Novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization

Abstract

The invention provides a novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization, which comprises a cathode, an anode, a first shell and a second shell, the first shell is provided with an air inlet hole, an air outlet hole and a liquid inlet hole, and the second shell is provided with a liquid outlet hole; the cathode is provided with a first through hole and the anode is provided with a second through hole; gas to be treated enters the space between the first shell and the cathode through the gas inlet hole, brackish water enters the space between the cathode and the anode through the liquid inlet hole and the first through hole, the gas is discharged through the gas outlet hole after CO2 is removed from the cathode, and the brackish water is discharged through the second through hole and the liquid outlet hole after being desalted between the cathode and the anode. In the electro-adsorption desalination process, the dissolution of CO2 at a three-phase interface is enhanced by utilizing a high-alkalinity environment generated by a cathode oxygen reduction reaction, the CO2 is synchronously enriched and recovered in the desalination process, the CO2 is continuously and modularly captured from each CO2 source in a high-capture-rate, high-energy-efficiency and pollution-free manner, the operation cost is reduced, and the energy consumption is reduced. And a new direction is developed for industrial application of the CDI technology.

Description

Technical Field

[0001] The present invention belongs to environmental brackish water treatment and CO 2 The field of absorption technology, specifically a new type of CO based on three-phase interface capacitive deionization 2 Electrochemical absorption device. Background Art

[0002] CO 2 It is a common greenhouse gas and is considered to be the main factor affecting global warming. The rapid development of industry and the burning of large amounts of fossil fuels have led to the 2 The emissions of CO2 in the atmosphere are increasing year by year. 2 The continued accumulation of CO leads to rising temperatures and disruption of global weather patterns. Therefore, controlling CO 2 Emissions have become one of the challenges. Currently, in order to control the CO 2 As concentrations continue to rise, researchers have developed a variety of CO 2 Capture technology captures carbon dioxide from industrial waste gas to atmospheric dilute sources. Existing technologies include adsorption, absorption, membrane separation, cryogenic separation, electrochemical methods, and biochemical methods. Among these technologies, chemical absorption is the most widely used CO 2 Absorption technology. Through the interaction between amines and carbon dioxide, CO 2 Absorbed by amine solvent. Although this technology has a high absorption efficiency, it requires a lot of heat energy for desorption and regeneration, which leads to high operating costs, toxic byproduct emissions, solvent loss and other negative effects. Therefore, a greener, safer, more energy-saving and applicable CO 2 The absorption method is still under development.

[0003] Alternative methods based on electrochemistry are gaining attention. Such methods use fewer chemicals and potentially minimize energy consumption. Researchers have explored various methods such as molten carbonate fuel cells, ion exchange membrane pH swing, electrochemical generation of nucleophiles, and ultracapacitor swing adsorption. However, electrochemical methods for capturing CO 2 Rely on redox-active carriers or pH changes to absorb and release CO 2, their practical application is still limited by low capture rates and sensitivity to oxygen present in most CO2 sources. Capacitive deionization (CDI) is an emerging electrochemical desalination technology consisting of activated carbon electrodes, mainly used in seawater desalination. When a constant voltage is applied across the electrodes, ions are moved from the electrolyte to the pores of the electrodes and stored in the electrical double layer (EDL). In this step, energy is temporarily stored in the electrodes due to the capacitance of the electrodes. When the current is reversed, the ions are desorbed from the pores of the electrodes into the electrolyte and the previously stored energy is released. At present, existing studies have shown that CO2 dissolved in water can be absorbed using CDI technology. 2 (HCO 3 - , CO 3 2- ), but traditional CDI is limited by CO 2 Due to the limitation of low solubility, the absorption capacity is still low. Therefore, developing a new air diffusion CDI electrode process can improve the exchange capacity of the cathode side to the gas phase and further expand the application field and performance of CDI. Summary of the invention

[0004] The present invention aims to solve the problems existing in the prior art and provides a novel CO deionization system based on three-phase interface capacitance. 2 Electrochemical absorption device, used in CDI brackish water desalination and CO 2 In the absorption field, it is possible to achieve CO 2 Enrichment and recovery.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a novel CO deionization system based on three-phase interface capacitance 2 The electrochemical absorption device comprises a cathode, an anode, a first shell and a second shell; the cathode and the anode are arranged between the first shell and the second shell, the first shell is provided with an air inlet, an air outlet and a liquid inlet, and the second shell is provided with a liquid outlet; the cathode is provided with a first through hole, and the anode is provided with a second through hole; the gas to be treated enters between the first shell and the cathode through the air inlet, and the brackish water to be treated enters between the cathode and the anode through the liquid inlet and the first through hole, the gas and the brackish water form a solid-liquid-gas three-phase interface at the cathode, and the gas removes CO on the surface of the cathode 2 After that, the brackish water is discharged through the air outlet hole. After being desalinated between the cathode and the anode, the brackish water is discharged through the second through hole and the liquid outlet hole in sequence. A pore structure is distributed in the cathode, and oxygen can undergo an oxygen reduction reaction on the cathode.

[0007] Furthermore, a pore structure is distributed in the cathode, and the cathode is prepared by: evenly coating carbon mud on a foam nickel current collector to form an electrode; and curing the electrode at high temperature to form a cathode.

[0008] Furthermore, the preparation method of the anode is: carbon mud is evenly coated on a graphite plate current collector to prepare the anode.

[0009] Furthermore, the carbon mud is prepared by adding polytetrafluoroethylene to anhydrous ethanol, performing ultrasonic treatment until the mixture is evenly dispersed, then adding activated carbon and conductive carbon black and performing ultrasonic treatment until the mixture is evenly mixed; and drying and stirring the mixed carbon slurry to obtain carbon mud.

[0010] Furthermore, the addition ratio of the polytetrafluoroethylene, anhydrous ethanol, activated carbon and conductive carbon black is 1g:40mL:1.5g:0.1875g.

[0011] Furthermore, the high temperature curing process of the cathode is as follows: placing the electrode in a muffle furnace, heating it to 350° C. at a rate of 10° C. / min, and subjecting it to a constant temperature treatment for 30 minutes to obtain the cathode.

[0012] Furthermore, the size of the nickel foam current collector is 8 cm×8 cm, and the size of the graphite plate current collector is 8 cm×8 cm.

[0013] Furthermore, it includes a first separator, a second separator and a third separator; the first separator and the second separator are respectively provided with a first through groove and a second through groove, the cathode is fixedly installed in the first through groove, and the anode is fixedly installed in the second through groove; the third separator is distributed between the first separator and the second separator, and the third separator is provided with a third through groove; the cathode and the anode are respectively arranged on both sides of the third through groove, and the third through groove is surrounded by an electrolyte cavity.

[0014] Furthermore, the first shell, the first partition, the third partition, the second partition and the second shell are respectively provided with corresponding fixing holes, which are fixedly connected by bolts.

[0015] Furthermore, a silicone gasket is provided between the first shell and the first partition, a silicone gasket is provided between the first partition and the third partition, a silicone gasket is provided between the third partition and the second partition, and a silicone gasket is provided between the second partition and the second shell.

[0016] Furthermore, the first shell, the first partition, the third partition, the second partition and the second shell are the same in shape and size.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) Traditional CDI absorbs CO 2The low absorption efficiency in the process is mainly limited by CO 2 The solubility of CO is low and the mass transfer between gas and liquid is slow. The present invention changes the structure of gas-liquid contact mass transfer in the CDI system through the three-phase interface electrode, solving the problem of CO 2 The absorption efficiency is limited by CO 2 Disadvantages of slow solubility and gas-liquid mass transfer.

[0019] (2) The gas diffusion electrode prepared by the present invention can enhance the oxygen reduction reaction in the treatment process while ensuring the desalination capacity. The high alkaline environment caused by the oxygen reduction reaction can enhance the CO 2 The dissolution at the three-phase interface further enhances the HCO 3 - Absorbed by the electrode, achieving simultaneous enrichment and recovery of CO during desalination 2 , with high capture rate, high energy efficiency and pollution-free way from various CO 2 Continuous, modular capture of CO at source 2 . It solves the problem of traditional electrochemical CO 2 Low oxygen sensitivity in absorption processes, CO 2 Absorption is limited by issues such as background oxygen, which reduces operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The schematic diagram and mechanism diagram of the T-CDI device designed for the present invention, wherein (a) the detailed model diagram of the T-CDI device, (b) the T-CDI desalination-CO 2 Schematic diagram of the absorption mechanism.

[0021] Figure 2 Desalination and CO removal of the T-CDI device designed for the present invention at different electrolyte concentrations 2 Absorption performance diagram, where (ac)T-CDI at different electrolyte concentrations and O 2 Conductivity change curve, adsorption capacity, and pH change curve under gas distribution; (df) T-CDI under different electrolyte concentrations and N 2 Conductivity change curve, adsorption capacity, and pH change curve under gas distribution; (g) T-CDI for CO 2 The absorption amount; (h) after the adsorption is completed, CO 2 Destination; (i) CO 2 The charge efficiency of absorption.

[0022] Figure 3 The T-CDI device designed for the present invention has different operating voltages and different CO 2 Desalination and CO concentration 2Absorption performance diagram, where (af) is the conductivity change curve, adsorption capacity, pH change curve, CO 2 Absorption, CO 2 The charge efficiency of absorption and the CO 2 Destination.

[0023] Figure 4 The T-CDI device designed for the present invention treats different CO 2 Performance diagram of the adsorption capacity of T-CDI at different concentrations, where (a) the adsorption capacity of T-CDI; (b) CO 2 Absorption; (c) charge efficiency.

[0024] Figure 5 The T-CDI device designed for the present invention absorbs CO 2 The results of the mechanism study are shown in Figure 2, where (a) T-CDI for HCO 3 - and Cl - (b) After adding anion exchange membrane, CO 2 Removal amount and destination; (c) CO 2 (d) pH change curve after adding anion exchange membrane; (e) rotating ring disk electrode test current diagram; (f) electron transfer test result diagram during the reaction.

[0025] Figure 6 The T-CDI device designed for the present invention absorbs CO 2 Cycle stability and operating cost analysis diagram, where (a) T-CDI absorbs CO 2 Conductivity curves and CO within 5 cycles 2 Removal amount; (b) T-CDI absorption of CO 2 operating costs.

[0026] The reference numerals in the accompanying drawings are:

[0027] 1. cathode; 2. anode; 3. first outer shell; 4. second outer shell; 5. first separator; 6. second separator; 7. third separator. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] Example 1

[0030] The embodiment of the present invention provides a novel CO deionization system based on three-phase interface capacitance 2 The electrochemical absorption device comprises a cathode 1, an anode 2, and a first shell 3, a first separator 5, a third separator 7, a second separator 6 and a second shell 4 which are fixedly connected in sequence.

[0031] like Figure 1 As shown, the first shell 3, the first partition 5, the third partition 7, the second partition 6 and the second shell 4 are rectangular in cross section with the same size, and are respectively provided with corresponding fixing holes, and are fixedly connected as a whole by bolts. A silicone gasket is provided between two adjacent structures to achieve a sealed connection.

[0032] like Figure 1 As shown, the first separator 5 and the second separator 6 are respectively provided with a first through groove and a second through groove, the cathode 1 is fixed in the first through groove, and the anode 2 is fixed in the second through groove. The third separator 7 is provided with a third through groove, the cathode 1 and the anode 2 are respectively arranged on both sides of the third through groove, and the third through groove is surrounded by a closed cavity for containing electrolyte (brackish water). The first shell 3 is provided with an air inlet, an air outlet and a liquid inlet, the second shell 4 is provided with a liquid outlet, the cathode 1 is provided with a first through hole, and the anode 2 is provided with a second through hole.

[0033] In this embodiment, the preparation method of cathode 1 is as follows: ① Add 1g PTFE (polytetrafluoroethylene) to 40mL anhydrous ethanol, and ultrasonically mix until the PTFE is evenly dispersed; ② Add 1.5g activated carbon and 0.1875g conductive carbon black to the above dispersion, and ultrasonically mix until the dispersion is evenly dispersed (ultrasonication until there are no large particles of activated carbon and conductive carbon black with obvious agglomeration); ③ Pour the evenly dispersed carbon slurry into a culture dish, slowly dry it, and then stir it into carbon mud; ④ Evenly coat the carbon mud on the surface of 8cm×8cm nickel foam collector to make an electrode; ⑤ Place the electrode in a muffle furnace, heat it to 350℃ at a rate of 10℃ / min and keep it at this temperature for 30min, then cool it to room temperature at the same rate, and take it out to obtain a three-phase interface electrode, i.e., a CDI cathode.

[0034] The preparation method of anode 2 is as follows: ① Add 1g PTFE (polytetrafluoroethylene) to 40mL anhydrous ethanol, and ultrasonically mix until the PTFE is evenly dispersed; ② Add 1.5g activated carbon and 0.1875g conductive carbon black to the above dispersion, and ultrasonically mix until evenly dispersed; ③ Pour the evenly dispersed carbon slurry into a culture dish, dry it, and stir it into carbon mud; ④ Evenly coat the carbon mud on an 8cm×8cm graphite plate current collector to make a CDI anode.

[0035] Application principle: The gas to be treated enters between the first housing 3 and the cathode 1 through the gas inlet hole, and the brackish water to be treated enters the cavity between the cathode 1 and the anode 2 through the liquid inlet hole and the first through hole. The gas to be treated and the brackish water form a solid-liquid-gas three-phase interface at the cathode 1. The O in the gas to be treated 2 Oxygen reduction reaction occurs on the cathode to generate hydroxide ions, and CO in the treated gas 2 Dissolves in the cathode alkaline electrolyte to generate HCO 3 - And adsorbed on the anode, CO 2 The anions and cations in the brackish water to be treated are adsorbed on the anode and cathode respectively to achieve salt removal. 2 The desalinated gas is discharged through the gas outlet, and the desalinated brackish water is discharged through the second through hole and the liquid outlet in sequence.

[0036] Compared with the traditional CDI electrode, the present invention uses nickel foam as the current collector, and the carbon slurry mixed with activated carbon, PTFE and conductive carbon black is coated on the surface of the nickel foam, and then cured at high temperature to form a gas diffusion electrode. The pore structure of the nickel foam cathode provides a back cavity for the cathode, and the activated carbon layer, brackish water and air form a solid-liquid-gas three-phase interface at the nickel foam, which enhances the mass transfer of the gas phase at the cathode and can better utilize the O in the mixed gas during the desalination process. 2 To enhance the oxygen reduction reaction. At the same time, the high alkaline environment caused by the oxygen reduction reaction further enhances the CO 2 dissolves and is absorbed by the electrode.

[0037] Example 2

[0038] In this example, the novel CO2-based three-phase interface capacitive deionization system constructed in Example 1 was tested at different electrolyte concentrations. 2 Electrochemical absorption device (T-CDI) CO 2 The absorption capacity and salt adsorption capacity were determined.

[0039] The cathode and anode prepared in Example 1 were connected to an electrochemical workstation, and NaCl solutions with concentrations of 500 mg / L, 1000 mg / L, 2000 mg / L and 5000 mg / L were used as salt solutions. A voltage of 1.8 V was applied across the cathode and anode to test the effects of T-CDI on CO at different electrolyte concentrations. 2 absorption capacity and salt adsorption capacity.

[0040] The results are as follows Figure 2 As shown, in O 2 Under the gas distribution, as the electrolyte concentration increases, the ionic strength in the solution also increases. The salt adsorption capacity (SAC NaCl) increases with the increase of electrolyte concentration, from 9.19 mg / g at 500 mg / L to 16.51 mg / g at 5000 mg / L. 2 The results under gas distribution are similar to those under O 2 Similar to the gas distribution, as the electrolyte concentration increases, the SAC of T-CDI NaCl Gradually increase.

[0041] As the electrolyte concentration increases, the SAC of the electrode increases and CO 2 The absorption amount also increases accordingly. Under oxygen distribution, as the electrolyte concentration increases, CO 2 The removal amount increased from 1.08mmol to 2.31mmol. The trend under nitrogen distribution is similar to that under oxygen. 2 The removal amount increased from 0.57 mmol to 2.06 mmol. It is worth noting that without power, about 0.45 mmol of CO 2 This is attributed to the excellent gas diffusion capacity of the three-phase interface cathode, which allows CO to be removed from the gas phase even without power. 2 It can also dissolve in contact with the electrolyte through the three-phase interface, eventually causing CO in the gas phase 2 The results show that the presence of oxygen can facilitate the oxygen reduction reaction. By utilizing the oxygen reduction reaction at the cathode, more CO 2 Dissolves into the solution and is then adsorbed by the electrode.

[0042] Example 3

[0043] In this embodiment, the novel CO based on three-phase interface capacitor deionization constructed in Example 1 is subjected to different voltages. 2 Electrochemical absorption device (T-CDI) CO 2 The absorption capacity and salt adsorption capacity were determined.

[0044] The cathode and anode prepared in Example 1 were connected to an electrochemical workstation, and the salt adsorption performance and CO2 absorption performance of the system were tested at voltages of 1.2 V, 1.5 V, 1.8 V, and 2.1 V, respectively. 2 Absorption capacity.

[0045] The results are as follows Figure 3 As shown, at 1.2V, 1.5V, 1.8V and 2.1V, the adsorption capacity of the T-CDI electrode in the present invention is 10.27, 13.69, 15.85 and 18.32 mg / g, respectively, and the adsorption capacity increases by 78.38% with the increase of voltage. 2 The absorption increases as a result, because the higher voltage promotes the transfer of ions from the water to the electrode surface, which means more HCO 3- The pH change curve shows that the Faraday reaction is enhanced as the voltage increases, but the charge contributing to salt adsorption decreases, resulting in a decrease in the charge efficiency of salt adsorption.

[0046] Example 4

[0047] In this example, different CO 2 At the concentration, the novel CO2-based three-phase interface capacitive deionization system constructed in Example 1 2 Electrochemical absorption device (T-CDI) CO 2 The absorption capacity and salt adsorption capacity were determined.

[0048] The T-CDI constructed in Example 1 was subjected to 5%, 10% and 15% CO 2 The salt adsorption performance and CO adsorption performance of the T-CDI system were tested under 2 Absorption capacity.

[0049] The results are as follows Figure 4 As shown, different CO 2 At the concentration, T-CDI absorbs CO 2 The performance is also different. According to Henry's law, at a certain temperature and equilibrium state, the solubility of a gas in a liquid is proportional to the equilibrium partial pressure of the gas. 2 The concentration increased, CO 2 The solubility at the three-phase interface increases accordingly. Therefore, under the condition of no electricity, as CO 2 As the concentration increases, CO 2 The amount of dissolved CO also increased. In the T-CDI desalination process, when the gas concentration increased to 10% and 15%, SAC decreased to 12.99 mg / g and 10.14 mg / g, respectively, down 18.04% and 36.03%. 2 The concentration increased, CO 2 The absorption amount increased from 2.00mmol to 5.87mmol. SAC NaCl The decrease is due to more CO 2 Dissolves into the electrolyte, HCO 3 - The adsorption occupies the adsorption sites of activated carbon.

[0050] Example 5

[0051] This embodiment uses a novel CO based on three-phase interface capacitor deionization constructed in Example 1. 2 Electrochemical absorption device (T-CDI) is a device that absorbs NaCl / NaHCO 3 The mixed solution was processed to determine the selectivity of the T-CDI electrode ( Figure 5 a). The results showed that Cl- and HCO 3 - The two ions are in a competitive relationship, and T-CDI has no specific selectivity for these two ions. Therefore, at a certain electrode adsorption capacity, the absorbed HCO 3 - It will cause the adsorption site to be occupied, resulting in Cl - Reduced absorption.

[0052] In addition, in order to explore the effect of oxygen reduction reaction on CO 2 In T-CDI, an anion exchange membrane is added to shield the Faraday reaction of the anode becoming acidic, which has an impact on O 2 and N 2 Gas distribution under CO 2 The absorption was compared ( Figure 5 b) The results show that after adding anion membrane, N 2 and O 2 Gas distribution under CO 2 The removal amount is enhanced because the solution becomes more alkaline after the oxidation reaction at the shielding anode, which means more CO 2 It can dissolve into the solution through the three-phase interface and be absorbed by the electrode, CO 2 The charge efficiency of absorption also increases. From the pH change during the reaction ( Figure 5 d) It can be seen that O 2 Under the gas distribution, the solution becomes more alkaline, which is because the three-phase interface provides sufficient oxygen supply for the oxygen reduction reaction. At the same time, the solution becomes more alkaline, which is also more conducive to CO 2 absorption.

[0053] In order to clarify the specific process of the reaction, the rotating ring disk electrode electrochemical test was carried out on the T-CDI electrode ( Figure 5 e), the results show that as the pH increases, the disk current of the electrode material increases. The disk currents at -0.4V are 0.287mA, 0.307mA and 0.340mA at pH = 5, pH = 7 and pH = 9, respectively. In addition, we can see that a more positive overpotential is exhibited at pH = 9. These results indicate that an increase in pH is conducive to the occurrence of oxygen reduction reactions. For the ring current, as the pH increases, the ring current decreases from 0.271mA to 0.253mA. The number of electron transfers during the reaction is calculated ( Figure 5 f) is about 3.5. This result shows that in T-CDI desalination and absorption of CO 2 During the process, the four-electron oxygen reduction reaction is dominant, and each time a molecule of oxygen is consumed, 4 OH groups are generated. - , which is more conducive to the solution becoming alkaline during the reaction and is beneficial to CO 2 absorb.

[0054] Example 6

[0055] This embodiment uses a novel CO based on three-phase interface capacitor deionization constructed in Example 1. 2 Electrochemical absorption device (T-CDI), the cycle stability test and operation cost analysis of the T-CDI system were carried out.

[0056] The results are as follows Figure 6 After 5 cycles of operation, the T-CDI system was still able to maintain high stability, desalination and CO 2 The absorption remained almost constant over 5 cycles.

[0057] CO absorption through T-CDI 2 The real-time current recorded during the process is used to calculate the operating power consumption and cost of the system. 2 It is an electrochemical technology based on CDI technology. It does not require the addition of additional chemical reagents and does not require high temperature and high pressure operating conditions. Its main energy consumption is only the consumption of electrical energy. Figure 6 As shown in b, assuming that 1000KgCO is absorbed 2 According to the current integration, at an operating voltage of 1.8 V, 2.004 mmol CO 2 It takes 1.165×10 -4 Calculated at 0.5 yuan / kWh of industrial electricity, it takes 1 ton of CO 2 It costs 660.61 yuan. This operating cost is comparable to the currently known new electrochemical recovery of CO 2 However, it is worth noting that if the by-products in the treatment process are recycled, the operating cost of T-CDI technology will be greatly reduced. For example: 1. Recycling the separated and purified CO 2 Currently, industrial CO 2 The price is 300 yuan / ton. According to our experimental results, T-CDI can release 1.32mmol CO after desorption. 2 Entering the recovery device, processing 1 ton of CO 2 During desorption, 0.659 tons of purified and separated CO can be obtained. 2 , worth 197.7 yuan. 2. Recycling carbonates. Carbonates have a wide range of important uses in chemical synthesis and the pharmaceutical industry. Our experimental results show that after each cycle of T-CDI desorption, 0.64 mmol HCO will remain in the electrolyte. 3 - Industrial NaHCO 3 Price: 24 yuan / ton, processing 1000kg CO 20.609 tons of NaHCO can be obtained in the process 3 , which is equivalent to a price of 14.616 yuan. 2 O 2 Based on our previous research, T-CDI can produce a certain amount of H during the desalination process. 2 O 2 When the electrolyte concentration is 2000 mg / L, 3.084 mg H can be produced per cycle. 2 O 2 . Treat 1000kg CO 2 0.034 tons of H can be obtained 2 O 2 .Industrial H 2 O 2 The selling price is 2,000 yuan / ton, so 68 yuan of costs can be recovered. 4. Desalination cost deduction. T-CDI can remove salt ions in water while absorbing carbon dioxide. 2 Absorption technology, if the salt ions in the electrolyte are treated, other desalination processes need to be added for removal. Based on previous studies, T-CDI can treat 1m 3 The cost of brine is 0.131 yuan, so the cost of treating 1000 kg CO 2 The desalination cost can be deducted by RMB 118.85. Finally, if various by-product recovery is taken into account, T-CDI can process 1000kg CO 2 Only 260.8 yuan is needed. Therefore, this solution greatly reduces the cost of desalination and CO removal. 2 cost.

[0058] The present invention provides a different CDI system carbon capture design for capturing CO in mixed gas 2 Through different cathode electrode designs and CDI system configuration improvements, a new three-phase interface CDI system (T-CDI) was designed, which uses the gas diffusion layer of the three-phase interface cathode to enhance CO 2 At the same time, the pH fluctuation caused by the oxygen reduction reaction during the T-CDI desalination process is used to enhance the CO 2 solubility to enhance CO 2 Capture and recovery of CO2, realizing simultaneous enrichment and recovery of CO2 during desalination 2 , with high capture rate, high energy efficiency and pollution-free way from various CO 2 Continuous, modular capture of CO at source 2 . Solved the electrochemical technology O 2 It reduces sensitivity issues, reduces operating costs, and opens up new directions for the industrial application of CDI technology.

[0059] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization, characterized in that: It comprises a cathode (1), an anode (2), a first housing (3) and a second housing (4); The cathode (1) and the anode (2) are arranged between a first shell (3) and a second shell (4); the first shell (3) is provided with an air inlet, an air outlet and a liquid inlet, and the second shell (4) is provided with a liquid outlet; the cathode (1) is provided with a first through hole, and the anode (2) is provided with a second through hole; The gas to be treated enters between the first housing (3) and the cathode (1) through the air inlet hole, and the salt solution to be treated enters between the cathode (1) and the anode (2) through the liquid inlet hole and the first through hole. The gas and the salt solution form a solid-liquid-gas three-phase interface at the cathode (1). The gas is discharged through the air outlet hole after CO2 is removed from the surface of the cathode (1). The salt solution is desalinated between the cathode (1) and the anode (2) and is discharged through the second through hole and the liquid outlet hole in sequence.

2. The novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization according to claim 1 is characterized in that: The cathode (1) has a pore structure distributed inside; The preparation method of the cathode (1) comprises: uniformly coating carbon mud on a nickel foam current collector to form an electrode; curing the electrode at high temperature to form a cathode; The preparation method of the anode (2) is: carbon mud is evenly coated on a graphite plate current collector to prepare the anode.

3. The novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization according to claim 2 is characterized in that: The preparation method of the carbon mud is: Polytetrafluoroethylene is added into anhydrous ethanol and dispersed evenly, and then activated carbon and conductive carbon black are added and mixed evenly; the mixed carbon slurry is dried and stirred to obtain carbon mud.

4. The novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization according to claim 3 is characterized in that: The addition ratio of polytetrafluoroethylene, anhydrous ethanol, activated carbon and conductive carbon black is 1g:40mL: 1.5g:0.1875g.

5. The novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization according to claim 2 is characterized in that: The high temperature curing process of the cathode (1) is as follows: The electrode was placed in a muffle furnace, heated to 350°C at a rate of 10°C / min, and kept at this temperature for 30 minutes to obtain a cathode.

6. The novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization according to claim 2 is characterized in that: The size of the nickel foam current collector is 8 cm×8 cm, and the size of the graphite plate current collector is 8 cm×8 cm.

7. The novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization according to claim 1 is characterized in that: It also includes a first partition plate (5), a second partition plate (6) and a third partition plate (7); The first separator (5) and the second separator (6) are respectively provided with a first through groove and a second through groove, the cathode (1) is fixedly installed in the first through groove, and the anode (2) is fixedly installed in the second through groove; The third separator (7) is distributed between the first separator (5) and the second separator (6), and the third separator (7) is provided with a third through groove; the cathode (1) and the anode (2) are arranged on both sides of the third through groove, and the third through groove is surrounded by an electrolyte cavity.

8. The novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization according to claim 7 is characterized in that: The first shell (3), the first partition (5), the third partition (7), the second partition (6) and the second shell (4) are respectively provided with fixing holes at corresponding positions and are fixedly connected by bolts.

9. The novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization according to claim 8 is characterized in that: A silicone gasket is provided between the first shell (3) and the first partition (5), a silicone gasket is provided between the first partition (5) and the third partition (7), a silicone gasket is provided between the third partition (7) and the second partition (6), and a silicone gasket is provided between the second partition (6) and the second shell (4).

10. The novel CO2 electrochemical absorption device based on three-phase interface capacitive deionization according to claim 8 is characterized in that: The first shell (3), the first partition (5), the third partition (7), the second partition (6) and the second shell (4) have the same shape and size.

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