Built-in biological carrier cage tube type microbial fuel cell device

Abstract

The invention aims to overcome the defects of a traditional microbial fuel cell (MFC), and provides a built-in biological carrier cage tube type microbial fuel cell device, namely a novel microbial fuel cell device in which a tubular reactor is coupled with the MFC. The built-in mesh cage type device is filled with macroporous adsorption resin serving as a biological carrier, when wastewater passes through, a biological membrane is formed on the surface of the built-in mesh cage type device so as to degrade organic pollutants and generate electrons and protons, the electrons are collected by a current collector and then flow to a cathode to form current, and the protons are transmitted to the cathode to be subjected to reduction reaction. The device structure main body can be formed by connecting a plurality of single-tube type MFC reactor units in series or in parallel, the device structure main body can be flexibly adjusted according to the actual application scale, and the parallel combination adopts U-shaped joints for connection. A single MFC unit has a specific structure and has a unique design of separation of an anode, a cathode and a carrier cage, and a biological carrier, namely macroporous adsorption resin, is stored in the carrier cage. Flanges are mounted at the head and tail of the MFC, so that maintenance operation is facilitated. According to the design, a plug flow reactor model is adopted, high efficiency and accuracy are ensured, accurate control and optimization of the reaction process are realized, the sewage treatment efficiency and effect are improved, and more thorough purification treatment and energy recovery are realized.

Description

Technical Field

[0001] This invention belongs to the field of microbial fuel cell technology and relates to a device that couples a tubular reactor with a microbial fuel cell. The carrier is filled with a multifunctional biological carrier. This device can achieve large-scale continuous operation and more efficient energy conversion through multi-stage series and parallel combinations. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Currently, traditional microbial fuel cell (MFC) reactors exhibit a series of significant advantages, such as strong adaptability to wastewater and the ability to treat various types of wastewater effectively; relatively low sludge production, effectively reducing the burden of solid waste treatment; and high energy conversion efficiency, capable of efficiently converting chemical energy into electrical energy. However, it is undeniable that this type of reactor also has several problems: First, in terms of reactor construction, scaling up is quite difficult, which limits its expansion into large-scale applications; second, when the substrate concentration changes, voltage reversal may occur in the fuel cell stack, inevitably leading to energy loss and affecting the efficient utilization of energy; third, most of the currently researched MFC devices operate intermittently, with small production capacity, making them difficult to apply effectively in actual factories and hindering their promotion in practical production scenarios. Summary of the Invention

[0004] To overcome the shortcomings of traditional MFCs, the present invention aims to design a novel wastewater treatment device that couples a tubular reactor with an MFC. The device has a built-in cage-type device filled with biological carriers, and multiple stages of devices are connected in series and parallel to form a battery pack. This allows wastewater to be treated and completely degraded at the discharge outlet after passing through the reactor, thereby improving the efficiency and effectiveness of wastewater treatment and achieving more thorough purification of wastewater.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a microbial fuel cell device with an embedded biological carrier cage, comprising: a plurality of tubular reactors; the plurality of tubular reactors are connected in series or in parallel, and each tubular reactor is provided with an MFC unit and a plurality of carrier cage units; The MFC unit includes an anode and two cathodes. The anode is located at the center of the tubular reactor, and the two cathodes are located on the left and right sides of the tubular reactor, respectively. The anode and cathodes are electrically connected. The carrier cage unit is located below the MFC unit, and the carrier cage is filled with macroporous adsorption resin.

[0006] Tubular reactors, as highly efficient and relatively low-cost reactors, possess numerous outstanding advantages and characteristics. By cleverly coupling them with microbial fuel cells containing built-in biological carrier cages, a novel bioelectrochemical reactor is formed. Combining these devices in multi-stage series or parallel configurations allows for sufficient contact time between the wastewater within the device and the biofilm on the carrier, enabling effective adsorption and degradation of pollutants in the water. The effluent then meets the set treatment targets. This not only significantly improves wastewater treatment efficiency and capacity but also fully leverages the unique advantages of this novel reactor. This design makes the entire wastewater treatment process more stable and reliable, providing more advanced and effective technologies and solutions for solving various complex wastewater problems such as coal chemical wastewater, playing a crucial role in promoting the development of the wastewater treatment field.

[0007] A second aspect of the present invention provides the application of the above-described built-in biological carrier cage-tube microbial fuel cell device in water treatment.

[0008] Beneficial effects of the present invention (1) This invention relates to a cage-tube microbial fuel cell device with an embedded biological carrier for treating various types of chemical organic wastewater. Utilizing the coupling mechanism of biofilm degradation and electrochemical power generation, combined with a series-parallel reactor structure, continuous operation is achieved, overcoming the challenge of large-scale device production and increasing the device's power density. This device offers advantages such as flexible assembly, convenient maintenance, and corrosion resistance, enabling efficient removal of pollutants from chemical organic wastewater (removal rate up to 95% or more) and stable energy recovery, meeting the requirements for industrial wastewater discharge compliance and energy recovery. It provides a feasible path for environmental governance and energy recycling in highly polluting industries such as chemical manufacturing.

[0009] (2) The present invention has less liquid-phase backmixing and approximates a plug flow reactor model. The wastewater flows in an orderly manner along the reactor axis, ensuring that the wastewater has sufficient contact reaction time with the biofilm in the carrier cage when flowing through each MFC unit, thereby improving the treatment efficiency.

[0010] (3) The device of the present invention has a simple structure, strong practicality, and is easy to promote. Attached Figure Description

[0011] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. Exemplary embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0012] Figure 1 This is a schematic diagram of the appearance of a tubular microbial fuel cell reactor.

[0013] Figure 2 This is a diagram of the internal structure of a tubular microbial fuel cell reactor, including the MFC unit and the carrier cage unit.

[0014] Figure 3 For two tubular reactor units connected in series, (1) Method 1 (2) Method 2.

[0015] Figure 4 The diagram shows the MFC unit, (1) is a schematic diagram of the MFC unit, (2) is a cross-sectional view of the MFC unit, and (3) is a tubular reactor formed by connecting MFC units in series. The number of series stages is 10, and the two tubular reactors are connected by a 180° bend.

[0016] Figure 5 A flowchart illustrating the application of a cage-tube microbial fuel cell device with an embedded biological carrier in the biochemical treatment of chemical wastewater.

[0017] Figure 6 This is a simplified left-side view of a cage-tube microbial fuel cell device with an embedded biological carrier.

[0018] Figure 7 This is a simplified top view of a cage-tube microbial fuel cell device with an embedded biological carrier.

[0019] Among them, 1-carrier cage, 2-macroporous adsorption resin, 3-cathode, 4-anode, 5-adjustable rheostat box, 6-wire, 7-tubular reactor, 8-flange; Among them, a-storage tank, b-coal chemical wastewater after physical pretreatment, c-filtration device, d-sealed homogenizing tank, e-homogenizing tank discharge pump, f(1), f(2), f(3), f(4), f(5)-built-in biological carrier cage tube microbial fuel cell device (main view simplified diagram), g-open homogenizing tank. Detailed Implementation

[0020] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they are used in accordance with conventional methods in the art or product instructions. Similarly, unless otherwise specified, the test methods of this invention are performed in accordance with conventional methods in the art or industry-standard methods or practices. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0022] This invention mainly proposes an MFC (Microbial Fuel Cell) device with built-in biological carrier cages, comprising: multiple tubular reactors; the multiple tubular reactors are connected in series or in parallel, and each tubular reactor is equipped with an MFC unit and multiple carrier cage units; The MFC unit includes an anode and two cathodes. The anode is located at the center of the tubular reactor, and the two cathodes are located on the left and right sides of the tubular reactor, respectively. The anode and cathodes are electrically connected. The carrier cage unit is located below the MFC unit, and the carrier cage is filled with macroporous adsorption resin.

[0023] The working principle of a cage-type microbial fuel cell device with an internal biological carrier is as follows: A carrier cage filled with macroporous adsorption resin is placed inside the reactor as a multifunctional biological carrier. Wastewater flows through the device and comes into full contact with the macroporous adsorption resin, allowing microorganisms to attach to the surface of the resin and form a biofilm. Through the synergistic action of microbial metabolism and electrochemical processes, organic matter and ammonia nitrogen in the wastewater are efficiently degraded, generating electrons and protons. The electrons generated in this process are collected by a current collector and flow from the anode to the cathode through the external circuit to form an electric current; while the protons generated are directly transferred to the cathode through the electrolyte. At the cathode, electrons, protons, oxygen, etc., undergo a reduction reaction under the action of a catalyst.

[0024] The apparatus of this invention is primarily composed of multiple identical tubular reactors connected in series or parallel. Each reactor has an internal length of 0.28 m, a tensile diameter of 0.04 m, and a surface area of ​​4.96 m². 2The reactor uses carbon brushes as the bioanode and employs a dual cathode system on both sides, each holding a 0.06m diameter Pt / C carbon cloth. The cathodes and anodes are connected by wires. Each reactor can hold four carrier cages, with the amount of macroporous adsorption resin in each cage depending on the wastewater treatment volume, and a maximum of 1kg of macroporous adsorption resin per cage. The entire unit is structured with a separate "anode-cathode-carrier cage" layout. Furthermore, the entire reactor is approximately 0.47m long and 0.3m in diameter, with each carrier cage unit being 0.12m long and 0.12m in diameter. Preferably, flanges are installed at the head and tail of the tubular reactor. This facilitates the connection of the units end-to-end, and the tail flange provides convenience for replacing the biocarrier. Manholes are installed on the outside of the reactor for subsequent maintenance.

[0025] Preferably, the built-in biological carrier cage-tube microbial fuel cell device can flexibly adjust its overall length and scale by increasing or decreasing the number of reactors. Multiple reactors connected in series with 180° bends can be arranged into tubular MFCs. For larger wastewater treatment volumes, multiple MFCs can be connected in parallel to achieve multi-feed feed. To accommodate different wastewater volumes required by different plant areas, the reactors can be disassembled or assembled in different combinations to adapt to varying treatment needs and scales.

[0026] Preferably, the carrier cage unit is a hollow mesh cavity, embedded in the beginning and end flanges of the tubular reactor. More preferably, the carrier cage in the carrier cage unit adopts an independent cylindrical cavity structure, with a height of 0.12m and a diameter of 0.12m, embedded in the beginning and end flanges of the unit. The carrier cage is made of high-density stainless steel mesh structure material. To facilitate the cleaning of the carrier cage and the replacement of the biological carrier (macroporous adsorption resin), a manhole flange is installed at the connection between the beginning and end flanges of the unit and the carrier cage. It is recommended to replace it after each operating cycle.

[0027] The volume and distribution of the carrier cages affect the resistance and pressure drop of wastewater passing through the carrier layer. If the carrier cage volume is too large, for example, using a cylindrical body close to the inner diameter of the outer shell, the resistance and pressure drop of wastewater passing through the carrier layer will increase significantly. When a biofilm forms on the carrier surface, the gaps between particles will be further reduced, and the wastewater channels will be further compressed. After a period of operation, this will lead to complete blockage and prevent normal operation. Therefore, this invention sets up four carrier cages and places them on the four sides, so that the wastewater can maintain axial orderly flow and full contact with the carrier. Moreover, the carrier cages filled with carriers can meet the reaction requirements. At the same time, the carrier cages are easy to disassemble, facilitating maintenance in case of problems during operation. Therefore, preferably, the carrier cage unit consists of four cages, evenly distributed on the circumference of the bottom of the tubular reactor.

[0028] The length and diameter of the reactor directly determine the flow rate and residence time of the fluid in the pipe. Therefore, this invention studies the length and diameter of the reactor. Preferably, the length of the reactor is 0.47-0.56m and the diameter is 0.3-0.32m to obtain better treatment efficiency.

[0029] The specifications of the carrier cage affect the fluid treatment effect and flow resistance. Therefore, this invention studies the length and diameter of the carrier cage. Preferably, the length of the carrier cage unit is 0.12-0.13m and the diameter is 0.12-0.13m. This invention is designed based on a continuous flow tubular reactor model. In a plug flow reactor, the fluid passes through the reactor for the same amount of time, and there is no backmixing. Although the solid carrier particles in the carrier cage of this invention have a certain impact on the liquid flow, in this type of liquid-solid reactor, the solid particles are generally in a dispersed fluidized state under the action of the fluid, and the impact on the flow characteristics of the liquid phase is very small. Therefore, backmixing is very small and can be ignored. It can be approximated as a plug flow model.

[0030] The filling amount of macroporous adsorption resin is one of the key process parameters affecting the water treatment effect. Its size is directly related to the adsorption contact time, treatment efficiency and system operating cost. Therefore, this invention studies the filling amount of macroporous adsorption resin. Preferably, the filling amount of macroporous adsorption resin is 0.8-1kg to obtain better treatment effect.

[0031] Preferably, the tubular reactor has multiple manholes on its sidewall to facilitate the replacement of the carrier cage.

[0032] This invention does not impose any special limitations on the types of cathode and anode materials; any material suitable for forming a microbial fuel cell is acceptable. Preferably, the cathode material is Pt / C carbon cloth (0.06 μm in diameter, 0.7 mg / cm³). 2 The catalyst (Pt, 30% moisture resistant) consists of a catalyst layer, a carbon base layer, and a polytetrafluoroethylene (PTFE) diffusion layer. The catalyst layer is formed by ultrasonic mixing of Pt / C, Nafion solution, deionized water, and isopropanol. The anode material is a carbon brush; more preferably, the carbon brush has a length of 0.28-0.3 m, a tensile diameter of 0.04-0.05 m, and a surface area of ​​4.96-5.2 m². 2 To achieve better water treatment results.

[0033] The carbon brush anode of the present invention is suspended in the reactor chamber by a straight rod, and a wire is connected from the top of the carbon brush to the resistor.

[0034] The diameter of Pt / C carbon cloth affects its electrochemical performance. Therefore, this invention studies the diameter of Pt / C carbon cloth. More preferably, the diameter of the Pt / C carbon cloth is 0.06-0.07 μm to obtain better water treatment effect.

[0035] The material of the carbon brush anode current collector affects its electrochemical performance. Therefore, this invention studies the material of the carbon brush anode current collector. More preferably, the core material of the carbon brush anode current collector is graphite carbon fiber with a single filament diameter of 7-10 μm, which has excellent conductivity and biocompatibility and is easy to adhere to biofilms.

[0036] The material of a tubular reactor affects its service life. Therefore, this invention has studied the material of the tubular reactor. Preferably, the tubular reactor is made of 316L stainless steel, and the inner wall of the tube is coated with a layer of polymer material to ensure that the service life can reach more than 50 years.

[0037] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0038] like Figure 1 As shown, the length of a single tubular reactor 7 of this invention is 0.47m and the diameter is 0.3m. Flanges 8 are installed at both ends for easy assembly and disassembly. The entire tube body is made of 316L stainless steel, and the inner wall of the tube is coated with a layer of polymer material, which is resistant to corrosion in chemical environments and has a service life of 50 years or more.

[0039] like Figure 2 As shown, the reactor includes an MFC unit and a carrier cage 1 unit. The MFC unit mainly includes an anode 4 (carbon brush) and a cathode 3. Using a carbon brush as the anode 4, Pt / C carbon cloth is placed in the left and right dual cathodes 3, which significantly improves its power generation efficiency compared to traditional anode and cathode materials. The anode 4 (carbon brush) is suspended in the reactor cavity by a straight rod, and a wire 6 is connected from the top of the carbon brush to an adjustable rheostat box 5. The adjustable rheostat box 5 is also connected to the left and right cathodes 3 respectively via wires 6. Figure 4 As shown.

[0040] The four carrier cages 1 in the carrier cage unit are all independent cylindrical cavity structures (0.12m high, 0.12m in diameter) made of dense stainless steel mesh material, used solely to store macroporous adsorption resin 2. Their mesh structure allows the wastewater to enter the carrier cage 1 and fully contact the macroporous adsorption resin 2. A manhole flange 8 is installed at the bottom of the carrier cage 1 for easy resin replacement. This invention sets up four carrier cages 1, evenly distributed on the four sides of the bottom of the tubular reactor 7, ensuring that the wastewater maintains axial orderly flow and full contact with the carrier. Furthermore, the carrier filled in the four carrier cages 1 is sufficient to meet the reaction requirements.

[0041] This device innovatively achieves a dual synergistic working mechanism of "biofilm degradation - electrochemical power generation". When wastewater enters the device, it first contacts the macroporous adsorption resin 2 in the carrier cage 1 to complete the initial physical adsorption, and then passes through a surface area of ​​4.96m². 2 The carbon brush anode current collector has a biofilm loaded on its surface, which further facilitates microbial degradation. Electrons generated during metabolism are collected and directed to the dual Pt / C cathode 3 via an external circuit, while protons are directly transferred to the cathode 3 via the electrolyte. On the cathode 3 side, the loading is 0.7 mg / cm³. 2 The Pt catalyst uses electrons, protons, and oxygen in a reduction reaction to produce water, and the dual-cathode design (one on each side) doubles the oxygen contact area. Through the synergistic effect of each unit, pollutants in wastewater are effectively degraded and transformed, thereby achieving wastewater purification and energy recovery.

[0042] Specific embodiments of the present invention: In implementing this invention, the principles of minimizing energy consumption and maximizing economic benefits are followed. The wastewater used in this process is phenol-containing wastewater from coal chemical production, with a COD content of 2500 mg / L and a target effluent COD of 100 mg / L. Wastewater that achieves a stable treatment effect at the effluent outlet can then be further transported to a large-scale wastewater treatment plant to reduce the COD to below 60 mg / L. For example... Figure 5 , Figure 6 , Figure 7 As shown, this embodiment employs a cage-tube microbial fuel cell device with an embedded biological carrier, and follows a "series + parallel" composite layout—a set of tubular reactors 7 consists of 140 individual reactors connected in series, with a bend added every 10 reactor sections (13 in total), for a total of 140 series stages. In a coal chemical wastewater treatment facility, a set of tubular reactors 7 can process up to 100m³ per day. 3The number of reactor groups and individual reactors can be flexibly increased or decreased according to the processing capacity. If multiple reactor groups are used, the reactor groups need to be connected in parallel. The main body of the tubular reactor 7 is made of 316L stainless steel, and the carrier cage 1 is a stainless steel mesh cylinder. Each cage is filled with 1 kg of macroporous adsorption resin 2. The wastewater is first pretreated in the storage tank a to obtain coal chemical wastewater b after physical pretreatment. After being filtered by the filtration device c, it enters the sealed homogenizing tank d. From the sealed homogenizing tank d, it enters one or more groups of built-in biological carrier cage tube microbial fuel cell devices f(1), f(2), f(3), f(4), f(5) through the flow distributor (homogenizing tank discharge pump e). At 25℃ and 101kPa, it flows orderly through the reactor to complete the wastewater degradation and enters the open homogenizing tank g for collection, while recovering electrical energy. During operation, the water quality is monitored every 4 hours, the equipment sealing is checked daily, the carrier cage 1 resin is replaced every time it is run, the carbon brush is cleaned every 60 days, and the cathode 3 is maintained every 180 days. Through such precise design and operation, efficient wastewater treatment is achieved, reaching the expected treatment effect and objectives, and ensuring that indicators such as COD are effectively reduced. In practice, it is necessary to strictly monitor and maintain reactor parameters, pay attention to the stability of MFC unit series connection and conduct timely inspections and maintenance, regularly check gas and liquid phase discharge pipelines, strictly control wastewater treatment volume and hydraulic retention time, and ensure corrosion and leakage prevention of equipment and pipelines to guarantee the safe and efficient operation of the entire system.

[0043] This invention designs a cage-tube microbial fuel cell device with an embedded biological carrier and applies it to the biochemical treatment section of phenol-containing wastewater in coal chemical industry. By connecting the devices in parallel, the overall power density of the section is improved. By connecting multiple battery units in series in a single reactor, the output voltage and power are increased, thus achieving the effect of continuous power generation and simultaneous treatment of phenol-containing wastewater in coal chemical industry using the cage-tube microbial fuel cell device with an embedded biological carrier.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cage-tube microbial fuel cell device with an embedded biological carrier, characterized in that, include: Multiple tubular reactors; The multiple tubular reactors are connected in series or in parallel, and each tubular reactor is equipped with an MFC unit and multiple carrier cage units. The MFC unit includes an anode and two cathodes. The anode is located at the center of the tubular reactor, and the two cathodes are located on the left and right sides of the tubular reactor, respectively. The anode and cathodes are electrically connected. The carrier cage unit is located below the MFC unit, and the carrier cage is filled with macroporous adsorption resin.

2. The built-in biological carrier cage-tube microbial fuel cell device as described in claim 1, characterized in that, Flanges are installed at the head and tail of the tubular reactor, respectively.

3. The built-in biological carrier cage-tube microbial fuel cell device as described in claim 1, characterized in that, Multiple tubular reactors are connected in series and linked by 180° bends to form tubular MFCs.

4. The built-in biological carrier cage-tube microbial fuel cell device as described in claim 1, characterized in that, The carrier cage unit is a hollow mesh cavity that is embedded in the front and rear flanges of the tubular reactor.

5. The built-in biological carrier cage-tube microbial fuel cell device as described in claim 4, characterized in that, The carrier cage unit consists of four units, which are evenly distributed on the circumference of the bottom of the tubular reactor.

6. The built-in biological carrier cage-tube microbial fuel cell device as described in claim 5, characterized in that, The reactor has a length of 0.47-0.56m and a diameter of 0.3-0.32m; Alternatively, the length of the carrier cage unit is 0.12-0.13m, and the diameter is 0.12-0.13m; Alternatively, the loading amount of macroporous adsorption resin is 0.8-1kg.

7. The built-in biological carrier cage-tube microbial fuel cell device as described in claim 1, characterized in that, The tubular reactor has multiple manholes on its sidewall.

8. The built-in biological carrier cage-tube microbial fuel cell device as described in claim 1, characterized in that, The cathode material is Pt / C carbon cloth, and the anode material is a carbon brush. Alternatively, the carbon brush may have a length of 0.28-0.3m, a draw diameter of 0.04-0.05m, and a surface area of ​​4.96-5.2m². 2 ; Alternatively, the Pt / C carbon cloth may be Pt / C carbon cloth with a diameter of 0.06-0.07 μm; Alternatively, the core material of the carbon brush anode current collector is graphite carbon fiber, with a single filament diameter of 7-10 μm.

9. The built-in biological carrier cage-tube microbial fuel cell device as described in claim 1, characterized in that, The tubular reactor is made of 316L stainless steel.

10. The application of the built-in biological carrier cage-tube microbial fuel cell device according to any one of claims 1-9 in water treatment.

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