CN118703364A - A manganese-resistant bacterial strain-loaded iron-manganese catalyst and its preparation method and application - Google Patents

Abstract

The present invention provides a manganese-resistant strain-loaded iron-manganese catalyst and a preparation method and application thereof, and belongs to the technical field of biomaterials and water purification environment. The manganese-resistant Enterobacter provided by the present invention has a strong manganese resistance and can grow in a manganese environment. Manganese-resistant Enterobacter is used as a carrier to load iron and manganese to prepare a manganese-resistant strain-loaded iron-manganese catalyst (Bio-Fe _x Mn _y O), which exhibits excellent ability to degrade organic matter when catalyzing ozone oxidation. Therefore, the strain is a good supplement to the existing catalytic ozone oxidation catalyst preparation type, and provides a feasible solution for the application of catalytic ozone oxidation process.

Description

A manganese-resistant bacterial strain-loaded iron-manganese catalyst and its preparation method and application

Technical Field

The invention relates to the technical field of biomaterials and water purification environment, and in particular to a manganese-resistant bacterial strain-loaded iron-manganese catalyst and a preparation method and application thereof.

Background Art

In view of the water quality pollution and human health hazards caused by refractory organic substances such as phenols and polycyclic aromatic hydrocarbons in the secondary effluent of coking wastewater, it is urgent to develop efficient methods for degrading such substances. At present, the main methods for degrading phenolic substances are physical method, biological method and advanced oxidation method. Among them, the biological method is easily affected by water quality and produces a large amount of sludge. Especially when treating coking wastewater, the biodegradability is poor and it is difficult to meet the discharge standards. The physical method has high cost and the regeneration system is difficult to operate. If the biochemical treatment of the previous process is not thorough, the residual organic pollutants in the coking wastewater will be deposited or adsorbed on the membrane surface, blocking the membrane pores, causing membrane pollution, and the replacement and backwashing of the membrane increase the treatment cost. As one of the advanced oxidation methods, the ozone oxidation method has the advantages of strong oxidizing ability, no introduction of other substances, and no secondary pollution compared with other advanced oxidation methods. It is widely used in the treatment of coking wastewater. Adding a catalyst can promote the decomposition of ozone, produce a large amount of ·OH, and improve the removal rate of pollutants in coking wastewater.

The material of the catalyst in the catalytic ozone oxidation process is very important. In recent years, a lot of research has been done on the development of heterogeneous catalytic ozone oxidation technology. Metal oxides have more active centers and better stability. Among them, Fe and Mn have become research hotspots because of their good catalytic activity in nature. They can have variable valence states in their oxides and can produce electron transfer pathways in the catalytic ozone oxidation process. The physical and chemical synthesis method usually requires dangerous and expensive chemicals as reducing agents or stabilizers, as well as extreme conditions such as high temperature and high pressure to prepare metal oxides. The biosynthesis method can effectively avoid these drawbacks because microorganisms can mediate the oxidation of metal ions, and the biosynthesized catalysts have a higher specific surface area, more crystal defects and unique crystal structures compared to similar products generated by chemicals.

Summary of the invention

Based on the above content, the purpose of the present invention is to provide a manganese-resistant bacterial strain-loaded iron-manganese catalyst and its preparation method and application. The preparation process of the manganese-resistant bacterial strain-loaded iron-manganese catalyst provided by the present invention is relatively simple, safe and low-cost. This method can improve the catalytic performance of the catalyst and provide a feasible solution for the application of catalytic ozone oxidation process.

In order to achieve the above-mentioned purpose, the present invention provides the following technical scheme: a manganese-resistant Enterobacter (Enterobacter sp.) FM-500, which was deposited in the China Center for Type Culture Collection on April 22, 2024, with a preservation address of Wuhan University, Wuhan, China, and a preservation number of CCTCC NO: M2024737.

The present invention also provides a bacterial agent, comprising the manganese-resistant Enterobacter described in the above technical solution.

The present invention also provides the use of the manganese-resistant Enterobacter or the bacterial agent described in the above technical solution in the preparation of a catalyst.

In some embodiments, the catalyst is a catalyst that catalyzes ozone oxidation.

The present invention also provides a manganese-resistant bacterial strain-loaded iron-manganese catalyst, comprising iron element and/or manganese element and the manganese-resistant Enterobacter; the iron element and/or manganese element is adsorbed on the manganese-resistant Enterobacter.

The present invention also provides a method for preparing the manganese-resistant bacterial strain-loaded iron-manganese catalyst, which comprises culturing iron salt and/or manganese salt with the manganese-resistant Enterobacter.

In some embodiments, the iron salt is ammonium ferric citrate, and the dosage of the iron salt is 0-2000 mg/L; the manganese salt is manganese sulfate, and the dosage of the manganese salt is 0-500 mg/L.

In some embodiments, the culturing is performed at 30° C. with shaking at 170 rpm/min for 5 days.

In some embodiments, the catalyst medium used in the culture has a formula of: 0.22 g/L yeast extract powder, 0.89 g/L peptone, 0.14 g/L CaCl2· _2H2O , 0.14 g/L _K2HPO4 · _3H2O , 0.22 g/ _{L MgSO4} · _7H2O , 0.22 g/ _{L NaNO3} , 0.11 g/L _NH4Cl .

In some embodiments, after the culturing is completed, the method further comprises collecting the precipitate, and washing and polishing the precipitate.

In some embodiments, the washing is performed by washing with sterile water for 4-8 times to remove surface impurities; and the polishing is performed by drying at 60° C. for 8 hours.

The invention also provides the use of the manganese-resistant bacterial strain loaded with an iron-manganese catalyst in catalyzing ozone oxidation and degradation of organic pollutants.

In some embodiments, the organic pollutants are organic pollutants in the secondary effluent of coking wastewater.

In some embodiments, the organic contaminant is phenol.

Beneficial technical effects:

1. In the manganese-resistant bacterial strain-loaded iron-manganese catalyst prepared by the present invention, metal oxides are uniformly attached to the bacterial surface in the form of ions, wherein Mn(II) is oxidized to Mn(III/IV) by microorganisms through enzymes or other pathways, and its kinetic constant can be 105 times higher than that of non-biological oxidation. This makes the obtained catalyst have higher catalytic performance and effectively degrade organic pollutants in the secondary effluent of coking wastewater.

2. The manganese-resistant strain-loaded iron-manganese catalyst prepared by the present invention has a higher specific surface area, more crystal defects and a unique crystal structure compared to similar products generated chemically.

3. The preparation process of the manganese-resistant bacterial strain-loaded iron-manganese catalyst prepared by the present invention does not require dangerous and expensive chemicals as reducing agents or stabilizers, nor does it require extreme conditions such as high temperature and high pressure.

4. The iron-manganese catalyst loaded with manganese-resistant bacteria prepared by the present invention uses iron-manganese oxides attached to the surface of bacteria, which is expected to reduce the demand for rare metals and expensive metals, making the catalyst more environmentally friendly and sustainable.

5. The manganese-resistant bacterial strain-loaded iron-manganese catalyst prepared by the present invention has stable properties in an oxidation system and good repeatability.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 these drawings without paying creative work.

FIG. 1 is an X-ray diffraction (XRD) pattern of the Bio-Fe ₅₀₀ Mn ₅₀₀ O catalyst in Example 1.

FIG2 is an X-ray photoelectron spectrum (XPS) of the Bio-Fe ₅₀₀ Mn ₅₀₀ O catalyst in Example 1; wherein (a) is Survey, (b) is Fe2p, and (c) is Mn2p.

FIG3 is a diagram showing the degradation efficiency of phenol wastewater in Example 2;

FIG. 4 is a morphological diagram of the strain of manganese-resistant Enterobacter in the present invention.

DETAILED DESCRIPTION

Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and/or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

Example 1

1. Strain origin, isolation and purification

The samples were collected from the drainage soil of a steel plant in Shijiazhuang, Hebei Province, China.

Screening for manganese-resistant Enterobacter sp. FM-500

1-1. Take 5g of sieved soil sample, add it to 45ml of 0.9% sterile saline, place it on a shaker for 1h, let it stand, take 5ml of supernatant, transfer it to 45ml of culture medium with 50mg/L MnSO ₄ ·H ₂ O, and culture it at 30℃ with shaking for 48h;

1-2. Take 0.1 ml of bacterial suspension and dilute it to 10 ^-1 , 10 ^-2 , 10 ^-3 , 10 ^-4 , 10 ^-5 , 10 ^-6 ;

1-3. Spread 0.2 ml of 10 ^-4 , 10 ^-5 , and 10 ^-6 bacterial suspensions on solid culture medium with a MnSO ₄ ·H ₂ O concentration of 50 mg/L, place in a 30°C incubator, and observe the bacterial growth;

1-4. If the growth condition is good, take the colonies with a colony count of 30-300 in the solid culture medium, transfer them to fresh culture medium with MnSO ₄ ·H ₂ O concentrations of 100 mg/L, 200 mg/L, and 500 mg/L, culture for 48 hours, and dilute them with sterile water to 10 ^-1 , 10 ^-2 , 10 ^-3 , 10 ^-4 , 10 ^-5 , and 10 ^-6 bacterial suspensions;

1-5. 10 ^-4 , 10 ^-5 , and 10 ^-6 bacterial suspensions were respectively coated on plates with a MnSO ₄ ·H ₂ O concentration of 500 mg/L, and cultured at 30°C for 48 hours. Single colonies with good growth and different colony morphology were selected and separated and purified by the plate streak method. The streak culture was repeated until a monoclonal colony was obtained. As shown in Figure 4, the colony morphology of the FM-500 strain on the Lb plate was light yellow, with regular edges, a round shape, slightly convex, a moist and smooth surface, and opaque.

PCR amplification was performed using universal primers for bacterial identification of 16S rDNA, and the sequencing results were submitted to NCBI for Blast comparison analysis. It was identified as Enterobacter sp. and manganese-resistant Enterobacter sp. FM-500 was obtained.

The manganese-resistant Enterobacter sp. FM-500 was deposited in the China Center for Type Culture Collection on April 22, 2024, with the deposit address being Wuhan University, Wuhan, China, and the deposit number being CCTCC NO: M2024737

2. The preparation method of the manganese-resistant strain-loaded iron-manganese catalyst in this embodiment is:

S1. Prepare a catalyst medium containing 0.22 g/L yeast extract powder, 0.89 g/L peptone, 0.14 g/L CaCl ₂ ·2H ₂ O, 0.14 g/L K ₂ HPO ₄ ·3H ₂ O, 0.22 g/L MgSO ₄ ·7H ₂ O, 0.22 g/L NaNO ₃ , and 0.11 g/L NH ₄ Cl.

S2. Add ammonium ferric citrate and MnSO ₄ ·H ₂ O to 0.75 L catalyst culture medium through a sterile 0.22 um membrane filter, and then inoculate bacteria from a culture dish. Place the inoculated catalyst culture medium at 30°C and shake it in an incubator at 170 rpm/min. Collect the precipitate after 5 days, wash it 8 times with sterile water, and gently dry it at 60°C for 8 hours to obtain a manganese-resistant strain-loaded iron-manganese catalyst, which is labeled as Bio-Fe _x Mn _y O catalyst, where x represents the dosage of ammonium ferric citrate and y represents the dosage of MnSO ₄ ·H ₂ O.

When the dosage of ammonium ferric citrate is 500 mg/L and the dosage of MnSO ₄ ·H ₂ O is 500 mg/L, Bio-Fe ₅₀₀ Mn ₅₀₀ O catalyst is obtained.

When the dosage of ammonium ferric citrate is 1000 mg/L and the dosage of MnSO ₄ ·H ₂ O is 200 mg/L, Bio-Fe ₁₀₀₀ Mn ₂₀₀ O catalyst is obtained.

When the dosage of ammonium ferric citrate is 0 mg/L and the dosage of MnSO ₄ ·H ₂ O is 500 mg/L, Bio-Mn ₅₀₀ O catalyst is obtained.

When the dosage of ammonium ferric citrate is 2000 mg/L and the dosage of MnSO ₄ ·H ₂ O is 0 mg/L, Bio-Fe ₂₀₀₀ O catalyst is obtained.

Figure 1 is an X-ray diffraction (XRD) diagram of the Bio-Fe ₅₀₀ Mn ₅₀₀ O catalyst provided by the present invention; Figure 2 is an X-ray photoelectron spectrum (XPS) diagram of the Bio-Fe ₅₀₀ Mn ₅₀₀ O catalyst provided by the present invention. It can be seen from Figures 1 and 2 that the high activity may come from its amorphous structure; the valence states of Fe and Mn are Fe(II, III) and Mn(III, IV) respectively, Fe(II) and Mn(IV) can react, and the multi-path redox reaction between metal and ozone is beneficial to the decomposition of ozone and the stability of the catalyst.

Example 2

The application of the iron-manganese catalyst ( _Bio - _FexMnyO ) loaded with a manganese-resistant strain provided in Example 1 is applied to the degradation of COD in phenol wastewater.

Effect verification:

This experiment is a simulated application of the catalyst prepared in Example 1 and catalytic ozone oxidation to efficiently degrade phenol, an organic pollutant in the secondary effluent of coking wastewater. 200 mg of phenol was dissolved in 1 L of deionized water to obtain a phenol solution with a concentration of 200 mg/L, which was loaded into a catalytic ozone reaction device. The catalyst prepared in Example 1 was then put into the catalytic ozone reaction device, and the catalyst dosage was 500 mg/L. Ozone was introduced into the reactor by aeration, and the ozone concentration was detected at the reactor outlet. Phenol wastewater in the reactor was taken every 15 minutes to detect its COD size.

The experimental results are shown in Figure 3. In Figure 3, The connecting line represents the removal rate of COD in phenol wastewater without adding catalyst. The connecting line represents the COD removal rate when the Bio-Fe ₅₀₀ Mn ₅₀₀ O catalyst prepared in Example 1 is added. The connecting line represents the COD removal rate when the Bio-Fe ₁₀₀₀ Mn ₂₀₀ O catalyst prepared in Example 1 is added. The connecting line represents the COD removal rate when the Bio-Mn ₅₀₀ O catalyst prepared in Example 1 is added. The connecting line represents the COD removal rate when the Bio-Fe ₂₀₀₀ O catalyst prepared in Example 1 is added. The results in Figure 3 show that after 90 minutes of reaction time, the COD removal rate of ozone oxidation without adding catalyst is 64%, and after 90 minutes of reaction, the COD removal rates of Bio-Fe ₅₀₀ Mn ₅₀₀ O, Bio-Fe ₁₀₀₀ Mn ₂₀₀ O, Bio-Mn ₅₀₀ O and Bio-Fe ₂₀₀₀ O catalysts are added, and the COD removal rates are 92%, 70%, 83% and 78% respectively. It can be seen that the Bio-FeMnOx catalysts prepared by the present invention all show the performance of highly efficient catalytic ozone oxidation degradation of COD in phenol wastewater, among which the catalytic performance of the Bio-Fe ₅₀₀ Mn ₅₀₀ O catalyst is the best.

The amount of metal ions dissolved from the Bio-Fe ₅₀₀ Mn ₅₀₀ O catalyst after catalytic ozone oxidation was tested using o-phenanthroline spectrophotometry. The results showed that after catalytic ozone oxidation, the amount of metal ions dissolved from the Bio-Fe ₅₀₀ Mn ₅₀₀ O catalyst was only 0.032 mg/L, indicating that the Bio-Fe ₅₀₀ Mn ₅₀₀ O catalyst has high stability.

The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims (10)

1. A manganese-resistant Enterobacter sp. FM-500, characterized in that the manganese-resistant Enterobacter sp. was deposited in the China Center for Type Culture Collection on April 22, 2024, with the deposit address being Wuhan University, Wuhan, China, and the deposit number being CCTCC NO: M2024737. 2. A bacterial agent, characterized in that it contains the manganese-resistant Enterobacter according to claim 1. 3. Use of the manganese-resistant Enterobacter according to claim 1 or the bacterial agent according to claim 2 in preparing a catalyst. 4. The use according to claim 3, characterized in that the catalyst is a catalyst for catalyzing ozone oxidation. 5. A manganese-resistant bacterial strain loaded with an iron-manganese catalyst, characterized in that it comprises iron and/or manganese elements and the manganese-resistant Enterobacter according to claim 1; the iron and/or manganese elements are adsorbed on the manganese-resistant Enterobacter. 6. A method for preparing the manganese-resistant strain-loaded iron-manganese catalyst according to claim 5, characterized in that iron salt and/or manganese salt are cultured with the manganese-resistant Enterobacter according to claim 1. 7. The preparation method according to claim 6, characterized in that the iron salt is ammonium ferric citrate, and the dosage of the iron salt is 0-2000 mg/L; the manganese salt is manganese sulfate, and the dosage of the manganese salt is 0-500 mg/L. 8. The preparation method according to claim 6, characterized in that the culturing is: culturing at 30°C with shaking at 170 rpm/min for 5 days. 9. Use of the manganese-resistant bacterial strain loaded with an iron-manganese catalyst as claimed in claim 5 in catalytic ozone oxidation degradation of organic pollutants. 10. Use of the manganese-resistant bacterial strain-loaded iron-manganese catalyst according to claim 9 in catalytic ozone oxidation degradation of organic pollutants, characterized in that the organic pollutants are organic pollutants in the secondary effluent of coking wastewater.