Bioelectrocatalytic adsorption regeneration and high-salinity wastewater treatment system and method based on modified activated carbon adsorbent

Abstract

The invention provides a bioelectrocatalysis adsorption regeneration and high-salinity wastewater treatment system and method based on a modified activated carbon adsorbent. The system and method can be used for treating high-salinity wastewater to remove organic pollutants. The treated industrial wastewater comes from high-salinity wastewater generated in a lithium battery production process, and the problem that organic matters in the high-salinity wastewater are difficult to biologically treat is solved by using a distributed integrated process. The process has the advantages of low cost, no pollution, simplicity in operation and remarkable water treatment effect, and energy-saving and efficient further treatment of the industrial wastewater is completed.

Description

Technical Field

[0001] The present invention belongs to the field of water treatment, and relates to a bioelectric driven catalytic regeneration method of a carbonaceous adsorbent with excellent catalytic activity and a step-by-step integrated process for treating and removing organic pollutants in high-salinity wastewater. The recycling of carbonaceous materials is achieved, and it has the advantages of low cost, no pollution, simple operation and significant water treatment effect, and provides a new technology applicable to energy-saving and efficient treatment of high-salinity wastewater (such as high-salinity lithium battery wastewater, etc.). Background Art

[0002] Biological treatment of wastewater has the advantages of low cost, green and sustainable, but most microorganisms find it difficult to adapt 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, and 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 green and economical treatment, but high salt and strong alkalinity conditions restrict the application of biological treatment processes in special wastewater, and advanced oxidation technology (AOPs) is 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 adsorbent 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 sewage 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 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 of 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. The microorganisms in the bioanode of EC-MFC can metabolize and transform organic pollutants, and transport the generated electrons to the cathode aerobic zone through an external circuit, where an oxygen reduction reaction occurs to generate current (oxygen reduction produces water or hydrogen peroxide), thereby realizing the recycling of energy in wastewater organic matter and the efficient degradation and treatment of organic pollutants. Compared with traditional wastewater treatment, this can not only achieve efficient removal of organic matter in high-salinity wastewater, but also expand the application methods and scope of biological treatment. The integrated steps also have the advantages of simple operation and resource recycling, and have a wide range of application potential.

[0004] The present invention also uses modified activated carbon with the characteristic of electrocatalytic oxygen reduction to form hydrogen peroxide to adsorb organic pollutants in high-salinity wastewater, places the adsorption-saturated modified activated carbon material in the EC-MFC cathode for desorption regeneration, and the EC-MFC cathode realizes electrocatalytic degradation of organic matter, and the EC-MFC anode treats the desorbed organic matter and the organic matter that is not completely degraded in the cathode effluent. Multiple adsorption-desorption regeneration cycles are performed to achieve the treatment of high-salinity wastewater in a step-by-step integrated manner. Summary of the invention

[0005] In view of the problems existing in the adsorption and regeneration of existing treatment processes, and the problem that it is impossible 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. The 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 from high-salt wastewater.

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

[0007] A bio-electrocatalytic 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 electricity generation system (EC-MFC);

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

[0009] The circulating liquid pool 8 is filled with circulating liquid 5, and an outlet is arranged 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;

[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 bio-electrocatalytic adsorption regeneration of the modified activated carbon adsorbent.

[0011] Furthermore, the electrocatalytic coupled microbial electricity generation system is an overall upper and lower structure, and the circulating liquid 5 operates in a bottom-in and top-out mode; 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 the bottom of the anode chamber 22 uses a second aeration head 24 to disperse water; one end of the anode conductive material 15 is connected to the wire 13 and then externally led, and the external resistor 12 and the cathode conductive material 17 are connected in series in sequence, and the external resistor 12 is connected in parallel with a voltmeter, 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 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.

[0012] The cathode material 20 is placed in the cathode chamber 18, 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 in the cathode material 20, and the first aeration head 19 is placed in the cathode chamber 18; the cathode conductive material 17 is connected to the external wire 13 to introduce 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, 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.

[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 domestication of the electricity-producing microorganisms is carried out by inoculating the electricity-producing strain of Shewanella into an incubator with a suitable temperature and culture medium, and when the microbial condition is stable, adding an appropriate amount of diluted wastewater into the incubator as a nutrient source, and during this period, the wastewater concentration is continuously increased to domesticate the microorganisms until the organisms can adapt to the original wastewater environment, and during this period, a voltmeter 16 is used to monitor the growth of the microorganisms.

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

[0019] Furthermore, the conductive materials of the anode and cathode are all treated with waterproof, insulating and anti-electrical treatment except for the part in contact with the bioanode and the part connected with the wire 13 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 an activated carbon adsorbent 3 that is saturated with adsorption in an 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 powder fell off, and the washed activated carbon was immersed in a dilute alkaline solution to remove organic matter adhering to the surface, and then drained, washed with water until neutral, and dried overnight to obtain washed activated carbon, named AC. 3 ) 2 and Ce(NO 3 ) 2 Add deionized water, then add urea and stir to obtain a homogeneous solution. Take a certain amount of the above-mentioned washed activated carbon and mix it with the homogeneous solution by equal volume immersion method and ultrasonic treatment, then dry it in a blast drying oven overnight to obtain dry particles, which are annealed at 400℃~500℃ in a muffle furnace for 2h~3h to obtain a carbonaceous material with excellent catalytic activity, named 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 Co(NO 3 ) 2 and Ce(NO 3 ) 2 The ratio of the amount of substance is 1:1 to 1:3;

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

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

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

[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-salinity wastewater treatment based on modified activated carbon adsorbent, the steps are as follows:

[0033] First, a water-permeable container containing an activated carbon adsorbent 3 is placed in the high-salt wastewater of 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 of the adsorption tank 4 for adsorption; the water flow regulating device (metering water pump 11) 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 (metering water pump 11), and then enters the cathode chamber 18, and the EC-MFC water overflows from the upper part of the cathode chamber 18 into the circulating liquid tank 8.

[0034] After the above-mentioned activated carbon adsorbent 3 and EC-MFC are desorbed and regenerated, 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 taken out from the wastewater in the adsorption tank 4 and drained, and then added to the cathode chamber 18 of the EC-MFC for desorption and regeneration. Repeat this step 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.

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

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

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

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

[0039] Furthermore, the amount of the circulating liquid 5 is 10 to 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 bio-electrocatalytic adsorption and regeneration method proposed in the present invention innovatively integrates desorption and regeneration of the adsorbent. Even under extreme conditions of conductivity of 39492μS / cm and pH ≥ 11, the present invention still achieves an excellent COD removal rate of 98.35% in wastewater by using EC-MFC, expanding the application mode and scope of biological treatment; the proposed high-salt wastewater treatment process can not only achieve efficient removal of organic matter in high-salt wastewater, but also the adsorbent is also its own regeneration catalyst in the process, greatly reducing the investment in treatment costs. The present invention provides a theoretical basis for the treatment of high-salt organic wastewater and provides applicable new technologies for energy-saving and efficient wastewater treatment (including lithium battery brine, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It 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. (a) shows the UV absorption of wastewater during the adsorption test of two activated carbon adsorbents. 254 (a) is the full spectrum scanning result of wastewater after 12 hours of adsorption by two activated carbon adsorbents, with the horizontal axis being the scanning wavelength (nm) and the vertical axis being the absorbance (Abs); (c) is the UV spectrum of wastewater 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) is a full spectrum scan of the degradation of organic matter by electrochemical microbial fuel cells, with the horizontal axis being the wavelength (nm) and the vertical axis being the absorbance (Abs).

[0045] Figure 4 The effect diagram of the four stages of lithium battery brine treatment using a step-by-step integrated process. (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 the first water gate; 2 the adsorption tank water inlet pipe; 3 the activated carbon adsorbent; 4 the adsorption tank; 5 the circulating liquid; 6 the second water gate; 7 the adsorption tank outlet pipe; 8 the circulating liquid tank; 9 the overflow outlet pipe; 10 the desorption tank outlet pipe; 11 the metering water pump; 12 the resistor; 13 the wire; 14 the air pump; 15 the conductive material of the anode; 16 the voltmeter; 17 the conductive material of the cathode; 18 the cathode chamber; 19 the first aeration head; 20 the cathode material; 21 the interlayer; 22 the anode chamber; 23 the filling anode; 24 the second aeration head; 25 the bottom water inlet of the biological treatment device. DETAILED DESCRIPTION

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

[0048] A bioelectrocatalytic adsorption regeneration and high-salinity 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 electricity 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 first sluice 1 from the water inlet pipe 2; after the wastewater is treated to meet the discharge standard, it is discharged from the outlet pipe 7 with the second sluice 6.

[0050] The circulating liquid pool 8 is filled with circulating liquid 5, and an outlet is arranged 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;

[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 bio-electrocatalytic adsorption regeneration of the modified activated carbon adsorbent.

[0052] The electrocatalytic coupled microbial electricity generation system is an overall upper and lower structure, and the circulating liquid 5 operates in a bottom-in and top-out mode; 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 (the layer diameter of the activated carbon particles 23 is d=35-65mm, the thickness is δ=15-25mm, and the filling rate is 85%), and the second aeration head 24 is used to disperse the water at the bottom of the anode chamber 22; one end of the anode conductive material 15 is connected to the wire 13 and then externally led, and the external resistor 12 and the cathode conductive material 17 are connected in series in sequence, and the external resistor 12 is connected in parallel with a voltmeter 16, and the electricity generation of the anode organisms is continuously monitored in real time by detecting the voltage situation; 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 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] The cathode material 20 is placed in the cathode chamber 18, 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 in the cathode material 20, and the first aeration head 19 is placed in the cathode chamber 18; the cathode conductive material 17 is connected to the wire 13 to introduce 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, 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. The conductive materials of the anode and cathode are covered with waterproof tape except for the part in contact with the biological anode and the part connected with the wire 13.

[0054] When in use, the circulating liquid 5 flows from the bottom water inlet 25 and the second aeration head 24 into the anode chamber 22 filled with activated carbon particles 23 loaded with Shewanella electrogenic bacteria, and after biological treatment, it intercepts microorganisms through the middle partition 21 and flows into the cathode chamber 18, and contacts the filled cathode material 20. The desorption of pollutants and the electrochemical catalytic reaction on the surface of the activated carbon cathode are realized. The anode chamber 22 is led out using an anode carbon rod 15 wrapped with a waterproof tape to collect and conduct electrons, and is connected to the cathode chamber 18 filled with cathode material 20 through a wire 13 and a cathode carbon rod 17, and a 100Ω adjustable external resistor 12 and a voltmeter 16 are connected to monitor the electricity generation of microorganisms. The cathode chamber 18 is aerated by an air pump 14, and air is introduced into the cathode material 20 through the first aeration head 19. The top cathode chamber 18 overflows with water, and flows back to the circulation pool 8 through the outlet pipe 9. The volume ratio of the anode chamber 22 to the cathode chamber 18 is 4:1. Preparation of biological anode: adsorb anode microorganisms containing Shewanella electrogenic bacteria on granular activated carbon. The mixed bacteria containing Shewanella electrogenic bacteria are obtained by culturing and domesticating the bottom mud of sea waters. The bacteria can be put into use after the stable potential of electricity production is measured by a 232 reference electrode and is greater than 0.1V.

[0055] When in use: First, place the permeable container containing the activated carbon adsorbent 3 into the high-salt wastewater of the adsorption tank 4 to adsorb organic matter. After the adsorption is completed, take out the activated carbon adsorbent 3 and drain it to obtain the adsorption-saturated activated carbon, which is then placed in the EC-MFC cathode chamber 18 for desorption and regeneration. At the same time, take another new activated carbon adsorbent 3 and soak it in the high-salt wastewater of the adsorption tank 4 for adsorption; turn on the water flow regulating device (metering water pump 11), and the circulating liquid 5 passes through the water flow regulating device (metering water pump 11) and continuously enters the bottom of the EC-MFC anode chamber 22, and then enters the cathode chamber 18, and the EC-MFC water overflows from the upper part of the cathode chamber 18 into the circulating liquid tank 8.

[0056] After the above-mentioned activated carbon adsorbent 3 and EC-MFC are desorbed and regenerated, 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 taken out from the wastewater in the adsorption tank 4 and drained, and then added to the cathode chamber 18 of the EC-MFC for desorption and regeneration. Repeat this step until the wastewater meets the treatment requirements. The treated wastewater that meets the standards is discharged from the adsorption tank outlet pipe 7 through the second sluice 6, and the first sluice 1 is opened to inject new wastewater from the adsorption tank inlet pipe 2.

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

[0058] Washed activated carbon adsorbent: A sufficient amount of granular activated carbon (diameter d = 0.5 ~ 1.0mm) was ultrasonically washed with water until no carbon powder fell off, and the washed activated carbon was immersed in a dilute alkaline solution (sodium hydroxide solution with a mass fraction of 3.5wt%) to remove organic matter adhering to the surface, kept for 10h and then drained, and washed with deionized water until the leaching solution was neutral, and dried at 75°C overnight to obtain washed activated carbon, named AC.

[0059] Carbonaceous material with catalytic activity: 0.596 g Co(NO 3 ) 2 and 2.92gCe(NO 3 ) 2 100 mL of deionized water was added, followed by urea and stirring to obtain a homogeneous solution, wherein the mass fraction of urea in the homogeneous solution was 2 wt %. 75 g of water-washed activated carbon was mixed by equal volume immersion method and ultrasonically treated for 30 min, and then dried in a 75°C forced air drying oven for 12 h. The obtained dried particles were further heated to 400°C in a muffle furnace at a heating rate of 5°C / min, and annealed for 2 h to obtain the final product, named CoCe / AC.

[0060] The water-washed activated carbon adsorbent (AC) and the carbonaceous material with catalytic activity (CoCe / AC) described in Example 2 were used for adsorption treatment. 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-irradiated. 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 hours of adsorption, the 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 an adsorption tank, which stores 500mL of high-salinity 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 .

[0063] (3) After being soaked and adsorbed for 24 hours, the activated carbon adsorbent is taken out and drained, and then transferred to the EC-MFC cathode chamber 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 1500mL 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 EC-MFC desorption and regeneration treatment time is 24h. The circulating liquid water samples are collected at intervals, and the collected water samples are subjected to UV 254 Tests such as Figure 3 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] Combination Figure 2 and Figure 3 , 150g of the prepared CoCe / AC material was filled into a permeable container with CoCe / AC, immersed in 500mL of high-salt wastewater, and the adsorption process was carried out for 8 hours. After the adsorption is completed, the CoCe / AC is taken out from the wastewater, drained to obtain adsorption saturated activated carbon, and then added to the EC-MFC cathode chamber for desorption and regeneration. At the same time, another 150g CoCe / AC was soaked in high-salt wastewater for 8 hours of adsorption. Turn on the metering water pump 11 to control the HRT of 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 cathode chamber of the EC-MFC is transferred to the adsorption tank; at the same time, the CoCe / AC in the adsorption tank is taken out and drained by the same method, and then transferred to the cathode chamber of the EC-MFC 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 adsorption tank outlet pipe 7, and 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 are performed, and the COD index of the wastewater in the adsorption tank meets the treatment requirements.

[0068] The above examples show that the present invention uses CeCe / AC materials that have adsorption and also act as their own regeneration catalysts, showing an adsorption effect that is superior to that of water-washed activated carbon adsorbents, and achieving an efficient desorption and regeneration effect. The examples use a step-by-step integrated treatment process to treat lithium battery high-salinity wastewater, using CoCe / AC to efficiently adsorb organic matter in high-salinity wastewater, and using electrochemical microbial fuel cells to desorb and regenerate CoCe / AC to achieve efficient bioelectrochemical treatment of organic matter in high-salinity wastewater, proving the feasibility of the present invention in actual lithium battery industrial wastewater treatment.

Claims

1. A bio-electrocatalytic adsorption regeneration and high-salinity wastewater treatment system based on modified activated carbon adsorbent, characterized in that: It comprises 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-salinity wastewater, and the activated carbon adsorbent (3) adsorbs organic matter in the high-salinity wastewater to achieve high-salinity wastewater treatment; The circulating liquid pool (8) is filled with circulating liquid (5), an outlet is arranged at the bottom of the circulating liquid pool (8), and 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 bio-electrocatalytic adsorption regeneration of the modified activated carbon adsorbent.

2. According to claim 1, a bio-electrocatalytic adsorption regeneration and high-salt wastewater treatment system based on modified activated carbon adsorbent is characterized in that: The electrocatalytic coupled microbial electricity generation system is an overall top-bottom structure, and the circulating liquid (5) operates in a bottom-in and top-out mode; 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 the bottom of the anode chamber (22) uses a second aeration head (24) to disperse water; 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 with 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 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 a 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 a 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 bio-electrocatalytic adsorption regeneration and high-salt wastewater treatment system based on modified activated carbon adsorbent according to claim 2 is 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 are domesticated by inoculating the electrogenic strain of Shewanella into an incubator with appropriate temperature and culture medium. When the microorganisms are stable, an appropriate amount of diluted wastewater is added to the incubator as a nutrient source. 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. The activated carbon particles (23) of the anode chamber (22) have a sheet diameter d=35-65 mm, a thickness δ=15-25 mm, and a filling rate of 85%-95%; The conductive materials of the anode and cathode are inert conductive materials such as 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 actual wastewater treatment conditions.

4. The bio-electrocatalytic 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 are all treated with waterproofing, insulation and anti-electricity treatment, except for the part in contact with the biological anode and the part connected with the wire (13), so as to improve the efficiency of electron transmission, for example, by wrapping and covering the conductive materials with waterproof tape; The cathode material (20) is an activated carbon adsorbent (3) that is saturated with adsorption in an adsorption cell (4).

5. The bio-electrocatalytic adsorption regeneration and high-salinity 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 is ultrasonically washed with water until no carbon powder falls off, and the washed activated carbon is immersed in a dilute alkaline solution to remove organic matter adhering to the surface, 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 are added to deionized water, and then urea is added and stirred to obtain a homogeneous solution; a certain amount of the above-mentioned washed activated carbon is 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, which are treated in a muffle furnace at an annealing temperature of 400°C to 500°C for 2h to 3h to obtain a carbonaceous material with excellent catalytic activity, named CoCe / AC.

6. The bio-electrocatalytic 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=0.5-1.0 mm; 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; the total mass fraction of the metal salt in the homogeneous solution is 2.5-5.0wt%.

7. The bio-electrocatalytic 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 to 1:3; the mass fraction of urea in the homogeneous solution is 1.5 to 2.5 wt%; the time for ultrasonic treatment of the activated carbon and the homogeneous solution is 20 to 30 minutes; the drying temperature is 70 to 85°C, and the drying time is 12 to 16 hours; the muffle furnace calcination heating rate is set to 4.8 to 5.2°C / min.

8. A method for treating high-salt wastewater by bioelectrocatalytic adsorption regeneration and modification based on activated carbon adsorbent is carried out by using a bioelectrocatalytic adsorption regeneration and modification based on activated carbon adsorbent as described in 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), and 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) and EC-MFC are desorbed and regenerated, 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 taken out 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 and regeneration; this step is repeated until the wastewater meets the treatment requirements; the wastewater that meets the treatment requirements 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-salinity wastewater treatment based on modified activated carbon adsorbent according to claim 8, characterized in that: The water-permeable container is a flexible filter screen 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-salinity 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 to 15 mL / g of activated carbon adsorbent; the hydraulic retention time of the circulating liquid (5) in the EC-MFC is 6 to 8 hours.

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