Method for efficiently removing organic pollutants and heavy metals in marine dredged mud

Abstract

The invention relates to a method for efficiently removing organic pollutants and heavy metals in marine dredged mud, which comprises the following steps: S1, pretreating the marine dredged mud, mixing the marine dredged mud with water, and shearing in a shearing device to obtain a treating fluid with the solid content of not more than 30wt%; s2, adding the treating fluid into a mass barrier discharge plasma reactor; and S3, rare gas is introduced into the mass barrier discharge plasma reactor, the mass barrier discharge plasma reactor is electrified, 20-30 kV voltage is loaded between the inner tube and the outer tube, the power is 50-100 W, the treatment time is 10-30 min, and a treated material is obtained. After being treated by the method, organic pollutants and heavy metals in the marine dredged mud can be remarkably reduced, two types of harmful substances are synchronously removed, the treatment process is shortened, and the method has industrial application prospects.

Description

Technical Field

[0001] The invention relates to a marine dredged mud treatment technology, in particular to a method for efficiently removing organic pollutants and heavy metals in marine dredged mud. Background Art

[0002] Marine dredged mud refers to the mud, gravel and other materials generated during the process of dredging and deepening harbors, waterway construction, excavation of port terminals, and implementation of seabed and shore projects. It can be in the form of sewage, sludge, and sediment, and has become the main component of marine dumping waste. As marine sediments, it is a sink and source of organic pollutants (such as organochlorine pesticides, perfluorinated compounds, etc.) and heavy metals (such as Cr, Cd, As, Pb, Cu, Hg, etc.) in seawater. If not effectively controlled, the pollutants will be released for a long time.

[0003] The traditional treatment methods for marine dredged mud are land reclamation and ocean dumping. However, land reclamation is limited, and the dumping area is becoming increasingly saturated, making it difficult to meet the growing demand for treatment. The expansion of the dumping area or offshore dumping can easily cause problems such as ecological environmental deterioration and changes in topography, and it is urgent to find efficient and beneficial disposal methods. At present, people are trying new pollutant control solutions, emphasizing the enhanced control of new pollutants. In recent years, persistent organic pollutants, antibiotics and other widely concerned new pollutants that are difficult to degrade have been found in sediments in different sea areas, and there are environmental and ecological risks.

[0004] The difficulty in treating marine dredged mud is mainly due to its complex composition, which is usually a mixture of solids and liquids. The pollutants in solids and liquids are different, and the objects of treatment and the corresponding treatment methods of the two are quite different. At present, the treatment technology of marine dredged mud includes solidification / stabilization physical separation, heat treatment and other methods to solidify inorganic pollutants, chemical degradation of organic pollutants, or microbial remediation, chemical leaching, electrochemistry and other methods. The main purpose is to remove heavy metal ions in dredged mud. However, the above methods all have the disadvantages of a single technology that only removes a single pollutant, a large amount of reagents, limited effects, and easy to cause secondary pollution. For example, although heavy metal ions are removed, the organic matter content in marine dredged mud is still very high, and new steps need to be developed to remove organic matter. This results in a long entire treatment process, low treatment efficiency, and difficulty in large-scale practical application. Therefore, the development of new dredged mud treatment technology has important practical significance and research value. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem of low efficiency of existing marine dredged mud treatment and provide a method for efficiently removing organic pollutants and heavy metals in marine dredged mud. Since organic pollutants are usually removed by oxidation, and heavy metal ions often need to be reduced to convert into low-toxic or non-toxic substances, these two types of pollutants cannot usually be removed simultaneously.

[0006] To this end, the inventors used a dielectric barrier discharge plasma reactor, which uses high voltage to break down rare gases to produce ultraviolet light of specific wavelength and frequency. After reacting with the treatment liquid of marine dredged mud, the organic molecules in the liquid to be treated undergo an oxidation reaction under the action of free radicals and are degraded, and organic free radicals are generated to promote the redox reaction in the liquid to be treated. With the cooperation of organic free radicals, the process of heavy metal ions being reduced by active substances such as hydrated electrons will become faster.

[0007] Since marine dredged mud usually has a high solid content, the amount of ultraviolet light that can propagate in the marine dredged mud is limited. Therefore, the marine dredged mud needs to be pre-treated. The particle size of the material is kept within an appropriate range through high-speed shearing, and water is added to adjust the solid content to no more than 30wt%. This ensures that when the dielectric barrier discharge plasma reactor is working, ultraviolet light can effectively propagate inside the material, obtain a higher content of free radicals, and thus improve the pollutant removal efficiency.

[0008] The specific plan is as follows:

[0009] A method for efficiently removing organic pollutants and heavy metals from marine dredged mud comprises the following steps:

[0010] S1, pre-treating the marine dredged mud, mixing the marine dredged mud with water, and performing shearing treatment in a shearing device to obtain a treatment liquid with a solid content not exceeding 30wt%;

[0011] S2, adding the treatment liquid into a plasma barrier discharge reactor, wherein the plasma barrier discharge reactor comprises a transparent inner tube and an outer tube, wherein the inner tube and the outer tube are sleeved, wherein a positive electrode is fixed in the inner tube, a negative electrode is fixed between the inner tube and the outer tube, a tube wall of the inner tube is provided with an interlayer for accommodating gas, and an outer wall of the inner tube is connected to a vent valve and communicated with the interlayer; the treatment liquid is added into the inner tube and the outer tube;

[0012] S3. Introduce a rare gas into the inner tube through the vent valve, power the mass barrier discharge plasma reactor, load a voltage of 20-30 kV between the inner tube and the outer tube, the power is 50-100 W, the processing time is 10-30 min, and the processed material is obtained.

[0013] Furthermore, the shearing device in S1 is a high-speed shearing machine with a rotation speed of 1000-10000 rpm, preferably 4000-8000 rpm.

[0014] Furthermore, the time for the shearing treatment in the shearing device in S1 is 30-300 minutes, preferably 100-250 minutes.

[0015] Furthermore, the solid content of the treatment liquid in S1 is 5-25wt%, preferably 8-20wt%.

[0016] Furthermore, the light transmittance of the treatment liquid in S1 is 50-90%, preferably 60-80%.

[0017] Furthermore, the inner tube and the outer tube of the plasma barrier discharge reactor in S2 are made of quartz glass, and the inner tube and the outer tube are concentric cylinders; preferably, the inner diameter of the inner tube is 20-100 cm, the inner diameter of the outer tube is 40-200 cm, and the height of the inner tube and the outer tube is 20-200 cm.

[0018] Furthermore, the rare gas in S3 is xenon or argon; preferably, the pressure of the rare gas is 10-500 Pa, preferably 50-300 Pa.

[0019] Furthermore, the voltage in S3 is 20-26 kV, the power is 70-90 W, and the processing time is 10-20 min.

[0020] Furthermore, the treatment liquid contains organic matter and heavy metals, wherein the organic matter includes hexachlorocyclohexane with a concentration of 1-100 mg / L, and the heavy metals include pentavalent arsenic with a concentration of 1-100 mg / L and / or hexavalent chromium with a concentration of 1-100 mg / L.

[0021] Furthermore, the oxidation removal rate of hexachlorocyclohexane is greater than or equal to 90%, the reduction removal rate of pentavalent arsenic is greater than or equal to 90%, and / or the reduction removal rate of hexavalent chromium is greater than or equal to 99%.

[0022] Beneficial effects: First, the present application performs pre-treatment on the marine dredged mud, which ensures the efficiency of subsequent treatment. If the marine dredged mud is directly used for plasma discharge, due to the low transmittance of light in the marine dredged mud, the outer layer of the marine dredged mud can be degraded, while the light cannot reach or reaches less areas inside the marine dredged mud, and the degradation rate of organic pollutants and heavy metals is less than 30%.

[0023] Secondly, the present application uses a dielectric barrier discharge plasma reactor to treat marine dredged mud. The discharge process can be carried out under normal temperature and pressure conditions, which greatly shortens the processing time and is easy to realize automated operation. More importantly, the working principle of this technology is to accelerate only electrons without accelerating ions in the electric field, thereby ensuring excellent energy efficiency. It is also worth mentioning that the entire treatment process does not require the addition of any additional chemicals, thereby avoiding the generation of secondary pollution.

[0024] Furthermore, the dielectric barrier discharge plasma reactor designed in this application adopts a transparent inner tube and outer tube sleeve connection method, and the liquid to be treated can be added to both the inner tube and the outer tube to improve the treatment efficiency. The ultraviolet light with a wavelength of 172nm generated by the device under high voltage has the characteristics of non-radiative self-absorption, and the photoelectric conversion efficiency is relatively high, generally reaching 20% ​​to 40%, which greatly reduces energy consumption.

[0025] Furthermore, the rare gas in the inner tube of the dielectric barrier discharge plasma reactor, preferably xenon, has a relatively long service life and can easily radiate ultraviolet light of a desired wavelength by exciting excimers in different states.

[0026] Finally, the present invention loads a voltage of 20-30 kV between the inner tube and the outer tube, and the power is 50-100 W, so that a relatively high intensity of 172 nm ultraviolet light can be obtained; under the irradiation of 172 nm ultraviolet light, a large amount of active substances such as hydroxyl radicals (·OH), hydrated electrons (e aq - ), oxygen free radicals (·O), hydrogen free radicals (·H), ozone (O3), hydrogen peroxide (H2O2), etc., thereby improving the efficiency of treating organic matter and heavy metal ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings will be briefly introduced below. Obviously, the accompanying drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0028] Figure 1 It is a schematic diagram of the structure of a dielectric barrier discharge plasma reactor provided by an embodiment of the present invention.

[0029] In the figure, 1 is a dielectric barrier discharge plasma reactor, 2 is a vent valve, 3 is an inner tube, 4 is an outer tube, 5 is a positive electrode, 6 is a negative electrode, and 7 is an interlayer. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. In the examples, those without specifying specific techniques or conditions are carried out according to the techniques or conditions described in the literature in this area or according to the product specification. Those without specifying the manufacturer of reagents or instruments used are all conventional products that can be obtained commercially. In the following examples, if not clearly stated, "%" refers to weight percentage.

[0031] The main detection methods used below include:

[0032] Hexachlorocyclohexane oxidation removal rate: The hexachlorocyclohexane content in the material before and after treatment was detected using the complexation-enrichment-elution-complexation-luminescence detection method. The specific method is as follows:

[0033] Complexation: The sample is mixed with a buffer solution of sodium carbonate-sodium bicarbonate solution, and then mixed with a complexing agent diethylenetriamine pentacarboxylate solution to form a complex; Enrichment: The water sample that forms the complex enters the enrichment-elution column, and under the catalytic action of the catalyst Ni and SiO2 mixture, the diethylenetriamine penta-methylenephosphonate composite material efficiently and selectively enriches the complex;

[0034] Elution: After the enrichment is completed, the water sample is discharged, and the eluent peroxy oxalate flows through the enrichment-elution column, and the eluted enriched complex enters the eluent;

[0035] Complexation: The eluent continues to flow in the pipeline, and is mixed with the buffer solution acetic acid-ammonium acetate solution and the complexing agent polyhydroxyacrylic acid solution in sequence, and forms a ternary complex under the pH conditions provided by the buffer solution;

[0036] Luminescence detection: The solution that forms the ternary complex is mixed with the luminescent agent lucigenin solution and enters the detection chamber together. The photomultiplier tube collects and amplifies the light signal emitted by the solution flowing through, and converts it into an electrical signal and sends it to the data processing device. The data processing device calculates the blank signal and sample signal obtained to obtain the concentration of hexachlorocyclohexane in the water.

[0037] The removal rate is calculated as the percentage of the initial concentration to the concentration after treatment.

[0038] Pentavalent arsenic reduction removal rate: The national standard method (GB / T17593.3-2006) was used to test the pentavalent arsenic content in the materials before and after treatment. The removal rate was calculated as the percentage of the initial concentration to the concentration after treatment.

[0039] Hexavalent chromium oxidation removal rate: The hexavalent chromium content in the material before and after treatment was tested using the national standard method (GB / T17593.3-2006). The removal rate was calculated as the percentage of the initial concentration to the concentration after treatment.

[0040] The main reagents used include:

[0041] Marine dredged mud samples, with a solid content of 42.5 wt%, were collected from the coastal area of ​​a bay in Fujian Province.

[0042] Since the composition of marine dredged mud samples from different regions varies greatly, in order to facilitate comparison, the following examples obtain simulated pollution source treatment objects with specific pollutant contents by adding pollutants to marine dredged mud samples.

[0043] Example 1

[0044] A method for efficiently removing organic pollutants and heavy metals from marine dredged mud comprises the following steps:

[0045] S1. Pre-treating the marine dredged mud: mixing the marine dredged mud with water, adding hexachlorocyclohexane and arsenic pentoxide, and shearing the mixture in a high-speed shearing machine at a speed of 4000 rpm for 100 min to obtain a treatment liquid with a solid content of 20 wt %. The light transmittance of the treatment liquid is 82%, wherein the concentration of hexachlorocyclohexane is 5 mg / L, and the content of pentavalent arsenic is 2 mg / L.

[0046] S2, adding the treatment solution into a mass barrier discharge plasma reactor, such as Figure 1 shown.

[0047] The plasma barrier discharge reactor 1 includes a transparent inner tube 3 and an outer tube 4, wherein the inner tube 3 and the outer tube 4 are sleeved, wherein a positive electrode 5 is fixed in the inner tube, a negative electrode 6 is fixed between the inner tube 3 and the outer tube 4, a tube wall of the inner tube 3 is provided with an interlayer 7 for accommodating gas, and an outer wall of the inner tube 3 is connected to a vent valve 2 and communicated with the interlayer.

[0048] The inner tube 3 and outer tube 4 of the reactor are made of quartz glass, which has the characteristics of high insulation and high temperature resistance, and can have high safety. The specific dimensions are: the inner diameter of the inner tube is 20cm, the inner diameter of the outer tube is 40cm, and the height of the inner tube and the outer tube is 50cm.

[0049] It should be noted that the structure of the dielectric barrier discharge plasma reactor in other embodiments is not limited to the above structure. For example, some existing excimer lamps driven by dielectric barrier discharge technology are highly flexible, and their device design is not limited by structure and can present a variety of shapes, as long as they can produce abundant active substances, which are effective for removing organic pollutants and reducing heavy metal ions, thereby realizing the treatment method of the present application.

[0050] A treatment liquid is added to the inner tube 3 of the reactor, and the positive electrode of the AC high-voltage power supply is connected to the reactor through the platinum metal positive electrode 5. A treatment liquid is also added to the outer tube 4 of the reactor, and the negative electrode of the AC high-voltage power supply is connected to the reactor through the platinum metal negative electrode 6. The treatment liquid completely immerses the positive and negative electrodes.

[0051] S3. Introduce rare gas xenon into the inner tube through the vent valve, the gas pressure is 100 Pa, the mass barrier discharge plasma reactor is powered on, a voltage of 20 kV is loaded between the inner tube and the outer tube, the power is 70 W, the processing time is 10 min, and the treated material is obtained.

[0052] The pollutants in the treated material were tested and it was calculated that the oxidation removal rate of hexachlorocyclohexane was 90% and the reduction removal rate of arsenic was 95%.

[0053] Example 2

[0054] A method for efficiently removing organic pollutants and heavy metals from marine dredged mud comprises the following steps:

[0055] S1. Pre-treating the marine dredged mud: mixing the marine dredged mud with water, adding hexachlorocyclohexane and arsenic pentoxide, and shearing the mixture in a high-speed shearing machine at a speed of 4000 rpm for 100 min to obtain a treatment liquid with a solid content of 20 wt %. The light transmittance of the treatment liquid is 82%, wherein the concentration of hexachlorocyclohexane is 5 mg / L, and the content of pentavalent arsenic is 2 mg / L.

[0056] S2. Add the treatment liquid into the plasma barrier discharge reactor in Example 1, add the treatment liquid into the inner tube 3 of the reactor, and connect the positive electrode of the AC high-voltage power supply to the reactor through the platinum metal positive electrode 5, add the treatment liquid into the outer tube 4 of the reactor, and connect the negative electrode of the AC high-voltage power supply to the reactor through the platinum metal negative electrode 6, and the treatment liquid completely immerses the positive and negative electrodes.

[0057] S3. Introduce rare gas xenon into the inner tube through the vent valve, the gas pressure is 100 Pa, the mass barrier discharge plasma reactor is powered on, a voltage of 24 kV is loaded between the inner tube and the outer tube, the power is 75 W, the processing time is 10 min, and the treated material is obtained.

[0058] The pollutants in the treated material were tested and the removal efficiency of hexachlorocyclohexane by oxidation was calculated to be 92% and the removal efficiency of arsenic by reduction was calculated to be 96%.

[0059] Example 3

[0060] A method for efficiently removing organic pollutants and heavy metals from marine dredged mud comprises the following steps:

[0061] S1. Pre-treating the marine dredged mud: mixing the marine dredged mud with water, adding hexachlorocyclohexane and arsenic pentoxide, and shearing the mixture in a high-speed shearing machine at a speed of 5000 rpm for 80 min to obtain a treatment liquid with a solid content of 20 wt %. The light transmittance of the treatment liquid was 82%, wherein the concentration of hexachlorocyclohexane was 5 mg / L, and the content of pentavalent arsenic was 2 mg / L.

[0062] S2. Add the treatment liquid into the plasma barrier discharge reactor in Example 1, add the treatment liquid into the inner tube 3 of the reactor, and connect the positive electrode of the AC high-voltage power supply to the reactor through the platinum metal positive electrode 5, add the treatment liquid into the outer tube 4 of the reactor, and connect the negative electrode of the AC high-voltage power supply to the reactor through the platinum metal negative electrode 6, and the treatment liquid completely immerses the positive and negative electrodes.

[0063] S3. Introduce rare gas argon into the inner tube through the vent valve, the gas pressure is 100 Pa, the mass barrier discharge plasma reactor is powered on, a voltage of 24 kV is loaded between the inner tube and the outer tube, the power is 75 W, the processing time is 10 min, and the treated material is obtained.

[0064] The pollutants in the treated material were tested and it was calculated that the oxidation removal rate of hexachlorocyclohexane was 86% and the reduction removal rate of arsenic was 88%.

[0065] Example 4

[0066] A method for efficiently removing heavy metals from marine dredged mud comprises the following steps:

[0067] S1. Pre-treat the marine dredged mud by mixing the marine dredged mud with water, adding sodium chromate, and shearing the mixture in a high-speed shearing machine at a rotation speed of 4000 rpm, a light transmittance of the treated liquid of 75%, and a treatment time of 100 min to obtain a treated liquid with a solid content of 20 wt%, wherein the hexavalent chromium content is 5 mg / L.

[0068] S2. Add the treatment liquid into the plasma barrier discharge reactor in Example 1, add the treatment liquid into the inner tube 3 of the reactor, and connect the positive electrode of the AC high-voltage power supply to the reactor through the platinum metal positive electrode 5, add the treatment liquid into the outer tube 4 of the reactor, and connect the negative electrode of the AC high-voltage power supply to the reactor through the platinum metal negative electrode 6, and the treatment liquid completely immerses the positive and negative electrodes.

[0069] S3. Introduce rare gas xenon into the inner tube through the vent valve, the gas pressure is 100 Pa, the mass barrier discharge plasma reactor is powered on, a voltage of 20 kV is loaded between the inner tube and the outer tube, the power is 70 W, the processing time is 10 min, and the treated material is obtained.

[0070] The pollutants in the treated material were tested and the reduction removal rate of hexavalent chromium was calculated to be 100%.

[0071] Example 5

[0072] A method for efficiently removing heavy metals from marine dredged mud comprises the following steps:

[0073] S1. Pre-treat the marine dredged mud by mixing the marine dredged mud with water, adding sodium chromate, and shearing the mixture in a high-speed shearing machine at a speed of 4000 rpm for 100 min to obtain a treatment liquid with a solid content of 20 wt %, a light transmittance of 75%, and a hexavalent chromium content of 5 mg / L.

[0074] S2. Add the treatment liquid into the plasma barrier discharge reactor in Example 1, add the treatment liquid into the inner tube 3 of the reactor, and connect the positive electrode of the AC high-voltage power supply to the reactor through the platinum metal positive electrode 5, add the treatment liquid into the outer tube 4 of the reactor, and connect the negative electrode of the AC high-voltage power supply to the reactor through the platinum metal negative electrode 6, and the treatment liquid completely immerses the positive and negative electrodes.

[0075] S3. Introduce rare gas xenon into the inner tube through the vent valve, the gas pressure is 50 Pa, the mass barrier discharge plasma reactor is powered on, a voltage of 22 kV is loaded between the inner tube and the outer tube, the power is 71 W, the processing time is 10 min, and the treated material is obtained.

[0076] The pollutants in the treated material were tested and the reduction removal rate of hexavalent chromium was calculated to be 100%.

[0077] Comparative Example 1

[0078] Refer to Example 2, except that S1 is not performed, as follows:

[0079] S1. Add marine dredged mud (with a light transmittance of 33%) into the plasma barrier discharge reactor in Example 1, add a treatment liquid into the inner tube 3 of the reactor, and connect the positive electrode of the AC high-voltage power supply to the reactor through the platinum metal positive electrode 5, add a treatment liquid into the outer tube 4 of the reactor, and connect the negative electrode of the AC high-voltage power supply to the reactor through the platinum metal negative electrode 6, and the treatment liquid completely immerses the positive and negative electrodes.

[0080] S3. Introduce rare gas xenon into the inner tube through the vent valve, the gas pressure is 100 Pa, the mass barrier discharge plasma reactor is powered on, a voltage of 24 kV is loaded between the inner tube and the outer tube, the power is 75 W, the processing time is 10 min, and the treated material is obtained.

[0081] The pollutants in the treated material were tested and the removal efficiency of hexachlorocyclohexane by oxidation was calculated to be 73% and the removal efficiency of arsenic by reduction was 62%.

[0082] It can be seen that if no pretreatment is carried out, due to the low light transmittance of marine dredged mud, the ultraviolet light generated during the mass barrier discharge is difficult to reach the deep part of the marine dredged mud evenly, and thus it is impossible to efficiently remove organic pollutants and heavy metals.

[0083] Comparative Example 2

[0084] Referring to Example 2, the difference is that the loading voltage in S3 is different, as follows:

[0085] S1. Pre-treating the marine dredged mud: mixing the marine dredged mud with water, adding hexachlorocyclohexane and arsenic pentoxide, and shearing the mixture in a high-speed shearing machine at a speed of 4000 rpm for 100 min to obtain a treatment liquid with a solid content of 20 wt %. The light transmittance of the treatment liquid is 82%, wherein the concentration of hexachlorocyclohexane is 5 mg / L, and the content of pentavalent arsenic is 2 mg / L.

[0086] S2. Add the treatment liquid into the plasma barrier discharge reactor in Example 1, add the treatment liquid into the inner tube 3 of the reactor, and connect the positive electrode of the AC high-voltage power supply to the reactor through the platinum metal positive electrode 5, add the treatment liquid into the outer tube 4 of the reactor, and connect the negative electrode of the AC high-voltage power supply to the reactor through the platinum metal negative electrode 6, and the treatment liquid completely immerses the positive and negative electrodes.

[0087] S3. Introduce rare gas xenon into the inner tube through the vent valve, the gas pressure is 100 Pa, the mass barrier discharge plasma reactor is powered on, a voltage of 16 kV is loaded between the inner tube and the outer tube, the power is 50 W, the processing time is 10 min, and the treated material is obtained.

[0088] The pollutants in the treated material were tested and the removal efficiency of hexachlorocyclohexane by oxidation was calculated to be 60% and the removal efficiency of arsenic by reduction was 51%.

[0089] It can be seen that when the plasma barrier discharge reactor is powered on, if the voltage is too low, it cannot produce suitable ultraviolet rays to degrade pollutants, and the degradation effect is poor.

[0090] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0091] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0092] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for efficiently removing organic pollutants and heavy metals from marine dredged mud, characterized in that: The following steps are involved: S1, pre-treating the marine dredged mud, mixing the marine dredged mud with water, and performing shearing treatment in a shearing device to obtain a treatment liquid with a solid content not exceeding 30wt%; S2, adding the treatment liquid into a plasma barrier discharge reactor, wherein the plasma barrier discharge reactor comprises a transparent inner tube and an outer tube, wherein the inner tube and the outer tube are sleeved, wherein a positive electrode is fixed in the inner tube, a negative electrode is fixed between the inner tube and the outer tube, a tube wall of the inner tube is provided with an interlayer for accommodating gas, and an outer wall of the inner tube is connected to a vent valve and communicated with the interlayer; the treatment liquid is added into the inner tube and the outer tube; S3. Introduce a rare gas into the inner tube through the vent valve, power the mass barrier discharge plasma reactor, load a voltage of 20-30 kV between the inner tube and the outer tube, the power is 50-100 W, the processing time is 10-30 min, and the processed material is obtained.

2. The method for efficiently removing organic pollutants and heavy metals from marine dredged mud according to claim 1, characterized in that: The shearing device in S1 is a high-speed shearing machine with a rotation speed of 1000-10000 rpm, preferably 4000-8000 rpm.

3. The method for efficiently removing organic pollutants and heavy metals from marine dredged mud according to claim 2, characterized in that: The time for the shearing treatment in the shearing device in S1 is 30-300 minutes, preferably 100-250 minutes.

4. The method for efficiently removing organic pollutants and heavy metals from marine dredged mud according to claim 3, characterized in that: The solid content of the treatment liquid in S1 is 5-25wt%, preferably 8-20wt%.

5. The method for efficiently removing organic pollutants and heavy metals from marine dredged mud according to claim 4, characterized in that: The light transmittance of the treatment liquid in S1 is 50-90%, preferably 60-80%.

6. The method for efficiently removing organic pollutants and heavy metals from marine dredged mud according to any one of claims 1 to 5, characterized in that: The inner tube and the outer tube of the mass barrier discharge plasma reactor in S2 are made of quartz glass, and the inner tube and the outer tube are concentric cylinders; preferably, the inner diameter of the inner tube is 20-100 cm, the inner diameter of the outer tube is 40-200 cm, and the height of the inner tube and the outer tube is 20-200 cm.

7. The method for efficiently removing organic pollutants and heavy metals from marine dredged mud according to claim 6, characterized in that: The rare gas in S3 is xenon or argon; preferably, the pressure of the rare gas is 10-500 Pa, preferably 50-300 Pa.

8. The method for efficiently removing organic pollutants and heavy metals from marine dredged mud according to claim 7, characterized in that: The voltage in S3 is 20-26 kV, the power is 70-90 W, and the processing time is 10-20 min.

9. The method for efficiently removing organic pollutants and heavy metals from marine dredged mud according to any one of claims 1 to 5, characterized in that: The treatment liquid contains organic matter and heavy metals, wherein the organic matter includes hexachlorocyclohexane with a concentration of 1-100 mg / L, and the heavy metals include pentavalent arsenic with a concentration of 1-100 mg / L and / or hexavalent chromium with a concentration of 1-100 mg / L.

10. The method for efficiently removing organic pollutants and heavy metals from marine dredged mud according to claim 9, characterized in that: The oxidation removal rate of hexachlorocyclohexane is greater than or equal to 90%, the reduction removal rate of pentavalent arsenic is greater than or equal to 90%, and / or the reduction removal rate of hexavalent chromium is greater than or equal to 99%.

Images