阅读说明：本技术 一种用于微生物燃料电池的包埋改性导电细菌及其制备方法 (Embedded modified conductive bacterium for microbial fuel cell and preparation method thereof ) 是由 阳晓宇 柳洁 耿伟 范依然 于 2020-04-30 设计创作，主要内容包括：本发明公开了一种用于微生物燃料电池的包埋改性导电细菌,通过对导电碳源进行亲水性改性,然后加入单宁酸溶液中,进一步超声改性,并利用铁盐与单宁酸形成的螯合产物(TA-Fe<Sup>3+</Sup>材料),一步实现导电细菌的包埋保护以及导电功能型纳米粒子与导电细菌之间的紧密结合；可有效降低电子转移电阻,促进细菌与电极之间的电子迁移,进一步提升导电细菌的产电效率；将其应用于微生物燃料电池领域,可集高活性与高产能于一体,有效解决微生物燃料电池活性低、产电效率低等问题；且涉及的制备方法简单,操作方便,处理周期短,环境友好,适合推广应用。(The invention discloses embedded modified conductive bacteria for a microbial fuel cell, which is prepared by hydrophilic modification of a conductive carbon source, then adding the modified conductive carbon source into a tannic acid solution for further ultrasonic modification, and utilizing a chelate product (TA-Fe) formed by iron salt and tannic acid 3+ Material), the embedding protection of the conductive bacteria and the tight combination between the conductive functional nano particles and the conductive bacteria are realized in one step; the electron transfer resistance can be effectively reduced, the electron transfer between the bacteria and the electrode is promoted, and the electricity generation efficiency of the conductive bacteria is further improved; the composite material is applied to the field of microbial fuel cells, can integrate high activity and high yield, and effectively solves the problems of low activity, low electricity generation efficiency and the like of the microbial fuel cells; the related preparation method is simple, the operation is convenient, the treatment period is short, and the environment is friendlyGood, suitable for popularization and application.)

1. A preparation method of embedded modified conductive bacteria for a microbial fuel cell is characterized by comprising the following steps:

1) adding a carbon source into the mixed acid solution, carrying out heating reaction under the stirring condition, standing and settling a reaction product, removing a supernatant, and washing to obtain a hydrophilic carbon material;

2) adding the hydrophilized carbon material into a tannic acid solution, and carrying out ultrasonic reaction to obtain a tannic acid suspension;

3) and (3) mixing the Shewanella solution with the tannin turbid liquid and the iron salt solution in sequence, and performing oscillation treatment, centrifugation and washing to obtain the embedded modified conductive bacteria.

2. The production method according to claim 1, wherein the carbon source is conductive carbon black or carbon nanotubes; wherein the diameter of the carbon nano tube is 20-30 nm, and the length of the carbon nano tube is 0.5-2 mu m; the conductive carbon black has an average particle diameter of 30 to 50 nm.

3. The method according to claim 1, wherein the iron salt is FeCl₃(ii) a The mixed acid solution is formed by mixing concentrated sulfuric acid and concentrated nitric acid.

4. The preparation method of claim 1, wherein the volume ratio of the carbon source to the mixed acid solution is 1: 1.5-2.

5. The preparation method according to claim 1, wherein the heating reaction temperature in step 1) is 90-100 ℃ for 2-3 h.

6. The method according to claim 1, wherein the concentration of tannic acid in the solution system for forming the tannic acid suspension in the step 2) is 0.05 to 0.063mmol/L, and the concentration of the hydrophilized carbon material is 8 to 10 g/L.

7. The preparation method according to claim 1, wherein the ultrasonic reaction time in the step 2) is 5-10 min.

8. The method according to claim 1, wherein OD of the Shewanella solution₆₀₀0.8 to 1.2; the concentration of the ferric salt solution is 0.04-0.05 mmol/L.

9. The preparation method according to claim 1, wherein the volume ratio of the Shewanella solution, the tannin suspension and the iron salt solution in the step 3) is (2-3): 1-1.5): 1.

10. An embedded modified conductive bacterium prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of electrochemistry, and particularly relates to embedded modified conductive bacteria for a microbial fuel cell and a preparation method thereof.

Background

At present, two fundamental problems of the sustainable development of human social energy are solving the increasingly serious environmental pollution problem and exploring new energy.

The microbial fuel cell is a new concept device capable of realizing energy conversion and energy production, and can be used as a device for producing energy by utilizing organic wastes to move to the world energy stage. The microbial fuel cell can convert organic matters in waste into electric energy by oxidation, and has huge application potential in wide fields such as wastewater treatment and the like. However, due to the limitation of the prior art, the problems of low bacterial activity, low bacterial load capacity, difficulty in electron transfer between bacteria and electrodes (mainly transporting electrons through conductive proteins on the surfaces of bacteria) and the like generally exist, so that the power density of the current microbial fuel cell is obviously lower than the theoretical value. Therefore, the modification of microorganisms such as conductive bacteria and the like is further carried out, and the modification has important research and application significance.

Disclosure of Invention

The invention mainly aims to provide the embedded modified conductive bacteria for the microbial fuel cell, aiming at the defects in the prior art, the embedded modified conductive bacteria can effectively maintain the activity of the conductive bacteria and improve the electricity generation performance of the conductive bacteria, remarkably improve the problems of low activity, low electricity generation efficiency and the like of the conventional microbial fuel cell, and the related preparation method is simple, convenient to operate and suitable for popularization and application.

In order to achieve the purpose, the invention adopts the technical scheme that:

a preparation method of embedded modified conductive bacteria for a microbial fuel cell comprises the following steps:

1) adding a carbon source into the mixed acid solution, carrying out heating reaction under the stirring condition, standing and settling a reaction product, removing a supernatant, and washing to obtain a hydrophilic carbon material;

2) adding the obtained hydrophilic carbon material into a tannic acid solution, and carrying out ultrasonic reaction to obtain a tannic acid suspension;

3) and (3) mixing the Shewanella solution with the tannin turbid liquid and the iron salt solution in sequence, and performing oscillation treatment, centrifugation and washing to obtain the embedded modified conductive bacteria.

In the above scheme, the carbon source is conductive carbon black or carbon nanotubes, preferably carbon nanotubes; wherein the diameter of the carbon nano tube is 20-30 nm, and the length of the carbon nano tube is 0.5-2 mu m; the conductive carbon black has an average particle diameter of 30 to 50 nm.

In the above scheme, the iron salt is FeCl₃。

In the scheme, the mixed acid solution is formed by mixing concentrated sulfuric acid and concentrated nitric acid according to the volume ratio of 3: 1-2.

In the scheme, the volume ratio of the carbon source to the mixed acid solution is 1-1.5: 2.

In the scheme, the heating reaction temperature in the step 1) is 90-100 ℃, and the time is 2-3 h.

In the scheme, in the solution system for forming the tannic acid suspension in the step 2), the concentration of the tannic acid is 0.05-0.063 mmol/L, and the concentration of the hydrophilized carbon material is 8-10 g/L.

In the scheme, the ultrasonic reaction time in the step 2) is 5-10 min, and the ultrasonic power is preferably 80W.

In the above scheme, OD of the Shewanella solution₆₀₀＝0.8～1.2。

In the scheme, the concentration of the ferric salt solution is 0.04-0.05 mmol/L.

In the scheme, the volume ratio of the Shewanella solution, the tannic acid turbid liquid and the iron salt solution in the step 3) is (2-3): 1-1.5): 1.

In the scheme, the Shewanella solution, the tannic acid solution and the iron salt solution are corresponding aqueous solutions.

In the scheme, the Shewanella is cultured in an anaerobic environment by using an MR-1 anaerobic culture medium.

In the above embodiment, the preparation method of the MR-1 anaerobic culture medium is preferably: 0.5g of yeast extract, 1g of peptone and 1g of NaCl are added to 100mL of water, the pH is adjusted to neutral after uniform mixing, and then 0.5mL of a 0.75 wt% sodium lactate solution is added.

In the scheme, the Shewanella bacitracinThe culture conditions are as follows: in CO₂And (3) carrying out shake cultivation for 10-12 h under the environment, wherein the temperature of a shaking table is 30-35 ℃, and the rotating speed is 200-220 rpm.

The embedded modified conductive bacteria obtained according to the scheme can keep good activity of the Shewanella under extreme conditions, can further solve the problems that electron transfer is difficult to carry out between the Shewanella and an electrode and the like, and can effectively improve the electricity generation efficiency when being applied to a microbial fuel cell.

Compared with the prior art, the invention has the beneficial effects that:

1) the invention carries out hydrophilic modification on a conductive carbon source, then adds the hydrophilic modification into a tannic acid solution for further ultrasonic modification, and utilizes a chelate product (TA-Fe) formed by iron salt and tannic acid³⁺Material), the embedding protection of the conductive bacteria and the tight combination between the conductive functional nano particles and the conductive bacteria are realized in one step; on the one hand TA-Fe formed on the surface of electrically conductive bacteria³⁺The shell layer of the material prevents the conductive bacteria from being interfered by external extreme environment and keeps good activity of the conductive bacteria; on the other hand, the conductive functional nano particles are tightly combined with conductive protein on the surface of the conductive bacteria, so that the electron transfer resistance can be effectively reduced, the electron transfer between the bacteria and the electrode is promoted, and the electricity generation efficiency of the conductive bacteria is further improved.

2)TA-Fe³⁺The material and the conductive functional nano particles (particularly the hydrophilic modified carbon nano tubes) can greatly reduce the impedance of bacteria and remarkably improve the power density of the microbial fuel cell taking the bacteria as the anode.

3) The preparation method provided by the invention is simple, convenient to operate, short in treatment period, environment-friendly and suitable for popularization and application.

Drawings

FIG. 1 is an SEM photograph of modified Shewanella embedding obtained in example 1;

FIG. 2 is a UV characterization chart of the embedding modified Shewanella and Eubacterium obtained in example 1;

FIG. 3 is a graph showing the AC impedance of the modified Shewanella embedding bacterium obtained in example 1;

FIG. 4 is a graph showing the electric power generation performance of the modified Shewanella embedded strain obtained in examples 1 and 2;

FIG. 5 is a graph showing the growth of Shewanella embedding modified strains and naked bacteria obtained in example 1;

FIG. 6 is a graph showing the survival rate of the embedded modified Shewanella and the naked bacterium obtained in example 1 under extreme conditions, which correspond to four use conditions of (a) a high temperature of 45 ℃; (b) 1.35% osmotic pressure; (c) carrying out 254nm ultraviolet irradiation; (d)10mg/mL lysozyme;

FIG. 7 is an SEM photograph of modified Shewanella embedding obtained in example 2;

FIG. 8 is a graph showing the AC impedance of the modified Shewanella embedding bacterium obtained in example 2;

FIG. 9 is a graph showing the AC impedance of the modified Shewanella bacteria obtained in comparative example 1;

FIG. 10 is an SEM photograph of the embedding modified Shewanella bacteria obtained in comparative example 2;

FIG. 11 is a graph showing the AC impedance of the embedded modified Shewanella bacteria obtained in comparative example 2.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the following examples, conductive black having an average particle diameter of 40nm was used; the diameter of the carbon nano tube is 20-30 nm, and the length of the carbon nano tube is 0.5-2 mu m; the sheet diameter of the graphene oxide is 0.5-5 mu m, and the number of layers is 1-6.