; the concentration of the obtained ferric nitrate solution is 1.2 mol / L. The ferric nitrate solution is a precursor for preparing an iron-carbon material.

[0067] Then, the dried small pieces of bamboo are soaked in an iron nitrate solution at a temperature of 60°C; the soaking is carried out under water bath conditions, the soaking time is 5 days, and then it is dried at 80°C for 1 day, soaking first and then drying, soaking and drying in the iron nitrate solution for a total of 3 times, and then roasting at 600°C for 3 hours. The roasted product is cooled to room temperature and then ground and sieved to obtain FeO / C material (iron-carbon material); the target particle size of the grinding is 2.4-2.7 mm.

[0068] The ground FeO / C material was used to prepare a suspension: 1 g of FeO / C material was weighed and added into 100 mL of inorganic salt culture medium, and ultrasonic treatment was first performed for 30 min, and then stirring treatment was performed for 24 h to obtain an iron-carbon material suspension. The composition of the inorganic salt culture medium is 0.5g / LKH2PO4, 0.5g / LK2HPO4, 2.5g / L(NH4)SO4, 1.0g / LNa2SO4, 0.1g / L CaCl2, 1.0g / LMgSO4, 10g / LNaCl, 3.36g / L sodium lactate and 1mL / L trace element solution; the composition of the trace element solution is: 0.1g / LNa2SeO4·2H2O, 1.0g / LFeSO4, 0.05g / LZnCl2, 0.01g / LNiCl2·6H2O, 0.015g / L CuSO4·5H2O and 0.001g / LH2MoO4·2H2O.

[0069] 2. Preparation method of Shewanella oneidensis MR-1 (S. oneidensis MR-1) bacterial suspension: inoculate Shewanella MR-1 into LB solid culture medium plate and culture it in a 30°C biochemical incubator for 48 hours, then pick Shewanella MR-1 and inoculate it into LB liquid culture medium, the culture temperature is 30°C, the rotation speed is 160r / min, the culture time is 24 hours, and the culture solution is obtained; after the incubation, collect the bacteria by centrifugation at 6000rpm for 5min, and wash three times with PBS buffer to remove the culture medium residue. When resuspending, the mass volume ratio of the buffer solution and the Shewanella MR-1 bacteria is 1:1. Wash with PBS buffer and resuspend with inorganic salt culture solution. The OD of the Shewanella MR-1 resuspension is 600 = 1, and placed in a 4°C refrigerator for later use. The composition of the culture medium is 10.0 g / L tryptone, 5.0 g / L yeast extract powder and 10.0 g / L NaCl.

[0070] 3. The Shewanella MR-1 bacterial suspension is added to the inorganic salt culture solution at a volume ratio of 3% (v / v), and the FeO / C suspension is added to the inorganic salt culture solution at a volume ratio of 3% (v / v), that is, 3.33 mL of Shewanella MR-1 bacterial suspension and 3.33 mL of FeO / C suspension are added to 100 mL of inorganic salt culture solution to obtain an iron-carbon material synergistic Shewanella composite system, namely FeO / C@S.oneidensis MR-1, referred to as the composite system.

[0071] Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) was used to analyze the morphology and composition structure of FeO / C@S.oneidensisMR-1 and Shewanella MR-1.

[0072] Results Figure 1 , Figure 1 (a) is an electron micrograph of Shewanella MR-1; Figure 1 (b) is an electron microscope image of the iron-carbon material and Shewanella composite system. It can be seen that the cell structure of Shewanella MR-1 in (a) is intact and undamaged, and is a slender rod structure; (b) when the FeO / C material is introduced, Shewanella MR-1 will gather on the FeO / C material and grow into a biofilm, indicating that the material can provide a suitable growth and reproduction space for bacteria.

[0073] Example 2

[0074] This example is an optimization experiment of the iron-carbon material and Shewanella composite system to simultaneously remove the combined pollution of malathion and Cr(VI). The electrochemical characterization of the iron-carbon material and Shewanella composite system was observed to verify that the composite system can improve electron transfer in the process of removing the combined pollution, thereby accelerating the reduction of Cr(VI) and the degradation of malathion.

[0075] In order to explore whether the iron-carbon material synergistic Shewanella composite system can enhance the removal effect of malathion and Cr(VI) composite pollution by affecting electron transfer, the following experiments were conducted:

[0076] S.oneidensis MR-1 group (blank group): Add an appropriate amount of inorganic salt culture medium to a 250mL anaerobic bottle, and add 3% (v / v) S.oneidensis MR-1 cell suspension after centrifugation and washing. The inorganic salt culture medium and S.oneidensis MR-1 cell suspension constitute the reaction system, and the total volume of the reaction system is set to 100mL. After that, sterile N2 is introduced to remove oxygen in the system, and the anaerobic bottle is sealed and placed in a constant temperature shaker at 35°C for reaction. Take the supernatant for measurement at the 96th hour, purge it with N2 for 1 hour, and then transfer it to the anoxic electrochemical cell. Before each measurement, the electrochemical cell is purged with N2 for 15 minutes. Set up 3 parallel experiments.

[0077] FeO / C@S.oneidensis MR-1 group (control group): Add an appropriate amount of inorganic salt culture medium to a 250mL anaerobic bottle, then add 0.1g / L FeO / C suspension, and then add 3% (v / v) S.oneidensis MR-1 cell suspension after centrifugation and washing. The inorganic salt culture medium, FeO / C suspension and S.oneidensis MR-1 cell suspension constitute the reaction system. The total volume of the reaction system is set to 100mL. Sterile N2 is introduced to remove oxygen in the system, and the anaerobic bottle is sealed and placed in a constant temperature shaker at 35°C for reaction. Take the supernatant for measurement at the 96th hour, purge it with N2 for 1 hour, and then transfer it to the anoxic electrochemical cell. Before each measurement, the electrochemical cell is purged with N2 for 15 minutes. Set up 3 parallel experiments.

[0078] FeO / C@S.oneidensis MR-1+malathion group: Add an appropriate amount of inorganic salt culture medium to a 250mL anaerobic bottle, then add 0.1g / L FeO / C suspension, and then add 3% (v / v) S.oneidensis MR-1 cell suspension after centrifugation and washing, and set the concentrations of Cr(VI) and malathion in the system to 20mg / L and 10mg / L, respectively. The total volume of the inorganic salt culture medium, FeO / C suspension and S.oneidensis MR-1 cell suspension reaction system was set to 100mL reaction system, sterile N2 was introduced to remove oxygen in the system, and the reaction container was sealed and placed in a constant temperature shaker at 35℃ for reaction. The supernatant was taken for measurement at 96h, purged with N2 for 1h, and then transferred to an oxygen-deficient electrochemical cell. Before each measurement, the electrochemical cell was purged with N2 for 15min. Three parallel experiments were set up.

[0079] FeO / C@S.oneidensis MR-1+Cr(VI) group: Add an appropriate amount of inorganic salt culture medium to a 250mL anaerobic bottle, then add 0.1g / L FeO / C suspension, and then add 3% (v / v) S.oneidensis MR-1 cell suspension after centrifugation and washing, and set the concentrations of Cr(VI) and malathion in the system to 5mg / L and 30mg / L, respectively. The inorganic salt culture medium, FeO / C suspension and S.oneidensis MR-1 cell suspension constitute the reaction system, and the total volume of the reaction system is set to 100mL. Sterile N2 is introduced to remove oxygen in the system, and the reaction container is sealed and placed in a constant temperature shaker at 35℃ for reaction. Take the supernatant for measurement at the 96th hour, purge it with N2 for 1h, and then transfer it to the anoxic electrochemical cell. Before each measurement, the electrochemical cell is purged with N2 for 15min. Set up 3 parallel experiments.

[0080] The electrochemical methods of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were used to evaluate the removal efficiency of the combined pollution of malathion and Cr(VI) in the above four groups.

[0081] The CV curves of Shewanella, iron-carbon materials and Shewanella composite system and composite system under different pollution systems are shown in Figure 2. Figure 2 As shown, after the iron-carbon material was added to the culture system, its response current was larger than that of the S. oneidensis MR-1 single bacteria system and the composite system before degradation, and the area surrounded by the CV curve was also much larger than that of the single bacteria system without the addition of iron-carbon material.

[0082] After the introduction of iron-carbon materials, the composite system of different pollutants showed significant redox peaks. Specifically, the reduction peak potential (Er) was observed to be 0.11V (vs. SCE), while the oxidation peak potential (Eo) was -0.24V (vs. SCE). After the degradation reaction, the reduction current (ir) and oxidation current (io) in the composite system reached 25.80μA and 21.02μA, and -9.42μA and -8.52μA, respectively. This phenomenon of increased current peak effectively indicates the increase in redox substances, further indicating that the electron transfer efficiency has been significantly improved compared with the blank group and the control group.

[0083] The differential pulse voltammetry (DPV) curves of Shewanella, iron-carbon material and Shewanella composite system and composite system under different pollution systems are shown in Figure 3 It can be seen that the peak current in the DPV at -1 V also increased from 11.08 μA in the blank group to 16.28 μA and 16.32 μA in the experimental group. The increase in peak current indicates that the Fe(Ⅲ) released by the addition of FeO / C material improves the degradation ability of S. oneidensis MR-1, resulting in an accelerated electron transfer rate.

[0084] Electrochemical impedance spectroscopy (EIS) curves of Shewanella, iron-carbon material and Shewanella composite system and composite system under different pollution systems are shown in Figure 4 ,according to Figure 4 The EIS results show that compared with the blank control group, the arc amplitude in the control group and the experimental group with the addition of FeO / C material is significantly reduced. This phenomenon indicates that the resistance of electron transfer is reduced, thereby increasing the conductivity and significantly improving the electron transfer efficiency in the system.

[0085] Example 3

[0086] 1. Treatment 1: Add an appropriate amount of inorganic salt culture medium to a 250mL anaerobic bottle, then add 0.05g / L FeO / C suspension, and then add S.oneidensis MR-1 cell suspension. The cell suspension accounts for 3% (v / v) of the volume of the inorganic salt culture medium. The inorganic salt culture medium, FeO / C suspension, and S.oneidensis MR-1 cell suspension constitute a reaction system. The concentrations of Cr(VI) and malathion in the system are set to 20mg / L and 10mg / L, respectively, to investigate the reduction rate of Cr(VI). Set the total volume of the reaction system to 100mL, then pass sterile N2 to remove oxygen from the system, and seal the reaction container and place it in a constant temperature shaker at 35℃ for reaction. Take the supernatant at 96h to determine the concentration of Cr(VI). Set up 3 parallel experiments.

[0087] Treatment 2: Same as treatment 1, the only difference is the addition of 0.1 g / L FeO / C suspension; 3 parallel experiments were set up;

[0088] Treatment 3: Same as treatment 1, the only difference is the addition of 0.3 g / L FeO / C suspension; 3 parallel experiments were set up;

[0089] Treatment 4: Same as treatment 1, the only difference is the addition of 0.5 g / L FeO / C suspension; 3 parallel experiments were set up;

[0090] Treatment 5: Same as treatment 1, the only difference is the addition of 1g / L FeO / C suspension; 3 parallel experiments were set up;

[0091] Blank control group: Same as treatment 1, the only difference is that no FeO / C suspension is added; set up 3 parallel experiments.

[0092] The results of each treatment are shown in Figure 5 ,from Figure 5 It can be seen that the blank control group has only 44.18% Cr(VI) removal efficiency, and the addition of FeO / C materials can significantly improve the bacterial reduction efficiency of Cr(VI). As a dissimilatory iron-reducing bacterium, S. oneidensis MR-1 can convert Fe(III) in the system into Fe(II) under the co-metabolism environment provided by FeO / C materials. The generated Fe(II) can further reduce Cr(VI), ultimately achieving efficient removal of Cr(VI). With the increase of the dosage of FeC / O material, the removal rate of Cr(VI) shows a gradually decreasing trend. When the dosage of FeO / C is 0, 0.05, 0.1, 0.3, 0.5, 1 g / L, the reduction rate of Cr(VI) is 44.18%, 64.93%, 64.81%, 52.95%, 47.64%, 44.42%, respectively, indicating that the high concentration of FeO / C material has biological toxicity to bacteria, resulting in a decrease in the reduction of Cr(VI). The optimal removal rate of Cr(VI) by the iron-carbon material synergistic Shewanella composite system of the present invention is 64.93%, which is 1.47 times that of the single bacteria treatment.

[0093] 2. Treatment 6: Add an appropriate amount of inorganic salt culture medium to a 250mL anaerobic bottle, then add 0g / L, 0.05g / L, 0.1g / L, 0.3g / L, 0.5g / L and 1g / L FeO / C suspension, and then add S.oneidensis MR-1 cell suspension, the cell suspension accounts for 3% (v / v) of the inorganic salt culture medium, the inorganic salt culture medium, FeO / C suspension, S.oneidensis MR-1 cell suspension, Cr(VI) and malathion form a reaction system, and the concentrations of Cr(VI) and malathion in the system are set to 5mg / L and 30mg / L, respectively, to investigate the degradation rate of malathion. Set the total volume of the reaction system to 100mL, then pass sterile N2 to remove oxygen in the system, and seal the reaction container and place it in a constant temperature shaker at 35°C for reaction. Take the supernatant at 72h to determine the concentration of malathion. Three groups of parallel experiments were set up.

[0094] Treatment 7: Same as treatment 6, the only difference is the addition of 0.1 g / L FeO / C suspension; set up 3 parallel experiments.

[0095] Treatment 8: Same as treatment 6, the only difference is the addition of 0.3 g / L FeO / C suspension; set up 3 parallel experiments.

[0096] Treatment 9: Same as treatment 6, the only difference is the addition of 0.5 g / L FeO / C suspension; set up 3 parallel experiments.

[0097] Treatment 10: Same as treatment 6, the only difference is the addition of 1 g / L FeO / C suspension; set up 3 parallel experiments.

[0098] Blank control 2: Same as treatment 6, except that no FeO / C suspension was added; 3 parallel experiments were set up.

[0099] The results of the effects of the FeO / C material dosage on the malathion removal rate in the above treatment groups are shown in Figure 6 ,according to Figure 6 It can be seen that, similar to the effect of Cr(VI) removal, after 72 hours of treatment, it can be seen that when the amount of FeO / C material added increased from 0.05g / L to 1g / L, the degradation rate of malathion decreased from 93.98% to 80.57%, which means that the amount of FeO / C material added is not the more the better. A higher concentration of iron-carbon material will agglomerate, resulting in a reduction in the available sites and surface functional groups for the reduction reaction, while limiting the electron transfer between bacteria and iron-carbon materials, thereby weakening the degradation ability of malathion. The optimal removal rate of malathion by the iron-carbon material and Shewanella composite system of the present invention is 93.98%, which is 1.17 times that of the single bacteria treatment.

[0100] 3. Treatment 11 (composite system): Add an appropriate amount of inorganic salt culture medium to a 250mL anaerobic bottle, then add 0.1g / L FeO / C suspension, and then add S.oneidensis MR-1 cell suspension. The cell suspension accounts for 1% (v / v) of the volume of the inorganic salt culture medium. The inorganic salt culture medium, FeO / C suspension, and S.oneidensis MR-1 cell suspension constitute a reaction system. The concentrations of Cr(VI) and malathion in the system are set to 20mg / L and 10mg / L, respectively, to investigate the reduction rate of Cr(VI). The total volume of the reaction system is set to 100mL, and then sterile N2 is introduced to remove oxygen from the system. The reaction container is sealed and placed in a constant temperature shaker at 35°C for reaction. Take the supernatant at 96h to determine the concentration of Cr(VI). Set up 3 parallel experiments.

[0101] Treatment 12 (composite system): Same as treatment 11, the only difference is that the volume of S. oneidensis MR-1 cell suspension in the inorganic salt culture medium is 3% (v / v), and three parallel experiments are set up.

[0102] Treatment 13 (composite system): Same as treatment 11, the only difference being that the cell suspension of S. oneidensis MR-1 accounts for 5% (v / v) of the volume of the inorganic salt culture medium, and three parallel experiments are set up.

[0103] Treatment 14 (composite system): Same as treatment 11, the only difference being that the cell suspension of S. oneidensis MR-1 accounts for 7% (v / v) of the volume of the inorganic salt culture medium, and three parallel experiments are set up.

[0104] Treatment 15 (composite system): Same as treatment 11, the only difference being that the volume of the S. oneidensis MR-1 cell suspension in the inorganic salt culture medium was 10% (v / v), and three parallel experiments were set up.

[0105] Blank control 3-1 (single system): Same as treatment 11, except that no FeO / C suspension was added; only S. oneidensis MR-1 cell suspension was added, and the volume of the cell suspension in the inorganic salt culture medium was 1% (v / v). Three parallel experiments were set up.

[0106] Blank control 3-2 (single system): Same as treatment 11, except that no FeO / C suspension was added; only S. oneidensis MR-1 cell suspension was added, and the volume of the cell suspension in the inorganic salt culture medium was 3% (v / v). Three parallel experiments were set up.

[0107] Blank control 3-3 (single system): Same as treatment 11, except that no FeO / C suspension was added; only S. oneidensis MR-1 cell suspension was added, and the volume of the cell suspension in the inorganic salt culture medium was 5% (v / v). Three parallel experiments were set up.

[0108] Blank control 3-4 (single system): Same as treatment 11, except that no FeO / C suspension was added; only S. oneidensis MR-1 cell suspension was added, and the volume of the cell suspension in the inorganic salt culture medium was 7% (v / v). Three parallel experiments were set up.

[0109] Blank control 3-5 (single system): Same as treatment 11, the only difference is that no FeO / C suspension was added; only S. oneidensis MR-1 cell suspension was added, and the volume of the cell suspension in the inorganic salt culture medium was 1% (v / v), 3% (v / v), 5% (v / v), 7% (v / v), and 10% (v / v), respectively. Three parallel experiments were set up.

[0110] After 96 hours of treatment, when the initial concentration was 20 mg / L Cr(VI), the Cr(VI) reduction rates of blank controls 3-1 to 3-5 were 39.64%, 47.65%, 50.73%, 51.71%, and 53.94%, respectively, and the Cr(VI) reduction rates of the composite systems of treatments 11 to 15 were 58.75%, 63.70%, 64.31%, 66.54%, and 70.86%, respectively.

[0111] After 72h treatment, as the inoculation amount increased from 1% to 10%, when the initial concentration was 30mg / L malathion, the degradation rate of blank controls 3-1 to 3-5 with an initial concentration of 30mg / L malathion increased from 81.21% to 95.40%, and the degradation rate of the composite system for malathion increased from 79.52% to 95.86% (the degradation rate of malathion was 95.86% when the inoculation amount was 3%). The degradation rate of MR-1 cell suspension inoculation amount changed slightly between 3% and 10%. Comprehensively considered, the inoculation amount of S. oneidensis MR-1 cell suspension of 3% had the best effect.

[0112] Example 4 Optimization of conditions for simultaneous removal of malathion / Cr(VI) by a composite system based on response surface methodology

[0113] 1. Establish regression model and variance analysis

[0114] Based on the single factor degradation test of composite pollution conditions, three factors (pH, dosage, inoculation amount) were selected, and the optimal degradation conditions for removing malathion / Cr (VI) composite pollutants in the composite pollution degradation system were obtained by response surface analysis. The inoculation amount of MR-1 bacterial suspension in Table 1 and Table 2, -1, 0 and 1, respectively represent 1%, 3% and 5%; the dosage of iron-carbon material suspension, -1, 0 and 1, respectively represent 0.05g / L, 0.1g / L, 0.3g / L, and the pH of -1, 0 and 1 represent 6, 7, 8, respectively. Table 1 and Table 2 are the experimental design and results of reduction rate, degradation rate and inoculation amount (A), dosage (B), pH (C), and the binary regression equations of the reduction rate D1 and D2 of each factor in the composite system are obtained as follows:

[0115] D1=-243.84+10.54A+122.71B+81.71C+-20.25AB+0.5096AC+16.31BC-1.53A 2

[0116] -444.56B 2 -6.24C 2

[0117] D2=-486.69+27.20A+235.04B+148.24C+30.29AB-1.4114AC-25.47BC-3.229A 2

[0118] -397.34B 2 -10.1C 2

[0119] Table 1 Experimental design and results of Cr(VI) reduction rate, inoculation amount, dosage, and pH

[0120]

[0121]

[0122] Table 2 Experimental design and results of malathion degradation rate, inoculation amount, dosage, and pH

[0123]

[0124]

[0125] It can be seen from the regression equation variance analysis table in Table 3 that the p value of the D1 regression model is less than 0.05, indicating that the modified quadratic model is statistically significant. The lack of fit value is 0.1732>0.05, indicating that the insignificance meets the requirements and can be used for further research to provide reliable predictions for the experiment of reducing Cr(VI) by the composite system. The size of the F value will affect the degree of interaction between the various factors in the regression model. The larger the F value, the more significant the impact. The influence of each factor on the reduction rate in the table is from large to small, in order: MR-1 bacterial suspension inoculation amount, FeO / C material suspension dosage, pH; the quadratic term A 2 , B 2 and C 2 All of them were significant; the interaction term AB reached a significant level, while BC and AC were not significant.

[0126] Table 3 Analysis of variance of Cr(VI) reduction rate

[0127] Sources of variance sum of squares Degrees of Freedom Mean Square F-number p-value Significance Regression Model 836.73 9 92.97 8.11 0.0058 Significant A-Inoculum size 62.56 1 62.56 5.46 0.0521 B-Dosage 52.63 1 52.63 4.59 0.0694 C-pH 12.51 1 12.51 1.09 0.3308 AB 102.48 1 102.48 8.94 0.0202 AC 4.15 1 4.15 0.3624 0.5662 BC 16.62 1 16.62 1.45 0.2677 <![CDATA[A 2 ]]> 157.31 1 157.31 13.72 0.0076 <![CDATA[B 2 ]]> 203.16 1 203.16 17.72 0.0040 <![CDATA[C 2 ]]> 163.90 1 163.90 14.30 0.0069 Residual 80.25 7 11.46 Lack of Fit 54.32 3 18.11 2.79 0.1732 Not significant Net Error 25.93 4 6.48 Total Difference 916.98 16

[0128] As can be seen from Table 4, the p value of the D2 regression equation model is 0.0035, indicating that the regression model is suitable for this experiment. In this case, the inoculation amount of MR-1 bacterial suspension (A), the dosage of FeO / C material suspension (B), and pH (C) are important model terms. The value of the determination coefficient (the determination coefficient of malathion degradation rate R 2 =0.9249) is an indicator of model fit, which indicates that there is a high correlation between the observed and predicted values. In this study, the lack of fit term (F value is 1.38, p value is 0.3694) shows that the quadratic model is effective for predicting any combination of independent factors. Therefore, this model can reflect the relationship between inoculum size, dosage, pH value and the degradation capacity of the composite system, and can better predict the degradation activity of the composite system on malathion.

[0129] Table 4 Analysis of variance of malathion degradation rate

[0130] Sources of variance sum of squares Degrees of Freedom Mean Square F-number p-value Significance Regression Model 2104.90 9 233.88 9.57 0.0035 Significant A-Inoculation volume 335.66 1 335.66 13.74 0.0076 B-Dosage 9.09 1 9.09 0.3719 0.5613 C-pH 27.53 1 27.53 1.13 0.3237 AB 229.30 1 229.30 9.39 0.0182 AC 31.87 1 31.87 1.30 0.2909 BC 40.55 1 40.55 1.66 0.2386 <![CDATA[A 2 ]]> 702.80 1 702.80 28.77 0.0010 <![CDATA[B 2 ]]> 162.30 1 162.30 6.64 0.0366 <![CDATA[C 2 ]]> 429.52 1 429.52 17.58 0.0041 Residual 171.03 7 24.43 Lack of Fit 87.05 3 29.02 1.38 0.3694 Not significant Net Error 83.98 4 20.99 Total Difference 2275.93 16

[0131] In summary, Shewanella cells can adhere to the surface of FeO / C materials and grow into biofilms, which can promote the simultaneous removal of malathion and Cr(VI) composite pollution by the composite system. The method for simultaneously removing malathion and Cr(VI) composite pollution by the composite system provided by the present invention is feasible, and the composite system has a high removal rate for malathion and Cr(VI) composite pollution.

[0132] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A composition for simultaneously removing organophosphorus pesticide and heavy metal composite pollution, characterized in that: The composition includes a ferro-carbon material and Shewanella bacteria.

2. The composition according to claim 1, characterized in that The composition also includes an inorganic salt culture solution.

3. The composition according to claim 1 or 2, characterized in that The components in the composition are packaged or form a composite system; in the composite system, the Shewanella is loaded on the iron-carbon material; the loading method includes the Shewanella growing on the surface of the iron-carbon material to form a biofilm.

4. The composition according to claim 1, characterized in that The Shewanella includes Shewanella MR-1, and the strain number is ATCC 700550.

5. The method for preparing the composition according to any one of claims 1 to 4, characterized in that: include: The iron-carbon material suspension and the Shewanella suspension are mixed to obtain a composition.

6. The preparation method according to claim 5, characterized in that: The preparation method of the composition comprises: mixing the iron-carbon material with a first part of an inorganic salt culture solution to obtain an iron-carbon material suspension; mixing the iron-carbon material suspension, the Shewanella suspension and a second part of an inorganic salt culture solution to obtain a composition; The inoculation amount of the Shewanella suspension is 1% to 10% of the volume of the second part of the inorganic salt culture solution; based on the volume of the second part of the inorganic salt culture solution, the addition amount of the iron-carbon material suspension is 0.05 to 1 g / L.

7. The preparation method according to claim 5, characterized in that: The first part of the inorganic salt culture solution and the second part of the inorganic salt culture solution respectively include: 0.5g / LKH2PO4, 0.5g / LK2HPO4, 2.5g / L(NH4)SO4, 1.0g / LNa2SO4, 0.1g / L CaCl2, 1.0g / LMgSO4, 10g / LNaCl, 3.36g / L sodium lactate and 1mL / L trace element solution; The trace element liquid comprises: 0.1 g / L Na2SeO4·2H2O, 1.0 g / L FeSO4, 0.05 g / L ZnCl2, 0.01 g / L NiCl2·6H2O, 0.015 g / L CuSO4·5H2O and 0.001 g / L H2MoO4·2H2O.

8. A method for simultaneously removing compound pollution of organophosphorus pesticides and heavy metals, characterized in that: include: The composition is mixed with a to-be-degraded object for removal; the to-be-degraded object contains compound pollution of organophosphorus pesticides and heavy metals; The composition is the composition according to any one of claims 1 to 4 or the composition prepared by the preparation method according to any one of claims 5 to 7.

9. The method according to claim 8, characterized in that The organophosphorus pesticide includes malathion; the heavy metal includes heavy metal ions, and the heavy metal ions include Cr(VI). The mass concentration of malathion in the product to be degraded is 10 to 50 mg / L; the mass concentration range of Cr(VI) in the product to be degraded is 5 to 40 mg / L.

10. The method according to claim 8, characterized in that The removal method includes degradation; the degradation temperature is 35° C.; the degradation time is 12 to 96 hours; and the degradation pH value is 7.

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