Iron-doped manganese oxide biological agent as well as preparation method and application thereof

Abstract

The invention provides an iron-doped manganese oxide biological agent as well as a preparation method and application thereof, and the preparation method of the iron-doped manganese oxide biological agent comprises the following steps: carrying out thallium tolerance domestication on manganese oxidizing bacteria to obtain high-thallium-tolerance manganese oxidizing bacteria; the method comprises the following steps: inoculating high-thallium-tolerance manganese-oxidizing bacteria into a first culture medium comprising divalent manganese ions, and carrying out oxidation reaction on the divalent manganese ions under the mediation of the high-thallium-tolerance manganese-oxidizing bacteria for 0-48 hours; iron ions are doped into the first culture medium, and an iron-doped manganese oxide biological agent is prepared through a mineralization reaction; wherein the time of the mineralization reaction is 12-36 hours, and the molar ratio of the iron ions to the divalent manganese ions is 0.2: 100. The iron-doped manganese oxide biological agent provided by the invention has the characteristics of simplicity in operation, low cost, good thallium immobilization effect, high thallium immobilization stability and the like, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and particularly relates to a preparation method and application of an iron-doped manganese oxide biological preparation. Background Art

[0002] Thallium (Tl) is one of the most toxic and hazardous heavy metals and has been listed as a priority metal pollutant in many countries. In water, thallium exists primarily in two forms: Tl(I) and Tl(III). Tl(I) is the dominant species in aquatic environments, highly mobile and difficult to remove. Tl(III) is unstable in water and easily hydrolyzes, forming precipitation. Thallium pollution has attracted widespread public attention worldwide. With the booming development of thallium-related mining activities, the widespread use of thallium in chemical plants, and the growing demand for thallium in high-tech industries, the risk of thallium release and environmental exposure has gradually increased. In recent years, with the increase in thallium pollution incidents and the in-depth study of thallium toxicity, people have gradually strengthened their attention to the environmental chemical behavior of thallium and thallium pollution control technologies.

[0003] Among commonly used technologies, chemical methods for treating thallium pollution primarily include precipitation, ion exchange, redox, and adsorption. With the continuous development of the industry, the shortcomings of these more traditional thallium pollution treatment technologies have become increasingly apparent. Specifically, chemical precipitation consumes large amounts of chemicals, easily generating difficult-to-treat waste and causing secondary pollution. Electrochemical precipitation requires electricity, resulting in high costs, limited applicability, and high water quality requirements. Ion exchange, for wastewater containing higher concentrations of thallium, requires frequent replacement or regeneration of resin, resulting in high resin consumption and poor economic benefits. The oxidants used in oxidation often cause secondary pollution.

[0004] Based on the above, it is necessary to provide a preparation method of an iron-doped manganese oxide biological agent and its application to alleviate or solve the above problems. Summary of the Invention

[0005] In order to solve the technical problems of poor thallium stabilization effect and easy secondary pollution in the above-mentioned common technologies, the present invention provides a method for preparing an iron-doped manganese oxide biological agent, comprising the steps of:

[0006] The manganese oxidizing bacteria are acclimated to thallium tolerance to obtain high thallium tolerant manganese oxidizing bacteria;

[0007] The high thallium-tolerant manganese-oxidizing bacteria are inoculated into a first culture medium composed of divalent manganese ions, and the divalent manganese ions are oxidized under the mediation of the high thallium-tolerant manganese-oxidizing bacteria to generate Mn 3+ and / or Mn 4+ ;

[0008] Iron ions are added to the first culture medium, and an iron-doped manganese oxide biological preparation is prepared through a mineralization reaction; wherein the molar ratio of the iron ions to the divalent manganese ions is 0.1 to 1:100.

[0009] Furthermore, the manganese oxidizing bacteria include the model bacteria Pseudomonas putida Mn B1.

[0010] Furthermore, the thallium tolerance acclimation includes the steps of:

[0011] Second culture media with different thallium concentration gradients are respectively prepared, wherein the monovalent thallium concentration gradients in the second culture media include 0, 0.01±0.001, 0.1±0.01, 0.5±0.1, 1±0.1, 5±1, 10±1, and 15±1 mg / L;

[0012] The manganese oxidizing bacteria are cultured in sequence according to the thallium ion concentration in the second culture medium from high to low to obtain the high thallium-tolerant manganese oxidizing bacteria.

[0013] Furthermore, the duration of the oxidation reaction is 0 to 36 hours, and the duration of the mineralization reaction is 12 to 36 hours.

[0014] Furthermore, before the step of inoculating the high-thallium-tolerant manganese oxidizing bacteria into the first culture medium composed of divalent manganese ions, the high-thallium-tolerant manganese oxidizing bacteria are activated, including the steps of placing the high-thallium-tolerant manganese oxidizing bacteria in a third culture medium for activation and culture to obtain an activated bacterial liquid, wherein the OD600 of the high-thallium-tolerant manganese oxidizing bacteria in the activated bacterial liquid is 0.8 to 1.0, and the volume ratio of the activated bacterial liquid to the first culture medium is 1 to 3:100.

[0015] Furthermore, the composition of the third culture medium includes: acid hydrolyzed casein, yeast extract powder, MgSO4, HEPES, CuSO4, and glucose, and the pH of the third culture medium is 6.9-7.1;

[0016] The first culture medium comprises acid hydrolyzed casein, yeast extract, MgSO4, HEPES, CuSO4, and divalent manganese ions. The pH of the first culture medium is 6.9-7.1, and the concentration of divalent manganese ions in the first culture medium is 80-120 mg / L.

[0017] Furthermore, in the step of adding iron ions to the first culture medium to prepare the iron-doped manganese oxide biological agent through a mineralization reaction, the molar ratio of the iron ions to the divalent manganese ions is 0.1 to 0.3:100.

[0018] Furthermore, the divalent manganese ions include divalent manganese in manganese sulfate, the iron ions include iron ions in FeCl3·6H2O, and the thallium ions include thallium ions in TlNO3.

[0019] The present invention provides an iron-doped manganese oxide biological preparation, which is prepared by any of the above methods for preparing the iron-doped manganese oxide biological preparation.

[0020] The present invention also provides an application of the iron-doped manganese oxide biological preparation as described above in thallium treatment, comprising the steps of: mixing the iron-doped manganese oxide biological preparation with thallium-containing wastewater, wherein the volume mass ratio of the iron-doped manganese oxide biological preparation to thallium in the thallium-containing wastewater is 100 mL: 1 mg to 1500 mg; and the thallium concentration in the thallium-containing wastewater is 0.1 mg / L-15 mg / L.

[0021] Compared with the prior art, the present invention has at least the following advantages:

[0022] The present invention provides a method for preparing an iron-doped manganese oxide biological agent. The prepared iron-doped manganese oxide biological agent has a dual thallium fixation mechanism - oxidation precipitation of thallium: Mn in the biological agent (i.e., the abbreviation of iron-doped manganese oxide biological agent, the same below) 4+ / Mn 3+ Manganese ore mainly oxidizes Tl(I) to Tl(III), forming Tl2O3 precipitation, which is deposited on the surface of the biological agent; non-oxidized solid thallium: thallium is fixed on the surface of the biological agent in the form of adsorption and complexation, Tl + Can replace H(Mn-OH+Tl + =Mn-O-Tl+H + Utilizing the dual thallium-fixing mechanism, biological agents can carry out targeted treatment of thallium-containing wastewater with a wide range of concentrations. Specifically, low-concentration thallium-containing wastewater oxidizes and precipitates thallium, while high-concentration thallium-containing wastewater fixes thallium non-oxidatively.

[0023] The biological preparation of the present invention includes high thallium-tolerant manganese-oxidizing bacteria, which helps to promote the cyclic oxidation of divalent manganese in the biological preparation system and enhances the thallium-fixing effect and stability of the biological preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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 only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0025] Figure 1This is a schematic diagram of the tolerance of the strain to different concentrations of thallium after thallium tolerance acclimation in Example 1 of the present invention;

[0026] Figure 2 Schematic diagram of the removal effect of the preparation on thallium (0.5 mg / L) at different Fe(III) doping levels in Example 2 of the present invention;

[0027] Figure 3 Schematic diagram of the removal effect of thallium (0.5 mg / L) by a preparation having an iron-manganese molar ratio of 0.2% at different Fe(III) doping times in Example 3 of the present invention;

[0028] Figure 4 This is a SEM-EDS characterization image of the main material of the biological preparation in Example 4 of the present invention;

[0029] Figure 5 This is the XRD characterization diagram of the main material of the biological preparation in Example 4 of the present invention;

[0030] Figure 6 The removal effect of the biological agent in Example 5 of the present invention on different concentrations of thallium;

[0031] Figure 7 Schematic diagram of thallium leaching concentration and leaching rate using the standard toxicity leaching method (TCLP) after thallium solidification in Example 6 of the present invention;

[0032] Figure 8 (a) is the mineral Mn2p fitting result after the strain MnB1 in the iron-doped biological manganese oxide biological preparation survives in Example 7 of the present invention, Figure 8 (b) is the mineral Mn 2p fitting result after thallium is fixed in the freeze-dried mineral material in the inactivated state of the strain MnB1 in the iron-doped biological manganese oxide biological preparation in Example 7 of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described 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 making any creative efforts are within the scope of protection of the present invention.

[0034] Moreover, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those in the examples of the present invention may also be used to implement the present invention.

[0036] The present invention provides a method for preparing an iron-doped manganese oxide biological agent, comprising the steps of:

[0037] S1. Acclimating manganese oxidizing bacteria to tolerate thallium to obtain highly thallium tolerant manganese oxidizing bacteria.

[0038] The manganese oxidizing bacteria used in the present invention is the model bacteria Pseudomonas putida MnB1, which is purchased from the American Type Culture Collection with the accession number of ATCC 23483.

[0039] In the present invention, thallium tolerance acclimation may include the steps of:

[0040] S11. Prepare second culture media with different thallium concentration gradients respectively, wherein the monovalent thallium concentration gradients in the second culture media include 0, 0.01, 0.1, 0.5, 1, 5, 10, and 15 mg / L.

[0041] In some embodiments, the composition of the second culture medium may include 1 g / L anhydrous glucose, 0.5 g / L acid hydrolyzed casein, 0.5 g / L yeast extract, 0.8 g / L MgSO4, 1.38 g / L HEPES, 1 μg / LCuSO4 and corresponding concentrations of thallium ions; the pH of the second culture medium may be 7.

[0042] In some embodiments, the thallium ions in the second culture medium are monovalent thallium ions, and the thallium ions can be thallium ions in TlN O3.

[0043] S12. The manganese oxidizing bacteria are cultured sequentially according to the thallium ion concentration in the second culture medium from high to low to obtain the high thallium-tolerant manganese oxidizing bacteria.

[0044] In some embodiments, the volume ratio of the manganese oxidizing bacteria to the second culture medium is 1-3 mL:100 mL.

[0045] In some specific embodiments, step S1 may include the steps of preparing a second culture medium with a thallium concentration gradient of 0, 0.01, 0.1, 0.5, 1, 5, 10, and 15 mg / L, inoculating manganese oxidizing bacteria into the second culture medium with thallium concentrations from high to low in sequence, culturing in a shaker at a constant temperature of 26°C and a constant speed of 170 rpm, regularly sampling and testing the growth and development activity of the strain, and after the manganese oxidizing bacteria are expanded from a low concentration to a high concentration, obtaining high thallium-tolerant manganese oxidizing bacteria, which are stored at a low temperature of -80°C for future use.

[0046] S2. inoculating the high thallium-tolerant manganese-oxidizing bacteria into a first culture medium composed of divalent manganese ions, wherein the divalent manganese ions are oxidized under the mediation of the high thallium-tolerant manganese-oxidizing bacteria to generate Mn 3+ and / or Mn 4+ .

[0047] In the present invention, divalent manganese ions are oxidized to obtain Mn 4+ / Mn 3+ The mixed manganese ore has a crystal form of weakly crystalline δ-MnO2.

[0048] In the present invention, the duration of the oxidation reaction is 0 to 36 hours. In some specific embodiments, the duration of the oxidation reaction can be 10 to 14 hours; in some more specific embodiments, the duration of the oxidation reaction can be 12 hours.

[0049] In the present invention, before the step of inoculating the high-thallium-tolerant manganese oxidizing bacteria into a first culture medium composed of divalent manganese ions, the high-thallium-tolerant manganese oxidizing bacteria are activated, including the steps of placing the high-thallium-tolerant manganese oxidizing bacteria in a third culture medium for activation culture to obtain an activated bacterial liquid, wherein the OD600 of the high-thallium-tolerant manganese oxidizing bacteria in the activated bacterial liquid is 0.8, and the volume ratio of the activated bacterial liquid to the first culture medium is 1 to 3:100.

[0050] In the present invention, the volume ratio of the high thallium-tolerant manganese oxidizing bacteria to the third culture medium may be 1 to 5:100.

[0051] In some embodiments, the composition of the third culture medium includes: acid hydrolyzed casein, yeast extract, MgSO4, HEPES, CuSO4, and glucose; in some more specific embodiments, the composition of the third culture medium includes: 0.5 g / L acid hydrolyzed casein, 0.5 g / L yeast extract, 0.8 g / L MgSO4, 1.38

[0052] g / L HEPES, 1μg / L CuSO4, 1g / L glucose.

[0053] In some embodiments, the pH of the third culture medium is 6.9-7.1.

[0054] In some specific embodiments of the present invention, activation of high-thallium-tolerant manganese-oxidizing bacteria comprises the steps of preparing 100 mL of an ion culture medium containing 0.5 g / L acid-hydrolyzed casein, 0.5 g / L yeast extract, 0.8 g / L MgSO4, 1.38 g / L HEPES, and 1 μg / L CuSO4, adjusting the pH to 7.0, sterilizing the culture medium at 121° C. in an autoclave for 45 min, and adding 1 g / L of glucose after the culture medium has cooled and sterilized by filtration using a 0.22 μm filter to obtain a third culture medium. 1 mL of a high-thallium-tolerant manganese-oxidizing bacteria culture medium stored at -80° C. is inoculated into the third culture medium, and the culture medium is placed in a shaker maintained at a constant temperature of 26° C. and a constant speed of 170 rpm, and incubated until OD600 = 0.8, thereby completing activation and obtaining an activated culture medium.

[0055] In some embodiments of the present invention, the first culture medium comprises acid-hydrolyzed casein, yeast extract, MgSO₄, HEPES, CuSO₄, and divalent manganese ions, wherein the concentration of divalent manganese ions in the first culture medium is 80-120 mg / L. In more specific embodiments, the first culture medium comprises 1 g / L anhydrous glucose, 0.5 g / L acid-hydrolyzed casein, 0.5 g / L yeast extract, 0.8 g / L MgSO₄, 1.38 g / L HEPES, 1 μg / L CuSO₄, and 100 mg / L divalent manganese ions; and the pH of the first culture medium may be 7.

[0056] In some embodiments, the divalent manganese ion may be a divalent manganese ion in manganese sulfate.

[0057] S3. Adding iron ions to the first culture medium to produce an iron-doped manganese oxide biological agent through a mineralization reaction; wherein the mineralization reaction lasts for 12 to 36 hours.

[0058] In some embodiments, the iron ions may be iron ions in FeCl 3 ·6H 2 O.

[0059] In some embodiments, the molar ratio of the iron ions to the divalent manganese ions is 0.1 to 1:100; in some specific embodiments, the molar ratio of the iron ions to the divalent manganese ions is 0.1 to 0.3:100; in some more specific embodiments, the molar ratio of the iron ions to the divalent manganese ions is 0.2 to 100. It should be noted that the divalent manganese ions herein are the divalent manganese ions in the first culture medium in step S1 before the oxidation reaction, and not the divalent manganese ions in the first culture medium after the oxidation reaction in step S2.

[0060] By controlling the molar ratio of iron ions and divalent manganese ions, the appropriate amount of iron ion doping can improve the Mn oxidation ability of manganese oxidizing bacteria MnB1. The interaction between iron ions and manganese ore increases the surface area of the mineral, providing more abundant reaction active sites.

[0061] In some specific embodiments, steps S2 and S3 may include the steps of placing the activated high-thallium-tolerant manganese oxidizing bacteria in a shaker at a constant temperature of 26°C and a constant speed of 170 rpm for incubation, and the oxidation of Mn(II) occurs synchronously with the expansion of the strain. After 12 hours of oxidation reaction, Fe(III) with an iron-manganese molar ratio of 0.2:100 is added to the first culture medium, and further mineralization is carried out for 24 hours to obtain an iron-doped biological manganese oxide biological preparation that can be used to fix thallium.

[0062] The present invention provides an iron-doped manganese oxide biological preparation, which is prepared by any of the above methods for preparing the iron-doped manganese oxide biological preparation.

[0063] The present invention provides an application of the iron-doped manganese oxide biological preparation as described above in thallium treatment, comprising the steps of: mixing the iron-doped manganese oxide biological preparation with thallium-containing wastewater, wherein the volume mass ratio of the iron-doped manganese oxide biological preparation to thallium in the thallium-containing wastewater is 100 mL: 1 mg to 1500 mg.

[0064] In some embodiments, the thallium concentration in the thallium-containing wastewater is 0.1 mg / L-15 mg / L. The thallium concentration gradient is only the experimental range provided by the present invention, and is not the limit range of thallium removal of the preparation.

[0065] The present invention reveals for the first time the enhanced effect of iron doping on thallium fixation in a biological manganese oxide system. The specific implementation method of the present invention is to, under the mediation of manganese oxidizing bacteria, oxidize Mn(II) to generate biological manganese oxide within 0-12 hours, dope Fe(III) at a 0.2% iron-manganese molar ratio to form an iron-doped biological manganese oxide preparation in a live bacteria system, and then introduce thallium-containing wastewater into the preparation or add an appropriate amount of the preparation into thallium-containing wastewater to achieve the effect of wastewater thallium fixation. Specific experimental results have verified that the preparation provided by the present invention has a thallium fixation rate of more than 90% for wastewater containing 0.1mg / L-15mg / L of thallium. The preparation provided by the present invention has the characteristics of simple operation, low cost, good thallium fixation effect and high thallium fixation stability, and has broad application prospects.

[0066] In order to facilitate those skilled in the art to further understand the present invention, examples are given below:

[0067] It should be noted that the growth and development activity of the strains in the following experiments was measured by measuring the absorbance of the bacterial solution at 600 nm using a UV spectrophotometer. Changes in thallium concentrations were measured by ICP-MS / OES. The thallium-containing wastewater used in the experiments was obtained by dissolving TlNO3 in pure water under laboratory conditions.

[0068] Example 1

[0069] A second culture medium with a thallium concentration gradient of 0, 0.01, 0.1, 0.5, 1, 5, 10, and 15 mg / L is prepared, and manganese oxidizing bacteria are sequentially inoculated into the second culture medium with decreasing thallium concentrations. The culture is maintained at a constant temperature of 26°C and a constant speed of 170 rpm in a shaking incubator. Sampling is performed periodically to test the growth and development activity of the strain. After the manganese oxidizing bacteria are expanded from a low concentration to a high concentration (OD600 value = 0.8-1.0), high-thallium-tolerant manganese oxidizing bacteria are obtained and stored at -80°C for future use. The second culture medium comprises 1 g / L anhydrous glucose, 0.5 g / L acid-hydrolyzed casein, 0.5 g / L yeast extract, 0.8 g / L MgSO4, 1.38 g / L HEPES, 1 μg / L CuSO4, and the corresponding concentrations of thallium ions. The pH of the second culture medium is 7.

[0070] The invention activates high-thallium-tolerant manganese oxidizing bacteria, comprising the steps of preparing 100 mL of an ion culture medium containing 0.5 g / L acid hydrolyzed casein, 0.5 g / L yeast extract, 0.8 g / L MgSO4, 1.38 g / L HEPES, and 1 μg / L CuSO4, adjusting the pH to 7.0, sterilizing the culture medium at 121°C for 45 minutes in a high-temperature sterilizer, adding 1 g / L of glucose by filtering and sterilizing the culture medium through a 0.22-micron filter after the culture medium is cooled to obtain a third culture medium, inoculating 1 mL of a high-thallium-tolerant manganese oxidizing bacteria liquid stored at -80°C into the third culture medium, placing the culture medium in a shaker at a constant temperature of 26°C and a constant speed of 170 rpm, and incubating the culture medium until OD600 is 0.8, thereby completing activation and obtaining an activated culture medium.

[0071] The activated bacterial liquid is placed in a first culture medium and incubated in a constant temperature of 26°C and a constant speed of 170 rpm on a shaker. The oxidation of Mn(II) occurs synchronously with the expansion of the strain. The composition of the first culture medium includes 1 g / L anhydrous glucose, 0.5 g / L acid hydrolyzed casein, 0.5 g / L yeast extract powder, 0.8 g / L MgSO4, 1.38 g / L HEPES, 1 μg / L CuSO4, and 100 mg / L divalent manganese ions. The volume ratio of the activated bacterial liquid to the first culture medium is 3:100. After 12 hours of oxidation reaction, Fe(III) is added to the first culture medium in an amount with an iron-manganese molar ratio of 0.2:100, and mineralization is further carried out for 24 hours to obtain an iron-doped bio-manganese oxide biological preparation that can be used for thallium fixation.

[0072] Thallium tolerance test of high thallium-tolerant manganese oxidizing bacteria MnB1: High thallium-tolerant manganese oxidizing bacteria MnB1 was added to the second culture medium containing thallium concentrations of 0, 0.5, 1, 5, 10, and 20 mg / L at a ratio of 1 mL:100 mL, respectively. The culture was carried out in a shaker at a constant temperature of 26°C and a constant speed of 170 rpm. Samples were taken regularly to test the growth and development activity of the strain. The results are as follows Figure 1 As shown, after acclimation to thallium tolerance, the growth and development of the manganese-oxidizing bacteria MnB1 was almost identical to that of the CK group (thallium concentration in the second culture medium was 0 mg / L) within a thallium concentration range of 0.5-10 mg / L. Only at the ultra-high thallium concentration of 20 mg / L was the growth and development activity somewhat inhibited. After acclimation to the thallium tolerance provided by this patent, the strain's thallium tolerance met the requirements for use.

[0073] Example 2

[0074] Test on the improvement of the effect of iron doping on thallium fixation: prepare an ion culture medium with a Mn(II) concentration of 100 mg / L, and inoculate the activated bacterial solution prepared in Example 1 at a ratio of 1 mL bacterial solution: 100 mL culture medium. Culture in a shaker at a constant temperature of 26°C and a constant speed of 170 rpm. After incubation for 12 hours, Fe(III) with an iron-manganese molar ratio of 0, 0.2%, 0.5%, and 1% was added, and the incubation was continued for 24 hours. The thallium concentration was added to thallium-containing wastewater of 0.5 mg / L, and the thallium concentration was sampled regularly to test the thallium removal rate. Figure 2 As shown in the figure, when the iron-manganese molar ratio is 0.2:100, the thallium solidification effect is obviously the best, which is increased by nearly 20% compared with CK, reaching more than 95%.

[0075] Example 3

[0076] The effect of iron doping time on the thallium fixation effect was tested: an ion culture medium with a Mn(II) concentration of 100 mg / L was prepared, and the activated bacterial solution prepared in Example 1 was inoculated at a ratio of 1 mL bacterial solution to 100 mL culture medium. The culture was cultured in a shaker at a constant temperature of 26°C and a constant speed of 170 rpm. Fe(III) with a molar ratio of 0.2% was added to the culture medium at 0 h, 12 h, 24 h, and 36 h after the strain was incubated for mineralization (where 0 h represents the direct addition of Fe(III) after inoculation). The results are shown in Figure 2. Figure 3 As shown in the figure, when 12h is doped with 0.2% Fe(III), it has a good thallium fixing effect during the entire time period of the thallium fixing reaction and has a wider range of applications. Therefore, the thallium removal effect of 12h with iron doping is the best; Figure 3 The CK group was the blank control group without Fe doping.

[0077] Example 4

[0078] The iron-doped bio-manganese oxide biopreparation prepared in Example 1 was removed from a 100 mL centrifuge tube and centrifuged at 8000 rpm for 5 minutes. The supernatant was removed. The obtained substrate was freeze-dried at -80°C. The obtained solid was ground and the powder obtained was subjected to SEM-EDS characterization to observe the microstructure of the preparation. The results are shown in Figure 2. Figure 4 As shown in Figure 2, the iron-doped biomanganese oxide mineral structure obtained under optimal conditions is loose and porous, the strain MnB1 is widely distributed on the surface of the mineral structure, and the iron element is widely doped in the mineral. The solid powder was further characterized by XRD to obtain its crystal structure. The results are shown in Figure 2. Figure 5 As shown, the crystal structure of iron-doped biomanganese oxide is a weakly crystalline δ-MnO2. Weak crystallinity usually has a larger surface area, and the loose structure can provide more reactive sites.

[0079] Example 5

[0080] An ion culture medium with a Mn(II) concentration of 100 mg / L was prepared, and the activated bacterial solution prepared in Example 1 was added at a ratio of 1 mL bacterial solution: 100 mL culture medium. The culture was carried out in a shaker at a constant temperature of 26°C and a constant speed of 170 rpm. After incubation for 12 hours, Fe(III) was added in an amount with an iron-manganese molar ratio of 0.2%. The culture was continued for 24 hours, and the culture was added to thallium-containing wastewater with thallium concentrations of 0.1, 0.5, 1, and 10 mg / L, respectively. The thallium concentration was sampled regularly to test the thallium removal rate. The results are as follows: Figure 6 As shown, the iron-doped biological manganese oxide biological preparation under the live bacteria system provided by this patent has a good removal effect on thallium in the range of 0.1-10 mg / L, with a removal rate of more than 90%.

[0081] Example 6

[0082] 5.7 mL of glacial acetic acid was dissolved in deionized water and the volume was adjusted to 1 L. The pH value of the solution was kept within the range of 2.88 ± 0.05 to prepare an extractant for use. An ion culture medium with a Mn (II) concentration of 100 mg / L was prepared. The activated bacterial solution obtained in Example 1 was inoculated at a ratio of 1 mL of bacterial solution to 100 mL of culture medium. The culture was carried out in a shaker at a constant temperature of 26° C. and a constant speed of 170 rpm. The culture was continued for 12 hours to form a mineral. Fe (III) was added at an iron-manganese molar ratio of 0.2%. The mineralization was continued for 24 hours. 10 mg / L of thallium-containing wastewater was added. After thallium removal, the wastewater was poured into a centrifuge tube, centrifuged at 8000 rpm for 5 minutes, and the substrate was taken out and freeze-dried at -80° C. for 24 hours. The extractant was added at a liquid-solid ratio of 20:1 (L / Kg) of extractant to substrate. The rotation speed was set to 30 ± 2 r / min on a Conrad shaker and the mixture was shaken at 23 ± 2° C. for 18 ± 2 hours. Subsequently, the leachate was taken out and the thallium concentration was tested using ICP-MS / OES, and the thallium leaching amount and leaching rate were further calculated.

[0083] The CK group was a control group without iron doping, and all other conditions were exactly the same as the experimental group. The results are as follows Figure 7 As shown, the iron-doped bio-manganese oxide biological preparation provided by this patent has an extremely low leaching amount after thallium fixation, with a leaching rate of less than 3%. Compared with the CK group, the stability of thallium fixation has been significantly enhanced.

[0084] Example 7

[0085] Comparing the iron-doped biological manganese oxide biological preparation prepared in Example 1 with the iron-doped biological manganese oxide biological preparation fixed with thallium under the optimal thallium fixing conditions after the strain is inactivated, the mineral XPS after thallium fixing is as follows: Figure 8 As shown, Figure 8 (a) is the mineral Mn2p fitting result after the system fixed thallium in the living state of strain MnB1, among which Mn(IV) accounts for 20.87%, Mn(III) accounts for 68.14%, and Mn(II) accounts for only 10.99%. Figure 8 (b) shows the Mn 2p fitting results for the mineral after thallium immobilization in the freeze-dried mineral material in the inactivated state of strain MnB1. Mn(IV) accounts for 19.73%, Mn(III) for 32.29%, and Mn(II) for 32.34%. This indicates that the mineral after thallium immobilization in the system with the viable strain MnB1 still retains a large proportion of high-valent manganese (Mn(III) / Mn(IV)). Compared to the sterilized material system, the proportion of high-valent manganese is 21.35%, indicating that the viable strain MnB1 is able to reoxidize the Mn(II) produced by the redox reaction between the mineral and thallium into high-valent manganese.

[0086] The above technical solutions of the present invention are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing an iron-doped manganese oxide biological agent, characterized in that: Including steps: The manganese oxidizing bacteria are acclimated to thallium tolerance to obtain high thallium tolerant manganese oxidizing bacteria; The high thallium-tolerant manganese-oxidizing bacteria are inoculated into a first culture medium composed of divalent manganese ions, and the divalent manganese ions are oxidized to generate Mn under the mediation of the high thallium-tolerant manganese-oxidizing bacteria. 3+ and / or Mn 4+ ; Iron ions are added to the first culture medium, and an iron-doped manganese oxide biological preparation is prepared through a mineralization reaction; wherein the molar ratio of the iron ions to the divalent manganese ions is 0.1 to 1:

100.

2. The method for preparing an iron-doped manganese oxide biological agent according to claim 1, characterized in that: The manganese oxidizing bacteria include the model bacteria Pseudomonas putida MnB1.

3. The method for preparing an iron-doped manganese oxide biological agent according to claim 2, characterized in that: The thallium tolerance training comprises the following steps: Second culture media with different thallium concentration gradients are respectively prepared, wherein the monovalent thallium concentration gradients in the second culture media include 0, 0.01±0.001, 0.1±0.01, 0.5±0.1, 1±0.1, 5±1, 10±1, and 15±1 mg / L; The manganese oxidizing bacteria are cultured in sequence according to the thallium ion concentration in the second culture medium from high to low to obtain the high thallium-tolerant manganese oxidizing bacteria.

4. The method for preparing an iron-doped manganese oxide biological agent according to claim 3, characterized in that: The duration of the oxidation reaction is 0 to 36 hours, and the duration of the mineralization reaction is 12 to 36 hours.

5. The method for preparing the iron-doped manganese oxide biological agent according to claim 3, characterized in that: Before the step of inoculating the high-thallium-tolerant manganese oxidizing bacteria into the first culture medium containing divalent manganese ions, the high-thallium-tolerant manganese oxidizing bacteria are activated, including the steps of placing the high-thallium-tolerant manganese oxidizing bacteria in a third culture medium for activation culture to obtain an activated bacterial liquid, wherein the OD600 of the high-thallium-tolerant manganese oxidizing bacteria in the activated bacterial liquid is 0.8-1.0, and the volume ratio of the activated bacterial liquid to the first culture medium is 1-3:

100.

6. The method for preparing an iron-doped manganese oxide biological agent according to claim 5, characterized in that: The third culture medium comprises: acid hydrolyzed casein, yeast extract powder, MgSO4, HEPES, CuSO4, and glucose, and the pH of the third culture medium is 6.9-7.1; The first culture medium comprises acid hydrolyzed casein, yeast extract, MgSO4, HEPES, CuSO4, and divalent manganese ions. The pH of the first culture medium is 6.9-7.1, and the concentration of divalent manganese ions in the first culture medium is 80-120 mg / L.

7. The method for preparing an iron-doped manganese oxide biological agent according to claim 1, characterized in that: In the step of adding iron ions to the first culture medium to prepare the iron-doped manganese oxide biological agent through a mineralization reaction, the molar ratio of the iron ions to the divalent manganese ions is 0.1 to 0.3:

100.

8. The method for preparing an iron-doped manganese oxide biological agent according to claim 3, characterized in that: The divalent manganese ions include divalent manganese in manganese sulfate, the iron ions include iron ions in FeCl 3 ·6H 2 O, and the thallium ions include thallium ions in TlNO 3 .

9. An iron-doped manganese oxide biological agent, characterized in that: The biopharmaceutical is prepared by the method for preparing the iron-doped manganese oxide biopharmaceutical according to any one of claims 1 to 8.

10. Use of the iron-doped manganese oxide biological agent according to claim 9 in thallium treatment, characterized in that: The method comprises the following steps: mixing the iron-doped manganese oxide biological preparation with thallium-containing wastewater, wherein the volume mass ratio of the iron-doped manganese oxide biological preparation to thallium in the thallium-containing wastewater is 100 mL: 1 mg to 1500 mg; and the thallium concentration in the thallium-containing wastewater is 0.1 mg / L to 15 mg / L.

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