A bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment system and method based on modified activated carbon adsorbent

Abstract

This invention provides a system and method for bioelectrocatalytic adsorption regeneration and high-salinity wastewater treatment based on modified activated carbon adsorbents, which can be used to treat high-salinity wastewater and remove organic pollutants. The industrial wastewater treated is derived from high-salinity wastewater generated during lithium battery production. Using a distributed integrated process, the system overcomes the difficulty of biologically treating organic matter in high-salinity wastewater. This process offers the advantages of low cost, pollution-free operation, simple operation, and significant water treatment results, enabling energy-efficient and efficient further treatment of this industrial wastewater.

Description

Technical Field

[0001] This invention, which belongs to the field of water treatment, relates to a bioelectrically driven catalytic regeneration method for a carbonaceous adsorbent with excellent catalytic activity and a step-by-step integrated process for treating and removing organic pollutants from high-salinity wastewater. This method achieves the recycling of carbonaceous materials and offers the advantages of low cost, zero pollution, simple operation, and significant water treatment results. It provides a new technology applicable for the energy-saving and efficient treatment of high-salinity wastewater (such as high-salinity lithium battery wastewater). Background Art

[0002] Biological treatment of wastewater has the advantages of low cost, green and sustainable, but most microorganisms have difficulty adapting to high-salinity environments, so it is difficult to directly use biological methods to treat high-salinity wastewater. A large amount of wastewater is generated during the production of lithium batteries, including typical high-concentration salt-containing wastewater, the main components of the solute are sodium chloride and organic matter COD. Since sodium chloride in wastewater can generate economic benefits and has a high concentration, the ideal way is to first remove the organic matter in the wastewater and then recycle the salt. Biological treatment has the advantage of being green and economical, but the high salt and strong alkaline conditions restrict the application of biological treatment processes in special wastewater. Advanced oxidation technologies (AOPs) are often required to enhance the removal of pollutants, but this increases treatment costs and energy consumption.

[0003] Adsorption can be used to separate and remove organic pollutants from high-salinity wastewater, which is also one of the common water treatment methods. Commonly used adsorbents include resins, activated carbon or composite adsorption materials. Among them, activated carbon is widely used in water treatment because of its wide source, low price, and excellent surface characteristics. Activated carbon can adsorb heavy metals, organic matter, etc. in wastewater, and is a common wastewater physicochemical treatment process. After the adsorbent is saturated with organic matter, it needs to be regenerated to restore its adsorption performance, so as to achieve recycling. One regeneration method is to desorb and recover the adsorbed organic matter, and the other regeneration method is to destroy the adsorbed organic matter. Using advanced oxidation technology to degrade and mineralize the desorbed pollutants is a common regeneration method, but it faces the problems of high energy consumption and reagent consumption. Therefore, it is necessary to improve the method for desorption and regeneration of adsorbents. The present invention uses a modified carbon adsorbent and EC-MFC combination to treat organic pollutants in high-salinity wastewater. Microorganisms in the bioanode of the EC-MFC metabolize and transform organic pollutants, transferring the generated electrons through an external circuit to the cathode aerobic zone, where an oxygen reduction reaction occurs to generate current (which in turn produces water or hydrogen peroxide). This allows for the efficient degradation and treatment of organic pollutants, as well as the efficient removal of energy from wastewater organic matter. Compared to traditional wastewater treatment, this not only achieves efficient removal of organic matter from high-salinity wastewater, but also expands the application methods and scope of biological treatment. The integrated process also offers advantages such as simple operation and resource recycling, thus possessing broad application potential.

[0004] The present invention also uses modified activated carbon, which electrocatalytically reduces oxygen to form hydrogen peroxide, to adsorb organic pollutants from high-salinity wastewater. The adsorbed modified activated carbon is then placed in the EC-MFC cathode for desorption and regeneration. The EC-MFC cathode electrocatalytically degrades the organic matter, while the EC-MFC anode treats the desorbed and partially degraded organic matter in the cathode effluent. Multiple adsorption-desorption and regeneration cycles are implemented in a step-by-step, integrated manner to achieve high-salinity wastewater treatment. Summary of the Invention

[0005] In response to the problems existing in the adsorption and regeneration of existing treatment processes, as well as the problem of being unable to achieve biodegradation of organic matter in high-salt wastewater, the present invention aims to provide a carbonaceous adsorbent with excellent catalytic activity, a bioelectrically driven catalytic regeneration method, and a step-by-step integrated process to achieve high-salt wastewater treatment and removal of organic pollutants. This method utilizes a carbonaceous adsorbent with catalytic activity to enrich and concentrate organic matter in high-salt wastewater, and utilizes EC-MFC to regenerate the carbonaceous adsorbent to achieve adsorbent reuse. The modified activated carbon is an adsorbent in the adsorption process, and is also a catalyst for its own regeneration, which greatly reduces the investment in treatment costs. The present invention has the advantages of low cost, no pollution, simple operation, and significant water treatment effect. It is an efficient bioelectrochemical treatment method for removing organic matter in high-salt wastewater.

[0006] The present invention is achieved through the following technical solutions:

[0007] A bioelectrocatalytic adsorption regeneration and high-salinity wastewater treatment system based on modified activated carbon adsorbent, comprising an adsorption tank 4, a circulating liquid tank 8, an activated carbon adsorbent 3, and an electrocatalytic coupled microbial power generation system (EC-MFC);

[0008] The adsorption tank 4 is used to store high-salt wastewater, and the activated carbon adsorbent 3 adsorbs organic matter in the high-salt wastewater to achieve high-salt wastewater treatment;

[0009] The circulating liquid pool 8 is filled with circulating liquid 5. An outlet is provided at the bottom of the circulating liquid pool 8 and is connected to the water inlet of the electrocatalytic coupled microbial power generation system. The water outlet of the electrocatalytic coupled microbial power generation system is connected to the inlet at the top of the circulating liquid pool 8.

[0010] After the activated carbon adsorbent 3 adsorbs organic matter in the high-salt wastewater in the adsorption tank 4, it is used as the cathode material 20 of the electrocatalytic coupled microbial electricity production system to achieve bioelectrocatalytic adsorption regeneration of the modified activated carbon adsorbent.

[0011] Furthermore, the electrocatalytically coupled microbial electricity generation system has an overall top-to-bottom structure, with the circulating fluid 5 flowing in and out from the bottom. The anode chamber 22 of the electrocatalytically coupled microbial electricity generation system is located at the bottom and filled with activated carbon granules 23 loaded with Shewanella exoelectrogenic bacteria. A second aeration head 24 is used at the bottom of the anode chamber 22 to disperse the incoming water. One end of the anode conductive material 15 is connected to a wire 13 and then externally connected to an external resistor 12 and a cathode conductive material 17 connected in series. A voltmeter is connected in parallel to the resistor 12 to monitor the voltage level for real-time and continuous electricity generation by the anode organisms. The other end of the anode conductive material 15 is inserted into the anode chamber 22. The cathode chamber 18 is located at the top and is filled with the circulating fluid 5 flowing out of the anode chamber 22. A partition 21 separates the anode chamber 22 and the cathode chamber 18.

[0012] The cathode material 20 is placed in the cathode chamber 18 and is in contact with the circulating liquid 5 in the cathode chamber 18 and the air input by the first aeration head 19. The cathode conductive material 17 is inserted into the cathode material 20, and the first aeration head 19 is placed in the cathode chamber 18. The cathode conductive material 17 is externally connected to the wire 13 to guide the electrons generated by the anode into the cathode chamber 18. The circulating liquid 5 continuously enters the bottom of the anode chamber 22 through the water inlet flow regulating device (metering water pump 11), flows through the biological anaerobic part and enters the cathode chamber 18. Finally, the treated effluent flows out from the overflow device at the top of the cathode chamber 18 to the circulating liquid tank 8 for circulation.

[0013] Furthermore, a single reactor uses a cylindrical container as a main body, and the volume can be changed according to the actual wastewater treatment needs.

[0014] Furthermore, the electrogenic microorganisms are domesticated by inoculating the electrogenic strain of Shewanella into an incubator with appropriate temperature and culture medium, and adding an appropriate amount of diluted wastewater as a nutrient source to the incubator when the microbial condition is stable. During this period, the wastewater concentration is continuously increased to domesticate the microorganisms until the organisms can adapt to the original wastewater environment. During this period, a voltmeter 16 is used to monitor the growth of the microorganisms.

[0015] Furthermore, the activated carbon particles 23 in the anode chamber 22 have a sheet diameter d=35 to 65 mm, a thickness δ=15 to 25 mm, and a filling rate of 85% to 95%;

[0016] Furthermore, the conductive materials of the anode and cathode are inert conductive materials such as carbon rods;

[0017] Furthermore, the volume ratio of the anode chamber 22 to the cathode chamber 18 is 6:1 to 1:1, which can be adjusted according to the actual wastewater treatment conditions;

[0018] Furthermore, the partition 21 is supported by a porous foam board having the same diameter as the reactor, and the porous foam board is wrapped with filter cloth gauze to intercept the detached biofilm, thereby enhancing the metabolism and water purification function of the anode microorganisms;

[0019] Furthermore, the conductive materials of the anode and cathode, except for the portion in contact with the bioanode and the portion connected to the wire 13, are all treated with waterproof and insulating anti-electrical treatment to improve the efficiency of electron transmission, for example, by wrapping and covering the conductive materials with waterproof tape;

[0020] Furthermore, the cathode material 20 is the activated carbon adsorbent 3 that is adsorbed saturated in the adsorption cell 4 .

[0021] Furthermore, the preparation method of the activated carbon adsorbent 3 is as follows:

[0022] A sufficient amount of granular activated carbon was ultrasonically washed with water until no carbon dust fell off. The washed activated carbon was then immersed in a dilute alkaline solution to remove organic matter adhering to the surface. The washed activated carbon was drained, washed with water until neutral, and dried overnight to obtain a washed activated carbon, designated AC. Co(NO₃)₂ and Ce(NO₃)₂ were then added to deionized water, followed by urea and stirred to obtain a homogeneous solution. A certain amount of the washed activated carbon was mixed with the homogeneous solution by immersion in equal volumes and ultrasonically treated. The dried granules were then dried in a forced air drying oven overnight. The resulting granules were then annealed in a muffle furnace at 400°C–500°C for 2–3 hours to produce a carbonaceous material with excellent catalytic activity, designated CoCe / AC.

[0023] Furthermore, the diameter of the granular activated carbon is d = 0.5 ~1.0 mm;

[0024] Furthermore, the dilute alkaline solution is a sodium hydroxide solution with a mass fraction of 3% to 4%;

[0025] Furthermore, the activated carbon is immersed in the dilute alkali for 10 to 12 hours;

[0026] Furthermore, the total mass fraction of the metal salt in the homogeneous solution is 2.5 to 5.0 wt%;

[0027] Furthermore, the molar ratio of Co(NO3)2 and Ce(NO3)2 is 1:1~1:3;

[0028] Furthermore, the mass fraction of urea in the homogeneous solution is 1.5 to 2.5 wt%;

[0029] Furthermore, the activated carbon and the homogeneous solution are ultrasonically treated for 20 to 30 minutes;

[0030] Furthermore, the drying temperature is 70-85°C and the drying time is 12-16 hours;

[0031] Furthermore, the muffle furnace calcination heating rate is set to 4.8 ~ 5.2 ° C / min.

[0032] A method for bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment based on modified activated carbon adsorbent, comprising the following steps:

[0033] First, a permeable container containing activated carbon adsorbent 3 is placed in the high-salinity wastewater in adsorption tank 4 to adsorb organic matter. After adsorption is complete, the activated carbon adsorbent 3 is removed and drained to obtain adsorption-saturated activated carbon. This is then placed in the EC-MFC cathode chamber 18 for desorption and regeneration. Simultaneously, fresh activated carbon adsorbent 3 is immersed in the high-salinity wastewater in adsorption tank 4 for adsorption. The water flow control device (metering water pump 11) is turned on, and circulating liquid 5 flows continuously through the water flow control device (metering water pump 11) into the bottom of the EC-MFC anode chamber 22 and then into the cathode chamber 18. EC-MFC water overflows from the top of the cathode chamber 18 and enters the circulating liquid tank 8.

[0034] After the activated carbon adsorbent 3 and the EC-MFC are desorbed and regenerated, the cathode material 20 in the EC-MFC cathode chamber 18 is transferred to the high-salinity wastewater in the adsorption tank 4 to adsorb organic matter. Simultaneously, the activated carbon adsorbent 3 is removed from the wastewater in the adsorption tank 4 and drained, then added to the EC-MFC cathode chamber 18 for desorption and regeneration. This process is repeated until the wastewater meets the treatment requirements. The treated wastewater is discharged through the adsorption tank outlet pipe 7 and is then refilled with new wastewater through the adsorption tank inlet pipe 2.

[0035] Furthermore, the water-permeable container is a flexible filter screen or a porous rigid container, and the pore diameter d is ≤1 mm.

[0036] Furthermore, the dosage of the activated carbon adsorbent 3 is 100-300 g per liter of saline wastewater.

[0037] Furthermore, the adsorption time is 6-9 h.

[0038] Furthermore, the circulating liquid 5 is tap water.

[0039] Furthermore, the amount of the circulating liquid 5 is 10-15 mL per gram of activated carbon adsorbent.

[0040] Furthermore, the hydraulic retention time of the circulating fluid 5 in the EC-MFC is 6 to 8 hours.

[0041] The present invention has the following beneficial effects: The proposed bioelectrocatalytic adsorption and regeneration method innovatively integrates adsorbent desorption and regeneration. Even under extreme conditions of conductivity of 39492 μS / cm and pH ≥11, the EC-MFC method achieves an excellent COD removal rate of 98.35% in wastewater, expanding the application of biological treatment methods and scope. The proposed high-salinity wastewater treatment process not only efficiently removes organic matter from high-salinity wastewater, but also significantly reduces treatment costs because the adsorbent acts as its own regeneration catalyst. This invention provides a theoretical basis for the treatment of high-salinity organic wastewater and offers a new technology suitable for energy-saving and efficient wastewater treatment, including lithium battery brine. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of the step-by-step integrated process of the present invention.

[0043] Figure 2 The adsorption effect of activated carbon adsorbent is shown in Figure 2. Among them, (a) is the UV of wastewater during the adsorption test of two activated carbon adsorbents. 254 The horizontal axis is the treatment time (h), and the vertical axis is the absorbance (Abs); (b) is the full spectrum scanning result of the wastewater after 12 hours of adsorption by two activated carbon adsorbents, the horizontal axis is the scanning wavelength (nm), and the vertical axis is the absorbance (Abs); (c) is the UV absorption of the wastewater when treated with different amounts of CoCe / AC adsorbents 254 The horizontal axis is the treatment time (h) and the vertical axis is the absorbance (Abs).

[0044] Figure 3 The desorption effect diagram of activated carbon adsorbent. Among them, (a) is the UV of activated carbon adsorbent desorption regeneration treatment with different hydraulic retention time 254 (a) The horizontal axis is the treatment time (h), and the vertical axis is the absorbance (Abs); (b) is the full spectrum scanning diagram of the degradation of organic matter by electrochemical microbial fuel cell, the horizontal axis is the wavelength (nm), and the vertical axis is the absorbance (Abs).

[0045] Figure 4 The effect diagram of the four-stage treatment of lithium battery brine using a step-by-step integrated process. Among them, (a) COD and UV of wastewater in the four stages 254 (a) is the full spectrum scanning result of wastewater in four stages, with the horizontal axis being the treatment stage and the vertical axis being the absorbance (Abs) and COD.

[0046] In the figure: 1 first water gate; 2 adsorption tank inlet pipe; 3 activated carbon adsorbent; 4 adsorption tank; 5 circulating liquid; 6 second water gate; 7 adsorption tank outlet pipe; 8 circulating liquid tank; 9 overflow outlet pipe; 10 desorption tank outlet pipe; 11 metering water pump; 12 resistor; 13 wire; 14 air pump; 15 conductive material of anode; 16 voltmeter; 17 conductive material of cathode; 18 cathode chamber; 19 first aeration head; 20 cathode material; 21 interlayer; 22 anode chamber; 23 filling anode; 24 second aeration head; 25 bottom water inlet of biological treatment device. DETAILED DESCRIPTION

[0047] The technical solutions and drawings of the present invention are further described below through examples, which are not intended to limit the scope of protection of the present invention.

[0048] A bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment system based on modified activated carbon adsorbent, such as Figure 1 As shown, it includes an adsorption tank 4, a circulating liquid tank 8, an activated carbon adsorbent 3 and an electrocatalytic coupled microbial power generation system (EC-MFC);

[0049] The adsorption tank 4 is used to hold high-salt wastewater, and the activated carbon adsorbent 3 adsorbs organic matter in the high-salt wastewater to achieve high-salt wastewater treatment; the wastewater enters the adsorption tank 4 through the adsorption tank inlet pipe 2 through the first sluice 1; after the wastewater is treated to meet the discharge standards, it is discharged through the outlet pipe 7 with the second sluice 6.

[0050] The circulating liquid pool 8 is filled with circulating liquid 5. An outlet is provided at the bottom of the circulating liquid pool 8 and is connected to the water inlet of the electrocatalytic coupled microbial power generation system. The water outlet of the electrocatalytic coupled microbial power generation system is connected to the inlet at the top of the circulating liquid pool 8.

[0051] After the activated carbon adsorbent 3 adsorbs organic matter in the high-salt wastewater in the adsorption tank 4, it is used as the cathode material 20 of the electrocatalytic coupled microbial electricity production system to achieve bioelectrocatalytic adsorption regeneration of the modified activated carbon adsorbent.

[0052] The electrocatalytically coupled microbial electricity generation system has an overall top-to-bottom structure, with the circulating liquid 5 operating in a bottom-in, top-out mode. The anode chamber 22 of the electrocatalytically coupled microbial electricity generation system is located at the bottom and filled with activated carbon granules 23 loaded with Shewanella exoelectrogenic bacteria (the activated carbon granules 23 have a layer diameter d = 35 to 65 mm, a thickness δ = 15 to 25 mm, and a filling rate of 85%). A second aeration head 24 is used at the bottom of the anode chamber 22 to disperse the incoming water. One end of the anode conductive material 15 is connected to a wire 13 and then externally connected to an external resistor 12 and a cathode conductive material 17 connected in series. The external resistor 12 is connected in parallel to a voltmeter 16, and the electricity generation of the anode organisms is continuously monitored in real time by detecting the voltage. The other end of the anode conductive material 15 is inserted into the anode chamber 22. The cathode chamber 18 is located at the top and is filled with the circulating liquid 5 flowing out of the anode chamber 22. The anode chamber 22 is separated from the cathode chamber 18 by a partition 21; the partition 21 is supported by a porous foam board with the same diameter as the reactor, and the porous foam board is wrapped with filter cloth gauze to intercept the detached biofilm, thereby enhancing the metabolism and water purification function of the anode microorganisms.

[0053] Cathode material 20 is placed in cathode chamber 18, in contact with circulating liquid 5 in cathode chamber 18 and air input from first aeration head 19. Cathode conductive material 17 is inserted into cathode material 20, and first aeration head 19 is placed in cathode chamber 18. Cathode conductive material 17 is connected to wire 13, which directs electrons generated by the anode into cathode chamber 18. Circulating liquid 5 continuously enters the bottom of anode chamber 22 through the inlet flow regulating device (metering water pump 11), flows through the biological anaerobic section, and enters cathode chamber 18. The treated effluent ultimately flows out of the overflow device at the top of cathode chamber 18 and into circulating liquid tank 8 for recirculation. The conductive materials of the anode and cathode, except for those in contact with the biological anode and connected to wire 13, are covered with waterproof tape.

[0054] During operation, the circulating liquid 5 flows from the bottom water inlet 25 and the second aeration head 24 into the anode chamber 22, which is filled with activated carbon granules 23 loaded with Shewanella exoelectrogenic bacteria. After biological treatment, the circulating liquid 5 passes through the intermediate barrier 21 to trap the microorganisms before flowing into the cathode chamber 18, where it comes into contact with the cathode material 20. This desorbs pollutants and allows the electrochemical catalytic reaction on the surface of the activated carbon cathode to degrade them. The anode chamber 22 is connected to the cathode chamber 18, which is filled with cathode material 20, via a conductor 13 and a cathode carbon rod 17. A 100Ω adjustable external resistor 12 and a voltmeter 16 are connected to monitor microbial electricity production. The cathode chamber 18 is aerated by an air pump 14, which introduces air into the cathode material 20 through the first aeration head 19. Water overflows from the top cathode chamber 18 and flows back into the circulating liquid tank 8 through the outlet pipe 9. The volume ratio of the anode chamber 22 to the cathode chamber 18 is 4:1. Preparation of the bioanode: The anode microorganisms containing Shewanella electrogenic bacteria are adsorbed on granular activated carbon. The mixed bacteria containing Shewanella electrogenic bacteria are obtained by culturing and domesticating the bottom mud of the sea water. The bacteria can be put into use after the stable electrogenic potential is measured by a 232 reference electrode and is greater than 0.1 V.

[0055] During use: First, a permeable container containing activated carbon adsorbent 3 is placed in the high-salinity wastewater in adsorption tank 4 to adsorb organic matter. After adsorption is complete, the activated carbon adsorbent 3 is removed and drained to obtain adsorption-saturated activated carbon, which is then placed in the EC-MFC cathode chamber 18 for desorption and regeneration. Simultaneously, fresh activated carbon adsorbent 3 is immersed in the high-salinity wastewater in adsorption tank 4 for adsorption. The water flow control device (metering water pump 11) is turned on, and circulating liquid 5 continuously flows through the water flow control device (metering water pump 11) into the bottom of the EC-MFC anode chamber 22 and then into the cathode chamber 18. EC-MFC water overflows from the top of the cathode chamber 18 and enters the circulating liquid tank 8.

[0056] After the activated carbon adsorbent 3 and the EC-MFC are desorbed and regenerated, the cathode material 20 in the EC-MFC cathode chamber 18 is transferred to the high-salinity wastewater in the adsorption tank 4 to adsorb organic matter. Simultaneously, the activated carbon adsorbent 3 is removed from the wastewater in the adsorption tank 4 and drained, then added to the EC-MFC cathode chamber 18 for desorption and regeneration. This process is repeated until the wastewater meets the treatment requirements. The treated wastewater is discharged from the adsorption tank outlet pipe 7 through the second sluice gate 6. The first sluice gate 1 is opened to allow new wastewater to be injected into the adsorption tank inlet pipe 2.

[0057] Among them, the preparation of activated carbon adsorbent with catalytic activity

[0058] Water-washed activated carbon adsorbent: A sufficient amount of granular activated carbon (diameter d = 0.5 ~ 1.0 mm) was ultrasonically washed with water until no carbon powder fell off. The washed activated carbon was soaked in a dilute alkaline solution (sodium hydroxide solution with a mass fraction of 3.5wt%) to remove organic matter adhering to the surface. After keeping it for 10 hours, it was drained and washed with deionized water until the leachate was neutral. It was dried at 75 °C overnight to obtain water-washed activated carbon, which was named AC.

[0059] Catalytically active carbonaceous material: 0.596 g of Co(NO₃)₂ and 2.92 g of Ce(NO₃)₂ were added to 100 mL of deionized water, followed by the addition of urea and stirring to obtain a homogeneous solution. The mass fraction of urea in the homogenous solution was 2 wt%. 75 g of water-washed activated carbon was mixed by equal volume immersion and ultrasonically treated for 30 minutes. The mixture was then dried in a 75°C forced air drying oven for 12 hours. The resulting dried particles were further heated to 400°C in a muffle furnace at a heating rate of 5°C / min and annealed for 2 hours to obtain the final product, designated CoCe / AC.

[0060] The adsorption treatment was performed using the water-washed activated carbon adsorbent (AC) and the catalytically active carbonaceous material (CoCe / AC) described in Example 2. The specific steps are as follows:

[0061] (1) 50 g of two different activated carbon adsorbents were weighed and filled in a permeable container (pore size d = 0.5 mm), and completely immersed in an adsorption tank containing 500 mL of high-salt wastewater for 24 h. Samples were taken every 6 h and UV-visible 254 Test and observe the adsorption of organic pollutants by activated carbon adsorbents, such as Figure 2 (a) in the figure; take the water sample after 12 hours of adsorption and conduct full spectrum scanning test, such as Figure 2 (b) After 24 h of adsorption, UV 254 A decrease of 56.63% and 81.31% respectively.

[0062] (2) Take 150g of CoCe / AC adsorbent, fill it in a permeable container, and completely immerse it in the adsorption tank, which stores 500mL of high-salt wastewater. Soak for 24 hours, take samples every 4 hours, and perform UV 254 Test and observe the adsorption of organic pollutants by activated carbon adsorbents, such as Figure 2 (c) in the.

[0063] (3) After the above-mentioned activated carbon adsorbent has been soaked and adsorbed for 24 hours, the water is removed and the adsorbent is transferred to the cathode chamber of the EC-MFC for desorption and regeneration. At the same time, the metering pump is turned on to pump the circulating liquid into the EC-MFC system. The circulating liquid flows through the filled bioanode and the partition into the cathode chamber to contact the adsorption-saturated CoCe / AC cathode material, and finally overflows into the desorption tank. The circulating liquid tank stores 1500 mL of circulating liquid (tap water), and the metering pump is adjusted to control the hydraulic retention time (HRT) of the EC-MFC system. The adsorption time of the activated carbon adsorbent and the desorption and regeneration time of the EC-MFC are 24 hours. The circulating liquid water samples are collected at intervals and the collected water samples are UV-tested. 254 Tests such as Figure 3 (a). After 24 hours of operation, the inlet and outlet water of the EC-MFC system were collected and a full spectrum scanning test was performed, such as Figure 3 Middle (b).

[0064] Lithium battery high-salt wastewater treatment:

[0065] Combine Figure 2 and Figure 3 , 150g of the prepared CoCe / AC material was filled into a permeable container and immersed in 500mL of high-salt wastewater for an 8-hour adsorption process. After the adsorption was completed, the CoCe / AC was removed from the wastewater and drained to obtain adsorption-saturated activated carbon, which was then added to the cathode chamber of the EC-MFC for desorption and regeneration. At the same time, another 150g of CoCe / AC was taken and immersed in high-salt wastewater for 8 hours of adsorption. Turn on the metering water pump 11 to control the HRT of the EC-MFC to 8 hours. The circulating liquid continuously enters the bottom of the anode chamber, flows through the biological anaerobic part and enters the cathode chamber, and finally the treated effluent flows from the overflow device at the top of the cathode chamber into the circulating liquid pool.

[0066] After the above-mentioned activated carbon adsorption and EC-MFC desorption and regeneration are completed, the CoCe / AC in the EC-MFC cathode chamber is transferred to the adsorption tank; at the same time, the CoCe / AC in the adsorption tank is taken out and drained using the same method, and then transferred to the EC-MFC cathode chamber for desorption and regeneration.

[0067] After that, the adsorption and EC-MFC desorption regeneration process is repeated until the organic matter in the wastewater in the adsorption tank meets the treatment requirements. The treated wastewater that meets the standards is discharged through the second water gate 6 and the adsorption tank outlet pipe 7. The first water gate 1 is opened to inject new wastewater from the adsorption tank inlet pipe 2, and then the next batch of wastewater treatment is carried out. During the treatment process, at the end of each stage, the water sample of the treated lithium battery brine is collected for UV254 and COD determination. Figure 4 (a) in the figure, and perform full spectrum scanning test at the same time, such as Figure 4In this embodiment, three cycles of adsorption and EC-MFC desorption and regeneration were performed, and the COD index of the wastewater in the adsorption tank met the treatment requirements.

[0068] The above examples demonstrate that the present invention, using CeCe / AC materials that both adsorb and act as a regeneration catalyst, exhibits superior adsorption performance compared to water-washed activated carbon adsorbents, achieving efficient desorption and regeneration. The examples utilize a step-by-step integrated process to treat lithium battery high-salinity wastewater. The CoCe / AC efficiently adsorbs organic matter from the high-salinity wastewater, and then uses an electrochemical microbial fuel cell to desorb and regenerate the CoCe / AC, achieving efficient bioelectrochemical treatment of organic matter in the high-salinity wastewater. This demonstrates the feasibility of the present invention in actual lithium battery industrial wastewater treatment.

Claims

1. A bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment system based on modified activated carbon adsorbent, characterized in that: It includes an adsorption tank (4), a circulating liquid tank (8), an activated carbon adsorbent (3) and an electrocatalytic coupled microbial electricity generation system; The adsorption tank (4) is used to store high-salt wastewater, and the activated carbon adsorbent (3) adsorbs organic matter in the high-salt wastewater to achieve high-salt wastewater treatment; The circulating liquid pool (8) is filled with circulating liquid (5), and an outlet is provided at the bottom of the circulating liquid pool (8), which is connected to the water inlet of the electrocatalytic coupled microbial electricity generation system, and the water outlet of the electrocatalytic coupled microbial electricity generation system is connected to the inlet at the top of the circulating liquid pool (8); After the activated carbon adsorbent (3) adsorbs organic matter in high-salt wastewater in the adsorption tank (4), it is used as the cathode material (20) of the electrocatalytic coupled microbial electricity production system to achieve bioelectrocatalytic adsorption regeneration of the modified activated carbon adsorbent.

2. The bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment system based on modified activated carbon adsorbent according to claim 1 is characterized in that: The electrocatalytic coupled microbial electricity generation system is a top-bottom structure, and the circulating liquid (5) operates in a bottom-in and top-out manner; the anode chamber (22) of the electrocatalytic coupled microbial electricity generation system is located at the bottom, and is filled with activated carbon particles (23) loaded with Shewanella electrogenic bacteria, and a second aeration head (24) is used at the bottom of the anode chamber (22) to disperse the influent; one end of the anode conductive material (15) is connected to the wire (13) and then externally connected to an external resistor (12) and a cathode conductive material (17) connected in series in sequence, and the external resistor (12) is connected in parallel to a voltmeter (16), and the electricity generation of the anode organism is continuously monitored in real time by detecting the voltage; the other end of the anode conductive material (15) is inserted into the anode chamber (22); the cathode chamber (18) is located at the top, and the cathode chamber (18) is filled with the circulating liquid (5) flowing out of the anode chamber (22); the anode chamber (22) and the cathode chamber (18) are separated by a partition (21); The cathode material (20) is placed in the cathode chamber (18) and is in contact with the circulating liquid (5) in the cathode chamber (18) and the air input by the first aeration head (19). The cathode conductive material (17) is inserted into the cathode material (20), and the first aeration head (19) is placed in the cathode chamber (18). The cathode conductive material (17) is externally connected to the wire (13) to guide the electrons generated by the anode into the cathode chamber (18). The circulating liquid (5) continuously enters the bottom of the anode chamber (22) through the water inlet flow regulating device, flows through the biological anaerobic part and enters the cathode chamber (18), and finally the treated effluent flows out from the overflow device at the top of the cathode chamber (18) to the circulating liquid pool (8) for circulation.

3. The bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment system based on modified activated carbon adsorbent according to claim 2, characterized in that: A single reactor uses a cylindrical container as the main body, and the volume can be changed according to the actual wastewater treatment needs; The electrogenic microorganisms were acclimated by inoculating the electrogenic strain of Shewanella into an incubator with appropriate temperature and culture medium. When the microorganisms were stable, an appropriate amount of diluted wastewater was added to the incubator as a nutrient source. During this period, the wastewater concentration was continuously increased to acclimate the microorganisms until the organisms could adapt to the original wastewater environment. During this period, a voltmeter (16) was used to monitor the growth of the microorganisms. The activated carbon particles (23) in the anode chamber (22) have a sheet diameter d=35~65mm, a thickness δ=15~25mm, and a filling rate of 85%~95%; The conductive materials of the anode and cathode are carbon rods; The volume ratio of the anode chamber (22) to the cathode chamber (18) is 6:1 to 1:1, which can be adjusted according to the actual wastewater treatment conditions.

4. The bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment system based on modified activated carbon adsorbent according to claim 2, characterized in that: The partition (21) is supported by a porous foam plate having the same diameter as the reactor, and the porous foam plate is wrapped with filter cloth gauze to intercept the detached biofilm, thereby enhancing the metabolism and water purification function of the anode microorganisms; The conductive materials of the anode and cathode, except for the part in contact with the biological anode and the part connected with the wire (13), are all covered with waterproof tape to provide waterproof, insulating and anti-electrical treatment to improve the efficiency of electron transmission; The cathode material (20) is an activated carbon adsorbent (3) that is adsorbed saturated in an adsorption cell (4).

5. The bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment system based on modified activated carbon adsorbent according to claim 1, characterized in that: The preparation method of activated carbon adsorbent (3) is as follows: A sufficient amount of granular activated carbon was ultrasonically washed with water until no carbon powder fell off, and the washed activated carbon was immersed in a dilute alkaline solution to remove organic matter adhering to the surface. It was drained, washed with water until neutral, and then dried overnight to obtain washed activated carbon, named AC; then Co(NO3)2 and Ce(NO3)2 were added to deionized water, and then urea was added and stirred to obtain a homogeneous solution; a certain amount of the above-mentioned washed activated carbon was mixed with the homogeneous solution by an equal volume immersion method and ultrasonically treated, and then dried in a blast drying oven overnight to obtain dry particles. The dry particles were annealed at a temperature of 400℃~500℃ in a muffle furnace for 2h~3h to obtain a carbonaceous material with excellent catalytic activity, named CoCe / AC.

6. The bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment system based on modified activated carbon adsorbent according to claim 5, characterized in that: The diameter of the granular activated carbon is d=0.5~1.0mm; the dilute alkali solution is a sodium hydroxide solution with a mass fraction of 3%~4%; the activated carbon is immersed in the dilute alkali for 10h~12h; and the total mass fraction of the metal salt in the homogeneous solution is 2.5~5.0wt%.

7. The bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment system based on modified activated carbon adsorbent according to claim 5, characterized in that: The molar ratio of the Co(NO3)2 and Ce(NO3)2 substances is 1:1~1:3; the mass fraction of urea in the homogeneous solution is 1.5~2.5wt%; the time for ultrasonic treatment of the activated carbon and the homogeneous solution is 20~30min; the drying temperature is 70~85℃, and the drying time is 12~16h; the muffle furnace calcination heating rate is set to 4.8~5.2℃ / min.

8. A method for treating high-salt wastewater by using a modified activated carbon adsorbent-based bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment system according to any one of claims 2 to 7, characterized in that: Here are the steps: First, a permeable container containing an activated carbon adsorbent (3) is placed in the high-salt wastewater in the adsorption tank (4) to adsorb organic matter; after the adsorption is completed, the activated carbon adsorbent (3) is taken out and drained to obtain adsorption-saturated activated carbon, which is then placed in the EC-MFC cathode chamber (18) for desorption and regeneration; at the same time, another new activated carbon adsorbent (3) is soaked in the high-salt wastewater in the adsorption tank (4) for adsorption; The water flow regulating device is turned on, and the circulating liquid (5) continuously enters the bottom of the EC-MFC anode chamber (22) through the water flow regulating device, and then enters the cathode chamber (18). The EC-MFC water overflows from the upper part of the cathode chamber (18) and enters the circulating liquid pool (8); After the above-mentioned activated carbon adsorbent (3) is desorbed and regenerated from the EC-MFC, the cathode material (20) in the cathode chamber (18) of the EC-MFC is transferred to the high-salt wastewater in the adsorption tank (4) to adsorb organic matter; At the same time, the previous activated carbon adsorbent (3) is removed from the wastewater in the adsorption tank (4) and drained in the same way, and then added to the EC-MFC cathode chamber (18) for desorption regeneration; this step is repeated until the wastewater meets the treatment requirements; the treated wastewater that meets the standards is discharged through the adsorption tank outlet pipe (7) and new wastewater is injected into the adsorption tank inlet pipe (2).

9. The method for bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment based on modified activated carbon adsorbent according to claim 8, characterized in that: The permeable container is a flexible filter or a porous rigid container, and the pore size d≤1mm; the dosage of the activated carbon adsorbent (3) is 100-300g / liter of saline wastewater; and the adsorption time is 6-9h.

10. The method for bioelectrocatalytic adsorption regeneration and high-salt wastewater treatment based on modified activated carbon adsorbent according to claim 8, characterized in that: The circulating liquid (5) is tap water; the amount of the circulating liquid (5) is 10-15 mL / g activated carbon adsorbent; and the hydraulic retention time of the circulating liquid (5) in the EC-MFC is 6-8 h.

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