Green and efficient regeneration method of activated carbon in brine acidification-activated carbon adsorption deodorization process

Abstract

The application discloses a green and efficient regeneration method of activated carbon in a brine acidification-activated carbon adsorption deodorization process, and is characterized by comprising the following steps: S1, water washing and salt removal through aeration; S2, ozone oxidation regeneration: adding an alkali liquor with the same volume as the activated carbon into an activated carbon adsorption tower, and then blowing ozone into the bottom of the activated carbon adsorption tower, so that the ozone is subjected to oxidation reaction with the activated carbon under the alkaline condition, and then waste alkali liquor is discharged; S3, water washing and alkali removal through aeration; S4, waste liquid reuse; and S5, waste material reuse. The application can not only avoid the loss of activated carbon caused by high-temperature burning, but also has short regeneration time of the activated carbon and no harmful substance residue, and is very suitable for the regeneration of the activated carbon in the acidification brine activated carbon adsorption deodorization process. In addition, the waste liquid and the waste material in the regeneration process of the activated carbon can be reused, the whole process is free of toxic and harmful waste emission, is green and environment-friendly, has low treatment cost, high efficiency, good economy, environmental protection and feasibility.

Description

Technical Field

[0001] This invention relates to a method for regenerating activated carbon, and more particularly to a green and efficient method for regenerating activated carbon in a brine acidification-activated carbon adsorption deodorization process. Background Technology

[0002] China's crude salt production capacity has reached 120 million tons, with most of it used for the chlor-alkali industry in addition to table salt. China is currently the world's largest producer and consumer of chlor-alkali. At present, my country's crude salt production mainly consists of sea salt, lake salt, and well / rock salt. Among these, well / rock salt, due to its higher quality, has gradually become the mainstream crude salt product. Sichuan Province has the highest output of well / rock salt, while Henan Province produces salt of relatively high quality. Henan Province has a prospective salt mine reserve of 350 billion tons, with a sodium chloride content of 75%-90%, averaging over 85%, belonging to the CASO4 type deposit. The content of harmful components and impurities in Henan's salt fields is low, meeting national high-quality salt standards. However, during the deposition and diagenesis of salt rocks, the salt layers contain some residual organic matter, including short-chain organic acid molecules and small amounts of hydrocarbons, causing the brine and finished salt to have a strong odor. Therefore, deodorization treatment of the brine is necessary in the production and processing of table salt.

[0003] Existing technologies for brine deodorization include baking, oxidation-reduction, macroporous resin adsorption, and aeration. However, these methods still have some drawbacks, mainly including poor deodorization efficiency, environmental unfriendliness, residues of harmful substances, and high deodorization costs. To address these issues, please refer to [link / reference needed]. Figure 1 The applicant proposed a method of first acidifying the brine by adding hydrochloric acid to adjust its pH to 3-5, followed by deodorization using activated carbon adsorption. This method significantly increases the adsorption capacity of activated carbon by first acidifying the brine. However, due to the low profit margin in salt production and the large amount of activated carbon used in brine deodorization, regenerating the activated carbon after deodorization is essential to reduce production costs. Currently, the main methods for regenerating activated carbon are as follows:

[0004] 1) Thermal regeneration method: The thermal regeneration method uses gases such as water vapor, inert gas, and carbon dioxide as activating gases for desorption and desorption at high temperatures. The advantages of this method are its non-selectivity towards adsorbed substances and high regeneration efficiency. However, the disadvantages are that thermal regeneration occurs at high temperatures (300-500℃), resulting in high energy consumption. Furthermore, activated carbon loss is significant, reaching 10%–20%. For brine deodorization processes that consume large amounts of activated carbon, this method is not conducive to reducing and controlling production costs.

[0005] 2) Chemical Solvent Regeneration Method: This method utilizes the equilibrium between activated carbon, solvent, and adsorbate. By altering conditions such as temperature and solvent pH, the equilibrium is disrupted, causing the adsorbate to desorb from the activated carbon. The advantages of this method are in-situ regeneration and lower cost. However, its disadvantages include incomplete regeneration, easy clogging of micropores, significant performance degradation after multiple regenerations, and, most importantly, the presence of residual chemical solvents, which poses potential food safety risks.

[0006] 3) Biological Regeneration Method: This method relies on microorganisms that multiply on activated carbon to oxidize and decompose the adsorbed organic matter, producing carbon dioxide and water, thereby restoring its adsorption performance. The advantage of this method is its simplicity and ease of implementation. However, its disadvantages include significant dependence on water quality and temperature, the presence of intermediate products in the activated carbon pores which can easily clog micropores, leading to incomplete regeneration, especially due to the excessively long regeneration time. This makes it difficult to apply in continuous salt production operations.

[0007] In summary, the existing activated carbon regeneration methods mentioned above are not well adapted to the regeneration of activated carbon after brine deodorization. Therefore, it is necessary to research and develop a new activated carbon regeneration method that can be applied to brine deodorization. Summary of the Invention

[0008] To address the aforementioned problems, the purpose of this invention is to provide a green and efficient method for regenerating activated carbon in a brine acidification-activated carbon adsorption deodorization process. This method not only avoids activated carbon loss caused by high-temperature burning, but also features a short regeneration and activation time and leaves no harmful residues. It is highly suitable for activated carbon regeneration in the acidification brine activated carbon adsorption deodorization process. Furthermore, the waste liquid and waste materials generated during the activated carbon regeneration process can be reused, and the entire process generates no toxic or harmful waste, making it green and environmentally friendly. Most importantly, it has low processing costs, high efficiency, and good economic, environmental, and feasibility.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows.

[0010] A green and efficient method for regenerating activated carbon in a brine acidification-activated carbon adsorption deodorization process is characterized by the following steps:

[0011] S1. Aeration and water washing desalination: Add water of the same volume as activated carbon to the activated carbon adsorption tower, and then blow air into the bottom of the activated carbon adsorption tower to fully mix the activated carbon and water to remove the salt in the activated carbon. Then the wastewater is discharged.

[0012] S2, Ozone Oxidation Regeneration: Add an alkaline solution of equal volume to the activated carbon into the activated carbon adsorption tower, and then blow ozone into the bottom of the activated carbon adsorption tower so that the ozone reacts with the activated carbon under alkaline conditions, and then discharge the waste alkaline solution.

[0013] S3. Aeration and water washing for alkali removal: Add water of the same volume as the activated carbon to the activated carbon adsorption tower, and then blow air into the bottom of the activated carbon adsorption tower to fully mix the activated carbon and water to remove the alkali from the activated carbon. Then discharge the wastewater to complete the regeneration of the activated carbon.

[0014] S4. Wastewater reuse: The wastewater collected in step S1 is directly pumped into the brine well for brine extraction; the waste alkali solution collected in step S2 and the wastewater collected in step S3 are combined and discharged into a wastewater storage tank. The pH of the combined wastewater is adjusted to neutral and then pumped into the brine well for brine extraction.

[0015] S5. Waste recycling: Activated carbon that has been regenerated and reused multiple times through steps S1, S2, and S3 is discharged into the boiler for reuse as fuel.

[0016] In the brine acidification-activated carbon adsorption deodorization process, when the acidified brine is passed into the activated carbon adsorption tower, the odor of the acidified brine cannot be adsorbed and removed by the activated carbon. That is, when the brine discharged from the activated carbon adsorption tower has an odor, it means that the activated carbon in the activated carbon adsorption tower is no longer suitable for deodorizing the next batch of brine. At this time, the activated carbon in the activated carbon adsorption tower needs to undergo the above-mentioned regeneration treatment.

[0017] In step S1 above, aeration desalination removes the salts adsorbed from the brine by the activated carbon, especially chloride ions, to prevent them from entering the next step where they are oxidized by ozone into toxic and harmful substances such as chlorite and chlorate. This would prevent the waste alkaline solution generated in step S2 and the wastewater generated in step S3 from being reused for brine washing. Since the activated carbon involved in this invention is used to adsorb odorous substances in the brine, these odorous substances are mostly low-grade fatty acids with 3-8 carbon atoms, as well as some short-chain alkanes and other gasoline-like substances. The target components are complex and have good water solubility. In particular, the threshold of the odorous substance isovaleric acid is as low as 1.5 ppm, demonstrating the adsorption capacity of the activated carbon used for brine deodorization. Higher performance requirements necessitate a more thorough activated carbon regeneration process. Step S2, conducted under alkaline conditions, enhances the oxidizing power of ozone. This allows ozone to oxidize the 3-8 carbon low-grade fatty acids, as well as some short-chain alkanes and other gasoline-like substances adsorbed by the activated carbon, into carbon dioxide and water. This rapid oxidation of low-molecular-weight organic matter enables in-situ regeneration of the activated carbon. Since some alkaline solution remains after ozone oxidation and regeneration, and alkaline conditions are detrimental to the adsorption and deodorization of brine, step S3, aeration and washing, is required to remove the alkaline solution from the activated carbon, thus completing the final regeneration.

[0018] In the above process, the wastewater in step S1 contains salt, so it can be directly pumped into the brine well for brine extraction to dissolve the rock salt in the well and form brine. The waste alkaline solution in step S2 and the wastewater in step S3 contain alkaline solution and a small amount of ozone, but do not contain toxic and harmful substances such as chlorite and chlorate. During the storage process, the ozone will also decompose rapidly. Therefore, the combined liquid of the two can also be used for brine extraction after the pH is adjusted. Thus, this invention achieves zero discharge of wastewater by reusing the wastewater generated in steps S1-S3 for brine extraction. In addition, after the activated carbon is regenerated multiple times in steps S1 to S3, the activated carbon with severely reduced adsorption activity can be discharged into the boiler as fuel after high-temperature drying. Therefore, the method of this invention can not only regenerate activated carbon, but also reuse the wastewater and waste materials in the process. There is no waste discharge throughout the process, which is more environmentally friendly and helps to improve the overall economic benefits of brine deodorization.

[0019] Preferably, in steps S1 and S3, air is intermittently blown into the bottom of the activated carbon adsorption tower, and ultrasonic treatment is applied to the material inside the activated carbon adsorption tower during the intervals between air blowing. In steps S1 and S3, repeated aeration and washing operations are often required to effectively remove salts and residual alkali from the activated carbon. However, repeated operations not only increase labor and material costs but also generate a large amount of wastewater. Using ultrasound in conjunction can significantly improve the aeration and washing effect. However, aeration and washing require air to be blown into the bottom of the activated carbon adsorption tower, and a large amount of wastewater is generated inside the activated carbon adsorption tower. The presence of air can cause more voids in the material, thus affecting the propagation of ultrasound and reducing its effectiveness. To address this, the present invention intermittently blows air into the bottom of the activated carbon adsorption tower and applies ultrasound treatment to the material inside the tower during the intervals between air injections. This maximizes the combined effect of the two methods, enabling the removal of salt and residual alkali from the activated carbon in steps S1 and S3 with only one aeration and water washing operation, eliminating the need for repeated aeration and water washing desalination and dealkali removal operations. This reduces processing costs and improves activated carbon regeneration efficiency.

[0020] Preferably, in steps S1 and S3, air is intermittently blown into the bottom of the activated carbon adsorption tower, i.e., every 2 to 5 minutes of air is blown in, followed by an interval of 1 to 2 minutes, and the total time for blowing in air is controlled to be 20 to 30 minutes; during the intervals of air blowing in, ultrasonic treatment with a frequency of 25 to 60 kHz is applied to the material in the activated carbon adsorption tower.

[0021] Preferably, in step S2, the alkaline solution is a NaOH solution with a mass concentration of 0.01% to 2.5%.

[0022] Preferably, in step S2, the alkaline solution is a 0.5% NaOH solution.

[0023] Preferably, in step S2, the ozone injection rate is 2-8 mg / L / min, and the ozone injection time is 15-45 min.

[0024] Preferably, in step S2, the ozone injection rate is 5 mg / L / min and the ozone injection time is 30 min.

[0025] Preferably, in step S2, excess ozone in the activated carbon adsorption tower is passed into an ozone destruction device for destruction.

[0026] Preferably, in step S5, the activated carbon that has been regenerated and reused 7 times in steps S1 and S2 is discharged into the boiler as fuel for reuse.

[0027] Preferably, the activated carbon is wood-based activated carbon with a particle size of 30-50 mesh; the acidified brine is brine whose pH is adjusted to 3-5 by adding hydrochloric acid.

[0028] The beneficial effects of this invention are as follows:

[0029] 1) Compared with existing technologies such as thermal regeneration, chemical solvent regeneration, and biological regeneration, this invention uses ozone to regenerate activated carbon under alkaline conditions. This not only avoids the loss of activated carbon caused by high-temperature burning, but also has a short regeneration and activation time and leaves no harmful residues. It is very suitable for activated carbon regeneration in the acidified brine activated carbon adsorption deodorization process. Furthermore, in this invention, the activated carbon adsorption capacity can still reach about 50% of the first use after 7 regenerations. That is, using the method of this invention to regenerate activated carbon, the activated carbon can be reused 7 times, thereby significantly reducing the amount of activated carbon used in the brine activated carbon adsorption deodorization production process. This is especially beneficial for the low-profit salt production industry.

[0030] 2) This invention avoids the oxidation of chloride ions into harmful substances such as chlorate and chlorite by ozone through aeration and washing desalination before activated carbon regeneration. This allows the wastewater from aeration and washing desalination, the waste alkaline solution from ozone oxidation regeneration, and the wastewater from aeration and washing dealkali removal to be returned to the well for brine extraction. Simultaneously, after multiple regenerations, activated carbon with severely diminished adsorption activity can be dried at high temperature and discharged into the boiler as fuel. In summary, this invention not only achieves activated carbon regeneration but also allows for the reuse of waste liquid and waste materials throughout the process. The entire process generates no toxic or harmful waste, making it green and environmentally friendly. Most importantly, the processing cost is very low, combining economic efficiency, environmental friendliness, and feasibility. Attached Figure Description

[0031] Figure 1 A flowchart of the activated carbon adsorption deodorization process for acidified brine;

[0032] Figure 2This is the carbon-oxygen energy spectrum of activated carbon.

[0033] Figure 3 This is the oxygen energy spectrum of activated carbon (the arrows in the figure indicate the trend of the binding energy of oxygen). Detailed Implementation

[0034] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0035] Example 1

[0036] A green and efficient method for regenerating activated carbon in the brine acidification-activated carbon adsorption deodorization process includes the following steps:

[0037] S1. Aeration and water washing desalination: Add water of the same volume as activated carbon to the activated carbon adsorption tower, and then blow air into the bottom of the activated carbon adsorption tower to fully mix the activated carbon and water to remove the salt in the activated carbon. Then discharge the wastewater. The above operation can be repeated 1 to 3 times to ensure that the salt is completely removed.

[0038] S2, Ozone Oxidation Regeneration: Add an alkaline solution of equal volume to the activated carbon into the activated carbon adsorption tower, and then blow ozone into the bottom of the activated carbon adsorption tower so that the ozone reacts with the activated carbon under alkaline conditions, and then discharge the waste alkaline solution.

[0039] S3. Aeration and water washing for alkali removal: Add water of equal volume to the activated carbon into the activated carbon adsorption tower, and then blow air into the bottom of the activated carbon adsorption tower to fully mix the activated carbon and water to remove the alkali solution from the activated carbon. Then discharge the wastewater. The above operation can be repeated 1 to 3 times to ensure that the residual alkali solution is completely removed, thus completing the regeneration of activated carbon.

[0040] S4. Wastewater reuse: The wastewater collected in step S1 is directly pumped into the brine well for brine extraction; the waste alkali solution collected in step S2 and the wastewater collected in step S3 are combined and discharged into a wastewater storage tank. The pH of the combined wastewater is adjusted to neutral and then pumped into the brine well for brine extraction.

[0041] S5. Activated carbon reuse: Activated carbon that has been regenerated and reused multiple times through steps S1, S2, and S3 is discharged into the boiler for reuse as fuel.

[0042] Example 2

[0043] A green and efficient method for regenerating activated carbon in the brine acidification-activated carbon adsorption deodorization process includes the following steps:

[0044] S1. Aeration and water washing desalination: Add water of the same volume as activated carbon to the activated carbon adsorption tower, and then blow air into the activated carbon adsorption tower from the bottom to make the activated carbon and water mix thoroughly to remove the salt in the activated carbon. Then discharge the wastewater and repeat the above operation 1 to 3 times to ensure that the salt is completely removed.

[0045] S2. Ozone Oxidation Regeneration: An alkaline solution of equal volume to the activated carbon is added to the activated carbon adsorption tower. Ozone is then blown in from the bottom of the tower to allow the ozone to oxidize the activated carbon under alkaline conditions. The waste alkaline solution is then discharged. The alkaline solution is a NaOH solution with a mass concentration of 0.01%–2.5%. The ozone flow rate is 2–8 mg / L / min, and the ozone flow time is 15–45 min. Excess ozone in the activated carbon adsorption tower is destroyed by an ozone destruction device.

[0046] S3. Aeration and water washing for alkali removal: Add water of equal volume to the activated carbon into the activated carbon adsorption tower, and then blow air into the bottom of the activated carbon adsorption tower to fully mix the activated carbon and water to remove the alkali solution from the activated carbon. Then discharge the wastewater and repeat the above operation 1 to 3 times to ensure that the residual alkali solution is completely removed, thus completing the regeneration of activated carbon.

[0047] S4. Wastewater reuse: The wastewater collected in step S1 is directly pumped into the brine well for brine extraction; the waste alkali solution collected in step S2 and the wastewater collected in step S3 are combined and discharged into a wastewater storage tank. The pH of the combined wastewater is adjusted to neutral and then pumped into the brine well for brine extraction.

[0048] S5. Activated carbon reuse: The activated carbon that has been regenerated and reused 7 times through steps S1, S2 and S3 is dried and discharged into the boiler for reuse as fuel.

[0049] Example 3

[0050] A green and efficient method for regenerating activated carbon in the brine acidification-activated carbon adsorption deodorization process includes the following steps:

[0051] S1. Aeration and water washing desalination: Add water of the same volume as activated carbon to the activated carbon adsorption tower, and then blow air into the activated carbon adsorption tower from the bottom. Control the blowing time to 20-30 minutes to make the activated carbon and water fully mix to remove the salt in the activated carbon. Then discharge the wastewater. Repeat the above operation twice to ensure that the salt is completely removed.

[0052] S2. Ozone Oxidation Regeneration: An alkaline solution of equal volume to the activated carbon is added to the activated carbon adsorption tower. Ozone is then blown in from the bottom of the tower to allow the ozone to oxidize the activated carbon under alkaline conditions. The waste alkaline solution is then discharged. The alkaline solution is a 0.5% (w / w) NaOH solution. The ozone flow rate is 5 mg / L / min, and the flow time is 30 min. Excess ozone in the activated carbon adsorption tower is destroyed by an ozone destruction device.

[0053] S3. Aeration and water washing for alkali removal: Add water of equal volume to the activated carbon into the activated carbon adsorption tower, and then blow air into the activated carbon adsorption tower from the bottom. Control the blowing time to 20-30 minutes to fully mix the activated carbon and water to remove the alkali solution from the activated carbon. Then discharge the wastewater and repeat the above operation twice to ensure that the residual alkali solution is completely removed, thus completing the regeneration of activated carbon.

[0054] S4. Wastewater reuse: The wastewater collected in step S1 is directly pumped into the brine well for brine extraction; the waste alkali solution collected in step S2 and the wastewater collected in step S3 are combined and discharged into a wastewater storage tank. The pH of the combined wastewater is adjusted to neutral and then pumped into the brine well for brine extraction.

[0055] S5. Activated carbon reuse: The activated carbon that has been regenerated and reused 7 times through steps S1, S2 and S3 is dried and discharged into the boiler for reuse as fuel.

[0056] Example 4

[0057] A green and efficient method for regenerating activated carbon in the brine acidification-activated carbon adsorption deodorization process includes the following steps:

[0058] S1. Aeration and water washing desalination: Add water of equal volume to the activated carbon into the activated carbon adsorption tower, and then intermittently blow air into the activated carbon adsorption tower from the bottom. That is, blow air for 2-5 minutes, then pause for 1-2 minutes, and control the total blowing time to 20-30 minutes to ensure that the activated carbon and water are fully mixed. During the interval between air blowing, apply ultrasonic treatment with a frequency of 25-60kHz to the material in the activated carbon adsorption tower to remove the salt from the activated carbon. Then discharge the wastewater to ensure that the salt is completely removed.

[0059] S2. Ozone Oxidation Regeneration: An alkaline solution of equal volume to the activated carbon is added to the activated carbon adsorption tower. Ozone is then blown in from the bottom of the tower to allow the ozone to oxidize the activated carbon under alkaline conditions. The waste alkaline solution is then discharged. The alkaline solution is a 0.5% (w / w) NaOH solution. The ozone flow rate is 5 mg / L / min, and the flow time is 30 min. Excess ozone in the activated carbon adsorption tower is destroyed by an ozone destruction device.

[0060] S3. Aeration and water washing for alkali removal: Add water of equal volume to the activated carbon into the activated carbon adsorption tower, and then intermittently blow air into the activated carbon adsorption tower from the bottom. That is, blow air for 2-5 minutes, then pause for 1-2 minutes, and control the total blowing time to 20-30 minutes to ensure that the activated carbon and water are fully mixed. During the interval between air blowing, apply ultrasonic treatment with a frequency of 25-60kHz to the material in the activated carbon adsorption tower to remove the alkali from the activated carbon. Then discharge the wastewater to ensure that the residual alkali is completely removed, thus completing the regeneration of the activated carbon.

[0061] S4. Wastewater reuse: The wastewater collected in step S1 is directly pumped into the brine well for brine extraction; the waste alkali solution collected in step S2 and the wastewater collected in step S3 are combined and discharged into a wastewater storage tank. The pH of the combined wastewater is adjusted to neutral and then pumped into the brine well for brine extraction.

[0062] S5. Activated carbon reuse: The activated carbon that has been regenerated and reused 7 times through steps S1, S2 and S3 is dried and discharged into the boiler for reuse as fuel.

[0063] Testing showed that after regenerating activated carbon using steps S1 to S3, the adsorption capacities of activated carbon for brine after 1 to 3 regenerations were 2820, 2640, and 2310 mg / L / min, respectively. Comparing these figures with those of Example 8, it can be seen that the intermittent air blowing and ultrasonic treatment during the aeration and washing desalination and aeration and washing dealkali removal steps do not affect the adsorption capacity of the regenerated activated carbon. However, the water washing operation does not need to be repeated in steps S1 and S3, which can save about a quarter of the process time and significantly reduce the water consumption for washing.

[0064] Example 5

[0065] Investigation of ozone flux during ozone oxidation regeneration.

[0066] 1. Experimental Methods

[0067] Add an appropriate amount of hydrochloric acid to the brine and stir until the pH is adjusted to 3-5, obtaining acidified brine. 900 iodine value, 30-50 mesh wood-based activated carbon is packed into an ion exchange column (in this embodiment, the ion exchange column is equivalent to an activated carbon adsorption tower) to obtain an activated carbon column. The acidified brine is passed through the activated carbon column, with a space velocity controlled at 30-35 L / h / kg. The endpoint is reached when an off-odor is detected in the brine after passing through the column, indicating that the activated carbon needs regeneration. The activated carbon in the column is then regenerated using steps S1-S3 of Example 3. The parameters differ from Example 3 in that, in step S2, the ozone flow rate is controlled at 2 mg / L / min, 5 mg / L / min, and 8 mg / L / min, respectively, to regenerate the activated carbon. The adsorption capacity after different regeneration cycles is then measured. The adsorption capacity is expressed as the weight ratio of the acidified brine to the packed activated carbon, and the endpoint is again reached when an off-odor is detected in the brine after passing through the column.

[0068] 2. Results Analysis

[0069] The results of the investigation on ozone injection rate during ozone oxidation regeneration are shown in Table 1.

[0070] Table 1. Effect of ozone flux on adsorption capacity of regenerated activated carbon

[0071] Ozone flux 2mg / L / min 5mg / L / min 8mg / L / min First use 3000 3000 3000 Regenerate once 2100 2850 2750 Regenerate 2 times 1200 2650 2260 Regenerate 3 times 500 2350 1650

[0072] As shown in Table 1, the regenerated activated carbon exhibits the highest adsorption capacity when the ozone injection rate is 5 mg / L / min. Therefore, in this invention, an ozone injection rate of 5 mg / L / min is preferred.

[0073] Example 6

[0074] An investigation into the ozone introduction time during ozone oxidation regeneration.

[0075] 1. Experimental Methods

[0076] Add an appropriate amount of hydrochloric acid to the brine and stir until the pH is adjusted to 3-5, obtaining acidified brine. Use wood-based activated carbon with an iodine value of 900 and a particle size of 30-50 mesh to pack into an ion exchange column (in this embodiment, the ion exchange column is equivalent to an activated carbon adsorption tower), obtaining an activated carbon column. Pass the acidified brine through the activated carbon column, controlling the space velocity at 30-35 L / h / kg. The endpoint is reached when the brine after passing through the column has an off-odor, indicating that the activated carbon needs regeneration. At this point, the activated carbon in the column is regenerated using the methods in steps S1-S3 of Example 3. The difference from Example 3 is that in step S2, the ozone flow rate is controlled at 15 mg / L / min, 30 mg / L / min, and 45 mg / L / min, respectively, to regenerate the activated carbon. The adsorption capacity after different regeneration cycles is measured. The adsorption capacity is expressed as the weight ratio of the acidified brine to the packed activated carbon, and the endpoint is again reached when the brine has an off-odor after passing through the column.

[0077] 2. Results Analysis

[0078] The results of the investigation on ozone introduction time in ozone oxidation regeneration are shown in Table 2.

[0079] Table 2. Effect of ozone introduction time on the adsorption capacity of regenerated activated carbon

[0080] Ozone introduction time 15min 30min 45min First use 3000 3000 3000 Regenerate once 2200 2850 2820 Regenerate 2 times 1800 2650 2520 Regenerate 3 times 1750 2350 2150

[0081] As shown in Table 2, the regenerated activated carbon exhibits the highest adsorption capacity when ozone is introduced for 20 minutes during regeneration. Therefore, in this invention, an ozone introduction time of 30 mg / L / min is preferable.

[0082] Example 7

[0083] Investigation of alkali concentration in ozone oxidation regeneration.

[0084] 1. Experimental Methods

[0085] Add an appropriate amount of hydrochloric acid to the brine and stir until the pH is adjusted to 3-5 to obtain acidified brine. 900 iodine value, 30-50 mesh wood-based activated carbon is packed into an ion exchange column (in this embodiment, the ion exchange column is equivalent to an activated carbon adsorption tower) to obtain an activated carbon column. The acidified brine is passed through the activated carbon column, with a space velocity controlled at 30-35 L / h / kg. The endpoint is reached when the brine exhibits an off-odor after passing through the column, indicating that the activated carbon needs regeneration. The activated carbon in the column is then regenerated using steps S1-S3 of Example 3. The parameters differ from those in Example 3, but in step S2, the mass concentration of the alkaline NaOH solution is controlled at 0.01%, 0.5%, and 2.5% to regenerate the activated carbon. The adsorption capacity after different regeneration cycles is then measured. The adsorption capacity is expressed as the weight ratio of the acidified brine to the packed activated carbon, and the endpoint is again reached when the brine exhibits an off-odor after passing through the column.

[0086] 2. Results Analysis

[0087] The results of the investigation on the concentration of alkali solution during ozone oxidation regeneration are shown in Table 3.

[0088] Table 3. Effect of alkali concentration on adsorption capacity of regenerated activated carbon

[0089] Alkali concentration 0.01％ 0.5％ 2.5％ First use 3000 3000 3000 Regenerate once 2200 2850 2100 Regenerate 2 times 1600 2650 1650 Regenerate 3 times 1100 2350 1250

[0090] As shown in Table 3, the regenerated activated carbon exhibits the highest adsorption capacity when regenerated in a 0.5% alkaline solution. Therefore, in this invention, a 0.5% alkaline solution concentration is preferred.

[0091] Example 8

[0092] An investigation into the number of times activated carbon can be regenerated.

[0093] 1. Experimental Methods

[0094] 1.1 Acidified brine activated carbon adsorption deodorization method: Add an appropriate amount of hydrochloric acid to the brine and stir evenly to adjust the pH of the brine to 3-5 to obtain acidified brine; use wood-based activated carbon with an iodine value of 900 and a particle size of 30-50 mesh to pack into an ion exchange column (in this embodiment, the ion exchange column is equivalent to an activated carbon adsorption tower) to obtain an activated carbon column; pass the acidified brine through the activated carbon column, control the space velocity at 30-35 L / h / kg, and the endpoint is when the brine after passing through the column has an off-odor, which indicates that the activated carbon needs to be regenerated;

[0095] 1.2 Activated Carbon Regeneration Method: The activated carbon was regenerated using steps S1 to S3 in Example 3. After regeneration, the activated carbon was used again for deodorizing acidified brine according to the method described in 1.1 above. The adsorption capacity of the activated carbon for the brine was tested after different numbers of regeneration cycles. The adsorption capacity was expressed as the weight ratio of acidified brine passing through the column to the loaded activated carbon, and the endpoint was set when an off-odor was detected after the brine passed through the column.

[0096] 2. Results Analysis

[0097] Table 4 Adsorption capacity of activated carbon after different numbers of regeneration cycles

[0098] Number of regenerations brine adsorption capacity First use 3000 Regenerate once 2850 Regenerate 2 times 2650 Regenerate 3 times 2350 Regenerated 4 times 2150 Regenerate 5 times 1950 Regenerated 6 times 1700 Regenerated 7 times 1500

[0099] As shown in Table 4, when using the method of this invention to regenerate activated carbon, the adsorption capacity of the activated carbon for brine gradually decreases with each regeneration. After seven regenerations, the adsorption capacity of the activated carbon is about 50% of the initial adsorption capacity, still retaining usability. However, further regeneration leads to a severe decline in adsorption activity, with the adsorption capacity dropping to below 50% of the initial capacity. If the adsorption capacity of the regenerated activated carbon is too low, the frequency of regeneration will increase, affecting production and increasing costs. Therefore, activated carbon should not be reused after seven regenerations. At this point, the activated carbon can be dried at high temperature and used as fuel in a boiler, avoiding waste pollution and resource waste.

[0100] Example 9

[0101] The effect of regenerating activated carbon using the method of the present invention on the oxygen-containing functional groups of activated carbon.

[0102] Oxygen-containing functional groups on the surface of activated carbon can alter its properties and behavior, thereby changing its adsorption performance for organic matter. In this embodiment, XPS energy dispersive spectroscopy was used to investigate the changes in the number and valence state of oxygen atoms in the oxygen-containing functional groups on the activated carbon surface.

[0103] 1. Experimental Methods

[0104] Using unused wood-based activated carbon with an iodine value of 900 and a particle size of 30-50 mesh, as well as activated carbon regenerated once and seven times in Example 8, as the test objects, the XPS full-energy spectra and fine C and O spectra of the three materials were detected by a Thermo Fisher Scientific Escalab xi+ X-ray photoelectron spectroscopy instrument. The changes in the carbon-oxygen ratio during the activated carbon regeneration process were also calculated. The results are shown in […]. Figure 2 , Figure 3 and Table 5, in which Figure 2 The carbon-oxygen energy spectrum of the three is shown. Figure 3 The oxygen energy spectra of the three are shown.

[0105] 2. Results Analysis

[0106] Table 5. Changes in carbon-oxygen ratio during activated carbon regeneration.

[0107] sample Oxygen atom ratio / % Carbon atom ratio / % Unused activated carbon 12.63 87.37 Activated carbon regeneration once 12.46 87.54 Activated carbon regeneration 7 times 12.46 87.54

[0108] Depend on Figure 2 It can be seen that the surface of unused activated carbon mainly consists of carbon and oxygen, indicating that the activated carbon is basically free of other impurities. Furthermore, the activated carbon after one and seven regenerations also showed virtually no introduction of heteroatoms. To investigate the changes in oxygen-containing species on the surface of activated carbon after use, [further details are needed]. Figure 3 It can be seen that after one regeneration of activated carbon, the binding energy of oxygen shifts towards a lower valence state, indicating that a small amount of oxygen-containing species on the surface of the activated carbon are reduced after one regeneration. After seven regenerations, it can be seen that the oxygen-containing species on the surface of the activated carbon are significantly reduced. As shown in Table 5, by comparing the oxygen atom ratio of the three activated carbon samples, after one ozone oxidation regeneration, the oxygen atom content of oxygen-containing functional groups on the surface of the activated carbon decreases slightly. However, the oxygen atom content remains unchanged between seven regenerations and one regeneration. This suggests that the reason for the decrease in the adsorption capacity of activated carbon for odor substances such as lower fatty acids may not be the reduction of oxygen-containing functional groups, but rather the decrease in adsorption capacity caused by the change in the valence state of oxygen.

Claims

1. A green and efficient regeneration method of activated carbon in the brine acidification-activated carbon adsorption deodorization process, characterized in that Includes the following steps: S1. Aeration and water washing desalination: Add water of the same volume as activated carbon to the activated carbon adsorption tower, and then blow air into the bottom of the activated carbon adsorption tower to fully mix the activated carbon and water to remove the salt in the activated carbon. Then the wastewater is discharged. S2, Ozone Oxidation Regeneration: Add an alkaline solution of equal volume to the activated carbon into the activated carbon adsorption tower, and then blow ozone into the bottom of the activated carbon adsorption tower so that the ozone reacts with the activated carbon under alkaline conditions, and then discharge the waste alkaline solution. S3. Aeration and water washing for alkali removal: Add water of the same volume as the activated carbon to the activated carbon adsorption tower, and then blow air into the bottom of the activated carbon adsorption tower to fully mix the activated carbon and water to remove the alkali from the activated carbon. Then discharge the wastewater to complete the regeneration of the activated carbon. S4. Wastewater reuse: The wastewater collected in step S1 is directly pumped into the brine well for brine extraction; the waste alkali solution collected in step S2 and the wastewater collected in step S3 are combined and discharged into a wastewater storage tank. The pH of the combined wastewater is adjusted to neutral and then pumped into the brine well for brine extraction. S5. Activated carbon reuse: Activated carbon that has been regenerated and reused multiple times through steps S1 to S3 is discharged into the boiler as fuel for reuse. In steps S1 and S3, air is intermittently blown into the bottom of the activated carbon adsorption tower, i.e., every 2 to 5 minutes of air is blown in, followed by an interval of 1 to 2 minutes, and the total time for blowing in air is controlled to be 20 to 30 minutes; during the interval of air blowing in, ultrasonic treatment with a frequency of 25 to 60 kHz is applied to the material in the activated carbon adsorption tower.

2. The green and efficient regeneration method for activated carbon in the brine acidification-activated carbon adsorption deodorization process as described in claim 1, characterized in that, In step S2, the alkaline solution is a NaOH solution with a mass concentration of 0.01% to 2.5%.

3. The green and efficient regeneration method for activated carbon in the brine acidification-activated carbon adsorption deodorization process as described in claim 1, characterized in that, In step S2, the alkaline solution is a 0.5% NaOH solution.

4. The green and efficient regeneration method for activated carbon in the brine acidification-activated carbon adsorption deodorization process as described in claim 1, characterized in that, In step S2, the ozone injection rate is 2–8 mg / L / min, and the ozone injection time is 15–45 min.

5. The green and efficient regeneration method for activated carbon in the brine acidification-activated carbon adsorption deodorization process as described in claim 4, characterized in that, In step S2, the ozone injection rate is 5 mg / L / min, and the ozone injection time is 30 min.

6. The green and efficient regeneration method of activated carbon in the brine acidification-activated carbon adsorption deodorization process as described in claim 1, characterized in that, In step S2, excess ozone in the activated carbon adsorption tower is passed into an ozone destruction device for destruction.

7. The green and efficient regeneration method for activated carbon in the brine acidification-activated carbon adsorption deodorization process as described in claim 1, characterized in that, In step S5, the activated carbon that has been regenerated and reused 7 times in steps S1 and S2 is discharged into the boiler as fuel for reuse.

8. The green and efficient regeneration method of activated carbon in the brine acidification-activated carbon adsorption deodorization process as described in claim 1, characterized in that, The activated carbon is wood-based activated carbon with a particle size of 30-50 mesh.

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