Method for deeply treating high-salt organic tail liquid by thermal activation persulfate coupling adsorption technology

Abstract

The invention provides a method for deeply treating high-salt organic tail liquid by a thermal activation persulfate coupling adsorption technology, which comprises the following steps: preheating the high-salt organic tail liquid, and then mixing the preheated high-salt organic tail liquid, persulfate and a carbon-based adsorbent for degradation reaction. According to the deep treatment method of the thermally activated persulfate coupling adsorption technology, provided by the invention, deep degradation of organic pollutants with complex components in the high-salt organic tail liquid can be realized, recycling of salt resources in a subsequent process is facilitated, and the purposes of harmlessness and recycling of the high-salt organic tail liquid are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of waste salt resource utilization and treatment, and relates to a method for deeply treating high-salt organic tail liquid using a thermally activated persulfate coupled adsorption technology. Background Art

[0002] Rare earth is an important strategic metal resource, which is of great significance to the national economic security, national defense security and the development of emerging industries. With the advancement of science and technology, the application field of rare earth is constantly expanding, and the demand for rare earth resources is increasing day by day. Extracting rare earth elements from ionic rare earth mines is an important way to supply rare earth resources, especially medium and heavy rare earth resources. However, in the process of rare earth resource mining and smelting, a large amount of high-salt mine tailings is inevitably produced. Because some organic matter present in the ore is dissolved into the leachate during the leaching process, and it continues to accumulate with the metallurgical processes such as leaching, neutralization and precipitation, it is finally enriched in the mine tailings, resulting in a more complex composition in the mine tailings. In addition to a large amount of inorganic salt components, there are also some natural organic matter.

[0003] At present, the treatment method for such high-salt organic tail liquid is mainly to dilute it by adding water directly, so that the pollutant concentration, salt concentration and turbidity in the tail liquid meet the discharge standards and then directly discharge it. This operation not only fails to fully utilize resources, but also consumes a large amount of precious fresh water resources, transfers pollution to the environment, and seriously harms the ecological environment.

[0004] Some researchers have also proposed using bipolar membrane electrolysis and salt separation crystallization to recover salt resources from tail liquid, thereby realizing resource utilization and harmless disposal of tail liquid. However, the organic pollutants contained in the tail liquid will not only cause serious contamination to the membrane during the reaction process, affecting the life of the membrane components, but will also be enriched in the final product, affecting product quality and reducing the economic feasibility of the salt resource recovery process. Therefore, there is an urgent need for a deep treatment method for such high-salt organic tail liquid.

[0005] Persulfate (PS) advanced oxidation technology refers to the use of light, electricity, heat, transition metals and other activation conditions to force the dioxygen bond in persulfate to break and produce sulfate free radicals (SO4 ·- ) is the main oxidizing active substance (see formula (1-1) and formula (1-2)), which is a new water treatment process for the degradation of macromolecular pollutants. Compared with the traditional chemical oxidation water treatment process, the sulfate radicals produced in the activated persulfate process have stronger oxidizing properties. Higher stability (half-life is 4s) and wider adaptability. In addition, compared with other activation methods, high-temperature thermal activation has many advantages such as wide applicability, no secondary pollution introduction and simple process, and is more suitable for the degradation of pollutants in high-salt organic tail liquid with complex components.

[0006]

[0007]

[0008] However, in the actual application of the persulfate advanced oxidation process, small molecular degradation products will remain, which will result in the inability to deeply remove organic matter in the wastewater, and fail to achieve the purpose of resource-based harmless disposal of mine wastewater.

[0009] Therefore, it is necessary to develop a process to solve the problem of residual small molecule degradation products of persulfate in the actual application process and to achieve deep treatment of high-salt organic tail liquid. Summary of the invention

[0010] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for deep treatment of high-salt organic tail liquid by thermally activated persulfate coupled adsorption technology. The present invention simultaneously introduces persulfate and carbon-based adsorbents, oxidizes and degrades organic pollutants in wastewater by free radicals generated by persulfate advanced oxidation technology, and deeply removes remaining pollutants by coupled adsorption technology. The carbon-based adsorbent can adsorb and remove small molecules generated in the solution after oxidation to obtain a relatively pure high-salt solution, which is conducive to the subsequent recycling of salt resources, thereby achieving near-zero emissions of high-salt organic tail liquid and high-value utilization of salt resources.

[0011] To achieve this object, the present invention adopts the following technical solutions:

[0012] In a first aspect, the present invention provides a method for deep treatment of high-salt organic tail liquid by thermally activated persulfate coupled adsorption technology, the method comprising:

[0013] The high-salt organic tail liquid is preheated, and then the preheated high-salt organic tail liquid, persulfate and carbon-based adsorbent are mixed to carry out a degradation reaction.

[0014] Adsorption technology is often used for deep treatment of water resources. It has many advantages such as high treatment level, stable effect, wide adaptability and low cost, especially in the removal of small molecule pollutants.

[0015] The invention provides a method for deeply treating high-salt organic tail liquid by using a thermally activated persulfate coupled adsorption technology. The method comprises the following steps: firstly, preheating the high-salt organic tail liquid, then mixing the preheated high-salt organic tail liquid, persulfate and a carbon-based adsorbent, activating the persulfate by utilizing the catalytic effect of the carbon-based adsorbent, reducing the energy demand in the activation process, promoting the oxidative decomposition of organic pollutants by free radicals, and simultaneously utilizing a relatively high ambient temperature and the oxidative activation effect of the persulfate on the adsorbent to adsorb and remove the remaining small molecule oxidation products in the solution, thereby achieving efficient degradation and deep removal of the organic pollutants in the tail liquid, obtaining a relatively pure high-salt solution, facilitating the subsequent recycling of salt resources, thereby achieving near-zero discharge of the high-salt organic tail liquid and high-value utilization of salt resources.

[0016] Exemplarily, the subsequent recycling of salt resources can be: the purified salt solution directly uses a bipolar membrane process to produce acid and alkali, which are returned to the front-end process for use.

[0017] Preferably, the high-salt organic tailings include tailings produced during the extraction of ionic rare earth ores, wherein the extraction process is the process of extracting rare earths and their associated resources.

[0018] Preferably, the pH value of the high-salt organic tail liquid is 5-9, for example, 5, 6, 7, 8 or 9.

[0019] Preferably, the concentration of salt substances in the high-salt organic tail liquid is 30-300 g / L, for example, it can be 30 g / L, 40 g / L, 50 g / L, 100 g / L, 150 g / L, 200 g / L, 250 g / L or 300 g / L.

[0020] Preferably, the persulfate includes at least one of sodium persulfate, sodium hydrogen persulfate, potassium persulfate, potassium hydrogen persulfate and ammonium persulfate.

[0021] Preferably, the carbon-based adsorbent includes at least one of activated carbon, coconut shell carbon, fruit shell carbon, carbon fiber and carbon black.

[0022] Preferably, the particle size of the carbon-based adsorbent is less than or equal to 5 mm, for example, it may be 5 mm, 4.5 mm, 4 mm, 3.5 mm, 3 mm, 2.5 mm, 2 mm or 1 mm.

[0023] Preferably, the specific surface area of ​​the carbon-based adsorbent is 200-1500m 3 / g, for example, it can be 200m 3 / g、300m 3 / g, 400m 3 / g、500m 3 / g、700m 3 / g、1000m 3 / g、1200m 3 / g or 1500m 3 / g, etc.

[0024] Preferably, the average pore size of the carbon-based adsorbent is 2-20 nm, for example, 2 nm, 3 nm, 5 nm, 7 nm, 10 nm, 12 nm, 15 nm or 20 nm, etc. Preferably, the ratio of the mass of the persulfate to the volume of the high-salt organic tail liquid is 5-50 g / L, for example, 5 g / L, 7 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L or 50 g / L, etc.

[0025] Preferably, the ratio of the mass of the carbon-based adsorbent to the volume of the high-salt organic tail liquid is 10-40 g / L, for example, it can be 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L or 40 g / L.

[0026] Preferably, the mass ratio of the persulfate to the carbon-based adsorbent is 1:(0.2-8), for example, it can be 1:0.2, 1:0.8, 1:1.6, 1:2.4, 1:3.2, 1:4.0, 1:4.8, 1:5.6, 1:6.4, 1:7.2 or 1:8.0, etc.

[0027] Preferably, the preheating temperature is 40-90°C, for example, it can be 40°C, 50°C, 60°C, 62°C, 65°C, 70°C, 80°C or 90°C.

[0028] Preferably, the mixing specifically comprises: adding persulfate and carbon-based adsorbent to the preheated high-salt organic tail liquid at the same time.

[0029] Preferably, the mixing temperature is 40-90°C, for example, it can be 40°C, 50°C, 60°C, 62°C, 65°C, 70°C, 80°C or 90°C.

[0030] Preferably, the mixing process is accompanied by stirring, and the stirring rate is 50-500r / min, for example, it can be 50r / min, 100r / min, 150r / min, 200r / min, 250r / min, 300r / min, 350r / min, 400r / min, 450r / min or 500r / min.

[0031] Preferably, the temperature of the degradation reaction is 40-90°C, for example, it can be 40°C, 50°C, 60°C, 62°C, 65°C, 70°C, 80°C or 90°C.

[0032] Preferably, the degradation reaction time is 20-240 min, for example, it can be 20 min, 30 min, 40 min, 50 min, 70 min, 100 min, 120 min, 140 min, 160 min, 180 min, 200 min, 220 min or 240 min, etc.

[0033] Preferably, the degradation reaction is accompanied by stirring, and the stirring rate is 50-500r / min, for example, it can be 50r / min, 100r / min, 150r / min, 200r / min, 250r / min, 300r / min, 350r / min, 400r / min, 450r / min or 500r / min.

[0034] As a preferred technical solution of the present invention, the method specifically comprises:

[0035] (1) preheating the high-salt organic tail liquid to 40-90° C., starting stirring so that the stirring rate is 50-500 r / min, and maintaining the temperature and stirring rate of the high-salt organic tail liquid constant;

[0036] (2) adding persulfate and a carbon-based adsorbent to the preheated high-salt organic tail liquid at the same time, and performing a degradation reaction for 20-240 minutes, wherein the ratio of the mass of the persulfate to the volume of the high-salt organic tail liquid is 5-50 g / L; and the ratio of the mass of the carbon-based adsorbent to the volume of the high-salt organic tail liquid is 10-40 g / L.

[0037] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The present invention provides a method for deeply treating high-salt organic tail liquid by using a thermally activated persulfate coupled adsorption technology. First, the high-salt organic tail liquid is preheated, and then the preheated high-salt organic tail liquid, persulfate and a carbon-based adsorbent are mixed. The persulfate is activated by the catalytic effect of the carbon-based adsorbent, thereby reducing the energy demand in the activation process and promoting the oxidative decomposition of organic pollutants by free radicals. At the same time, the relatively high ambient temperature and the oxidative activation effect of the persulfate on the adsorbent are used to adsorb and remove the remaining small molecule oxidation products in the solution, thereby achieving efficient degradation and deep removal of organic pollutants in the tail liquid, and obtaining a relatively pure high-salt solution, which is beneficial to the subsequent recycling of salt resources, thereby achieving near-zero discharge of high-salt organic tail liquid and high-value utilization of salt resources;

[0040] (2) In the method of the present invention, no acid, alkali or toxic reagent is added, and the oxidation product sodium sulfate is an original component in the high-salt organic tail liquid, and no secondary pollution is generated;

[0041] (3) The present invention can achieve a TOC (Total Organic Carbon) removal rate of 99% or more in high-salt organic tail liquid, and has the advantages of high degradation efficiency, no generation of new pollutants, wide application range, strong applicability and simple process. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of a process for deep treatment of high-salt organic tail liquid using a thermally activated persulfate coupled adsorption technology provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0043] In one embodiment, the present invention provides a method for deep treatment of high-salt organic tail liquid by thermally activated persulfate coupled adsorption technology, the process of which is as follows: Figure 1 As shown, including:

[0044] The preheated high-salt organic tail liquid, persulfate and carbon-based adsorbent are mixed for advanced oxidation and adsorption. The organic pollutants in the high-salt organic tail liquid are degraded by advanced oxidation of persulfate, and the remaining pollutants are deeply removed by coupled adsorption technology to obtain a relatively pure salt solution, which can directly enter the bipolar membrane for waste salt resource treatment.

[0045] The following Examples 1-12 and Comparative Examples 1-2 respectively provide methods for treating high-salt organic tail liquid, wherein the TOC content in the high-salt organic tail liquid is 1100 mg / L, and the inorganic components in the high-salt organic tail liquid and their respective contents are shown in Table 1.

[0046] Table 1

[0047] Components content / % <![CDATA[SO4 2- ]]> 48.05 <![CDATA[Na + ]]> 45.77 <![CDATA[Cl - ]]> 6.02 <![CDATA[K + ]]> 0.11 <![CDATA[Al 3+ ]]> 0.01

[0048] Example 1

[0049] This embodiment provides a method for deep treatment of high-salt organic tail liquid using thermally activated persulfate coupled adsorption technology, comprising:

[0050] (1) Use a measuring cylinder to measure 200 mL of high-salt organic tail liquid with a TOC value of 1100 mg / L and place it in a three-necked flask. At this time, the solution is neutral and the pH is about 8;

[0051] (2) Place the three-necked flask in a constant temperature water bath and heat it to 40°C. Then turn on the stirring device and set the stirring rate to 50 r / min. Keep the temperature and stirring rate constant and add 10.0 g of sodium persulfate and 4.0 g of activated carbon to the waste liquid at the same time. The particle size of the activated carbon is 1-2 mm and its specific surface area is 613.80 m 3 / g, the average pore size is 2.12nm, the concentration of sodium persulfate in the solution is 50g / L, the dosage of activated carbon is 20g / L, and the degradation reaction is carried out for 240min;

[0052] (3) After the reaction in step (2) is completed, the three-necked flask is taken out, and the solution is filtered while hot, and the filtrate is the reaction water.

[0053] Test: The reaction effluent obtained in step (3) was measured and calculated according to the environmental protection industry standard HJ / 501-2009 of the People's Republic of China to obtain the TOC value of the reaction effluent and the TOC removal rate in the liquid after the reaction. The results are shown in Table 2.

[0054] Example 2

[0055] This embodiment provides a method for deep treatment of high-salt organic tail liquid using thermally activated persulfate coupled adsorption technology, comprising:

[0056] (1) Use a measuring cylinder to measure 200 mL of high-salt tail liquid with a TOC value of 1100 mg / L into a three-necked flask. At this time, the solution is neutral and the pH is about 8;

[0057] (2) Place the three-necked flask in a constant temperature water bath and heat it to 80°C. Then turn on the stirring device and set the stirring rate to 200 r / min. Keep the temperature and stirring rate constant and add 1.0 g of sodium persulfate and 8.0 g of activated carbon to the waste liquid at the same time. The particle size of the activated carbon is 1-2 mm and its specific surface area is 613.80 m 3 / g, the average pore size is 2.12nm, the concentration of sodium persulfate in the solution is 5g / L, the dosage of activated carbon is 40g / L, and the degradation reaction is carried out for 100min;

[0058] (3) After the reaction in step (2) is completed, the three-necked flask is taken out, and the solution is filtered while hot, and the filtrate is the reaction water.

[0059] The reaction water obtained in step (3) was tested using the test method provided in Example 1. The results are shown in Table 2.

[0060] Example 3

[0061] This embodiment provides a method for deep treatment of high-salt organic tail liquid using thermally activated persulfate coupled adsorption technology, comprising:

[0062] (1) Use a measuring cylinder to measure 200 mL of high-salt tail liquid with a TOC value of 1100 mg / L into a three-necked flask. At this time, the solution is neutral and the pH is about 8;

[0063] (2) placing the three-necked flask in a constant temperature water bath, heating it to 90° C., then turning on the stirring device, setting the stirring rate to 500 r / min, keeping the temperature and stirring rate constant, and simultaneously adding 3.4 g of sodium persulfate and 2.0 g of activated carbon to the waste liquid, wherein the particle size of the activated carbon is 1-2 mm, the specific surface area is 613.80 m3 / g, and the average pore size is 2.12 nm, so that the concentration of sodium persulfate in the solution is 17 g / L, and the amount of activated carbon added reaches 10 g / L, and a degradation reaction is carried out for 20 min;

[0064] (3) After the reaction in step (2) is completed, the three-necked flask is taken out, and the solution is filtered while hot, and the filtrate is the reaction water.

[0065] The reaction water obtained in step (3) was tested using the test method provided in Example 1. The results are shown in Table 2.

[0066] Example 4

[0067] This embodiment provides a method for deep treatment of high-salt organic tail liquid using thermally activated persulfate coupled adsorption technology, comprising:

[0068] (1) Use a measuring cylinder to measure 200 mL of high-salt tail liquid with a TOC value of 1100 mg / L into a three-necked flask. At this time, the solution is neutral and the pH is about 8;

[0069] (2) placing the three-necked flask in a constant temperature water bath, heating it to 80° C., then turning on the stirring device, setting the stirring rate to 150 r / min, keeping the temperature and stirring rate constant, and simultaneously adding 3.0 g of sodium persulfate and 6.0 g of activated carbon to the waste liquid, wherein the particle size of the activated carbon is 1-2 mm, the specific surface area is 613.80 m3 / g, and the average pore size is 2.12 nm, so that the concentration of sodium persulfate in the solution is 15 g / L, and the amount of activated carbon added reaches 30 g / L, and a degradation reaction is carried out for 120 min;

[0070] (3) After the reaction in step (2) is completed, the three-necked flask is taken out, and the solution is filtered while hot, and the filtrate is the reaction water.

[0071] The reaction water obtained in step (3) was tested using the test method provided in Example 1. The results are shown in Table 2.

[0072] Example 5

[0073] This embodiment provides a method for treating high-salt organic tail liquid, comprising:

[0074] (1) Use a measuring cylinder to measure 200 mL of high-salt tail liquid with a TOC value of 1100 mg / L into a three-necked flask. At this time, the solution is neutral and the pH is about 8;

[0075] (2) placing the three-necked flask in a constant temperature water bath, raising the temperature to 80° C., then turning on the stirring device, setting the stirring rate to 150 r / min, keeping the temperature and stirring rate constant, and adding 3.0 g of sodium persulfate to the waste liquid to make the concentration of sodium persulfate in the solution 15 g / L, and carrying out a degradation reaction for 60 min;

[0076] (3) Then, 6.0 g of activated carbon was added to the solution after the reaction in step (2). The particle size of the activated carbon was 1-2 mm and the specific surface area was 613.80 m 3 / g, the average pore size is 2.12nm, the dosage of activated carbon in the solution reaches 30g / L, and the adsorption reaction is carried out for 120min;

[0077] (4) After the reaction in step (3) is completed, the three-necked flask is taken out, and the solution is filtered while hot, and the filtrate is the reaction water.

[0078] The reaction effluent was tested using the test method provided in Example 1, and the results are shown in Table 2.

[0079] Example 6

[0080] The difference between this embodiment and embodiment 4 is that the temperature of step (2) is adjusted to 60° C., and the rest is exactly the same as embodiment 4.

[0081] The reaction effluent was tested using the test method provided in Example 1, and the results are shown in Table 2.

[0082] Example 7

[0083] The difference between this embodiment and embodiment 4 is that before heating, the pH value of the high-salt organic tail liquid is adjusted to 11 using sodium hydroxide, and the rest is exactly the same as embodiment 4.

[0084] The reaction effluent was tested using the test method provided in Example 1, and the results are shown in Table 2.

[0085] Example 8

[0086] The difference between this embodiment and embodiment 4 is that before heating, the pH value of the high-salt organic tail liquid is adjusted to 3 using sulfuric acid, and the rest is exactly the same as embodiment 4.

[0087] The reaction effluent was tested using the test method provided in Example 1, and the results are shown in Table 2.

[0088] Example 9

[0089] The difference between this embodiment and embodiment 4 is that sodium persulfate is replaced by potassium persulfate, and the rest is exactly the same as embodiment 4.

[0090] The reaction effluent was tested using the test method provided in Example 1, and the results are shown in Table 2.

[0091] Example 10

[0092] The difference between this embodiment and embodiment 4 is that the specific surface area is 613.80m 3 / g granular activated carbon is replaced by a carbon with a specific surface area of ​​1314.29m 3 / g of activated carbon powder, and the rest is exactly the same as in Example 4.

[0093] The reaction effluent was tested using the test method provided in Example 1, and the results are shown in Table 2.

[0094] Embodiment 11

[0095] The difference between this embodiment and embodiment 4 is that the amount of activated carbon is adjusted so that the mass ratio of sodium persulfate to activated carbon is adjusted to 1:9, and the rest is exactly the same as embodiment 4.

[0096] The reaction effluent was tested using the test method provided in Example 1, and the results are shown in Table 2.

[0097] Example 12

[0098] The difference between this embodiment and embodiment 4 is that the amount of activated carbon is adjusted so that the mass ratio of sodium persulfate to activated carbon is adjusted to 1:0.1, and the rest is exactly the same as embodiment 4.

[0099] The reaction effluent was tested using the test method provided in Example 1, and the results are shown in Table 2.

[0100] Comparative Example 1

[0101] The difference between this comparative example and Example 4 is that sodium persulfate is not added in step (2), and the rest is exactly the same as Example 4.

[0102] The reaction effluent was tested using the test method provided in Example 1, and the results are shown in Table 2.

[0103] Comparative Example 2

[0104] The difference between this comparative example and Example 4 is that no activated carbon is added in step (2), and the rest is exactly the same as Example 4.

[0105] The reaction effluent was tested using the test method provided in Example 1, and the results are shown in Table 2.

[0106] Table 2

[0107]

[0108]

[0109] analyze:

[0110] It can be seen from the data of Examples 1-11 that the method for deep treatment of high-salt organic tail liquid by thermally activated persulfate coupled adsorption technology provided by the present invention utilizes the coupled synergistic effect of persulfate and carbon-based adsorbent under high temperature conditions to activate the adsorption sites on the carbon-based adsorbent while free radicals oxidize organic matter, thereby improving the degradation and removal effect of organic matter in the reaction system, facilitating the subsequent process of recycling salt resources in the high-salt tail liquid, and ultimately achieving the purpose of harmlessness and resource utilization of high-salt organic tail liquid.

[0111] From the data comparison of Examples 1, 3, 4 and 6, it can be seen that increasing the degradation reaction temperature and the amount of persulfate added have a certain effect on the degradation of organic pollutants. When the reaction temperature and the amount of persulfate added are controlled within a certain range, a higher TOC removal rate can be obtained. When the reaction temperature is too high or the amount of persulfate added is too large, the persulfate itself will decompose, the adsorbent active sites will be lost, the reagent loss will increase when the optimal degradation effect is achieved, and the degradation cost will be increased. When the reaction temperature is too low, the removal effect of organic pollutants will also be reduced.

[0112] It can be seen from the data of Example 4 and Example 5 that when persulfate and carbon-based adsorbent are added to the preheated high-salt organic tail liquid at the same time, a better organic pollutant removal effect can be achieved.

[0113] It can be seen from the data of Examples 4 and 7-8 that when the pH value of the high-salt organic tail liquid is too large, the sulfate radical will first activate the hydroxide ions present in the system, producing hydroxyl radicals with poor oxidizability, affecting the removal effect of organic pollutants; when the pH value of the high-salt organic tail liquid is neutral or acidic, the activated persulfate coupled activated carbon adsorption technology has a better removal effect on such organic pollutants, but if the pH value of the high-salt organic tail liquid is too low, it will cause a waste of reagents. It can be seen from the data of Examples 1 and 9 that the use of potassium persulfate as an oxidant can still effectively ensure that organic pollutants have a higher removal rate.

[0114] It can be seen from the data of Example 1 and Example 10 that the use of powdered activated carbon as an adsorbent can still effectively ensure a high removal rate of organic pollutants.

[0115] It can be seen from the data of Example 4 and Examples 11-12 that when the mass ratio of sodium persulfate to activated carbon is too small, it will make it difficult for the macromolecular organic pollutants in the solution to be completely degraded into small molecular substances that can be adsorbed and removed, affecting the removal effect; when the mass ratio of sodium persulfate to activated carbon is too large, it will cause excessive oxidation of activated carbon by free radicals, reducing the adsorption capacity of the adsorbent.

[0116] From the data comparison of Example 4 and Example 5 and Comparative Examples 1-2, it can be seen that under high temperature conditions, persulfate interacts with the carbon-based adsorbent, which improves the oxidation efficiency of persulfate on organic pollutants and the adsorption capacity of the adsorbent, significantly improves the removal rate of TOC in the tail liquid, and allows the treated high-salt solution to be directly processed for waste salt resource treatment. Among them, from the data of Example 4 and Example 5, it can be seen that if persulfate is added first for degradation for a period of time and then a carbon-based adsorbent is added for degradation, the removal effect of organic pollutants will be reduced. The data of Example 4 and Comparative Examples 1-2 show that if persulfate or carbon-based adsorbent is omitted, the removal effect of organic pollutants will be poor.

[0117] In summary, the method for deep treatment of organic matter in high-salt organic tail liquid provided by the present invention combines the persulfate oxidation process with the adsorption process, and utilizes the coupling effect between persulfate and carbon-based adsorbent under high temperature conditions to achieve a TOC removal rate of more than 99% in the treated tail liquid, and the TOC value of the reaction water can meet the subsequent bipolar membrane feed requirements. The method provided by the present invention can realize the secondary recycling of waste salt resources in high-salt tail liquid and the near-zero discharge of high-salt mine tail liquid.

[0118] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for deep treatment of high-salt organic tail liquid by thermally activated persulfate coupled adsorption technology, characterized in that: The method comprises: The high-salt organic tail liquid is preheated, and then the preheated high-salt organic tail liquid, persulfate and carbon-based adsorbent are mixed to carry out a degradation reaction.

2. The method according to claim 1, characterized in that The high-salt organic tailings include tailings produced during the extraction of ionic rare earth ores; Preferably, the pH value of the high-salt organic tail liquid is 5-9; Preferably, the concentration of salt substances in the high-salt organic tail liquid is 30-300 g / L.

3. The method according to claim 1 or 2, characterized in that: The persulfate includes at least one of sodium persulfate, sodium hydrogen persulfate, potassium persulfate, potassium hydrogen persulfate and ammonium persulfate.

4. The method according to any one of claims 1 to 3, characterized in that: The carbon-based adsorbent includes at least one of activated carbon, coconut shell carbon, fruit shell carbon, carbon fiber and carbon black; Preferably, the particle size of the carbon-based adsorbent is less than or equal to 5 mm; Preferably, the specific surface area of ​​the carbon-based adsorbent is 200-1500m 3 / g; Preferably, the average pore size of the carbon-based adsorbent is 2-20 nm.

5. The method according to any one of claims 1 to 4, characterized in that: The ratio of the mass of the persulfate to the volume of the high-salt organic tail liquid is 5-50 g / L; Preferably, the ratio of the mass of the carbon-based adsorbent to the volume of the high-salt organic tail liquid is 10-40 g / L.

6. The method according to any one of claims 1 to 5, characterized in that: The mass ratio of the persulfate to the carbon-based adsorbent is 1:(0.2-8).

7. The method according to any one of claims 1 to 6, characterized in that: The preheating temperature is 40-90°C.

8. The method according to any one of claims 1 to 7, characterized in that: The mixing specifically comprises: adding persulfate and carbon-based adsorbent simultaneously into the preheated high-salt organic tail liquid; Preferably, the mixing temperature is 40-90°C; Preferably, the mixing process is accompanied by stirring, and the stirring rate is 50-500r / min.

9. The method according to any one of claims 1 to 8, characterized in that: The temperature of the degradation reaction is 40-90°C; Preferably, the degradation reaction time is 20-240 min; Preferably, the degradation reaction is accompanied by stirring at a rate of 50-500 r / min.

10. The method according to any one of claims 1 to 9, characterized in that: The method specifically comprises: (1) preheating the high-salt organic tail liquid to 40-90° C., starting stirring so that the stirring rate is 50-500 r / min, and maintaining the temperature and stirring rate of the high-salt organic tail liquid constant; (2) adding persulfate and a carbon-based adsorbent to the preheated high-salt organic tail liquid at the same time, and performing a degradation reaction for 20-240 minutes, wherein the ratio of the mass of the persulfate to the volume of the high-salt organic tail liquid is 5-50 g / L; and the ratio of the mass of the carbon-based adsorbent to the volume of the high-salt organic tail liquid is 10-40 g / L.

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