A composite material of sludge carbon supported schwertmannite immobilizing iron-sulfur reducing bacteria, and its preparation method and application

Abstract

The present invention discloses a composite material of sludge carbon supported with schwertmannite for immobilizing iron-sulfur reducing bacteria, its preparation method and application. The method includes subjecting sludge to high-temperature pyrolysis to obtain sludge carbon; mixing the sludge carbon with a ferrous sulfate solution and then adding a hydrogen peroxide solution for an oxidation reaction, followed by solid-liquid separation to obtain the sludge carbon supported with schwertmannite material; adding the sludge carbon supported with schwertmannite material to a culture medium containing iron-sulfur reducing bacteria and performing bacterial culture until the culture medium turns black, and then performing solid-liquid separation to obtain the product. The mineral-microbe composite material obtained by the present invention has excellent adsorption performance, a large adsorption capacity and strong stability, and can efficiently remove heavy metal ions such as Sb(V), Cd(II) and Pb(II), and is particularly suitable for the remediation of heavy metal pollution in mining areas.

Description

Technical Field

[0001] The present invention relates to mineral microbial materials, specifically to a composite material of sludge carbon supported with schwertmannite and immobilized iron-sulfur reducing bacteria, and also relates to a preparation method and application thereof, belonging to the field of environmental protection technology. Background Art

[0002] During the process of metal mine exploitation, a large amount of acid mine drainage (AMD) is generated, which is the main source of heavy metal pollution. Sulfate minerals are the main associated minerals in the AMD environment, including schwertmannite (Sch), jarosite, and hydroxy-sulfate green rust, etc. The formation process of these minerals is often accompanied by the fixation of heavy metals. Since these associated minerals are in a metastable state in the environment, they are very likely to further undergo phase transformation under redox conditions to form structurally stable goethite, hematite, etc. During this process, some of the heavy metals fixed by them will be released into the environment, posing a serious threat to the surrounding water ecology and the safety of agricultural products.

[0003] Sch and sulfate-reducing bacteria (SRB) are important active components in the AMD sediments of mining areas and have a significant impact on the heavy metal environment. The structure of Sch has strong flexibility in regulating the size and charge of metal ions. Heavy metals can replace different structural sites of it and be enriched inside the mineral at the same time, making Sch an important host mineral for heavy metals in the mining area environment. SRB can not only use free SO 4 2- in the environment as an electron acceptor to reduce hexavalent sulfur and promote the biomineralization process of heavy metals, but also use extracellular polymeric substances (EPS) to fix heavy metals through enzymatic action. However, Sch is a metastable mineral initially formed by the hydrolysis of Fe(III) in the AMD environment and is very likely to undergo secondary phase transformation. During the phase transformation process, heavy metals will be released back into the environment, causing environmental pollution. In addition, when microorganisms are directly exposed to an acidic environment and a heavy metal-polluted environment, the activity of microorganisms will also be inhibited, reducing their ability to fix heavy metals.

[0004] In the prior art, sulfate minerals or sulfate-reducing bacteria are directly used to adsorb and remove heavy metals, resulting in unstable removal of heavy metals, limited adsorption capacity, and easy generation of secondary pollution.

[0005] Therefore, it is of great significance to develop a new type of mineral microbial composite material to achieve efficient and stable remediation of AMD pollution in mining areas, thereby reducing the pollution of the mining area environment. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technologies, the first object of the present invention is to provide a composite material of sludge carbon supported with schwertmannite and immobilized iron-sulfur reducing bacteria. This material has a large specific surface area, high activity, excellent adsorption performance, strong stability, and can adapt to acidic environments.

[0007] The second object of the present invention is to provide a preparation method of the composite material of sludge carbon supported with schwertmannite and immobilized iron-sulfur reducing bacteria. This method is simple, has low costs, and is suitable for industrial production.

[0008] The third object of the present invention is to provide an application of the composite material of sludge carbon supported with schwertmannite and immobilized iron-sulfur reducing bacteria. This material can effectively adsorb heavy metal ions, has a large adsorption capacity, and a high removal efficiency.

[0009] To achieve the above technical objects, the present invention provides a preparation method of the composite material of sludge carbon supported with schwertmannite and immobilized iron-sulfur reducing bacteria. The method is as follows: the sludge is subjected to high-temperature pyrolysis to obtain sludge carbon; the sludge carbon is mixed with a ferrous sulfate solution and then hydrogen peroxide solution is added for an oxidation reaction, and solid-liquid separation is performed to obtain the sludge carbon supported schwertmannite material; the sludge carbon supported schwertmannite material is added to a culture medium containing iron-sulfur reducing bacteria and bacterial culture is carried out until the culture medium turns black, and then solid-liquid separation is performed to obtain the product.

[0010] By immobilizing iron-sulfur reducing bacteria on the sludge carbon supported schwertmannite matrix material, the adsorption performance and stability of the material can be greatly improved. First, sludge carbon has a strong fixation ability for heavy metals in water bodies, which can significantly reduce the bioavailability and toxicity of heavy metals in water bodies. Second, sludge carbon can effectively inhibit the phase transformation process of schwertmannite and enhance the fixation ability of schwertmannite for (pseudo) heavy metals. Third, the porous structure, relatively large specific surface area, and rich functional group structure of sludge carbon can provide a better living environment for microorganisms, enhance the activity of microorganisms, and further enhance the fixation ability of microorganisms for heavy metals. Through the synergistic effect of the three, the adsorption performance and stability of the material are significantly improved.

[0011] In addition, by synthesizing schwertmannite in a system containing sludge carbon, the stability of the sludge carbon supported schwertmannite can be enhanced. Part of the schwertmannite can adhere to the surface of the sludge carbon through strong interactions, and has better stability than the composite formed by traditional ball milling of sludge carbon and schwertmannite spheres.

[0012] As a preferred solution, the sludge is municipal sludge or printing and dyeing sludge.

[0013] As a preferred solution, the water content of the sludge does not exceed 10 wt%.

[0014] As a preferred solution, the sludge is dried at 40-50 °C until the water content does not exceed 10 wt%.

[0015] As a preferred solution, the conditions for the high-temperature pyrolysis are as follows: the atmosphere is a protective atmosphere, the temperature is 400-600 °C, and the time is 2-3 h.

[0016] As a preferred solution, the protective atmosphere is nitrogen. The flow rate of nitrogen is 30-50 mL / min.

[0017] As a preferred solution, the particle size of the sludge carbon is 200 mesh.

[0018] As a preferred solution, the mass ratio of the iron element in the sludge carbon to that in ferrous sulfate is 0.5-2:1.

[0019] As a preferred solution, the molar concentration of ferrous sulfate is 0.06-0.1 mol / L.

[0020] As a preferred solution, the mass concentration of hydrogen peroxide in the hydrogen peroxide solution in the reaction system is 11.12-16.67 g / L.

[0021] As a preferred solution, the mass concentration of the hydrogen peroxide solution is 30-50%.

[0022] As a preferred solution, the particle size of the sludge carbon loaded with schwertmannite material is 200 mesh.

[0023] As a preferred solution, after solid-liquid separation, the obtained solid is washed with acid and water until the pH value of the washing liquid remains stable, and then the solid is subjected to freeze-drying and grinding and sieving treatment.

[0024] As a preferred solution, the number of washing times is 3-5 times.

[0025] As a preferred solution, the acid solution is dilute nitric acid, and the pH value of the dilute nitric acid is 1.5-2.5.

[0026] As a preferred solution, the iron-sulfur reducing bacterium is Cedecea sp. ISRB13.

[0027] As a preferred solution, the temperature of freeze-drying is -60 to -80 °C.

[0028] As a preferred solution, the iron-sulfur reducing bacterium is pretreated by activation in an LB medium. The activation time is 12-24 h.

[0029] As a preferred embodiment, after adding the sludge carbon-supported schwertmannite material to the culture medium containing iron-sulfur reducing bacteria, sterile liquid paraffin is added to seal the liquid surface. The thickness of the sterile liquid paraffin is 2 - 3 cm.

[0030] As a preferred embodiment, the conditions for culturing the bacteria are as follows: the temperature is 25 - 35 °C and the time is 24 - 48 h.

[0031] As a preferred embodiment, the concentration of the bacterial strain after culturing the bacteria is 5 - 10×10 9 CFU / mL.

[0032] As a preferred embodiment, after the completion of culturing the bacteria, the solid product obtained by solid-liquid separation is washed with physiological saline and then freeze-dried to obtain a sludge carbon-supported schwertmannite-immobilized iron-sulfur reducing bacteria composite material.

[0033] As a preferred embodiment, the number of washing times is 3 - 5 times. The temperature for freeze-drying is -60 - 80 °C.

[0034] As a preferred embodiment, the freeze-dried solid is ground and sieved.

[0035] As a preferred embodiment, the particle size of the sludge carbon-supported schwertmannite-immobilized iron-sulfur reducing bacteria composite material is 200 mesh.

[0036] The present invention also provides a sludge carbon-supported schwertmannite-immobilized iron-sulfur reducing bacteria composite material, which is prepared by the above method.

[0037] The present invention also provides an application of the sludge carbon-supported schwertmannite-immobilized iron-sulfur reducing bacteria composite material, which is used for adsorbing and removing heavy metal ions in a liquid.

[0038] As a preferred embodiment, it is used for adsorbing and removing heavy metal ions in wastewater.

[0039] As a preferred embodiment, the wastewater is acidic mine wastewater. The pH value of the wastewater is 4 - 6.

[0040] As a preferred embodiment, the heavy metal ions include at least one of Sb(V), Cd(II), and Pb(II).

[0041] As a preferred embodiment, the dosage of the sludge carbon-supported schwertmannite-immobilized iron-sulfur reducing bacteria composite material in the wastewater is 1 - 2 g / L.

[0042] As a preferred embodiment, the concentration of heavy metal ions in the wastewater is 50 - 200 ppm.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The composite material of sludge carbon loaded with schwertmannite immobilizing iron-sulfur reducing bacteria of the present invention has the advantages of large specific surface area, high activity, excellent adsorption performance, strong stability, being able to adapt to acidic environment, and being renewable and recyclable;

[0045] (2) This composite material can efficiently immobilize heavy metal ions such as Sb(V), Cd(II), Pb(II), etc., with less dosage, large adsorption capacity, and can effectively remove heavy metals in water, especially suitable for the treatment of toxic heavy metal ions in acidic mine wastewater, and has broad application prospects;

[0046] (3) The present invention uses microorganisms and schwertmannite widely existing in nature, as well as sludge solid waste as raw materials, and the raw material sources are wide and the cost is low;

[0047] (4) The preparation method is simple, with less investment, no special dedicated equipment required, and the process is easy to control. Description of the Drawings

[0048] Figure 1 It is the XRD pattern of schwertmannite (Sch), sludge carbon (SC) and the composite material of sludge carbon loaded with schwertmannite immobilizing iron-sulfur reducing bacteria (SC / Sch-Fe / SRB) prepared in Example 1 of the present invention.

[0049] Figure 2 It is the scanning electron micrograph of schwertmannite (A) and sludge carbon (B).

[0050] Figure 3 It is the scanning electron micrograph of the composite material of sludge carbon loaded with schwertmannite immobilizing iron-sulfur reducing bacteria prepared in Example 1 of the present invention. Detailed Embodiments

[0051] The present invention will be further described in detail below in conjunction with examples and drawings, but the embodiments and protection scope of the present invention are not limited thereto.

[0052] Example 1

[0053] A preparation method of a composite material of sludge carbon loaded with schwertmannite immobilizing iron-sulfur reducing bacteria (SC / Sch-Fe / SRB) is as follows:

[0054] The selected strain is the microorganism Cedecea sp. ISRB13 with iron-sulfur reduction function screened by the applicant from mineral soil in the early stage. The strain was preserved in the Guangdong Microbial Culture Collection Center on December 19, 2023, with the preservation number of GDMCC NO.64081.

[0055] Preparation of sludge carbon (SC): Place municipal sludge in an oven, adjust the temperature to 50 °C, and dry it until the moisture content of the sludge is 8%. Place the dried sludge in a tube furnace for anaerobic pyrolysis at a pyrolysis temperature of 600 °C for 2 h. During pyrolysis, control the nitrogen flow rate at 50 mL / min. Grind the pyrolyzed sample and pass it through a 200-mesh sieve to obtain sludge carbon.

[0056] Preparation of sludge carbon supported Schwertmannite material (SC / Sch): Dissolve 27.80 g of ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) in 1 L of deionized water (0.1 mol / L). Add 11.2 g of the above-mentioned sludge carbon, stir evenly, and then slowly add 15 mL of a 30% hydrogen peroxide (H 2 O 2 ) solution using a peristaltic pump. After reacting fully at room temperature for 48 h, centrifuge at 8000 rpm for 5 min, collect the solid in the mixture, and wash it with dilute nitric acid solution with a pH of 2 and deionized water until the pH value of the washing liquid remains constant. Then, freeze-dry the washed solid at -68 °C for 48 h, and then grind it and pass it through a 200-mesh sieve to obtain the sludge carbon supported Schwertmannite sample.

[0057] Preparation of SC / Sch-Fe / SRB material: Activate the above-screened microorganism Cedecea sp. ISRB13 (1 mL of the original strain solution) in LB medium (100 mL) for 24 h, then add the above-mentioned sludge carbon supported Schwertmannite material, mix well, gently add sterile liquid paraffin to seal the liquid surface, with the thickness of the sterile liquid paraffin being 3 cm, tighten the stopper, and incubate statically at a constant temperature of 30 °C for 24 h until the whole medium shows a thick black color (at this time, the bacterial concentration is 5×10 9 CFU / mL) to obtain the modified product solution. After centrifuging at 8000 rpm for 3 minutes, wash it with normal saline, repeat the operation 3 times, freeze-dry the washed solid at -80 °C for 24 h, and then grind it and pass it through a 200-mesh sieve to obtain the SC / Sch-Fe / SRB material.

[0058] Comparative Example 1

[0059] Preparation of sludge carbon-supported microorganisms (SC-Fe / SRB): After activating the microorganism Cedecea sp. ISRB13 screened in Example 1 in LB medium for 24 h, the sludge carbon material prepared in Example 1 was added. The mass ratio of the microorganism to the sludge carbon material was 1:50. The mixture was shaken well, and sterile liquid paraffin was gently added to seal the liquid surface. The thickness of the sterile liquid paraffin was 3 cm. The stopper was tightened, and the mixture was incubated statically at 30 °C for 24 h until the whole medium turned thick black, obtaining a modified product solution. Then, it was centrifuged at 8000 rpm for 3 minutes and washed with physiological saline. The operation was repeated 3 times. The washed solid was freeze-dried at -60 °C for 24 h and then ground through a 200-mesh sieve to obtain the SC-Fe / SRB material.

[0060] Comparative Example 2

[0061] Preparation of schwertmannite (Sch): Dissolve 22.24 g of FeSO 4 ·7H 2 O in 1 L of deionized water (DIW) and stir well. During the stirring process, 15 mL of hydrogen peroxide (H 2 O 2 , 30%) was slowly added using a peristaltic pump. After the mixture was allowed to react statically for 24 hours, the solid in the mixture was collected by centrifugation. Subsequently, the solid was washed with dilute acid solution (pH ≈ 2) and deionized water until the pH value of the washing solution remained stable. Finally, the obtained solid was freeze-dried and stored in a desiccator. To ensure the consistency of the mineral particles, the mineral was ground and screened through a 200-mesh sieve before use.

[0062] Preparation of schwertmannite-supported microorganisms (Sch-Fe / SRB): After activating the microorganism Cedecea sp. ISRB13 screened in Example 1 in LB medium for 24 h, the above-mentioned schwertmannite material was added. The mixture was shaken well, and sterile liquid paraffin was gently added to seal the liquid surface. The thickness of the sterile liquid paraffin was 3 cm. The stopper was tightened, and the mixture was incubated statically at 30 °C for 24 h until the whole medium turned thick black, obtaining a modified product solution. Then, it was centrifuged at 8000 rpm for 3 minutes and washed with physiological saline. The operation was repeated 3 times. The washed solid was freeze-dried at -60 °C for 24 h and then ground through a 200-mesh sieve to obtain the Sch-Fe / SRB material.

[0063] Comparative Example 3

[0064] The sludge carbon in Example 1 and the schwertmannite in Comparative Example 2 were mixed and ball-milled according to the mass ratio of Fe elements in the sludge carbon and schwertmannite of 2:1 to obtain a composite material of ordinary sludge carbon and schwertmannite (N-SC / Sch).

[0065] After activating the screened microorganism Cedecea sp. ISRB13 in LB medium for 24 h, the above-mentioned ordinary sludge carbon and Struvite composite material (N-SC / Sch) were added, mixed well, and gently covered with sterile liquid paraffin to seal the liquid surface. The thickness of the sterile liquid paraffin was 3 cm. The stopper was tightened, and the mixture was incubated statically at a constant temperature of 30 °C for 24 h until the whole medium showed a thick black color, obtaining a modified product solution. Then, it was centrifuged at 8000 rpm for 3 minutes and washed with physiological saline, and the operation was repeated 3 times. The washed solid was freeze-dried at -80 °C for 24 h and then ground through a 200-mesh sieve to obtain the N-SC / Sch -Fe / SRB material.

[0066] The X-ray diffraction analysis (XRD) of SC, Sch, and SC / Sch-Fe / SRB materials is as Figure 1 shown. The SC / Sch-Fe / SRB material significantly changed the characteristic diffraction peaks of Struvite and SC. Especially near the diffraction peak of 35 degrees (the characteristic diffraction peak of Sch), the diffraction peak intensity of the SC / Sch-Fe / SRB material was significantly stronger than that of the SC material, indicating that Struvite was successfully loaded on the sludge carbon, and the prepared material was a new mineral material. The scanning electron microscope (SEM) images were analyzed, and the results are as Figure 2 and Figure 3 shown. The morphology of Struvite was a spherical structure ( Figure 2 (A)), the sludge carbon was a lamellar structure ( Figure 2 (B)), and the SEM of the SC / Sch-Fe / SRB material ( Figure 3 ) could clearly show that the spherical Struvite and the lamellar sludge carbon were combined together, and the rod-shaped microorganisms were loaded on their surfaces, indicating that the microorganisms in the newly prepared material were successfully immobilized on the sludge carbon loaded with Struvite material.

[0067] Potassium antimonyl tartrate was dissolved in sterile distilled water to prepare a Sb(V) solution with a concentration of 50 mg / L; 0.1 g of Sch (Struvite), Sch-Fe / SRB (Struvite loaded with iron-sulfur reducing bacteria), SC (sludge carbon), SC-Fe / SRB (sludge carbon loaded with iron-sulfur reducing bacteria), SC / Sch (the sludge carbon loaded with Struvite material in Example 1), N-SC / Sch-Fe / SRB (the sludge carbon loaded with Struvite immobilized with iron-sulfur reducing bacteria in Comparative Example 3), and the SC / Sch-Fe / SRB material in Example 1 were weighed and placed in conical flasks respectively. After mixing, they were placed in a constant temperature shaker and shaken for 48 h, and then the supernatant was taken to measure the concentration of Sb in the solution with an atomic absorption spectrophotometer.

[0068] The Sb adsorption capacities of Sch, Sch-Fe / SRB, SC, SC-Fe / SRB, SC / Sch, N-SC / Sch-Fe / SRB, and SC / Sch-Fe / SRB were measured to be 17.35, 45.23, 20.22, 35.67, 18.32, 41.77, and 75.09 mg / g after 2 days of reaction (Table 1). It can be seen that compared with schwertmannite, schwertmannite-loaded iron-sulfur reducing bacteria, sludge carbon, sludge carbon-loaded iron-sulfur reducing bacteria, sludge carbon-loaded schwertmannite, and the ordinary sludge carbon-loaded schwertmannite-immobilized iron-sulfur reducing bacteria material prepared in Comparative Example 3, the composite material (SC / Sch-Fe / SRB) obtained by compositing the schwertmannite matrix material synthesized during the sludge carbon loading process with iron-sulfur reducing bacteria in the present invention has a greatly improved Sb removal rate, indicating that the three materials have an obvious synergistic effect, making the entire composite material exhibit excellent Sb removal effect.

[0069] Example 2

[0070] A preparation method of a sludge carbon-loaded schwertmannite-immobilized iron-sulfur reducing bacteria composite material (SC / Sch-Fe / SRB) is as follows:

[0071] The selected strain is the same as that in Example 1.

[0072] Preparation of sludge carbon: Place the printing and dyeing sludge in an oven, adjust the temperature to 45 °C, dry it until the moisture content of the sludge is 8%, place the dried sludge in a tubular furnace for anaerobic pyrolysis, the pyrolysis temperature is 550 °C, the pyrolysis time is 2.5 h, control the nitrogen flow rate at 40 mL / min during pyrolysis, grind the pyrolyzed sample through a 200-mesh sieve to obtain sludge carbon.

[0073] Preparation of sludge carbon-loaded schwertmannite material (SC / Sch): Dissolve 22.42 g of ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) in 1 L of deionized water, add 5.6 g of the above-mentioned sludge carbon, stir evenly, and then slowly add 12 mL of a 30% hydrogen peroxide (H 2 O 2 ) solution using a peristaltic pump. React fully at room temperature for 36 h, centrifuge at 7000 rpm for 4 min, collect the solid in the mixture, and wash it with a dilute acid solution with a pH of 2 and deionized water until the pH value of the washing solution remains constant. Finally, freeze-dry the washed solid at -65 °C for 36 h, and then grind it through a 200-mesh sieve to obtain a sludge carbon-loaded schwertmannite sample.

[0074] Preparation of SC / Sch-Fe / SRB material: After activating the screened microorganism Cedecea sp. ISRB13 (2 mL of the original strain solution) in LB medium (100 mL) for 36 h, the above-mentioned sludge carbon-supported schwertmannite material was added, mixed and shaken well, and sterile liquid paraffin was gently added to seal the liquid surface. The thickness of the sterile liquid paraffin was 2.5 cm. The stopper was tightened, and the mixture was cultured statically at a constant temperature of 25 °C for 36 h until the whole medium showed a thick black color (at this time, the bacterial concentration was 10×10 9 CFU / mL), obtaining a modified product solution. Then, it was centrifuged at 7000 rpm for 4 minutes and washed with physiological saline, and the operation was repeated 4 times. The washed solid was freeze-dried at -60 °C for 36 h, and the obtained solid was ground through a 200-mesh sieve to obtain the SC / Sch-Fe / SRB material.

[0075] Potassium antimonyl tartrate was dissolved in sterile distilled water to prepare a 50 mg / L Sb(V) solution. 0.1 g of the SC / Sch-Fe / SRB material was weighed into a conical flask. After mixing, it was placed in a constant-temperature shaker and shaken for 48 h. Then, the supernatant was taken and the concentration of Sb in the solution was measured by an atomic absorption spectrophotometer.

[0076] It was measured that after 2 days of reaction, the adsorption capacity of the SC / Sch-Fe / SRB prepared in Example 2 for Sb was 64.64 mg / g (Table 1), indicating that the SC / Sch-Fe / SRB of the present invention has a high removal rate for Sb and good removal effect.

[0077]

[0078] Example 3

[0079] The SC and SC / Sch-Fe / SRB materials obtained in Example 1 were used for the removal of heavy metal Cd(II).

[0080] Potassium antimonyl tartrate was dissolved in sterile distilled water to prepare a 50 mg / L Cd(II) solution; 0.1 g of the SC and SC / Sch-Fe / SRB materials were weighed into conical flasks respectively. After mixing, they were placed in a constant-temperature shaker and shaken for 48 h. Then, the supernatant was taken and the concentration of Cd(II) in the solution was measured by an atomic absorption spectrophotometer.

[0081] It was measured that after 2 days of reaction, the adsorption capacities of the SC and SC / Sch-Fe / SRB in Example 1 for Cd(II) were 13.22 mg / g and 40.19 mg / g respectively, indicating that the SC / Sch-Fe / SRB composite material prepared by the present invention can greatly improve the removal rate of Cd(II) and shows excellent Cd(II) removal effect.

[0082] Example 4

[0083] The SC and SC / Sch-Fe / SRB materials obtained in Example 1 were used for the removal of heavy metal Pb(II).

[0084] Lead nitrate was dissolved in sterile distilled water to prepare a Pb(II) solution with a concentration of 200 mg / L; 0.1 g of SC and the SC / Sch-Fe / SRB material prepared in the example were respectively weighed and placed in a conical flask. After mixing, they were placed in a constant temperature shaker and shaken for 48 h. Then the supernatant was taken and the concentration of Pb(II) in the solution was measured by an atomic absorption spectrophotometer.

[0085] After 2 days of the reaction, it was measured that the adsorption capacity of SC for Pb(II) was 23.56 mg / g, while the adsorption capacity of the SC / Sch-Fe / SRB material in Example 1 for Pb(II) reached 156.33 mg / g. It can be seen that the removal rate of Pb(II) by the composite material of sludge carbon loaded with schwertmannite immobilized iron-sulfur reducing bacteria in the present invention was significantly improved, showing excellent adsorption and removal effects.

Claims

1. A method for preparing a composite material of sewage sludge charcoal loaded with Schweiner mineral-immobilized iron-sulfur-reducing bacteria, characterized in that: The sludge is subjected to high-temperature pyrolysis to obtain sludge charcoal; the sludge charcoal is mixed with a ferrous sulfate solution and then a hydrogen peroxide solution is added to perform an oxidation reaction, and solid-liquid separation is performed to obtain a sludge charcoal-loaded Schrödinger mineral material; the sludge charcoal-loaded Schrödinger mineral material is added to a culture medium containing iron-sulfur-reducing bacteria and the bacteria are cultured until the culture medium turns black, and then solid-liquid separation is performed to obtain the sludge charcoal-loaded Schrödinger mineral material; The mass ratio of the sludge carbon to the iron element in ferrous sulfate is 0.5-2:1; The sludge is municipal sludge or printing and dyeing sludge; The iron-sulfur reducing bacteria is Cedecea sp. ISRB13.

2. The method for preparing a composite material of sewage sludge charcoal loaded with Schweiner mineral-immobilized iron-sulfur-reducing bacteria according to claim 1, characterized in that: The conditions for high temperature pyrolysis are: the atmosphere is a protective atmosphere, the temperature is 400-600° C., and the time is 2-3 hours.

3. The method for preparing a composite material of sewage sludge charcoal loaded with Schweiner mineral-immobilized iron-sulfur-reducing bacteria according to claim 1, characterized in that: The molar concentration of the ferrous sulfate solution is 0.06-0.1 mol / L.

4. The method for preparing a composite material of sewage sludge charcoal loaded with Schweiner mineral-immobilized iron-sulfur-reducing bacteria according to claim 1 or 3, characterized in that: The concentration of hydrogen peroxide in the reaction system is 11.12-16.67 g / L.

5. The method for preparing a composite material of sewage sludge charcoal loaded with Schweiner mineral-immobilized iron-sulfur-reducing bacteria according to claim 1, characterized in that: The bacterial culture conditions are: temperature of 25-35°C and time of 24-48h.

6. The method for preparing a composite material of sewage sludge charcoal loaded with Schweiner mineral-immobilized iron-sulfur-reducing bacteria according to claim 1 or 5, characterized in that: The concentration of the bacterial strain after bacterial culture is 5~10×10 9 CFU / mL.

7. A composite material of sewage sludge charcoal loaded with Schweiner mineral and immobilized iron-sulfur-reducing bacteria, characterized in that: The method is prepared by any one of claims 1 to 6.

8. The use of the composite material of sewage sludge charcoal loaded with Schweiner mineral-immobilized iron-sulfur-reducing bacteria according to claim 7, characterized in that: Used to adsorb and remove heavy metal ions in liquids.

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