Method and system for removing organic pollutants in reverse osmosis concentrated liquid of coking wastewater based on electron beam irradiation process

Abstract

The application provides a method and system for removing organic pollutants in coking wastewater reverse osmosis concentrated liquid based on an electron beam irradiation process, which comprises the following steps: sequentially passing the RO concentrated liquid through a high-dose electron beam irradiation unit, an electric adsorption treatment unit and a low-dose electron beam irradiation unit; when passing through the high-dose electron beam irradiation unit, the salt substances in the RO concentrated liquid are ionized into hydrated electrons and oxidizing free radicals by high-dose irradiation, which effectively reduces the quenching of the oxidizing free radicals generated in the irradiation process by the salt substances, and simultaneously enhances the removal of the organic pollutants in the reverse osmosis concentrated liquid; when the effluent passes through the electric adsorption treatment unit, the salt ions are removed by adsorption under the action of an electric field; when the effluent further passes through the low-dose electron beam irradiation unit, the organic pollutants in the effluent are removed by low-dose electron beam irradiation and decomposition; the effluent can be further returned to the electric adsorption treatment unit for cyclic treatment until the COD in the effluent of the low-dose electron beam irradiation unit is less than or equal to 10 mg / L.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a method and system for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation. Background Technology

[0002] Coking wastewater is characterized by its complex composition, high concentration, and recalcitrant biodegradability, making it a difficult-to-treat industrial wastewater. Biological treatment is one of the most widely used processes in industrial wastewater treatment. However, biological treatment processes cannot effectively remove toxic, harmful, and recalcitrant organic pollutants from coking wastewater. This results in the treated effluent failing to meet the requirements for direct discharge.

[0003] To address the aforementioned issues, advanced treatment processes are typically added after biological treatment to improve the overall treatment efficiency. Advanced oxidation processes, such as Fenton oxidation and ozone oxidation, are commonly used advanced treatment technologies. Although advanced oxidation processes can further reduce organic pollutants in biological effluent, the effluent indicators still do not meet reuse requirements. To improve wastewater reuse rates and achieve the goal of "zero discharge," advanced oxidation technology coupled with membrane processes is commonly used in practice. The use of membrane processes generates membrane concentrate. Membrane concentrate is characterized by high salinity and high COD. The treatment of membrane concentrate faces the challenge that the high salinity significantly affects the removal of organic pollutants, resulting in limited effectiveness of existing wastewater treatment processes for treating membrane concentrate.

[0004] Electron beam irradiation is a novel advanced oxidation technology. Its main principle for wastewater treatment relies on the direct action of the electron beam (energy deposition) and the indirect action of the active species generated by the activation of water molecules to remove pollutants. Compared with traditional advanced oxidation processes, it has advantages such as better treatment effect, shorter treatment time, and no need to add chemical substances. However, when using electron beam irradiation alone to treat membrane concentrate, the presence of high salt in the concentrate usually requires a very high irradiation dose to achieve the desired treatment effect, leading to a significant increase in treatment costs.

[0005] Therefore, how to reduce the impact of high salt content in the membrane concentrate on the removal of organic pollutants by electron beam irradiation, and how to recover and utilize the salt in the membrane concentrate while considering the removal of organic pollutants, and ultimately achieve the resource utilization of salt, are urgent problems to be solved. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, this invention provides a method and system for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation. The method uses electron beam irradiation coupled with electroadsorption to treat the concentrate, thereby achieving the removal of organic pollutants and the recovery of salts from the reverse osmosis concentrate of coking wastewater.

[0007] The specific details of the invention are as follows:

[0008] In a first aspect, the present invention provides a method for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation, the process comprising:

[0009] The reverse osmosis concentrate is passed into a high-dose electron beam irradiation unit. Under the irradiation of the electron beam, some salt substances are ionized to generate hydrated electrons and oxidative free radicals. The hydrated electrons charge some organic pollutants, and the oxidative free radicals decompose some organic pollutants, thereby obtaining pre-purified water.

[0010] The primary pre-purified water is passed into the electro-adsorption treatment unit, whereby, under the action of an electric field, salt ions and some of the charged organic pollutants in the primary purified water are removed by electro-adsorption. The H2O2 generated during the irradiation process is activated into hydroxyl radicals by the anode of the electro-adsorption treatment unit. The hydroxyl radicals decompose the organic pollutants adsorbed on the electrode surface, thereby obtaining secondary pre-purified water.

[0011] The secondary pre-purified water is passed into a low-dose electron beam irradiation unit to remove organic pollutants from the secondary pre-purified water, thus obtaining tertiary pre-purified water.

[0012] The pre-purified water from the three stages is returned to the electro-adsorption treatment unit for further recycling until the COD in the effluent from the low-dose electron beam irradiation unit is ≤10mg / L, thus completing the removal of organic pollutants from the coking wastewater reverse osmosis concentrate.

[0013] Optionally, in the reverse osmosis concentrate, 150 mg / L ≤ COD ≤ 500 mg / L, and 10000 μS / cm ≤ conductivity ≤ 100000 μS / cm.

[0014] Optionally, the high-dose electron beam irradiation dose is between 20 and 100 kGy.

[0015] Optionally, the inlet water flow rate of the electro-adsorption unit is between 1m. 3 / h~20m 3 / h.

[0016] Optionally, the voltage applied by the electroadsorption treatment unit is between 1.2 and 1.7V.

[0017] Optionally, the anode of the electroadsorption treatment unit is composed of carbon-coated iron-nickel material;

[0018] The cathode of the electro-adsorption treatment unit is composed of a titanium plate or a carbon material.

[0019] Optionally, the carbon-coated iron-nickel material includes one or more combinations of graphene-coated iron-nickel material, biochar-coated iron-nickel material, modified graphene-coated iron-nickel material, and modified biochar-coated iron-nickel material.

[0020] Optionally, the low-dose electron beam irradiation dose is between 1 and 10 kGy.

[0021] Optionally, the number of cycles is 1-20.

[0022] In a second aspect, the present invention provides a system for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation, the system being applicable to the method described in the first aspect above, comprising:

[0023] A high-dose electron beam irradiation unit is used to ionize the salts in the reverse osmosis concentrate into hydrated electrons and oxidizing free radicals; the hydrated electrons charge some organic pollutants, and the oxidizing free radicals decompose some organic pollutants, thereby obtaining pre-purified water.

[0024] An electro-adsorption treatment unit is used to adsorb salt ions and a portion of the charged organic pollutants in the primary pre-purified water; and to activate H2O2 generated by irradiation into hydroxyl radicals, which decompose the organic pollutants adsorbed on the electrode surface, thereby obtaining secondary pre-purified water.

[0025] A low-dose electron beam irradiation unit is used to decompose organic pollutants in the secondary pre-purified water to obtain purified water.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] This invention provides a method for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation. By directly applying high-dose electron beam irradiation to the reverse osmosis concentrate of coking wastewater, the salts in the concentrate are directly ionized into hydrated electrons and corresponding oxidizing free radicals. This reduces the quenching effect of salts on active species in the water while increasing the concentration of active species in the system, thereby increasing the system's ability to remove organic pollutants from the concentrate. Furthermore, the effluent from the high-dose electron beam irradiation is subjected to electroadsorption treatment, using a carbon-coated iron-nickel material as the anode material in the electroadsorption treatment unit (the iron-nickel co-modified carbon material forms distinct positive and negative charge regions on its surface, which is beneficial for adsorption). The system absorbs salt ions, thus achieving better brine separation. Furthermore, the concentrate treated under electron beam irradiation contains a certain amount of H2O2. The carbon-coated iron-nickel material can effectively adsorb H2O2 and activate it into hydroxyl radicals. These hydroxyl radicals remove organic pollutants adsorbed on the electrode surface, further removing organic pollutants from the concentrate. The low-concentration organic pollutants remaining in the concentrate after electro-adsorption treatment are further decomposed and removed under low-dose electron beam irradiation. If the effluent COD is greater than 10 mg / L, the effluent can be returned to the electro-adsorption unit for cyclic treatment with the low-dose electron beam irradiation unit until the effluent COD is less than 10 mg / L.

[0028] The present invention provides a method for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation. The method is simple to operate, requires no chemical additives, and reduces organic pollutants in the membrane concentrate while facilitating salt recovery and utilization. It has broad application prospects in the field of RO concentrate treatment of coking wastewater. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A flowchart of a method for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation technology, provided in an embodiment of the present invention, is shown.

[0031] Figure 2 This invention provides a schematic diagram of a system structure for removing organic pollutants from reverse osmosis concentrate of coking wastewater using electron beam irradiation technology, as shown in an embodiment of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention. Furthermore, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of the present invention.

[0033] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of this specification.

[0034] In the description of this invention, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0035] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] Before providing a detailed description of the treatment system and process for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation provided by this invention, it is necessary to explain the relevant technologies as follows:

[0037] Current research and practical applications primarily utilize the indirect effects of electron beam irradiation for wastewater treatment, neglecting the direct effects of electron beam irradiation. Furthermore, when the concentration of organic pollutants in the concentrate is low, the concentration of salts is much higher than the concentration of organic pollutants. This means that the reactive species generated during electron beam irradiation react more with the salts, failing to effectively remove the low concentration of organic pollutants. If electron beam irradiation is used alone to remove low concentrations of organic pollutants from the concentrate, a significantly higher irradiation dose is typically required than theoretically necessary, significantly increasing treatment costs.

[0038] Electroadsorption utilizes an electric field to cause ions in water to migrate towards electrodes with opposite charges, where they are adsorbed and stored within the electrical double layer. Studies have shown that electroadsorption can be used to separate salts and water. However, it cannot remove organic pollutants from water. Furthermore, the choice of electrode material is crucial for the electroadsorption separation of salts and water.

[0039] Based on the above considerations, this invention aims to achieve electron beam irradiation coupled with electroadsorption treatment of concentrates, thereby removing organic pollutants from reverse osmosis concentrates of coking wastewater. Specific implementation details are as follows:

[0040] In a first aspect, the present invention provides a method for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation. Figure 1 The following is a flowchart illustrating a method for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation, as provided in an embodiment of the present invention. Figure 1 As shown, the method includes:

[0041] S1. The reverse osmosis concentrate is passed into a high-dose electron beam irradiation unit. Under the irradiation of the electron beam, some salt substances are ionized to produce hydrated electrons and oxidative free radicals. The hydrated electrons charge some organic pollutants, and the oxidative free radicals decompose some organic pollutants, thus obtaining pre-purified water.

[0042] S2. The pre-purified water is passed into the electro-adsorption treatment unit, so that the salt ions and some charged organic pollutants in the pre-purified water are removed by electro-adsorption under the action of the electric field; the H2O2 generated during the irradiation process is activated into hydroxyl radicals by the anode of the electro-adsorption treatment unit. The hydroxyl radicals decompose the organic pollutants adsorbed on the electrode surface, thereby obtaining the secondary pre-purified water.

[0043] S3. Pass the secondary pre-purified water into a low-dose electron beam irradiation unit to remove organic pollutants from the secondary pre-purified water to obtain tertiary pre-purified water.

[0044] S4. The pre-purified water from the three stages is returned to the electro-adsorption treatment unit for further recycling until the COD in the effluent from the low-dose electron beam irradiation unit is ≤10mg / L, thus completing the removal of organic pollutants from the reverse osmosis concentrate of the coking wastewater.

[0045] In specific implementation, embodiments of the present invention utilize the direct effect of high-dose electron beam irradiation to directly ionize some salt substances, generating corresponding hydrated electrons and oxidizing free radicals, wherein the oxidizing free radicals include, but are not limited to, O2· - Cl· SO4 - • and NO3· etc. The transformation of salt substances reduces their quenching effect on active species, while the generated active species can also enhance the oxidation capacity of organic pollutants in the concentrate. The high-dose electron beam irradiation dose is between 20 and 100 kGy. On the other hand, hydrated electrons are also generated during electron beam irradiation, which makes the originally neutral organic pollutants charged, thereby causing electroadsorption to remove some organic pollutants from the concentrate.

[0046] When the electron beam irradiation dose applied to the RO concentrate is between 20 and 100 kGy, some of the salts in the concentrate are ionized and decomposed, and some organic pollutants are decomposed under the action of the ionization products. Further electroadsorption can then be used to separate the remaining salts and water. The voltage applied during the electroadsorption process is between 1.2 and 1.7 V. Furthermore, this invention uses carbon-coated iron-nickel material as the positive electrode material of the electroadsorption treatment unit, which has excellent adsorption properties for H₂O₂ generated during electron beam irradiation and activates it into hydroxyl radicals. These hydroxyl radicals can be used to remove organic pollutants adsorbed on the electrode surface, improve the purity of the salts adsorbed by the electrode material, and increase the recovery value of the salts.

[0047] In the effluent after electroadsorption treatment, the remaining low-concentration organic pollutants can be removed by downstream low-dose electron beam irradiation. If the COD of the effluent after low-dose electron beam irradiation is greater than 10 mg / L, the effluent can be returned to the electroadsorption treatment unit for cyclic treatment by both units until the COD is less than 10 mg / L. This invention effectively removes organic pollutants from the membrane concentrate through the synergistic effect of electron beam irradiation and electroadsorption, ultimately enabling the resource utilization of experimental salts.

[0048] In practical implementation, high-dose electron beam irradiation can directly ionize a portion of the salts in the RO concentrate into hydrated electrons and oxidative free radicals, while the remaining salts are further removed by electro-adsorption. Therefore, this invention can treat high-salt coking wastewater reverse osmosis concentrate, where the salt content, expressed as solution conductivity, can reach a maximum of 100,000 μS / cm and a minimum of not less than 10,000 μS / cm. Furthermore, the treatment process provided by this invention is suitable for RO concentrates with organic matter concentrations between 150 mg / L and COD between 500 mg / L.

[0049] In some embodiments, the anode of the electroadsorption treatment unit is composed of carbon-coated iron-nickel material; the cathode of the electroadsorption treatment unit is composed of titanium plate or carbon material. Preferred carbon-coated iron-nickel materials include one or more combinations of graphene-coated iron-nickel material, biochar-coated iron-nickel material, modified graphene-coated iron-nickel material, and modified biochar-coated iron-nickel material. Since the electron beam irradiation process generates H2O2, the carbon-coated iron-nickel material serves as the anode for electroadsorption. The iron-nickel modification increases the active sites on the electrode surface, enhancing its adsorption capacity for salts in wastewater. Simultaneously, it lowers the energy barrier required for the activation of H2O2 (oxidant) in the activation system, activating H2O2 into hydroxyl radicals. These hydroxyl radicals can remove organic pollutants adsorbed on the electrode surface, improving the purity of the adsorbed salts and thus increasing their recovery value. Furthermore, the addition of thiourea introduces both sulfur and nitrogen into the electrode material. Sulfur is a multivalent element with abundant electrons, which enhances the electron transport and exchange capabilities of the electrode material, further promoting the activation of the adsorbed oxidant. This gives the electrode material not only excellent salt separation properties but also the ability to adsorb and activate oxidants. The presence of nitrogen causes the iron and nickel in the composite material to complex with nitrogen, forming a more stable structure and effectively preventing material loss or failure caused by the dissolution of iron and nickel during actual use.

[0050] In some embodiments, biochar-coated iron-nickel material can be obtained by the following preparation method: 20 ml of 0.1 M potassium ferricyanide solution is added dropwise to 20 ml of 0.15 M solution, aged in air for 12 h, filtered, and washed three times with deionized water to obtain a Prussian blue analogue. Then, it is dried in a 60 °C oven for 12 h. 0.5 g of the dried Prussian blue solid and 1.5 g of chitosan are placed in 50 ml of deionized water, sonicated for 10 min, stirred for 1 h, and then dried in an 80 °C oven for 12 h. 1 g of the dried solid is mixed with 10 g of thiourea solid and ground evenly. The ground powder is placed in a tube furnace. Under nitrogen conditions, the temperature is increased to 550 °C at 3 °C / min and held for 1 h, then increased to 900 °C at 5 °C / min and held for 1 h. After natural cooling, the obtained solid is washed three times with deionized water and then dried in a 60 °C oven. The obtained solid is the carbon-coated iron-nickel material.

[0051] In some embodiments, graphene-coated iron-nickel material can be obtained by the following preparation method: 20 ml of 0.1 M potassium ferricyanide solution is added dropwise to 20 ml of 0.2 M solution, aged in air for 10 h, filtered, and washed three times with deionized water to obtain a Prussian blue analogue. Then, it is dried in an oven at 80 °C for 12 h. 0.5 g of the dried Prussian blue solid and 2 g of modified graphene are placed in 50 ml of deionized water, sonicated for 10 min, stirred for 1 h, and then dried in an oven at 80 °C for 12 h. 1 g of the dried solid is mixed with 15 g of thiourea solid and ground evenly. The ground powder is placed in a tube furnace. Under nitrogen conditions, the temperature is increased to 550 °C at 3 °C / min and held for 1 h, then increased to 900 °C at 5 °C / min and held for 1 h. After natural cooling, the obtained solid is washed three times with deionized water and then dried in an oven at 60 °C. The obtained solid is the carbon-coated iron-nickel material.

[0052] In some implementations, the pre-purified water is recycled to the electro-adsorption treatment unit 5-20 times to achieve a COD ≤ 10 mg / L in the effluent.

[0053] Secondly, the present invention provides a system for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation technology, the system being applicable to the method described in the first aspect above. Figure 2 This diagram illustrates a system structure for removing organic pollutants from reverse osmosis concentrate of coking wastewater using electron beam irradiation, as provided in an embodiment of the present invention. Figure 2 As shown, it includes:

[0054] The high-dose electron beam irradiation unit is used to ionize the salts in the reverse osmosis concentrate into hydrated electrons and oxidizing free radicals; the hydrated electrons charge some organic pollutants, and the oxidizing free radicals decompose some organic pollutants, thereby obtaining pre-purified water.

[0055] The electro-adsorption treatment unit is used to adsorb salt ions and some charged organic pollutants in the primary pre-purified water; and to activate H2O2 generated by irradiation into hydroxyl radicals, which decompose the organic pollutants adsorbed on the electrode surface, thereby obtaining secondary pre-purified water.

[0056] A low-dose electron beam irradiation unit is used to decompose organic pollutants in secondary pre-purified water to obtain purified water.

[0057] To enable those skilled in the art to more clearly understand the present invention, the following embodiments will be used to provide a detailed description of the method and system for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation.

[0058] The specific treatment method for coking wastewater is as follows: RO concentrate first passes through the first stage electron beam irradiation treatment unit (high-dose electron beam irradiation unit), the effluent enters the electro-adsorption treatment unit, and finally enters the second stage electron beam irradiation treatment unit (low-dose electron beam irradiation unit). The effluent is directly discharged (COD in the effluent is less than 10 mg / L), or returned to the electro-adsorption treatment unit for multiple cycles. After the COD of the effluent from the low-dose electron beam irradiation unit is less than 10 mg / L, it is discharged, thus completing the treatment of the membrane concentrate.

[0059] Example 1

[0060] RO concentrate from a coking plant in Hebei Province had an initial COD of 247 mg / L and a conductivity of 17500 μS / cm. The anode of the electroadsorption unit was iron-nickel modified coconut shell carbon, and the cathode was a titanium plate. The flow rate was 1 m / s². 3 / h. The electron beam irradiation dose in the first stage is 30kGy, and the electron beam irradiation dose in the second stage is 5kGy. After three cycles of treatment, the effluent COD is <10mg / L.

[0061] Example 2

[0062] RO concentrate from a coking plant in Hebei Province had an initial COD of 247 mg / L and a conductivity of 17500 μS / cm. The anode of the electroadsorption unit was iron-nickel modified coconut shell carbon, and the cathode was a titanium plate. The flow rate was 1 m / s². 3 / h. The electron beam irradiation dose in the first stage is 50kGy, and the electron beam irradiation dose in the second stage is 10kGy. After two cycles of treatment, the effluent COD is <10mg / L.

[0063] Example 3

[0064] The RO concentrate from a coking plant in Hebei Province had an initial COD of 376 mg / L and a conductivity of 77500 μS / cm. The anode of the electroadsorption unit was iron-nickel modified coconut shell carbon, and the cathode was a titanium plate. The flow rate was 1 m / s². 3 / h. The electron beam irradiation dose in the first stage is 70kGy, and the electron beam irradiation dose in the second stage is 10kGy. After 6 cycles of treatment, the effluent COD is <10mg / L.

[0065] Comparative Example 1

[0066] RO concentrate from a coking plant in Hebei Province had an initial COD of 247 mg / L and a conductivity of 17500 μS / cm. It was treated with electron beam irradiation at a dose of 150 kGy, resulting in an effluent COD of 134 mg / L.

[0067] Comparative Example 2

[0068] RO concentrate from a coking plant in Hebei Province had an initial COD of 376 mg / L and a conductivity of 77,500 μS / cm. After treatment with a single electron beam irradiation dose of 150 kGy, the COD of the treated effluent was 277 mg / L.

[0069] As can be seen from the above embodiments, electron beam irradiation coupled electroadsorption technology can effectively reduce the impact of high salt content. Since no chemical substances are added during the entire process, the final salt purity is high. Therefore, electron beam irradiation coupled electroadsorption technology has the advantages of simple operation, good processing effect, and high salt purity.

[0070] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0071] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0072] The present invention provides a detailed description of a method and system for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for removing organic pollutants from reverse osmosis concentrate of coking wastewater based on electron beam irradiation, characterized in that, The method includes: The reverse osmosis concentrate is passed into a high-dose electron beam irradiation unit, where the high-dose electron beam irradiation dose is between 20 and 100 kGy. Under the irradiation of the electron beam, some salt substances are ionized to generate hydrated electrons and oxidative free radicals. The hydrated electrons charge some organic pollutants, and the oxidative free radicals decompose some organic pollutants, thereby obtaining pre-purified water. The primary pre-purified water is passed into an electro-adsorption treatment unit. The anode of the electro-adsorption treatment unit is composed of carbon-coated iron-nickel material, so that under the action of an electric field, the salt ions and some of the charged organic pollutants in the primary pre-purified water are electro-adsorbed and removed. The H2O2 generated during the irradiation process is activated into hydroxyl radicals by the anode of the electro-adsorption treatment unit. The hydroxyl radicals decompose the organic pollutants adsorbed on the electrode surface, thereby obtaining secondary pre-purified water. The secondary pre-purified water is passed into a low-dose electron beam irradiation unit, where the low-dose electron beam irradiation dose is between 1 and 10 kGy, to remove organic pollutants from the secondary pre-purified water, thus obtaining tertiary pre-purified water. The pre-purified water from the three stages is returned to the electro-adsorption treatment unit for recycling until the COD in the effluent of the low-dose electron beam irradiation unit is ≤10 mg / L, thus completing the removal of organic pollutants from the reverse osmosis concentrate of the coking wastewater. The preparation process of the carbon-coated iron-nickel material includes: Potassium ferricyanide solution was added dropwise to a solution of a certain concentration, aged in air, filtered, and washed to obtain a Prussian blue analogue. The dried Prussian blue analogue and carbon precursor were placed together in deionized water, stirred and dried. The resulting solid was mixed with thiourea solid and then ground. The ground material was heated to 550°C at a certain heating rate under a nitrogen atmosphere, and then calcined to 900°C at a certain heating rate to obtain the carbon-coated iron-nickel material. The carbon precursor is selected from chitosan or modified graphene.

2. The method according to claim 1, characterized in that, In the reverse osmosis concentrate, 150 mg / L ≤ COD ≤ 500 mg / L, and 10000 μS / cm ≤ conductivity ≤ 100000 μS / cm.

3. The method according to claim 1, characterized in that, The influent flow rate of the electro-adsorption treatment unit is between 1 m³ / h and 20 m³ / h.

4. The method according to claim 1, characterized in that, The voltage applied by the electro-adsorption treatment unit is between 1.2 and 1.7 V.

5. The method according to claim 1, characterized in that, The cathode of the electro-adsorption treatment unit is composed of a titanium plate or a carbon material.

6. The method according to claim 1, characterized in that, The carbon-coated iron-nickel material includes one or more combinations of modified graphene-coated iron-nickel material and biochar-coated iron-nickel material.

7. The method according to claim 1, characterized in that, The number of cycles is 1-20.

8. A system for treating organic pollutants in reverse osmosis concentrate of coking wastewater based on electron beam irradiation technology, characterized in that, The system employs the method described in any one of claims 1-7, comprising: A high-dose electron beam irradiation unit is used to ionize the salts in the reverse osmosis concentrate into hydrated electrons and oxidizing free radicals; the hydrated electrons charge some organic pollutants, and the oxidizing free radicals decompose some organic pollutants, thereby obtaining pre-purified water. An electro-adsorption treatment unit is used to adsorb salt ions and a portion of the charged organic pollutants in the primary pre-purified water; and to activate H2O2 generated by irradiation into hydroxyl radicals, which decompose the organic pollutants adsorbed on the electrode surface, thereby obtaining secondary pre-purified water. A low-dose electron beam irradiation unit is used to decompose organic pollutants in the secondary pre-purified water to obtain tertiary pre-purified water.

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