Hydrothermal alkali regeneration and recycling method for chemical wastewater treatment saturated active coke

Abstract

The invention provides a hydrothermal alkali regeneration and recycling method for chemical wastewater treatment saturated active coke, and relates to the technical field of water treatment. The method comprises the following steps: S1, putting saturated active coke for wastewater treatment in a chemical industry park into a hydrothermal reaction kettle; s2, adding a base catalyst into the hydrothermal reaction kettle to obtain a solid-liquid mixture; s3, sealing the hydrothermal reaction kettle, heating the solid-liquid mixture, and carrying out hydrothermal catalytic regeneration reaction; s4, after the regeneration reaction is completed, discharging regenerated active coke and waste liquid generated in the regeneration process; s5, the regenerated active coke is recycled after being washed, and waste liquid generated in the regeneration process is subjected to resource utilization. The method aims at solving the problems that in the prior art, the active coke regeneration effect is poor, the carbon loss is high, and the regeneration energy consumption is large.

Description

Technical Field

[0001] The present application relates to the field of water treatment technology, and in particular to a method for hydrothermal alkali regeneration and resource utilization of saturated activated coke in chemical wastewater treatment. Background Art

[0002] Activated coke contains more mesopores and is suitable for deep treatment of wastewater to adsorb difficult-to-degrade pollutants. In particular, its price is lower than that of activated carbon, and it has good application prospects in deep treatment of chemical wastewater. However, if saturated activated coke is directly treated as hazardous waste, it will directly lead to high costs for activated coke adsorption technology, which will limit the promotion of the technology. Therefore, the key to reducing the cost of wastewater treatment is to regenerate and reuse saturated activated coke.

[0003] At present, the mature activated carbon regeneration method is pyrolysis regeneration, which realizes the regeneration of saturated carbon through high-temperature carbonization and activation process under anoxic conditions. This high-temperature regeneration method easily destroys the carbon skeleton, resulting in high carbon loss, which leads to reduced adsorption performance of activated carbon. In addition, a large amount of waste gas will be released during the regeneration process, and the adsorbed pollutants may volatilize into the gas phase and cause environmental pollution. The hydrothermal treatment regeneration of saturated activated carbon is a method of regenerating activated carbon by using water as the reaction medium to promote the desorption, transformation and decomposition of difficult-to-degrade organic matter at a lower hydrothermal temperature. Hydrothermal regeneration of activated carbon usually requires a temperature of more than 300°C to degrade pollutants and obtain a better activated carbon regeneration effect. The pollutants adsorbed on the activated carbon usually undergo desorption, degradation and other processes.

[0004] A large number of refractory pollutants are adsorbed on the saturated activated coke used in the deep treatment of wastewater in chemical parks. Simple hydrothermal regeneration has poor effect and produces high-concentration regeneration waste liquid. Currently, there is no enhanced hydrothermal regeneration method for saturated activated coke used in the deep treatment of chemical wastewater. Therefore, it is necessary to strengthen the hydrothermal regeneration process to achieve efficient regeneration of saturated activated coke used in the deep treatment of wastewater in industrial parks and resource utilization of regeneration waste liquid. Summary of the invention

[0005] The present application provides a method for hydrothermal alkali regeneration and resource utilization of saturated activated coke in chemical wastewater treatment, aiming to improve the problems of poor activated coke regeneration effect, high carbon loss and high regeneration energy consumption in the prior art.

[0006] The embodiment of the present application is implemented as follows:

[0007] In a first aspect, the present invention provides a method for hydrothermal alkali regeneration and resource utilization of saturated activated coke in chemical wastewater treatment, the method comprising:

[0008] S1: placing saturated activated coke from chemical park wastewater treatment in a hydrothermal reactor;

[0009] S2: adding a base catalyst into a hydrothermal reactor to obtain a solid-liquid mixture;

[0010] S3: sealing the hydrothermal reactor, heating the solid-liquid mixture, and performing a hydrothermal catalytic regeneration reaction;

[0011] S4: After the regeneration reaction is completed, the regenerated activated coke and the waste liquid generated during the regeneration process are discharged;

[0012] S5: The regenerated activated coke is rinsed and reused, and the waste liquid generated during the regeneration process is recycled.

[0013] In an optional embodiment, in S1, the hydrothermal reactor is a stainless steel reactor, the operating temperature is not higher than 300°C, and the operating pressure is not higher than 8.0 MPa.

[0014] In an optional embodiment, in S2, the component of the alkaline catalyst includes sodium hydroxide with a concentration of 0.5 to 1.5 mol / L.

[0015] In an optional embodiment, S3 includes:

[0016] The solid-liquid mixture is treated in a hydrothermal reactor at a solid-liquid ratio of 0.25 to 1, a temperature of 100 to 200° C., and a pressure of 0.45 to 1.80 MPa for 1 to 4 hours.

[0017] In an optional embodiment, the solid-liquid ratio of the solid-liquid mixture is 0.5.

[0018] In an optional embodiment, S3 includes:

[0019] The solid-liquid mixture was placed in a hydrothermal reactor and subjected to hydrothermal catalytic reaction at 150°C for 2 h with a heating rate of 5°C / min.

[0020] In an optional embodiment, S4 includes:

[0021] The hydrothermal reactor was cooled to below 70°C and opened to discharge the activated coke and waste liquid generated during the regeneration process.

[0022] In an optional embodiment, S5 includes:

[0023] The regenerated activated coke is rinsed with 1-2 mol / L hydrochloric acid solution and tap water.

[0024] In an optional embodiment, S5 includes:

[0025] When the regenerated activated coke is used for re-adsorption, the dosage is 1g / L, and the wastewater used is the effluent from the secondary sedimentation tank after biological treatment of the centralized sewage treatment plant in the chemical park, with a COD of 132-150mg / L.

[0026] In an optional embodiment, S5 includes:

[0027] When the regenerated activated coke is used for re-adsorption, the regenerated activated coke is mixed with wastewater at 150 rpm to 200 rpm for at least 96 hours.

[0028] The method provided in the present application regenerates and reuses the saturated granular activated coke produced by the deep treatment of chemical wastewater in situ through the synergistic effect of hydrothermal and alkaline catalysis, and at the same time realizes resource utilization of the waste liquid generated in the regeneration process. Among them, hydrothermal treatment can realize the in-situ desorption regeneration of saturated activated coke, without the need for additional drying steps and high operating temperatures, and has potential advantages in terms of energy consumption and operating procedures. The alkaline catalyst enhances the desorption and decomposition of the adsorbed substances, realizing low-temperature and efficient regeneration of saturated activated coke. The present application can avoid the problems of high energy consumption and high quality loss in the pyrolysis regeneration of saturated activated coke, and realize the low-temperature catalytic regeneration and resource utilization of saturated activated coke in the deep treatment of chemical wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A flow chart of a method for the hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment provided in an embodiment of the present application;

[0031] Figure 2 The adsorption amount of COD and TOC (total organic carbon) in wastewater by the regenerated activated coke and the original activated coke;

[0032] Figure 3 is the regeneration efficiency and mass loss of saturated activated coke in the regeneration cycle. DETAILED DESCRIPTION

[0033] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0034] The study found that a large number of difficult-to-degrade pollutants, such as benzene series, amine lipids, ketones, alcohols, long-chain alkanes, etc., were adsorbed on the saturated activated coke used in the deep treatment of wastewater in chemical parks. The traditional hydrothermal regeneration has poor effect and produces high-concentration regeneration waste liquid. Therefore, it is necessary to provide a cost-effective method for hydrothermal alkaline regeneration and resource utilization of saturated activated coke.

[0035] The inventors found that through the synergistic effect of hydrothermal and alkaline catalysts, the saturated granular activated coke produced by the deep treatment of industrial park wastewater can be regenerated and reused, and the generated regeneration liquid can be used as a resource. Organic desorption, catalytic degradation and improved activated carbon pores are the main reasons for the regeneration of saturated activated coke. Hydrothermal alkaline treatment can decompose pollutants adsorbed on saturated activated carbon and release the adsorption sites of activated carbon. Compared with traditional pyrolysis regeneration methods, it has advantages in energy consumption and regeneration effect; alkaline catalysts enhance the desorption / decomposition of organic matter and improve the pore structure of activated coke.

[0036] Therefore, the embodiment of the present invention proposes a method for hydrothermal alkali regeneration and resource utilization of saturated activated coke in chemical wastewater treatment (hereinafter referred to as: method), which aims to improve the problems of poor activated coke regeneration effect, high carbon loss and high regeneration energy consumption in the prior art.

[0037] The following is a specific description of the method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment according to the embodiment of the present application:

[0038] Please refer to Figure 1 , the method comprises the following steps:

[0039] S1: Place the saturated activated coke from chemical park wastewater treatment in a hydrothermal reactor.

[0040] Among them, the saturated activated coke mainly adsorbs benzene series, amine lipids, ketones, alcohols, long-chain alkanes and other substances in the wastewater. The particle size of the saturated activated coke is 8-30 meshes, and the moisture content is 29.08wt%-36.60wt%.

[0041] S2: adding a base catalyst into a hydrothermal reactor to obtain a solid-liquid mixture.

[0042] Among them, the hydrothermal reactor is a high-temperature and high-pressure stainless steel reactor with an operating temperature not higher than 300°C and a working pressure not higher than 8.0Mpa. The main component of the alkaline catalyst is sodium hydroxide with a concentration of 0.5-1.5 mol / L. Sodium hydroxide is cheap and easy to obtain in chemical parks. A 0.5-1.5 mol / L sodium hydroxide solution can promote the desorption and decomposition of adsorbed organic matter and improve the pore structure of activated coke; a high-concentration sodium hydroxide solution can cause severe corrosion of the carbon skeleton of activated coke, reduce regeneration efficiency and increase reagent costs. The solid-liquid mixture is the activated coke mixture.

[0043] S3: The hydrothermal reactor is sealed to heat the solid-liquid mixture to perform a hydrothermal catalytic regeneration reaction.

[0044] Among them, the solid-liquid mixture is treated in a hydrothermal reactor for 1 to 4 hours at a solid-liquid ratio of 0.25 to 1, a temperature of 100 to 200°C, and a pressure of 0.45 to 1.80Mpa. The optimal solid-liquid ratio of the solid-liquid mixture in this embodiment is 0.5, which can achieve the regeneration of saturated activated coke while producing less high-concentration regeneration waste liquid; the hydrothermal alkali regeneration temperature is lower than 100°C, and the adsorbed organic matter is difficult to desorb and decompose; the temperature is higher than 200°C, while the regeneration efficiency of saturated activated coke is improved, the regeneration pressure and energy consumption are significantly increased; the setting of the above technical parameters comprehensively considers the issues of regeneration efficiency, equipment process and energy consumption. On this basis, the optimal technical parameters for the regeneration and resource utilization of saturated activated coke in chemical parks can be obtained.

[0045] S4: After the regeneration reaction is completed, the regenerated activated coke and the waste liquid generated during the regeneration process are discharged.

[0046] After the regeneration reaction is completed, the hydrothermal reactor is cooled to below 70° C., and the hydrothermal reactor is opened to discharge the activated coke and waste liquid generated during the regeneration process.

[0047] S5: The regenerated activated coke is rinsed and reused, and the waste liquid generated during the regeneration process is recycled.

[0048] Among them, the active coke flushing liquid is 1-2 mol / L hydrochloric acid solution and tap water.

[0049] When the regenerated activated coke is used for re-adsorption, the dosage is 1g / L. The wastewater used is the effluent from the secondary sedimentation tank after biological treatment of the centralized sewage treatment plant in the chemical park, with a COD of 132-150mg / L. The regenerated activated coke is tested for adsorption with the wastewater in the chemical park to truly reflect the adsorption capacity of the regenerated activated coke. The regenerated activated coke is mixed with the wastewater at 150rpm-200rpm for at least 96h.

[0050] The COD adsorption capacity of the activated coke obtained by the method is 66.4% to 110.6% of the original activated coke adsorption capacity, the COD of the waste liquid is 8215 mg / L to 14342 mg / L, and the ratio of biochemical oxygen demand to chemical oxygen demand (BOD / COD) is 0.39 to 0.52.

[0051] The waste liquid produced by regeneration shows good biodegradability, and the BOD (biochemical oxygen demand) / COD value can reach 0.52; this means that the regeneration waste liquid is easily biodegradable, and also shows that during the regeneration process, a large amount of difficult-to-degrade organic matter decomposes to produce small molecules that can be directly used by microorganisms, thereby increasing the BOD / COD value.

[0052] After hydrothermal alkaline catalytic treatment, the luminescence inhibition rate of the luminescent bacteria in the regenerated waste liquid is less than 1%, about 0.9%, which is significantly lower than the 22.4% of the saturated activated coke extract, and lower than the inhibition rate of chemical wastewater on luminescent bacteria (11.5%). The lower the luminescence inhibition rate, the smaller the impact of the water sample on bacterial growth, which further shows that the organic matter on the saturated activated coke is significantly degraded during the regeneration process, weakening the acute toxicity of the regenerated waste liquid and showing good biodegradability. After proper treatment, the regenerated waste liquid can be sent to the wastewater biochemical treatment unit as a carbon source for resource utilization.

[0053] The method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment provided by the embodiment of the present invention includes the following beneficial effects:

[0054] First, a feasible hydrothermal alkali regeneration method is adopted. This regeneration method is simple and easy to implement, and has advantages in energy consumption and regeneration effect compared with the traditional pyrolysis thermal regeneration method;

[0055] Second, during the hydrothermal alkaline catalytic regeneration process, by adding an alkaline catalyst, regenerated activated coke with good re-adsorption capacity can be obtained; and the main component of the alkaline catalyst is sodium hydroxide, which is cheap and easy to obtain. Therefore, the saturated activated coke regeneration method provided in this embodiment is economically feasible;

[0056] Third, please refer to Figure 2 The regenerated activated coke in the present invention has a COD adsorption capacity of 62.2 mg / g in chemical wastewater containing 146 mg / LCOD (chemical oxygen demand) at a dosage of 1 g / L, which is 91.6% of the adsorption capacity of the original activated coke, which can reduce the use of commercial activated coke in the deep treatment of wastewater, and significantly reduce the treatment cost of wastewater and the purchase cost of activated coke. Considering that the wastewater contains a high proportion of nitrates and chlorides, the COD reagent tube test may be affected by the suspended matter formed after digestion. The inventors also tested the total organic carbon (TOC) in the wastewater to verify the results. The results show that the regenerated activated coke has a TOC removal capacity comparable to that of the original activated coke, further verifying the effectiveness of the method.

[0057] Fourth, please refer to Figure 3 After four cycles, the COD removal performance of the regenerated activated coke only decreased by 7%. Usually after multiple adsorption regenerations, the physical characteristics of the regenerated activated coke change, thus affecting its adsorption performance. The mass loss of activated coke increases linearly with the hydrothermal alkaline regeneration cycle. The mass loss of activated coke after the first regeneration was 4.2%, and after four regeneration cycles, the total weight loss was 13.3%. This percentage is significantly lower than the mass loss of pyrolysis regeneration of granular activated coke (about 8%-10% per regeneration cycle). It can reduce the use of commercial activated coke in deep wastewater treatment, significantly reducing the cost of wastewater treatment and the purchase cost of activated coke.

[0058] The following is a further detailed description of the method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment of the present application in conjunction with the embodiments.

[0059] Example 1

[0060] This embodiment provides a method for hydrothermal alkali regeneration and resource utilization of saturated activated coke in chemical wastewater treatment, and the specific method is as follows:

[0061] (1-1) Saturated activated coke from the activated coke adsorption tank of the centralized wastewater treatment plant in the chemical park was dried at 100°C to constant weight, and its moisture content was measured. The test showed that the moisture content of the saturated activated coke was 30.9wt%.

[0062] (1-2) Prepare an alkaline catalyst, wherein the main component of the alkaline catalyst is sodium hydroxide with a concentration of 1.0 mol / L.

[0063] (1-3) 10 g of saturated activated coke and an alkali catalyst were mixed at a solid-liquid ratio of 1:2 (g:mL), wherein the solid mass was calculated based on the dry weight of the saturated activated coke, to obtain a solid-liquid mixture.

[0064] (1-4) The solid-liquid mixture of step (1-3) is placed in a hydrothermal reactor and subjected to a hydrothermal catalytic reaction at 150° C. for 2 h at a heating rate of 5° C. / min.

[0065] (1-5) After the reaction of step (1-4) is completed and the hydrothermal reactor is cooled to below 70° C., the regenerated activated coke and the waste liquid generated during the regeneration process are collected.

[0066] (1-6) The activated coke collected in step (1-5) was treated with 10 mL of 1 mol / L HCl under shaking at 150 rpm for 3 h, then the sample was rinsed twice with tap water, 30 mL of tap water was added, and shaking was continued for 3 h. Finally, the sample was rinsed with tap water to make the pH of the rinse water reach 7, and then dried at 60° C. to obtain regenerated activated coke.

[0067] (1-7) Add the regenerated activated coke treated in step (1-5) to the chemical park wastewater. The added amount of the regenerated activated coke is 1 g / L. The mixture of the chemical park wastewater and the regenerated activated coke is placed in a shaker and shaken at a speed of 150 rpm and maintained at 25°C for 96 hours. The results show that the pH value of the wastewater is 7.2 and the COD content in the wastewater is 146 mg / L. The adsorption amount of COD in the wastewater by the regenerated activated coke is 91.6% of the adsorption amount of the original activated coke.

[0068] (1-8) The waste liquid collected in step (1-5) was filtered through a 0.45 μm polyethersulfone filter and subjected to a biodegradability test. The test showed that the COD / BOD value of the waste liquid was 0.52, indicating good biodegradability.

[0069] Example 2

[0070] This embodiment provides a method for hydrothermal alkali regeneration and resource utilization of saturated activated coke in chemical wastewater treatment. The difference between this embodiment and embodiment 1 is only that:

[0071] (1-3) 10 g of original saturated activated coke and alkali catalyst were mixed at a solid-liquid ratio of 1:10 (g:mL). Except for the solid-liquid ratio, the other conditions were the same as those in Example 1.

[0072] The treated regenerated activated coke was added to the wastewater from the chemical park. The added amount of regenerated activated coke was 1g / L. The mixture was placed in a shaker and shaken at a speed of 150rpm and kept at 25℃ for 96h. The pH value of the wastewater was 7.2, and the COD content in the wastewater was 146mg / L. The adsorption of COD in the wastewater by the regenerated activated coke was 106.0% of the adsorption of the original activated coke.

[0073] Example 3

[0074] This embodiment provides a method for hydrothermal alkali regeneration and resource utilization of saturated activated coke in chemical wastewater treatment. The difference between this embodiment and embodiment 1 is only that:

[0075] (1-3) 10 g of original undried saturated activated coke and an alkali catalyst were mixed at a solid-liquid ratio of 3:4 (g:mL). Except for the solid-liquid ratio, the other conditions were the same as those in Example 1.

[0076] The treated regenerated activated coke was added to the wastewater from the chemical park. The added amount of regenerated activated coke was 1g / L. The mixture was placed in a shaker and shaken at a speed of 150rpm and kept at 25℃ for 96h. The pH value of the wastewater was 7.2, and the COD content in the wastewater was 146mg / L. The adsorption amount of COD in the wastewater by the regenerated activated coke was 85.6% of the adsorption amount of the original activated coke.

[0077] Example 4

[0078] This embodiment provides a method for hydrothermal alkali regeneration and resource utilization of saturated activated coke in chemical wastewater treatment. The difference between this embodiment and embodiment 1 is only that:

[0079] (1-4) The hydrothermal catalytic reaction was carried out at 180°C for 2 hours with a heating rate of 5°C / min. Except for the different temperature of the hydrothermal alkaline catalytic regeneration reaction, the other conditions were the same as those in Example 1.

[0080] The treated regenerated activated coke was added to the wastewater from the chemical park. The added amount of regenerated activated coke was 1g / L. The mixture was placed in a shaker and shaken at a speed of 150rpm and kept at 25℃ for 96h. The pH value of the wastewater was 7.2, and the COD content in the wastewater was 146mg / L. The adsorption of COD in the wastewater by the regenerated activated coke was 95.5% of the adsorption of the original activated coke.

[0081] Example 5

[0082] This embodiment provides a method for hydrothermal alkali regeneration and resource utilization of saturated activated coke in chemical wastewater treatment. The difference between this embodiment and embodiment 1 is that the water content of the saturated activated coke is different, and the regeneration scale is expanded, as follows:

[0083] (1-1) Take the saturated activated coke from the deep treatment activated coke adsorption tank of the centralized wastewater plant in the chemical park, dry it at 100°C to constant weight, and measure its moisture content. The test shows that the moisture content of the saturated activated coke is 36.60wt%;

[0084] (1-2) Prepare an alkaline catalyst, wherein the main component of the alkaline catalyst is sodium hydroxide with a concentration of 1.0 mol / L.

[0085] (1-3) 20 kg of original saturated activated coke and an alkali catalyst were mixed at a solid-liquid ratio of 1:2 (g:mL), wherein the solid mass was calculated based on the dry weight of the saturated activated coke, to obtain a solid-liquid mixture.

[0086] (1-4) The hydrothermal reaction was carried out at 180 °C for 2 h with a heating rate of 5 °C / min.

[0087] (1-5) After the reaction of step (1-4) is completed and the hydrothermal reactor is cooled to below 70° C., the regenerated activated coke and the regeneration waste liquid generated during the regeneration process are collected.

[0088] (1-6) 10 g of the regenerated activated coke collected in step (1-5) was treated with 10 mL of 1 mol / L HCl at 150 rpm for 3 h, then the sample was rinsed twice with tap water, 30 mL of tap water was added, and the shaking was continued for 3 h. Finally, the sample was rinsed with tap water to a pH of 7, and then dried at 60° C. to obtain regenerated activated coke.

[0089] (1-7) Add the regenerated activated coke treated in step (1-5) to the wastewater from the chemical park. The amount of the regenerated activated coke added is 1 g / L. The mixture is placed in a shaker and shaken at a speed of 150 rpm and maintained at 25° C. for 96 hours. The pH value of the wastewater is 7.2, and the COD content in the wastewater is 146 mg / L. The adsorption amount of COD in the wastewater by the regenerated activated coke is 87.7% of the adsorption amount of the original activated coke.

[0090] (1-8) The regeneration waste liquid collected in step (1-5) was filtered through a 0.45 μm polyethersulfone filter and subjected to biodegradability testing. The test showed that the COD / BOD value of the regeneration waste liquid was 0.42.

[0091] Comparative Example 1

[0092] This comparative example provides a method for hydrothermal regeneration and resource utilization of saturated activated coke in chemical wastewater treatment. The specific method is as follows:

[0093] (1-1) Take the saturated activated coke from the deep treatment activated coke adsorption tank of the centralized wastewater plant in the chemical park, dry it at 100°C to constant weight, and measure its moisture content. The test shows that the moisture content of the saturated activated coke is 30.9wt%;

[0094] (1-2) The original undried saturated activated coke and water are mixed at a solid-liquid ratio of 1:2 (g:mL) (without adding an alkali catalyst), wherein the solid mass is calculated based on the dry weight of the saturated activated coke, to obtain a solid-liquid mixture.

[0095] (1-3) The solid-liquid mixture of step (1-2) is placed in a hydrothermal reactor and subjected to a hydrothermal catalytic reaction at 150° C. for 2 h at a heating rate of 5° C. / min.

[0096] (1-4) After the reaction of step (1-3) is completed and the hydrothermal reactor is cooled to below 70° C., the regenerated activated coke and the regeneration waste liquid generated during the regeneration process are collected.

[0097] (1-5) The regenerated activated coke collected in step (1-5) was treated with 10 mL of 1 mol / L HCl under 150 rpm shaking for 3 h, then the sample was rinsed twice with tap water, 30 mL of tap water was added, and the shaking was continued for 3 h. Finally, the sample was rinsed with tap water to make the pH of the rinse water reach 7. The sample was dried at 60° C. to obtain regenerated activated coke.

[0098] (1-6) Add the regenerated activated coke treated in step (1-5) to the chemical wastewater. The amount of the regenerated activated coke added is 1 g / L. The mixture is placed in a shaker and shaken at a speed of 150 rpm and maintained at 25° C. for 96 hours. The pH value of the wastewater is 7.2, and the COD content in the wastewater is 146 mg / L. The adsorption amount of COD in the wastewater by the regenerated activated coke is 57.5% of the adsorption amount of the original activated coke.

[0099] Comparative Example 2

[0100] This comparative example provides a method for hydrothermal regeneration and resource utilization of saturated activated coke in chemical wastewater treatment. The difference between this comparative example and comparative example 1 is only that:

[0101] (1-1) Take the saturated activated coke from the deep treatment activated coke adsorption tank of the centralized wastewater plant in the chemical park, dry it at 100°C to constant weight, and measure its moisture content. The test shows that the moisture content of the saturated activated coke is 30.9wt%;

[0102] (1-2) The original undried saturated activated coke and water are mixed at a solid-liquid ratio of 1:2 (g:mL) (without adding an alkali catalyst), wherein the solid mass is calculated based on the dry weight of the saturated activated coke, to obtain a solid-liquid mixture.

[0103] (1-3) The solid-liquid mixture of step (1-2) is placed in a hydrothermal reactor and subjected to a hydrothermal catalytic reaction at 180° C. for 2 h at a heating rate of 5° C. / min.

[0104] Except for the different temperature of the hydrothermal catalytic regeneration reaction, other steps are the same as those in Comparative Example 1.

[0105] The treated regenerated activated coke was added to the wastewater from the chemical park. The added amount of regenerated activated coke was 1g / L. The mixture was placed in a shaker and shaken at 150rpm and kept at 25℃ for 96h. The pH value of the wastewater was 7.2, and the COD content in the wastewater was 146mg / L. The adsorption of COD in the wastewater by the regenerated activated coke was 63.1% of the adsorption of the original activated coke.

[0106] The embodiment of the present application provides a method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment. By adopting the hydrothermal alkali catalytic principle, the saturated activated coke can be directly regenerated at a temperature far lower than that required by the pyrolysis activation regeneration furnace, thereby reducing waste gas emissions, carbon loss and regeneration costs, and improving regeneration efficiency. The regeneration waste liquid generated by this method has low acute biological toxicity and is easily biodegradable, and can be used as a carbon source for biochemical systems for resource utilization.

[0107] The above are only specific embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for the hydrothermal alkali regeneration and resource utilization of saturated activated coke in chemical wastewater treatment, characterized in that: The method comprises: S1: placing saturated activated coke from chemical park wastewater treatment in a hydrothermal reactor; S2: adding a base catalyst into the hydrothermal reaction kettle to obtain a solid-liquid mixture; S3: sealing the hydrothermal reactor, heating the solid-liquid mixture, and performing a hydrothermal catalytic regeneration reaction; S4: After the regeneration reaction is completed, the regenerated activated coke and the waste liquid generated during the regeneration process are discharged; S5: The regenerated activated coke is rinsed and reused, and the waste liquid generated during the regeneration process is recycled.

2. The method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment according to claim 1, characterized in that: In S1, the hydrothermal reactor is a stainless steel reactor with an operating temperature not higher than 300°C and a working pressure not higher than 8.0 MPa.

3. The method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment according to claim 1, characterized in that: In S2, the main component of the alkaline catalyst is sodium hydroxide, and the concentration is 0.5-1.5 mol / L.

4. The method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment according to claim 1, characterized in that S3 include: The solid-liquid mixture is treated in the hydrothermal reactor at a solid-liquid ratio of 0.25 to 1, a temperature of 100 to 200° C., and a pressure of 0.45 to 1.80 MPa for 1 to 4 hours.

5. The method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment according to claim 4, characterized in that: The optimal solid-to-liquid ratio of the solid-to-liquid mixture is 0.

5.

6. The method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment according to claim 1, characterized in that: S3 includes: The solid-liquid mixture is placed in the hydrothermal reactor and subjected to hydrothermal catalytic reaction at 150° C. for 2 h with a heating rate of 5° C. / min.

7. The method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment according to claim 1, characterized in that: S4 includes: The hydrothermal reactor is cooled to below 70° C., and the hydrothermal reactor is opened to discharge the activated coke and waste liquid generated during the regeneration process.

8. The method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment according to claim 1, characterized in that: S5 includes: The regenerated activated coke is rinsed with 1-2 mol / L hydrochloric acid solution and tap water.

9. The method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment according to claim 1, characterized in that S5 include: When the regenerated activated coke is used for re-adsorption, the dosage is 1g / L, and the wastewater used is the effluent from the secondary sedimentation tank after biological treatment of the centralized sewage treatment plant in the chemical park, with a COD of 132-150mg / L.

10. The method for hydrothermal alkali regeneration and resource utilization of saturated activated coke for chemical wastewater treatment according to claim 1, characterized in that S5 include: When the regenerated activated coke is used for re-adsorption, the regenerated activated coke is mixed with wastewater at 150 rpm to 200 rpm for at least 96 hours.

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