Device for removing metal ions in water by connecting multiple stages of MFCs in series

Abstract

The utility model relates to the technical field of microbial electrochemistry, in particular to a device for removing metal ions in water by connecting multiple stages of MFCs in series. The device comprises multiple stages of MFC units, each stage of MFC unit comprises a cathode chamber and an anode chamber, wastewater is contained in the cathode chamber, and the cathode chamber is sequentially provided with an inlet and an outlet from bottom to top; wastewater is contained in the anode chamber, and the anode chamber is communicated with the cathode chamber through a proton exchange membrane; the outlet of each cathode chamber is sequentially connected with the inlet of each cathode chamber in series through a series pipeline, so that the plurality of cathode chambers are connected in series; and during liquid adding, wastewater treated in the first cathode chamber on the series pipeline is supplemented into the next cathode chamber, so that the wastewater in the cathode chamber at the tail end of the series pipeline is discharged. According to the utility model, the plurality of cathode chambers are connected in series, so that the electrode adsorption time is indirectly increased, the contact area is increased, and the removal rate of metal ions in water is improved. Meanwhile, the removal rate of metal ions in water is also improved by adopting a bottom-inlet and top-outlet water inlet and outlet mode.

Description

Technical Field

[0001] This invention relates to the field of microbial electrochemical technology, specifically a device for removing metal ions from water using multi-stage MFC series connection. Background Technology

[0002] The current global energy and environmental crisis has made the search for a new, green, and environmentally friendly wastewater treatment technology that can both solve environmental pollution and provide clean energy a focus of attention for countries around the world. Microbial fuel cells (MFCs), which use microorganisms as catalysts to degrade organic matter and convert the released chemical energy into electrical energy during the decomposition process, have attracted increasing attention due to their wide availability of raw materials, mild reaction conditions, and clean and efficient operation.

[0003] When treating wastewater, the cathode treatment of MFC removes metal ions from the water within the cathode chamber without requiring additional energy. Electrons generated by the oxidation and decomposition of organic matter by anodic microorganisms in the MFC anode chamber travel through wires and external resistors to the cathode. Protons in the solution move to the cathode through the proton exchange membrane, resulting in the directional movement of electrons that reduce the metal ions at the cathode. In other words, through the metabolic action of electrogenic microorganisms, the chemical energy in organic matter is converted into electrical energy. Metal ions in the wastewater are adsorbed onto the electrodes, thus removing metal ions from the water.

[0004] However, when treating wastewater of the same concentration, the wastewater treatment effect of a single MFC is limited in a short period of time. In order to meet the removal effect of metal ions in the wastewater by a single MFC, the wastewater is treated in a single MFC for a long time. After a long reaction time, the electricity generation of the microorganisms in the electrogenic microbial solution in the anode chamber of the MFC becomes weak. When the wastewater cannot be discharged in time, metal ions desorb from the electrode plate and re-enter the water body, resulting in a decrease in the removal rate of heavy metals in the wastewater. Summary of the Invention

[0005] The purpose of this invention is to overcome the aforementioned problems in the prior art and to provide a device for removing metal ions from water using a multi-stage MFC series connection. This invention solves the problem of low heavy metal removal rate in wastewater.

[0006] This utility model provides a device for removing metal ions from water using multi-stage MFC series connection, comprising: a device for removing metal ions from water using multi-stage MFC series connection, characterized in that it includes: multi-stage MFC units, each MFC unit comprising:

[0007] A sealed cathode chamber contains wastewater and a cathode electrode, and the cathode chamber has an inlet and an outlet arranged sequentially from bottom to top.

[0008] A sealed anode chamber is inoculated with an electrogenic mixed bacterial solution and an anode electrode. A proton exchange membrane that allows protons to pass through is provided between the anode chamber and the cathode chamber.

[0009] The outlet of each cathode chamber is connected in series with the inlet of each cathode chamber via a series pipeline, which is used to connect multiple cathode chambers in series.

[0010] When wastewater is pressurized or injected into the cathode chamber at the beginning of the series connection, the wastewater treated in the previous cathode chamber is replenished to the next cathode chamber. This is to ensure that the wastewater in the cathode chamber at the end of the series connection is discharged when the electricity generated by the mixed bacteria solution is sufficient.

[0011] Preferably, both the cathode chamber and the anode chamber have cylindrical cross-sections.

[0012] Preferably, the cathode electrode is located at the center of the cathode chamber, and the anode electrode is located at the center of the anode chamber.

[0013] Preferably, both the anode electrode and the cathode electrode are carbon cloth electrodes.

[0014] Preferably, a one-way valve is provided on the outlet of the cathode chamber at the first end of the series connection and on the outlet of the cathode chamber at the last end of the series connection.

[0015] Preferably, both the cathode chamber and the anode chamber include a bottle body, a first bottle cap is detachably connected to the cathode chamber, a second bottle cap is detachably connected to the anode chamber, and the cathode chamber and the anode chamber are connected by a delivery pipe and a proton exchange membrane.

[0016] Preferably, at least three cathode chambers are connected in series to form a device for removing metal ions from water.

[0017] Preferably, the diameter of the inlet and outlet pipes is 8mm to 12mm.

[0018] Preferably, both the anode electrode and the cathode electrode are connected to an electrical component via wires, and the electrical component is a 1000Ω resistor.

[0019] Compared with the prior art, the beneficial effects of this utility model are:

[0020] 1. The device for removing metal ions from water provided by this utility model uses pipelines to connect the cathodes of each MFC unit in series. Compared with a single MFC unit, the electricity generation in the anode chamber of a multi-stage MFC unit is improved by the wastewater containing metal ions coming into contact with the electrode plates multiple times, which indirectly increases the electrode adsorption time, increases the contact area, and improves the removal rate of metal ions in the water.

[0021] Meanwhile, the multiple cathode chambers of this utility model are connected in series in a bottom-in, top-out water inlet and outlet manner. This is beneficial for the wastewater containing heavy metals in the previous cathode chamber to enter the next cathode chamber after pressurization or liquid addition. This allows the wastewater to contact the electrode plates more fully, increases the contact time between the liquid and the electrode plates, and allows the treated wastewater to overflow from a high position, which greatly increases the adsorption time of metal ions by the electrode plates and improves the removal rate of metal ions in the water.

[0022] 2. The electrical energy used in this invention comes from the conversion of chemical energy in organic matter by microorganisms, which greatly saves resources and reduces carbon emissions.

[0023] 3. The electrode used in this invention is made of carbon cloth, which has a large specific surface area and strong adsorption capacity, effectively adsorbing metal ions and improving the removal efficiency of metal ions in water.

[0024] 4. The device provided by this utility model has a simple structure, is easy to disassemble and operate, and is inexpensive, which greatly reduces costs. Attached Figure Description

[0025] Figure 1 This is an exploded view of a single MFC structure in a multi-stage MFC series device for removing metal ions from water according to this utility model.

[0026] Figure 2 This is a front view of a single MFC structure in a multi-stage MFC series device for removing metal ions from water according to this utility model.

[0027] Figure 3 This is an overall structural diagram of a multi-stage MFC series device for removing metal ions from water according to this utility model.

[0028] Figure 4 To utilize the multi-stage MFC series cascade device of this invention for removing metal ions from water, the effects of different numbers of MFCs on Cu in water were measured. 2+ Comparison chart of ion removal efficiency.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Electrical components; 2. Cathode chamber cap; 3. Outlet; 4. Cathode electrode; 5. Inlet; 6. Cathode chamber; 7. Proton exchange membrane; 8. Anode chamber; 9. Anode electrode; 10. Anode chamber cap; 11. Series pipeline; 12. Delivery pipe. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1 ~Attached Figure 4The specific embodiments of this utility model are described in detail below, but it should be understood that the protection scope of this utility model is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the protection scope of this utility model.

[0032] The inventors discovered that after a single MFC unit removes metal ions from wastewater, the amount of microorganisms added to the battery is fixed, and the microorganisms in the battery generate very little electricity during long-term operation. If the wastewater from which metal ions have been removed is not discharged in time, the metal ions may desorb from the plates and re-enter the water body, thus affecting the removal rate of metal ions in the wastewater.

[0033] In view of this, the present invention provides a device for removing metal ions from water by connecting multiple MFC units in series. This device improves the single electroadsorption capacity by connecting multiple MFC units in series, ensuring the amount of electrogenic microorganisms in the battery. It prevents metal ions from desorbing from the plates and re-entering the water due to weak microbial electrogenic capacity. In addition, the treated wastewater can be discharged in a timely manner, which further avoids the desorption of metal ions from the plates and their re-entry into the water, thereby improving the removal rate of metal ions in wastewater.

[0034] like Figures 1-3 As shown, this utility model provides a device for removing metal ions from water using multi-stage MFC series connection, comprising: multi-stage MFC units, each MFC unit including: a sealed cathode chamber 6 and a sealed anode chamber 8, wherein:

[0035] The sealed cathode chamber 6 contains wastewater and cathode electrode 4. The cathode chamber 6 is provided with an inlet 5 and an outlet 3 from bottom to top.

[0036] The sealed anode chamber 8 is inoculated with electrogenic mixed bacterial solution and anode electrode 9. A proton exchange membrane 7 that allows protons to pass through is provided between the anode chamber 8 and the cathode chamber 6.

[0037] The outlet 3 of each cathode chamber 6 is connected in series with the inlet 5 of each cathode chamber 6 via a series pipe 11, which is used to connect multiple cathode chambers 6 in series.

[0038] When air is pressurized or wastewater is added to the inlet 5 of the first cathode chamber 6 in the series, the treated wastewater in the previous cathode chamber 6 in the series is replenished to the next cathode chamber 6. This is to ensure that when the wastewater in the cathode chamber 6 at the end of the series has sufficient electricity generated by the mixed bacteria solution, metal ions are adsorbed on the electrode plate. At this time, the wastewater is discharged, which improves the removal rate of metal ions in the wastewater.

[0039] Specifically, both the cathode chamber 6 and the anode chamber 8 have cylindrical cross-sections. This cylindrical cross-section allows for more uniform flow of the electrolyte (or other fluid) within the chambers. The fluid flow within the cylindrical container reduces dead zones and uneven flow rates, thus preventing stagnation and improving the efficiency of the electrolysis reaction. Furthermore, the cylindrical structure contributes to a more uniform distribution of the electric field within the cathode chamber 6 and anode chamber 8. A uniform electric field distribution contributes to the stability of the electrolysis reaction and improves electrolysis efficiency.

[0040] Specifically, the cathode electrode 4 is located at the center of the cathode chamber 6, and the anode electrode 9 is located at the center of the anode chamber 8. Placing the electrode at the center of the anode chamber aims to maximize the contact area between the microorganisms in the bacterial solution and the anode, thereby improving electron transfer efficiency. Placing the cathode electrode at the center aims to improve the removal efficiency of metal ions.

[0041] Specifically, both the anode electrode 9 and the cathode electrode 4 are carbon cloth electrodes. Carbon cloth electrodes have advantages such as low cost, large specific surface area, and strong adsorption capacity, which are beneficial for adsorbing metal ions.

[0042] Specifically, one-way valves are provided on both the outlet 3 of the cathode chamber 6 at the beginning of the series connection and the outlet 3 of the cathode chamber 6 at the end of the series connection. These valves are used to prevent backflow from causing liquid disturbance and affecting the electrode reaction.

[0043] Specifically, the specific structures of the cathode chamber 6 and the anode chamber 8 are given. Both the cathode chamber 6 and the anode chamber 8 include a bottle body. A first bottle cap 2 is detachably connected to the cathode chamber 6, and a second bottle cap 10 is detachably connected to the anode chamber 8. The cathode chamber 6 and the anode chamber 8 are connected by a delivery pipe 12 and a proton exchange membrane 7.

[0044] The cathode chamber 6 and anode chamber 8 are configured in this way because the microorganisms in the anode chamber 8 live in an anaerobic environment. The purpose of detachably connecting the second cap 10 to the anode chamber 8 is to ensure that the anode chamber 8 is not connected to the atmosphere and to maintain the anaerobic state of the anode chamber 8. The cathode chamber 6 needs to be connected to the atmosphere when liquid is added, and it needs to be sealed when the cathode chamber 6 is pressurized. Therefore, in both cases, it is necessary to open or close the first cap 2.

[0045] Specifically, at least three cathode chambers (6) connected in series form a device for removing metal ions from water. Experiments have shown that this device can improve the removal rate of metal ions from wastewater.

[0046] Specifically, the pipe diameters of inlet 5 and outlet 3 are 8mm to 12mm, preferably 10mm, to avoid the liquid from inlet 5 and outlet 3 disturbing the liquid surface of the wastewater in the cathode chamber and affecting the removal rate of metal ions in the wastewater.

[0047] Specifically, both the anode electrode 9 and the cathode electrode 4 are connected to the power-consuming element 1 via wires, and the power-consuming element 1 is a 1000Ω resistor. The 1000Ω resistor is not used to remove metal; in the MFC device, the external circuit needs to form a closed loop. All studies have reported that the microbial power generation effect is optimal when an external 1000Ω resistor is applied.

[0048] Both pressurizing and adding wastewater to the cathode chamber 6 at the beginning of the series connection can improve the removal rate of metal ions in the wastewater. However, the optimal solution is to add wastewater to the cathode chamber 6 at the beginning of the series connection. This is because adding liquid ensures the continuous operation of the multi-stage MFC series device for removing metal ions from water. Pressurizing (injecting gas) may cause discontinuity in the solution, affecting the removal rate of metal ions in the wastewater.

[0049] MFC units such as Figure 1 and Figure 2 As shown, the MFC unit includes an anode chamber 8 and a cathode chamber 6. An anode electrode 9 is located in the anode chamber 8. A wire is used to connect one end of the wire, through the anode chamber cap 10, to the anode electrode 9, and the other end of the wire is connected to a 1000Ω resistor 1. A cathode electrode 4 is located in the cathode chamber 6. Another wire is used to connect one end of the wire, through the cathode chamber cap 2, to the cathode electrode 4, and the other end of the wire is connected to the 1000Ω resistor 1. An output pipe is connected between the anode chamber 8 and the cathode chamber 6, and a proton exchange membrane 7 is placed inside the connection end of the output pipe. An inlet 5 and an outlet 3 are sequentially arranged from bottom to top on the other side of the cathode chamber 6 connected to the anode chamber 8. After assembling the MFC unit, electrogenic mixed bacteria solution is inoculated in the anode chamber 8, and wastewater is added to the cathode chamber 6 until the liquid level is flush with the upper outlet 3. Figure 3 As shown, a rubber tube 11 connects the outlet 3 above the cathode chamber 6 of one MFC unit to the inlet 5 below the cathode chamber 6 of another MFC unit. Appropriate MFC units are stacked according to the actual types and concentrations of metal ions in the water to complete the construction of a multi-stage MFC series removal device for metal ions in water.

[0050] When using this device to treat wastewater, the electrogenic mixed bacteria solution needs to be inoculated into the anode chamber 8 of the series-connected multi-stage MFC units. Wastewater is then fed into the cathode chamber 6 of the first series-connected MFC unit, maintaining the liquid level at the outlet 3 of the cathode chamber 6. After a period of reaction, the wastewater to be treated is added to the inlet 5 of the cathode chamber 6 of the first MFC unit. The wastewater from the cathode chamber 6 of the first MFC unit flows out through the outlet 3 of the cathode chamber 6 and into the cathode chamber 6 of the second MFC unit, until the liquid level in the cathode chamber 6 of the second MFC unit is maintained at the outlet 3 of the cathode chamber 6. Once the mixture is leveled, stop adding liquid to the inlet 5 of the cathode chamber 6 of the first MFC unit. Allow it to react for a period of time. Repeat this process until liquid needs to be sent to the cathode chamber 6 of the MFC unit at the end of the series. Then, add the wastewater to be treated to the inlet 5 of the cathode chamber 6 of the first MFC unit again. The amount of liquid added should be sufficient to ensure that the wastewater in the cathode chamber 6 of the penultimate MFC unit is sent to the cathode chamber 6 of the end MFC unit and reacts for a period of time in the cathode chamber 6 of the end MFC unit. When the treated wastewater in the cathode chamber 6 of the end MFC unit needs to be discharged, simply add liquid to the cathode chamber 6 at the beginning of the series.

[0051] Example

[0052] This invention relates to a device for removing metal ions from water using a multi-stage MFC series connection. The device is configured according to... Figure 3 The assembly is performed in the following manner. This invention connects three MFC units in series. A laboratory-preserved electrogenic mixed bacterial solution is added to the anode chamber 8, and a 0.1% NaCl solution is added to the cathode chamber 6 to promote electron transfer. The solutions in the cathode chamber 6 and anode chamber 8 are replaced periodically. After about two weeks until the electrogenic process is stable, the three MFC units are considered to have been successfully started.

[0053] Empty the cathode chambers 6 of the three MFC units. Add an 80 mg / L CuCl2 solution from inlet 5 of the first-stage MFC unit's cathode chamber 6 until the liquid level reaches the outlet 3 of that chamber. Then, add 50 mL of solution every 10 minutes. After 2 hours, measure and calculate the effect of the three MFC units on the CuCl2 concentration in the solution. 2+ The removal rates, as tested, were 70.29%, 85.17%, and 97.38%, respectively. Figure 4 As shown. Figure 4 It can be seen that connecting three MFC units in series will improve the removal rate and efficiency of metal ions in wastewater.

[0054] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for removing metal ions from water using multi-stage MFC series connection, characterized in that, include: Multi-level MFC units, each level of MFC unit includes: A sealed cathode chamber (6) contains wastewater and a cathode electrode (4). The cathode chamber (6) is provided with an inlet (5) and an outlet (3) from bottom to top. A sealed anode chamber (8) is inoculated with electrogenic mixed bacterial solution and an anode electrode (9). A proton exchange membrane (7) that allows protons to pass through is provided between the anode chamber (8) and the cathode chamber (6). The outlet (3) of each cathode chamber (6) and the inlet (5) of each cathode chamber (6) are connected in series in sequence through a series pipe (11) to connect multiple cathode chambers (6) in series. When wastewater is pressurized or injected into the first cathode chamber (6) in the series connection, the treated wastewater in the previous cathode chamber (6) connected in the series connection is replenished into the next cathode chamber (6), so that the wastewater in the cathode chamber (6) at the end of the series connection is discharged when the electricity generated by the mixed bacteria solution is sufficient.

2. The device for removing metal ions from water using a multi-stage MFC series connection according to claim 1, characterized in that, Both the cathode chamber (6) and the anode chamber (8) have cylindrical cross-sections.

3. The device for removing metal ions from water using a multi-stage MFC series connection according to claim 2, characterized in that, The cathode electrode (4) is located at the center of the cathode chamber (6), and the anode electrode (9) is located at the center of the anode chamber (8).

4. The device for removing metal ions from water using a multi-stage MFC series connection according to claim 1, characterized in that, Both the anode electrode (9) and the cathode electrode (4) are carbon cloth electrodes.

5. The device for removing metal ions from water using a multi-stage MFC series connection according to claim 1, characterized in that, One-way valves are provided on the outlet (3) of the cathode chamber (6) at the first end of the series connection and the outlet (3) of the cathode chamber (6) at the last end of the series connection.

6. The device for removing metal ions from water using a multi-stage MFC series connection according to claim 1, characterized in that, Both the cathode chamber (6) and the anode chamber (8) include a bottle body. The cathode chamber (6) is detachably connected to a first bottle cap (2), and the anode chamber (8) is detachably connected to a second bottle cap (10). The cathode chamber (6) and the anode chamber (8) are connected by a delivery pipe (12) and a proton exchange membrane (7).

7. The device for removing metal ions from water using a multi-stage MFC series connection according to claim 1, characterized in that, At least three cathode chambers (6) are connected in series to form a device for removing metal ions from water.

8. The device for removing metal ions from water using a multi-stage MFC series connection according to claim 1, characterized in that, The diameter of the inlet (5) and outlet (3) is 8mm to 12mm.

9. The device for removing metal ions from water using a multi-stage MFC series connection according to claim 1, characterized in that, Both the anode electrode (9) and the cathode electrode (4) are connected to the power supply element (1) via wires. The power supply element (1) is a 1000Ω resistor.

Images