Method for generating hydrogen peroxide by biomass power generation

Abstract

Aiming at the problems of high cost and large consumption of hydrogen peroxide in the use and transportation process, the invention discloses a method for generating hydrogen peroxide by utilizing biomass to transfer electrons to a cathode through a wire to complete reaction through electron transfer of microorganisms under the condition of no electric energy input. The method also comprises a device for producing hydrogen peroxide, organic matters in the wastewater are used for providing energy for electroactive microorganisms, and the hydrogen peroxide generated in the cathode chamber can be directly used for a Fenton system to degrade the wastewater, so that the cost of a Fenton reagent is effectively reduced, and the purpose of treating wastes with wastes by using the hydrogen peroxide is achieved. The method can effectively reduce the transportation cost of the hydrogen peroxide and improve the utilization rate of the hydrogen peroxide, the device is simple in structure, and low-cost application of the Fenton system is realized.

Description

Technical Field

[0001] The invention belongs to the field of water treatment, and specifically relates to a method for in-situ production of hydrogen peroxide by an active bioelectrochemical system and the use of the method to degrade difficult-to-degrade industrial wastewater. Background Art

[0002] With the rapid development of society and the continuous utilization of resources, environmental issues have gradually become major issues that cannot be ignored worldwide, and wastewater treatment has also become an important part of environmental issues. As an advanced oxidation technology, Fenton oxidation is an efficient and effective method for treating industrial wastewater. Because of its advantages of simple operating procedures and low equipment investment, it is widely used in sewage treatment, and it has unique advantages in the oxidation and degradation of persistent organic pollutants. However, the characteristic defect of hydrogen peroxide in Fenton reagent is extremely volatile, resulting in high production, transportation and storage costs, which limits its large-scale use in industry. Based on the research of Fenton technology, some scholars have discovered electro-Fenton technology, that is, under the condition of external power input, the cathode chamber can react to produce hydrogen peroxide. Although this discovery solves the transportation and storage cost problems of hydrogen peroxide, the input of external power still requires a lot of investment, which is still the bottleneck for the popularization and application of this technology. Summary of the invention

[0003] In order to solve the above problems, the present invention cleverly utilizes the microbial electrochemical system to achieve the production of low-cost Fenton reagent, uses microorganisms as a medium to decompose organic matter in the solution, realizes the conversion of chemical energy into electrical energy, and "in situ produces" H2O2 by electrochemical reduction of molecular oxygen in the cathode chamber, thereby achieving low-cost production of hydrogen peroxide.

[0004] In order to achieve the above objectives, this application adopts the following technical solutions:

[0005] A method for generating hydrogen peroxide by using biomass to generate electricity, wherein hydrogen peroxide is generated by a microbial electrochemical system, wherein the microbial electrochemical system uses microorganisms as a medium to decompose organic matter in an anolyte and simultaneously generates hydrogen peroxide by electrochemically reducing molecular oxygen in a cathode chamber.

[0006] The microbial electrochemical system comprises a hydrogen peroxide production device and an external oxygen supply device, wherein the hydrogen peroxide production device comprises a hollow shell with a detachable top and openings I and II on the top of the shell, the shell is separated into an anode chamber and a cathode chamber by a proton exchange membrane placed therein, the anode chamber is provided with an anode electrode and an anode liquid is added, the cathode chamber is provided with a cathode electrode and a cathode liquid is added, the anode electrode and the cathode electrode are respectively connected to an external resistor through an external wire, the microbial membrane attached to the anode electrode can transfer electrons to the cathode chamber through the wire through its own extracellular electron transfer effect, the hydrogen ions generated by ionization in the anode chamber are transferred to the cathode chamber through the proton exchange membrane, the cathode chamber is aerated by an external oxygen supply device, and oxygen and hydrogen ions react in the cathode chamber to generate hydrogen peroxide under the action of electrons.

[0007] Furthermore, the microorganisms of the present application may be microorganisms of the class γ-Proteobacteria.

[0008] The best microorganism in this application is Shewanella MR-1.

[0009] Furthermore, when the cathode electrode of the present application is a platinum sheet and the external resistance is 200Ω, the maximum and stable hydrogen peroxide output concentration is 0.46 mg / L.

[0010] Furthermore, the present application method specifically comprises the following steps:

[0011] a. Take out the purchased Shewanella lyophilized powder, pour in sterile water, mix well, take out an appropriate amount of the mixture with a pipette or inoculation loop, apply it on the prepared solid culture medium, and place the culture medium in a constant temperature incubator at 30°C for 2-3 days;

[0012] b. On a sterile operating table, use an inoculation loop to pick up a small amount of colonies growing in the solid culture medium, place them in a liquid culture medium, and culture the culture medium in a constant temperature shaking incubator at 30°C for 1-2 days;

[0013] c. Under a sterile environment, use a sterile measuring cylinder to measure 40 ml of the anolyte and place it in the anode chamber. Take an appropriate amount of liquid culture medium into a centrifuge tube and centrifuge it in a centrifuge at 3500 r / s for 3 minutes. Then, place the bacteria obtained by centrifugation into the anode chamber for cultivation;

[0014] d. In the startup phase of the dual-chamber bioelectrochemical system, the anode needs to be inoculated so that the extracellular electrogenic bacteria occupy the anode to form a biofilm to ensure the operation of the subsequent reactor. Shewanella MR-1 and 40 ml of anode liquid are added to the anode chamber for inoculation, and 0.1 M anhydrous sodium sulfate solution is added to the cathode chamber; after the first inoculation is completed, the dual-chamber bioelectrochemical system is connected in series with a 200 Ω resistor, and the dual-chamber bioelectrochemical system is placed in a constant temperature shaking incubator for culture, and the anode inoculation liquid is replaced every two days until the microorganisms are successfully inoculated and begin to grow normally;

[0015] e. After the electrogenic bacteria successfully occupy the surface of the anode sheet and gradually proliferate to form a biofilm, the subsequent electricity generation performance and hydrogen peroxide production performance can be measured.

[0016] The microbial electrochemical system mentioned in the present invention is a new wastewater treatment technology that couples biotechnology with electrochemical methods to treat wastewater. It can use the action of microorganisms to convert chemical energy in organic matter into electrical energy, and achieve synchronous electricity generation while treating wastewater. The present invention uses active organisms and adopts microbial electrochemical methods to use the microorganisms' own electricity generation to transfer electrons so that the device produces hydrogen peroxide, and then couples with the Fenton system to improve the degradation efficiency of wastewater.

[0017] The present application integrates the degradation of wastewater and the preparation of hydrogen peroxide, which can achieve green environmental protection, reduce costs, and improve safety and reliability.

[0018] Advantages of this application:

[0019] 1. "No reagents, no power" reduces production costs. The raw materials used in the traditional anthraquinone method for preparing hydrogen peroxide are mainly 2-ethylanthraquinone, but the raw material cost is high and the reaction conditions are harsh, which leads to a significant increase in its production cost. The present invention uses wastewater as a microbial matrix, does not require additional reagents and has no external energy input, effectively reducing the production cost of hydrogen peroxide.

[0020] 2. "In-situ production" saves transportation costs. Since hydrogen peroxide is highly corrosive, volatile and explosive, its transportation costs are greatly increased. The present invention realizes the method of in-situ production of hydrogen peroxide by electro-reducing molecular oxygen, thereby eliminating transportation costs.

[0021] 3. "Prepared on use" eliminates storage costs. Due to the characteristic defects of hydrogen peroxide being extremely volatile and easy to decompose, it suffers serious loss during storage. The present invention prepares hydrogen peroxide in wastewater, and the produced hydrogen peroxide is used for wastewater treatment simultaneously, without the need for storage, thus eliminating storage costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram of a hydrogen peroxide production device according to the present invention.

[0023] Figure 2 This is a diagram of the microbial electrochemical system of the present invention.

[0024] Figure 3 The figure is a working principle diagram of the method of the present invention.

[0025] Figure 4 H2O2 concentration produced by the system when using different cathode materials.

[0026] In the figure, 1, shell; 2, opening I; 3, opening II; 4, proton exchange membrane; 5, anode electrode; 6, cathode electrode; 7, anode liquid; 8, cathode liquid; 9, wire; 10, resistor. DETAILED DESCRIPTION

[0027] The hydrogen peroxide production device used in the microbial electrochemical system of the present invention is a hollow shell 1 with a detachable top made of glass. The top of the shell 1 is provided with two through holes with an aperture of 5 mm each: opening I 2 and opening II 3; opening I 2 and opening II 3 are respectively located at the top of the anode chamber and the cathode chamber; the pretreated proton exchange membrane 4 is placed in the shell 1 to separate the anode chamber and the cathode chamber, the volume ratio of the anode chamber and the cathode chamber is 1:1, and the anode liquid 7 and the cathode liquid 8 are respectively added to the anode chamber and the cathode chamber; the anode chamber is provided with an anode electrode 5, and the cathode chamber is provided with a cathode electrode 6, and the cathode electrode 6 and the anode electrode 5 are respectively connected to an external resistor 10 through an external copper wire 9, and its structure is as follows: Figure 1 shown.

[0028] (1) Anode chamber microbial culture:

[0029] a. Take out the purchased Shewanella lyophilized powder, pour in sterile water, mix well, take out an appropriate amount of the mixture with a pipette or inoculation loop, apply it on the prepared solid culture medium, and place the culture medium in a constant temperature incubator at 30℃ for 2-3 days.

[0030] b. On a sterile operating table, use an inoculation loop to pick up a small amount of colonies growing on the solid culture medium, put them into the liquid culture medium, and place the culture medium in a constant temperature shaking incubator at 30°C for 1-2 days.

[0031] c. Under sterile conditions, use a sterile measuring cylinder to measure 40 ml of the anode liquid and place it in the anode chamber. Take an appropriate amount of liquid culture medium into a centrifuge tube and centrifuge it in a centrifuge at 3500 r / s for 3 minutes. Then place the bacteria obtained by centrifugation into the anode chamber for culture.

[0032] d. In the startup phase of the dual-chamber bioelectrochemical system, the anode needs to be inoculated so that the extracellular electrogenic bacteria occupy the anode to form a biofilm to ensure the operation of the subsequent reactor. In this experiment, Shewanella MR-1 and 40 ml of anode liquid were added to the anode chamber for inoculation, and 0.1 M anhydrous sodium sulfate solution was added to the cathode chamber. After the first inoculation, the dual-chamber bioelectrochemical system was connected in series with a 200Ω resistor, and the dual-chamber bioelectrochemical system device was placed in a constant temperature shaking incubator for cultivation. The anode inoculation liquid was replaced every two days until the microorganisms were successfully inoculated and began to grow normally.

[0033] e. After the electrogenic bacteria successfully occupy the surface of the anode sheet and gradually proliferate to form a biofilm, the subsequent electricity generation performance and hydrogen peroxide production performance can be measured.

[0034] (2) Preparation of experimental materials and reagents:

[0035] a. The anode liquid: first prepare 5×M9 mother liquid in a 1L volumetric flask, take 200mL of the mother liquid into another clean 1L volumetric flask, add distilled water to about 800ml, and sterilize. On a clean bench disinfected with ultraviolet light, add 5% antibiotic-free LB culture medium, 1mL 0.1mM sterile CaCl solution, 1mL 1M sterile MgSO4 solution, the corresponding antibiotics and an appropriate amount of IPTG solution into the volumetric flask. Add an appropriate amount of sterile matrix mother liquid according to the experimental requirements, and finally make up to 1L with sterile water. The cathode liquid: weigh 24.693gK3[Fe(CN)6], 13.063g K2HPO4 and 10.207gKH2PO4 on an electronic balance and place them in a large beaker, add an appropriate amount of distilled water, stir with a clean glass rod, shake well, and dissolve completely by ultrasound. The final volume is 1.5L;

[0036] b. The 1×M9 solution: adjust its pH to 7.3 using Na2HPO4 (6 g / L), KH2PO4 (3 g / L), NaCl (0.5 g / L) and NH4Cl (1 g / L). After sterilization in a fully automatic high-pressure steam sterilizer (121°C, 20 minutes), add MgSO4 solution with a final concentration of 1 mM and CaCl2 solution with a final concentration of 0.1 mM;

[0037] c. The filter membrane used in this application meets the requirements of air permeability and water impermeability, such as polytetrafluoroethylene hydrophobic membrane;

[0038] d. The cathode electrode and anode electrode used in this application are made of carbon paper (anode 2.5cm×2.5cm, cathode 2.5cm×2.5cm). Draw a cutting line on the carbon cloth with a marker pen, and then cut the carbon cloth with scissors along the cutting line. Put the cut carbon cloth into a beaker and rinse it with water several times to remove surface dirt. Add 1M HCl solution to the beaker, soak overnight, rinse three times with sterile water, then add pure acetone to the beaker and soak overnight (the beaker is sealed with plastic film to prevent acetone from volatilizing). Finally, wash the carbon cloth with sterile water to remove acetone and use it after drying.

[0039] (3) Principle and implementation effect:

[0040] a. During operation, the Shewanella attached to the anode sheet can transfer electrons to the cathode chamber through an external wire through its own extracellular electron transfer function. The hydrogen ions generated by ionization in the anode chamber are transferred to the cathode chamber through the proton exchange membrane. The cathode chamber is aerated with an oxygen pump. Oxygen and hydrogen ions react in the cathode chamber under the action of electrons to generate hydrogen peroxide. By changing the value of the external resistor, the multimeter can detect the current between the positive and negative electrodes. The hydrogen peroxide generated in the cathode chamber is titrated using the titanium oxalate spectrophotometry method. During the measurement, 4 mL of cathode effluent is taken into a beaker with a pipette, and then 1 mL of potassium titanium oxalate solution (0.02 mol / L) is added thereto. The color is developed at room temperature for 15 minutes, and the absorbance is measured at 385 nm using a quartz cuvette. The standard curve equation of H2O2 measured by this method is y=0.09x-0.03(R 2 =0.996).

[0041] b. The system can generate electricity continuously within 12 hours and maintain a high output power. The final output power can reach 2.7W / m 2 .

[0042] c. Figure 4 During the experiment, the changes in the concentration of H2O2 produced by the cathode were measured for four different cathode materials and three different electrolyte concentrations. The analysis showed that when platinum sheet was used as the cathode material, the cathode could produce H2O2 with a relatively stable concentration, and the final accumulated H2O2 concentration was 0.46 mg / L. When carbon paper and carbon felt were used as cathode materials, the H2O2 produced by the cathode was second only to platinum sheet. When nickel mesh was used as the cathode material, the concentration of H2O2 produced by the cathode was the smallest.

[0043] d. Change the external resistor value to 200Ω, 400Ω and 600Ω respectively, and measure the change in the concentration of H2O2 produced by the system. When the external resistor value is 200Ω, the cathode H2O2 concentration is the largest, which is 0.46mg / L.

[0044] The present application is described in detail above in conjunction with specific embodiments. The above description is only an illustrative specific implementation of the present invention. Without departing from the principle of the present invention, any equivalent changes and modifications made by a person skilled in the art shall fall within the scope of protection of the present invention.

Claims

1. A method for producing hydrogen peroxide by using biomass to generate electricity, characterized in that: The method produces hydrogen peroxide through a microbial electrochemical system. The microbial electrochemical system uses microorganisms as a medium to decompose organic matter in an anolyte and simultaneously produces hydrogen peroxide by electrochemically reducing molecular oxygen in a cathode chamber.

2. A method for producing hydrogen peroxide by using biomass to generate electricity as claimed in claim 1, characterized in that: The microbial electrochemical system comprises a hydrogen peroxide production device and an external oxygen supply device, wherein the hydrogen peroxide production device comprises a hollow shell with a detachable top and openings I and II on the top of the shell, the shell is separated into an anode chamber and a cathode chamber by a proton exchange membrane placed therein, the anode chamber is provided with an anode electrode and an anode liquid is added, the cathode chamber is provided with a cathode electrode and a cathode liquid is added, the anode electrode and the cathode electrode are respectively connected to an external resistor through an external wire, the microbial membrane attached to the anode electrode can transfer electrons to the cathode chamber through the wire through its own extracellular electron transfer effect, the hydrogen ions generated by ionization in the anode chamber are transferred to the cathode chamber through the proton exchange membrane, the cathode chamber is aerated by an external oxygen supply device, and oxygen and hydrogen ions react in the cathode chamber under the action of electrons to generate hydrogen peroxide.

3. A method for producing hydrogen peroxide by using biomass to generate electricity as claimed in claim 2, characterized in that: The microorganism is a γ-Proteobacteria microorganism.

4. A method for producing hydrogen peroxide by using biomass to generate electricity as claimed in claim 2, characterized in that: The microorganism is Shewanella MR-1.

5. A method for producing hydrogen peroxide by using biomass to generate electricity as claimed in claim 2, characterized in that: The cathode electrode is a platinum sheet, and when the external resistance is 200Ω, the output concentration of hydrogen peroxide is 0.46 mg / L, which is the maximum and most stable.

6. A method for producing hydrogen peroxide by using biomass to generate electricity as claimed in claim 1 or 2, characterized in that: The method specifically comprises the following steps: a. Take out the purchased Shewanella lyophilized powder, pour in sterile water, mix well, take out an appropriate amount of the mixture with a pipette or inoculation loop, apply it on the prepared solid culture medium, and place the culture medium in a constant temperature incubator at 30°C for 2-3 days; b. On a sterile operating table, use an inoculation loop to pick up a small amount of colonies growing in the solid culture medium, place them in a liquid culture medium, and culture the culture medium in a constant temperature shaking incubator at 30°C for 1-2 days; c. Under a sterile environment, use a sterile measuring cylinder to measure 40 ml of the anolyte and place it in the anode chamber. Take an appropriate amount of liquid culture medium into a centrifuge tube and centrifuge it in a centrifuge at 3500 r / s for 3 minutes. Then, place the bacteria obtained by centrifugation into the anode chamber for cultivation; d. In the startup phase of the dual-chamber bioelectrochemical system, the anode needs to be inoculated so that the extracellular electrogenic bacteria occupy the anode to form a biofilm to ensure the operation of the subsequent reactor. Shewanella MR-1 and 40 ml of anode liquid are added to the anode chamber for inoculation, and 0.1 M anhydrous sodium sulfate solution is added to the cathode chamber; after the first inoculation is completed, the dual-chamber bioelectrochemical system is connected in series with a 200 Ω resistor, and the dual-chamber bioelectrochemical system is placed in a constant temperature shaking incubator for culture, and the anode inoculation liquid is replaced every two days until the microorganisms are successfully inoculated and begin to grow normally; e. After the electrogenic bacteria successfully occupy the surface of the anode sheet and gradually proliferate to form a biofilm, the subsequent electricity generation performance and hydrogen peroxide production performance can be measured.

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