CN104103847B - Single-double chamber coupling MFC (microbial fuel cell) stack and self-regulation method of PH value - Google Patents

Abstract

The invention discloses a single-double-chamber coupled microbial fuel cell stack and a method for self-adjusting pH value; the single-double-chamber coupled microbial fuel cell stack includes n single-chamber microbial fuel cells and n double-chamber microbial fuel cells; n is set to ≥ 1 is a natural number; it is characterized in that: the single-chamber microbial fuel cell is a single-chamber microbial fuel cell using an air cathode, and the double-chamber microbial fuel cell uses a catholyte and separates the cathode chamber and the anode chamber with a proton exchange membrane double-chamber microbial fuel cell; the waste liquid outlet of the anode chamber of the first double-chamber microbial fuel cell is connected to the culture solution inlet of the first single-chamber microbial fuel cell; the waste liquid outlet of the first single-chamber microbial fuel cell It is connected with the culture solution inlet of the anode chamber of the second dual-chamber microbial fuel cell; the invention solves the problem of medium acidification, and the battery stack can be enlarged and stacked according to needs; it can be widely used in the fields of biology, energy, and environmental protection.

Description

Single and double chamber coupled microbial fuel cell stack and method for self-adjusting pH value

technical field

The present invention relates to a microbial fuel single-cell stack, in particular to a single-double-chamber coupling microbial fuel cell stack and a method for self-adjusting pH value.

Background technique

Microbial fuel cell (MFC) can use electrogenic bacteria to directly degrade organic matter to generate electricity, and is considered to be a very potential technology for generating energy from wastewater. However, the voltage of a single microbial fuel cell is low, and multiple microbial fuel cells need to be connected in series on the circuit to increase the voltage to meet the needs of practical applications. At the same time, the wastewater treatment capacity of a single microbial fuel cell is limited, and multiple microbial fuel cells need to be connected in series on the waterway to improve the wastewater treatment effect and wastewater treatment capacity.

Traditional microbial fuel cell stacks simply use dual-chamber microbial fuel cells or single-chamber microbial fuel cells in series, but both have shortcomings:

When a single-chamber microbial fuel cell is used to form a stack, since adjacent cells share the electrolyte, it is easy to cause a short circuit of the electrolyte, resulting in a serious loss of stack voltage (Zhuang and Zhou2009).

When the stack is composed of dual-chamber microbial fuel cells alone, the culture medium will be acidified. Since the traditional dual-compartment microbial fuel cell uses a proton exchange membrane to separate the chambers, it is easy to cause proton accumulation at the anode (Rozendal, Hamelers, and Buisman2006). If the pH buffering capacity of the medium is insufficient, it will lead to anodic acidification and affect the metabolic activity of anodoelectrotrophs (Puiget al. 2010). The series connection of multiple battery anode waterways will inevitably lead to aggravated acidification problems. However, unfavorable operating conditions such as anodic acidification and lack of medium induce the reverse polarity of the stack, which limits the output power of the stack (Oh and Logan2007). Therefore, some scholars adopt the method of artificially adjusting the pH (Zhuang et al.2012) (Zhang et al.2013), but this method cannot continuously adjust the pH of the medium and requires additional manpower. Some scholars try to use high-concentration buffer solutions to solve the acidification problem of the medium (Fan, Hu, and Liu2007), but high-concentration buffer solutions are not only expensive, but also cause environmental pollution. Some buffer solutions can even enhance the growth of methanogens, compete with electrogenic bacteria, and affect the metabolism of electrogenic bacteria (Fan, Hu, and Liu2007). Recently, some scholars have proposed to prevent the acidification of the anolyte by circulating the anode and cathode solution (Freguia et al.2008), but this method is likely to cause the formation of biofilm in the cathode chamber and blockage, which is not conducive to the use of more efficient electrolysis liquid.

Therefore, the problem of medium acidification hinders the scale-up of microbial fuel cell stacks and affects the practical application of microbial fuel cells.

Contents of the invention

The technical problem to be solved by the present invention is to provide a microbial fuel cell stack and a method for self-adjusting the pH value, so as to realize the automatic adjustment of the pH value, thereby improving the performance of the microbial fuel cell stack.

In order to solve the problems of the technologies described above, the first technical solution of the present invention is to include the following steps:

A. Make n single-chamber microbial fuel cells that only use air cathodes; and set culture solution inlets and waste liquid outlets in the battery chamber; n takes a natural number ≥ 1;

B, make n only adopt catholyte and use proton exchange membrane to separate the dual-chamber microbial fuel cell of cathode chamber and anode chamber; and electrolyte outlet;

C. Inoculate n single-chamber microbial fuel cells and n double-chamber microbial fuel cells with activated sludge so that they can generate continuous current;

D. Connect the culture solution inlet of the anode chamber of the first dual-chamber microbial fuel cell to the culture medium storage, the waste liquid outlet of the anode chamber of the first dual-chamber microbial fuel cell and the culture fluid of the first single-chamber microbial fuel cell Inlet connection; the waste liquid outlet of the first single-chamber microbial fuel cell is connected to the culture solution inlet of the second double-chamber microbial fuel cell anode chamber; the waste liquid outlet of the second double-chamber microbial fuel cell anode chamber is connected to the second double-chamber microbial fuel cell anode chamber The culture solution inlets of two single-chamber microbial fuel cells are connected; and so on; the waste liquid outlet of the anode chamber of the nth double-chamber microbial fuel cell is connected with the culture fluid inlet of the nth single-chamber microbial fuel cell; all double-chamber microorganisms The electrolyte inlet of the cathode chamber of the fuel cell is connected to the electrolyte storage at the same time, and the waste liquid outlet of the cathode chamber of all dual-chamber microbial fuel cells is connected to the waste liquid tank;

E. The culture medium is injected in a continuous batch or continuous flow mode, and the culture medium will flow through the first double-chamber microbial fuel cell anode chamber, the first single-chamber microbial fuel cell chamber, and the second double-chamber Microbial fuel cell anode chamber, the second single-chamber microbial fuel cell chamber...the nth double-chamber microbial fuel cell anode chamber and the nth single-chamber microbial fuel cell chamber;

F. The catholyte is injected into the cathode chamber of the dual-chamber microbial fuel cell through the electrolyte inlet provided in the cathode chamber.

The principle of the method for the self-regulating pH value of the microbial fuel cell stack of the present invention is: the cathode biofilm in the single-chamber microbial fuel cell of the present invention has undergone the following reactions due to being close to the air:

CH ₃ COO ^- +H ⁺ +2O ₂ →2CO ₂ +2H ₂ O

It can be seen that in a single-chamber microbial fuel cell, the consumption of 1 mol of acetate is accompanied by the consumption of 1 mol of hydrogen ions, which indicates that the reaction of degrading the medium to generate electricity in the single-chamber microbial fuel cell is accompanied by the consumption of hydrogen ions. Therefore, the hydrogen ions accumulated in the chambers of the dual-chamber MFC were consumed in the single-chamber MFC, thereby keeping the culture medium neutral and realizing the continuous adjustment of pH.

The proton exchange membrane of the dual-chamber microbial fuel cell increases the ion conduction resistance between two adjacent microbial fuel cells and avoids the occurrence of electrolyte short circuit between adjacent cells.

The second technical solution of the present invention is that the single-double-chamber coupled microbial fuel cell stack includes n single-chamber microbial fuel cells and n double-chamber microbial fuel cells; n is a natural number ≥ 1; it is characterized in that:

The single-chamber microbial fuel cell is a single-chamber microbial fuel cell using an air cathode, and a culture solution inlet and a waste liquid outlet are arranged in the cell chamber; the double-chamber microbial fuel cell is a catholyte and a proton exchange membrane A dual-chamber microbial fuel cell that separates the cathode chamber and the anode chamber, and the culture solution inlet and waste liquid outlet are arranged in the anode chamber, and the electrolyte inlet and electrolyte outlet are arranged in the cathode chamber;

The culture solution inlet of the anode chamber of the first dual-chamber microbial fuel cell is connected to the culture medium storage, and the waste liquid outlet of the anode chamber of the first double-chamber microbial fuel cell is connected with the culture solution inlet of the first single-chamber microbial fuel cell; The waste liquid outlet of the first single-chamber microbial fuel cell is connected with the culture solution inlet of the anode chamber of the second double-chamber microbial fuel cell; the waste liquid outlet of the anode chamber of the second double-chamber microbial fuel cell is connected with the second single-chamber microbial fuel cell The culture solution inlet of the nth single-chamber microbial fuel cell is connected; and so on; the waste liquid outlet of the anode chamber of the nth double-chamber microbial fuel cell is connected to the culture fluid inlet of the nth single-chamber microbial fuel cell; all double-chamber microbial fuel cells The electrolyte inlet of the cathode chamber is connected to the electrolyte storage at the same time, and the waste liquid outlet of the cathode chamber of all dual-chamber microbial fuel cells is connected to the waste liquid tank;

The medium is injected in a continuous batch or continuous flow mode, and the medium will flow through the anode chamber of the first dual-chamber microbial fuel cell, the first single-chamber microbial fuel cell chamber, and the second dual-chamber microbial fuel cell Anode chamber, the second single-chamber microbial fuel cell chamber...the nth double-chamber microbial fuel cell anode chamber and the nth single-chamber microbial fuel cell chamber; catholyte enters the electrolyte through the cathode chamber Injection into the cathode chamber of a dual-chamber microbial fuel cell;

The n single-chamber microbial fuel cell electrodes are connected in series, parallel or mixed connection with the n double-chamber microbial fuel cell electrodes.

The present invention proposes that a single-chamber microbial fuel cell and a double-chamber microbial fuel cell are combined to form an electric stack, and the anolyte of the double-chamber microbial fuel cell in the electric stack is adjusted to pH neutrality by the single-chamber microbial fuel cell, so that the lower microbial fuel cell is not affected. Media acidification effect. The existence of the dual-chamber microbial fuel single cell avoids the occurrence of electrolyte short circuit. The single-chamber microbial fuel cell cooperates with the double-chamber microbial fuel cell to maintain a high output power and improve the overall performance of the stack.

The beneficial effects of the single-double-chamber coupled microbial fuel cell stack and the method for self-adjusting pH value of the present invention are: the anolyte of the double-chamber microbial fuel cell in the electric stack of the present invention is adjusted to be pH neutral through the single-chamber microbial fuel cell, The lower-level microbial fuel cell is not affected by the acidification of the medium; and the combination of the single-chamber microbial fuel cell and the double-chamber microbial fuel cell maintains a higher output power and improves the overall performance of the stack; the invention solves the problem of medium acidification The problem is that the microbial fuel cell stack can be enlarged and stacked according to the needs; it can be widely used in the fields of biology, energy, environmental protection, etc., and has a good application prospect.

Description of drawings

Figure 1 is a schematic diagram of the structure and electrode connections of Embodiment 4.

Figure 2 is a schematic diagram of the electrode hybrid structure.

Fig. 3 is the discharge curve, the pH variation diagram and the sodium acetate variation diagram obtained by the method of Example 1.

Fig. 4 is the power curve of the electric stack of embodiment 4.

Fig. 5 is the polarization curve of the electric stack of embodiment 4.

detailed description

The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

Embodiment 1: the method for self-regulating pH value of microbial fuel cell stack, it is characterized in that: comprise the steps:

A. Make a single-chamber microbial fuel cell. The cathode of the single-chamber microbial fuel cell is a carbon cloth modified with platinum on one side and treated with hydrophobic treatment. The platinum-containing catalyst side faces the middle chamber, and the other side faces the air; and in the battery chamber The chamber is equipped with a culture solution inlet and a waste solution outlet;

B. Make a dual-chamber microbial fuel cell that adopts catholyte and separates the cathode chamber and the anode chamber with a proton exchange membrane; set the culture solution inlet and the waste liquid outlet in the anode chamber, and set the electrolyte inlet in the cathode chamber and electrolyte outlet;

C. Inoculate single-chamber microbial fuel cells and double-chamber microbial fuel cells with activated sludge so that they can generate continuous current;

D. Assembling the microbial fuel cell stack: connect the culture medium inlet of the anode chamber of the dual-chamber microbial fuel cell to the culture medium storage, and connect the waste liquid outlet of the anode chamber of the double-chamber microbial fuel cell to the culture fluid inlet of the single-chamber microbial fuel cell; The waste liquid outlet of the single-chamber microbial fuel cell is connected to the culture solution inlet of the anode chamber of the dual-chamber microbial fuel cell; the electrolyte inlet of the cathode chamber of the dual-chamber microbial fuel cell is connected to the electrolyte storage, and the cathode chamber of the dual-chamber microbial fuel cell The waste liquid outlet of the waste liquid is connected to the waste liquid tank; and the electrode of the double-chamber microbial fuel cell is connected in parallel with the electrode of the single-chamber microbial fuel cell;

E. The culture medium is injected in a continuous batch mode, so that the culture medium flows through the anode chamber of the double-chamber microbial fuel cell and the chamber of the single-chamber microbial fuel cell in sequence; the composition of the culture medium is Na ₂ HPO ₄ ·12H ₂ O:15.35g/ L, KH ₂ PO ₄ : 3g/L, CH ₃ COONa·3H ₂ O: 10.14g/L, NaCl: 0.5g/L, NH ₄ Cl: 0.1g/L, MgSO ₄ ·7H ₂ O: 0.1g/L L, CaCl ₂ : 11.327mg/L;

F. The catholyte is stored in the electrolyte storage, and injected into the cathode chamber of the double-chamber microbial fuel cell through the electrolyte inlet provided in the cathode chamber, and the catholyte is 30 mM·L ^-1 potassium ferricyanide solution.

Observe the operating parameters of the stack, see Figure 3. During the operation of the stack, although the pH value dropped slightly, it finally stabilized at around 6.8. Moreover, it can maintain a stable output voltage above 0.5V during operation.

It can also be seen from Figure 3 that the voltage of the stack composed of dual-chamber-double-chamber microbial fuel cells continues to drop and cannot remain stable. However, although the electric stack composed of single-chamber-single-chamber microbial fuel cells can maintain a stable pH of about 7.5, the output voltage is only 80% of that of Example 1.

Embodiment 2: the method for microbial fuel cell stack self-regulation pH value, comprises the steps:

A. Make two single-chamber microbial fuel cells. The cathode of the single-chamber microbial fuel cell is carbon paper modified with platinum on one side and treated with hydrophobic treatment. The platinum-containing catalyst side faces the middle chamber and the other side faces the air; and in the battery chamber The chamber is equipped with a culture solution inlet and a waste solution outlet;

B. Make two double-chamber microbial fuel cells that adopt the catholyte and separate the cathode chamber and the anode chamber with a proton exchange membrane; and set the culture solution inlet and the waste liquid outlet in the anode chamber, and set the electrolyte in the cathode chamber Import and export of electrolyte;

C. Inoculate the single-chamber microbial fuel cell and the dual-chamber microbial fuel cell with activated sludge so that it can generate continuous current;

D. Assembling the microbial fuel cell stack: the culture solution inlet of the anode chamber of the first double-chamber microbial fuel cell is connected to the culture medium storage, the waste liquid outlet of the anode chamber of the first double-chamber microbial fuel cell is connected to the first single chamber The culture solution inlet of the microbial fuel cell is connected; the waste liquid outlet of the first single-chamber microbial fuel cell is connected to the culture fluid inlet of the anode chamber of the second double-chamber microbial fuel cell; the anode chamber of the second double-chamber microbial fuel cell The waste liquid outlet of the second single-chamber microbial fuel cell is connected to the culture solution inlet of the second single-chamber microbial fuel cell, and the waste liquid outlet of the second single-chamber microbial fuel cell is connected to the waste liquid tank; the electrolyte inlet of the cathode chamber of all double-chamber microbial fuel cells At the same time, the electrolyte storage is connected, and the waste liquid outlets of the cathode chambers of all double-chamber microbial fuel cells are connected to the waste liquid tank; and the electrodes of the four microbial fuel cells are connected in series;

E. Inject the culture medium in a continuous flow mode, so that the culture medium flows through the first double-chamber microbial fuel cell anode chamber, the first single-chamber microbial fuel cell chamber, and the second double-chamber microbial fuel cell anode chamber chamber and the second single-chamber microbial fuel cell chamber, and then discharged through the second single-chamber microbial fuel cell waste liquid outlet; the medium composition is Na ₂ HPO ₄ ·12H ₂ O:8.35g/L, KH ₂ PO ₄ : 2g/L, CH ₃ COONa·3H ₂ O: 8.14g/L, NaCl: 0.75g/L, NH ₄ Cl: 0.2g/L, MgSO ₄ · 7H ₂ O: 0.2g/L, CaCl ₂ : 13.327 mg/L;

F. The catholyte is injected into the cathode chamber of the dual-chamber microbial fuel cell through the electrolyte inlet provided in the cathode chamber, and the catholyte is 40 mM·L ⁻¹ potassium sulfite solution.

Embodiment 3: the method for microbial fuel cell stack self-regulation pH value, comprises the steps:

A, making n single-chamber microbial fuel cells that only use air cathodes; the single-chamber microbial fuel cells are carbon papers modified with platinum and treated with water repellent on one side, the platinum-containing catalyst faces the middle chamber, and the other side faces the air ; And the culture solution inlet and the waste solution outlet are set in the battery chamber; n is a natural number ≥ 3;

B, make n only adopt catholyte and use proton exchange membrane to separate the dual-chamber microbial fuel cell of cathode chamber and anode chamber; and electrolyte outlet;

C. Inoculate n single-chamber microbial fuel cells and n double-chamber microbial fuel cells with activated sludge so that they can generate continuous current;

D. Assembling the microbial fuel cell stack: connect the culture solution inlet of the anode chamber of the first double-chamber microbial fuel cell to the culture medium storage, and connect the waste liquid outlet of the anode chamber of the first double-chamber microbial fuel cell to the first single-chamber The culture solution inlet of the microbial fuel cell is connected; the waste liquid outlet of the first single-chamber microbial fuel cell is connected to the culture fluid inlet of the anode chamber of the second double-chamber microbial fuel cell; the anode chamber of the second double-chamber microbial fuel cell The waste liquid outlet of the second single-chamber microbial fuel cell is connected to the culture liquid inlet; and so on; the waste liquid outlet of the nth double-chamber microbial fuel cell anode chamber is connected to the culture liquid inlet of the nth single-chamber microbial fuel cell Connection, the waste liquid outlet of the nth single-chamber microbial fuel cell is connected to the waste liquid tank; the electrolyte inlet of the cathode chamber of all double-chamber microbial fuel cells is connected to the electrolyte storage at the same time, and the cathode chamber of all double-chamber microbial fuel cells The waste liquid outlet is connected to the waste liquid tank; and each single-chamber microbial fuel cell electrode is connected in parallel with a double-chamber microbial fuel cell electrode, and then the electrodes connected in parallel are connected in series, that is, a hybrid connection is adopted; the electrode connection diagram is shown in figure 2;

E. The culture medium is injected in a continuous flow mode, and the culture medium will flow through the first double-chamber microbial fuel cell anode chamber, the first single-chamber microbial fuel cell chamber, and the second double-chamber microbial fuel cell anode chamber in sequence chamber, the second single-chamber microbial fuel cell chamber...the nth double-chamber microbial fuel cell anode chamber and the nth single-chamber microbial fuel cell chamber, and then through the waste liquid outlet of the nth single-chamber microbial fuel cell discharge;

F. The catholyte is injected into the cathode chambers of all double-chamber microbial fuel cells through the electrolyte inlet provided in the cathode chamber.

In a specific embodiment, the medium components include: Na ₂ HPO ₄ ·12H ₂ O: 2.56-15.35g/L, KH ₂ PO ₄ : 0.5-3g/L, CH ₃ COONa·3H ₂ O: 2.25- 10.14g/L, NaCl: 0.5-1g/L, NH ₄ Cl: 0.1-0.3g/L, MgSO ₄ 7H ₂ O: 0.1-0.3g/L, CaCl ₂ : 11.327-15mg/L.

The catholyte may be a potassium ferricyanide solution of 20-60 mM·L ^-1 or a potassium sulfite solution with a concentration of 20-60 mM·L ^-1 .

In a specific embodiment, a phosphate slow-release agent with a pH of 4.8 and a concentration of 40-80 mM L ^-1 can also be added to the catholyte, and the added phosphate slow-release agent and potassium ferricyanide solution or potassium sulfite solution The ratio is 4:1.

Embodiment 4: Referring to Fig. 1, the single-double chamber coupled microbial fuel cell stack consists of two single-chamber microbial fuel cells that adopt an air cathode and two double chambers that use a catholyte and separate the cathode chamber and the anode chamber with a proton exchange membrane. The single-chamber microbial fuel cell consists of a single-chamber microbial fuel cell cathode made of carbon cloth modified with platinum on one side and treated with water-repellent treatment, the platinum-containing catalyst side faces the middle chamber, and the other side faces the air; Liquid inlet and waste liquid outlet; the anode chamber of the dual-chamber microbial fuel cell is provided with a culture solution inlet and a waste liquid outlet, and the cathode chamber is provided with an electrolyte inlet and an electrolyte outlet;

The single-chamber microbial fuel cell and the double-chamber microbial fuel cell are inoculated with activated sludge so that they can generate continuous current;

Connect the culture solution inlet of the anode chamber of the first dual-chamber microbial fuel cell to the culture medium storage, the waste liquid outlet of the anode chamber of the first dual-chamber microbial fuel cell and the culture solution inlet of the first single-chamber microbial fuel cell Connection; the waste liquid outlet of the first single-chamber microbial fuel cell is connected to the culture solution inlet of the anode chamber of the second double-chamber microbial fuel cell; the waste liquid outlet of the anode chamber of the second double-chamber microbial fuel cell is connected to the second Only the culture solution inlet of the single-chamber microbial fuel cell is connected; the waste liquid outlet of the second single-chamber microbial fuel cell is connected to the waste liquid tank; the electrolyte inlet of the cathode chamber of all the double-chamber microbial fuel cells is connected to the electrolyte storage at the same time, and all The waste liquid outlet of the cathode chamber of the dual-chamber microbial fuel cell is connected to the waste liquid tank;

The electrodes of the four microbial fuel cells are connected in parallel, that is, the first dual-chamber microbial fuel cell is connected in parallel with the first single-chamber microbial fuel cell, and the second dual-chamber microbial fuel cell is connected to the second single-chamber microbial fuel cell. The fuel cell electrodes are connected in parallel, and the electrodes connected in parallel are then connected in series; the culture medium is injected in a continuous flow mode, so that the culture medium flows through the first double-chamber microbial fuel cell anode chamber and the first single-chamber microbial fuel cell chamber in sequence. , the second double-chamber microbial fuel cell anode chamber and the second single-chamber microbial fuel cell chamber, and then discharged through the second single-chamber microbial fuel cell waste liquid outlet;

The medium composition is Na ₂ HPO ₄ 12H ₂ O: 6.35g/L, KH ₂ PO ₄ : 1g/L, CH ₃ COONa 3H ₂ O: 10.14g/L, NaCl: 0.5g/L, NH ₄ Cl : 0.3g/L, MgSO ₄ 7H ₂ O: 0.3g/L, CaCl ₂ : 15.327mg/L;

The catholyte is injected into the cathode chambers of all dual-chamber microbial fuel cells through the electrolyte inlet provided in the cathode chamber; the catholyte is 40mM·L ^-1 potassium ferricyanide solution, and the pH is 4.8, concentration It is 60mM·L ^-1 phosphate slow-release agent, the ratio of added phosphate slow-release agent to potassium ferricyanide solution or potassium sulfite solution is 4:1.

Observe the operation parameters of the electric stack, see Fig. 4, Fig. 5, during the operation of the electric stack, the maximum power of the electric stack is 5.21mW. It can also be seen from Fig. 4 that the electric stack composed of four double-chamber microbial fuel cells in embodiment 4 The maximum power of the stack is 44% higher than that of the stack composed of four single-chamber microbial fuel cells, which is 56% higher.

In Example 4, the electrodes of the microbial fuel cell can also be connected in series or in parallel as required.

Embodiment 5: a single-double-chamber coupled microbial fuel cell stack, including n single-chamber microbial fuel cells and n double-chamber microbial fuel cells; n is a natural number ≥ 1; it is characterized in that:

The single-chamber microbial fuel cell is a single-chamber microbial fuel cell using an air cathode, and a culture solution inlet and a waste liquid outlet are arranged in the cell chamber; the double-chamber microbial fuel cell is a catholyte and a proton exchange membrane A dual-chamber microbial fuel cell that separates the cathode chamber and the anode chamber, and the culture solution inlet and waste liquid outlet are arranged in the anode chamber, and the electrolyte inlet and electrolyte outlet are arranged in the cathode chamber;

The culture solution inlet of the anode chamber of the first dual-chamber microbial fuel cell is connected to the culture medium storage, and the waste liquid outlet of the anode chamber of the first double-chamber microbial fuel cell is connected with the culture solution inlet of the first single-chamber microbial fuel cell; The waste liquid outlet of the first single-chamber microbial fuel cell is connected with the culture solution inlet of the anode chamber of the second double-chamber microbial fuel cell; the waste liquid outlet of the anode chamber of the second double-chamber microbial fuel cell is connected with the second single-chamber microbial fuel cell The culture solution inlet of the nth single-chamber microbial fuel cell is connected; and so on; the waste liquid outlet of the anode chamber of the nth double-chamber microbial fuel cell is connected to the culture fluid inlet of the nth single-chamber microbial fuel cell; all double-chamber microbial fuel cells The electrolyte inlet of the cathode chamber is connected to the electrolyte storage at the same time, and the waste liquid outlet of the cathode chamber of all dual-chamber microbial fuel cells is connected to the waste liquid tank;

The medium is injected in a continuous batch or continuous flow mode, and the medium will flow through the anode chamber of the first dual-chamber microbial fuel cell, the first single-chamber microbial fuel cell chamber, and the second dual-chamber microbial fuel cell Anode chamber, the second single-chamber microbial fuel cell chamber...the nth double-chamber microbial fuel cell anode chamber and the nth single-chamber microbial fuel cell chamber; catholyte enters the electrolyte through the cathode chamber Injection into the cathode chamber of a dual-chamber microbial fuel cell;

The electrodes of the single-chamber microbial fuel cell are connected in series, in parallel or in combination with the electrodes of the double-chamber microbial fuel cell;

In a specific embodiment, the medium components include: Na ₂ HPO ₄ ·12H ₂ O: 2.56-15.35g/L, KH ₂ PO ₄ : 0.5-3g/L, CH ₃ COONa·3H ₂ O: 2.25- 10.14g/L, NaCl: 0.5-1g/L, NH ₄ Cl: 0.1-0.3g/L, MgSO ₄ 7H ₂ O: 0.1-0.3g/L, CaCl ₂ : 11.327-15mg/L.

The catholyte may be a potassium ferricyanide solution of 20-60 mM·L ^-1 or a potassium sulfite solution with a concentration of 20-60 mM·L ^-1 .

In a specific embodiment, a phosphate slow-release agent with a pH of 4.8 and a concentration of 40-80 mM L ^-1 can also be added to the catholyte, and the added phosphate slow-release agent and potassium ferricyanide solution or potassium sulfite solution The ratio is 4:1.

Claims (8)

1. the method for self-regulating pH value of microbial fuel cell stack, it is characterized in that: comprise the steps: A. Make n single-chamber microbial fuel cells that only use air cathodes; and set the culture solution inlet and waste liquid outlet in the battery chamber; n takes a natural number ≥ 2; B, make n only adopt catholyte and use proton exchange membrane to separate the dual-chamber microbial fuel cell of cathode chamber and anode chamber; and electrolyte outlet; C. Inoculate n single-chamber microbial fuel cells and n double-chamber microbial fuel cells with activated sludge so that they can generate continuous current; D. Connect the culture solution inlet of the anode chamber of the first dual-chamber microbial fuel cell to the culture medium storage, the waste liquid outlet of the anode chamber of the first dual-chamber microbial fuel cell and the culture fluid of the first single-chamber microbial fuel cell Inlet connection; the waste liquid outlet of the first single-chamber microbial fuel cell is connected to the culture solution inlet of the second double-chamber microbial fuel cell anode chamber; the waste liquid outlet of the second double-chamber microbial fuel cell anode chamber is connected to the second double-chamber microbial fuel cell anode chamber The culture solution inlets of two single-chamber microbial fuel cells are connected; and so on; the waste liquid outlet of the anode chamber of the nth double-chamber microbial fuel cell is connected with the culture fluid inlet of the nth single-chamber microbial fuel cell; all double-chamber microorganisms The electrolyte inlet of the cathode chamber of the fuel cell is connected to the electrolyte storage at the same time, and the waste liquid outlet of the cathode chamber of all double-chamber microbial fuel cells is connected to the waste liquid tank; After the electrodes of the battery are connected in series, parallel or mixed connection, the electrodes of the obtained single-double chamber coupled microbial fuel cell stack are connected to an external load; E. The culture medium is injected in a continuous batch or continuous flow mode, and the culture medium will flow through the first double-chamber microbial fuel cell anode chamber, the first single-chamber microbial fuel cell chamber, and the second double-chamber Microbial fuel cell anode chamber, the second single-chamber microbial fuel cell chamber...the nth double-chamber microbial fuel cell anode chamber and the nth single-chamber microbial fuel cell chamber; F. The catholyte is injected into the cathode chamber of the dual-chamber microbial fuel cell through the electrolyte inlet provided in the cathode chamber. 2. The method for self-regulating pH value of microbial fuel cell stack according to claim 1, characterized in that: said culture medium composition comprises: Na ₂ HPO ₄ 12H ₂ O: 2.56-15.35g/L, KH ₂ PO ₄ : 0.5-3g/L, CH ₃ COONa·3H ₂ O: 2.25-10.14g/L, NaCl: 0.5-1g/L, NH ₄ Cl: 0.1-0.3g/L, MgSO ₄ 7H ₂ O: 0.1 -0.3g/L, CaCl ₂ : 11.327-15mg/L. 3. the method for self-regulating pH value of microbial fuel cell stack according to claim 1 or 2, is characterized in that: described catholyte is the potassium ferricyanide solution of 20～60mM L ^-1 or concentration is 20～60mM · L ^-1 potassium sulfite solution. 4. the method for self-regulating pH value of microbial fuel cell stack according to claim 3, is characterized in that: in catholyte, also adding pH is 4.8, and concentration is 40～80mM·L ^-1 phosphate slow-release agent, so The ratio of added phosphate slow-release agent to potassium ferricyanide solution or potassium sulfite solution is 4:1. 5. A single- and double-chamber coupled microbial fuel cell stack, including n single-chamber microbial fuel cells and n double-chamber microbial fuel cells; n is a natural number ≥ 2; it is characterized in that: The single-chamber microbial fuel cell is a single-chamber microbial fuel cell using an air cathode, and a culture solution inlet and a waste liquid outlet are arranged in the cell chamber; the double-chamber microbial fuel cell is a catholyte and a proton exchange membrane A dual-chamber microbial fuel cell that separates the cathode chamber and the anode chamber, and the culture solution inlet and waste liquid outlet are arranged in the anode chamber, and the electrolyte inlet and electrolyte outlet are arranged in the cathode chamber; The culture solution inlet of the anode chamber of the first dual-chamber microbial fuel cell is connected to the culture medium storage, and the waste liquid outlet of the anode chamber of the first double-chamber microbial fuel cell is connected with the culture solution inlet of the first single-chamber microbial fuel cell; The waste liquid outlet of the first single-chamber microbial fuel cell is connected with the culture solution inlet of the anode chamber of the second double-chamber microbial fuel cell; the waste liquid outlet of the anode chamber of the second double-chamber microbial fuel cell is connected with the second single-chamber microbial fuel cell The culture solution inlet of the nth single-chamber microbial fuel cell is connected; and so on; the waste liquid outlet of the anode chamber of the nth double-chamber microbial fuel cell is connected to the culture fluid inlet of the nth single-chamber microbial fuel cell; all double-chamber microbial fuel cells The electrolyte inlet of the cathode chamber is connected to the electrolyte storage at the same time, and the waste liquid outlet of the cathode chamber of all dual-chamber microbial fuel cells is connected to the waste liquid tank; The medium is injected in a continuous batch or continuous flow mode, and the medium will flow through the anode chamber of the first dual-chamber microbial fuel cell, the first single-chamber microbial fuel cell chamber, and the second dual-chamber microbial fuel cell Anode chamber, the second single-chamber microbial fuel cell chamber...the nth double-chamber microbial fuel cell anode chamber and the nth single-chamber microbial fuel cell chamber; catholyte enters the electrolyte through the cathode chamber Injection into the cathode chamber of a dual-chamber microbial fuel cell; The n single-chamber microbial fuel cell electrodes are connected in series, parallel or mixed connection with the n double-chamber microbial fuel cell electrodes. 6. The single-double chamber coupled microbial fuel cell stack according to claim 5, characterized in that: the medium components include: Na ₂ HPO ₄ ·12H ₂ O: 2.56-15.35g/L, KH ₂ PO ₄ : 0.5-3g/L, CH ₃ COONa 3H ₂ O: 2.25-10.14g/L, NaCl: 0.5-1g/L, NH ₄ Cl: 0.1-0.3g/L, MgSO ₄ 7H ₂ O: 0.1-0.3 g/L, CaCl ₂ : 11.327-15mg/L. 7. The single-double chamber coupled microbial fuel cell stack according to claim 5 or 6, characterized in that: the catholyte is a potassium ferricyanide solution of 20-60 mM L ^-1 or a concentration of 20-60 mM L ^-1 solution of potassium sulfite. 8. The single-double chamber coupling microbial fuel cell stack according to claim 7, characterized in that: a phosphate slow-release agent with a pH of 4.8 and a concentration of 40 to 80 mM·L ^-1 is added to the catholyte, and the added The ratio of phosphate slow-release agent to potassium ferricyanide solution or potassium sulfite solution is 4:1.