River and lake dredged sediment phosphorus form transformation method based on MoS2 / Fe < 2 + > enhanced electro-Fenton reaction device

Abstract

The invention discloses a river and lake dredged sediment phosphorus form transformation method based on a MoS2 / Fe < 2 + > enhanced electro-Fenton reaction device, and relates to the field of river and lake dredged sediment treatment.The method comprises the steps that a preset number of parts of compounds are selected to be mixed and stirred with original dredged sediment, and dredged sediment to be treated is obtained; selecting preset parts of compounds to prepare an overlying solution, and respectively immersing the cathode plate and the anode plate into the overlying solution and the dredged sediment to be treated; connecting the cathode plate with the anode plate, connecting a power supply to perform enhanced electro-Fenton phosphorus form conversion operation on the dredged sediment to be treated, and measuring the form content of phosphorus in the dredged sediment to be treated after conversion; analyzing the decomposition degree of phosphorus in the dredged sediment after morphological transformation, and verifying the balance condition of phosphorus morphological transformation according to the decomposition degree to obtain morphological transformation efficiency. According to the method, the organic phosphorus form is converted to the inorganic phosphorus form, and the phosphorus form conversion efficiency of the dredged sediment is improved.

Description

Technical Field

[0001] The present invention relates to the field of river and lake dredging sludge treatment, and in particular to a method for treating dredged sludge based on MoS2 / Fe 2+ A method for transforming phosphorus forms in dredged river and lake sediments using an enhanced electro-Fenton reaction device. Background Art

[0002] Sediment is an important component of the ecological environment of rivers and lakes, an important link in their material cycle and energy flow, and the main accumulation place of various land-based pollutants such as nitrogen and phosphorus nutrients, heavy metals, and organic pollutants. When control measures are taken for exogenous pollution, the sediment and water interface environment changes, and pollutants will be released again through the sediment and enter the upper water body, causing secondary pollution. Contaminated sediment will become a potential source of water pollution. Therefore, environmental dredging has become the main measure for the treatment of polluted rivers and lakes, and it is also an important method to reduce endogenous pollution in river environmental governance projects. Globally, a large number of dredging activities will produce a large amount of dredged sediment every year. For example, the annual dredging volume in Europe is about 3×10 8 m 3 In the past five years, the average dredging volume generated by China's environmental protection dredging projects is about 7.4×10 6 m 3 Although environmental dredging has a huge effect, it will produce a large amount of dredged sludge, which brings challenges to environmental management. The treatment and disposal of dredged sludge has always been a global problem in the field of environmental governance.

[0003] On the one hand, the dredged sludge has the characteristics of high water content, low permeability, complex pollution components, large area and large volume, and cannot be quickly dehydrated and reduced. Direct landfill not only causes a large amount of land to be unable to restore its original function in time, but also creates the risk of re-pollution with surface runoff. At the same time, a large amount of dredged sludge requires expensive transportation, storage and treatment costs, and often contains a large amount of pollutants. Developing effective technologies to improve dehydration efficiency and remove potential toxic elements is crucial for the environmental safety management of dredged sludge. On the other hand, dredged sludge is rich in organic matter, nitrogen, phosphorus, potassium and other natural resources, and has a high utilization value. Treating dredged sludge as waste is contrary to the goal of sustainable development. Therefore, treating dredged sludge as a source of sustainable resources rather than toxic waste, and harmlessly treating and recycling it is the direction of future research efforts.

[0004] Phosphorus (P) is an essential element for life and is vital to organisms. Due to its sedimentary cycle, phosphorus is a limiting factor in the biological productivity of many ecosystems on Earth. Unfortunately, a large amount of phosphorus is discharged into the environment, resulting in a waste of precious phosphorus resources. The loss of P in the soil and the accumulation of excessive P in water bodies are causing serious environmental problems worldwide. Therefore, it is of great significance to study the recovery of P resources in waste to achieve P recycling.

[0005] Common treatment routes for dredged sediment (such as Figure 2 The first step in the treatment of dredged sludge is to dehydrate it, generally reducing the water content to below 75% to achieve volume reduction, and then carry out a certain degree of drying treatment (including chemical treatment, heat treatment, biological treatment, etc.) depending on the choice of subsequent treatment and disposal process: for sludge with serious pollution and excessive heavy metals, heavy metal solidification and stabilization treatment is usually carried out, or corresponding disposal is carried out after incineration; for sludge with less pollution, resource treatment or comprehensive utilization is carried out depending on its pollution characteristics and its mud properties. However, since the proportion of inorganic matter in dredged sludge is relatively high and the proportion of organic matter is relatively low, in order to focus on the purpose of harmlessness and resource utilization of inorganic matter, the common treatment route is obviously no longer applicable.

[0006] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0007] In view of the problems in the related art, the present invention proposes a method based on MoS2 / Fe 2+ A method for transforming phosphorus forms in dredged mud from rivers and lakes using an enhanced electro-Fenton reaction device is provided to overcome the above-mentioned technical problems existing in the existing related technologies.

[0008] To this end, the specific technical solution adopted by the present invention is as follows: A MoS2 / Fe 2+ A method for transforming phosphorus forms in river and lake dredged sludge using an enhanced electro-Fenton reaction device, the method comprising: S1. Adjusting the pH of the original dredged sludge, and after the adjustment is completed, selecting a preset number of compounds and mixing them with the original dredged sludge to obtain the dredged sludge to be treated; S2, selecting a preset number of compounds to prepare an overlying solution, and immersing the cathode plate and the anode plate into the overlying solution and the dredged sludge to be treated respectively; S3, connecting the cathode plate and the anode plate, connecting to the power supply to perform enhanced electro-Fenton phosphorus form conversion operation on the dredged sludge to be treated, and measuring the phosphorus form content in the dredged sludge to be treated after the conversion; S4. Combine the phosphorus form content with infrared spectroscopy technology to analyze the decomposition degree of phosphorus in the dredged mud after the form conversion, and verify the balance of phosphorus form conversion based on the decomposition degree to obtain the form conversion efficiency.

[0009] Preferably, the pH of the original dredged sludge is adjusted, and after the adjustment is completed, a preset number of compounds are selected and mixed with the original dredged sludge to obtain the dredged sludge to be treated, which includes: S11. Selecting alkaline and acidic substances according to the initial pH value of the original dredged sludge, and adjusting the pH of the original dredged sludge to a preset range; S12, compounding each type of compound according to preset requirements to obtain compound materials of corresponding mass fractions, marking the compound materials and sending them into a stirring device for stirring to obtain a mixed compound; S13, mixing the mixed compound with the original dredged sludge and sending them into a stirring device for stirring to obtain a mixture, and collecting the motion state of the stirring blades in the stirring device in real time during the stirring process; S14. Analyze the mixing condition of the mixture in the stirring device according to the motion state, obtain the uniformity test result of the mixed stirring, and adjust the driving state of the stirring device based on the uniformity test result, and obtain the dredged sludge to be processed after the uniformity meets the mixing requirements.

[0010] Preferably, each type of compound includes soluble sodium salt, soluble iron salt and molybdenum disulfide; The soluble sodium salt includes at least one of sodium sulfate, sodium nitrate, sodium chloride and sodium perchlorate; the soluble iron salt includes at least one of ferrous sulfate, ferric sulfate, ferric chloride, ferrous chloride, ferric nitrate and ferrous nitrate.

[0011] Preferably, the mixing state of the mixture in the stirring device is analyzed according to the motion state, a uniformity detection result of the mixing and stirring is obtained, and the driving state of the stirring device is adjusted based on the uniformity detection result, and the dredged sludge to be processed is obtained after the uniformity reaches the mixing requirement, including: S141, analyzing a change in stirring speed of the stirring device during the stirring process based on the motion state, and obtaining a change in temperature of the mixture in the stirring device according to the change in speed; S142, calculating a real-time stirring efficiency coefficient of the stirring device based on the speed change and the temperature change, and comparing the real-time stirring efficiency coefficient with a standard efficiency coefficient range; S143, analyzing the uniformity of the mixture in the stirring device according to the comparison result, and matching the uniformity detection result with the adjustment rule to adjust the driving state of the stirring device; S144. Continue stirring the mixture according to the adjustment result of the stirring equipment, and obtain the dredged sludge to be processed after the uniformity reaches the mixing requirement.

[0012] Preferably, the expression of the stirring efficiency coefficient is: ; In the formula, γ i represents the stirring efficiency coefficient at the i-th moment, Δθ i represents the change in stirring speed at the i-th moment, Δθ0 represents the change in standard stirring speed, and Δζ i represents the temperature change at the i-th moment, Δζ0 represents the standard temperature change, and α represents Δθ iThe preset weight coefficient corresponding to the ratio of Δθ0, β represents Δζ i The preset weight coefficient corresponding to the ratio of Δζ0.

[0013] Preferably, when analyzing the uniformity of the mixture in the stirring device according to the comparison result, and matching the uniformity detection result with the adjustment rule to adjust the driving state of the stirring device, when the real-time stirring efficiency coefficient is within the standard efficiency coefficient range, it means that the mixing result of the mixture in the stirring device meets the requirements; When the real-time stirring efficiency coefficient is less than the standard efficiency coefficient range, it means that the current stirring equipment is inefficient and the stirring speed of the stirring blade needs to be increased; When the real-time stirring efficiency coefficient is greater than the standard efficiency coefficient range, it means that the current stirring equipment is highly efficient and the stirring rate of the stirring blades needs to be reduced.

[0014] Preferably, connecting the cathode plate and the anode plate, connecting to a power source to perform an enhanced electro-Fenton phosphorus form conversion operation on the dredged sludge to be treated, and determining the phosphorus form content in the dredged sludge to be treated after the conversion includes: S31, use titanium wire to connect the power supply to the cathode plate and the anode plate respectively, adjust the voltage and current according to the reaction amount of the dredged mud to be treated, and then turn on the power supply to run the MoS2 / Fe 2+ Enhanced electro-Fenton reaction device; S32, using MoS2 / Fe 2+ The enhanced electro-Fenton reaction device starts the anode reaction and the cathode reaction to release hydrogen ions and hydroxide ions, and generates hydroxyl radicals based on ferrous ions and hydrogen peroxide during the cathode region reaction process; S33. Based on the hydroxyl radical oxidation of phosphorus forms, an enhanced electro-Fenton phosphorus form conversion operation is performed in the dredged sediment to be treated. After the conversion is completed, samples are weighed and combined with the phosphorus form graded extraction method to determine the phosphorus form content in the dredged sediment to be treated after the conversion.

[0015] Preferably, the distance between the cathode plate and the anode plate is 10 cm to 15 cm, and the operating range of the current is 20 mA to 150 mA.

[0016] Preferably, the phosphorus form content is combined with infrared spectroscopy technology to analyze the decomposition degree of phosphorus in the dredged sediment after the form conversion, and the balance of phosphorus form conversion is verified according to the decomposition degree to obtain the form conversion efficiency, including: S41, weighing a preset mass of a test product from the converted dredged sediment, and drying, crushing and sieving the test product to obtain a sediment sample; S42, combining the sediment sample with the potassium chloride mixture to prepare a potassium chloride tablet, and measuring the potassium chloride tablet using an infrared spectrometer to obtain a sediment spectrum; S43, analyzing the absorption peak corresponding to the sediment spectrum, judging the degree of phosphorus decomposition according to the intensity change of the absorption peak, and verifying the phosphorus form conversion efficiency by combining the decomposition degree with the phosphorus form content; S44. Evaluation of MoS2 / Fe based on phosphorus form conversion efficiency 2+ Enhance the operating efficiency of the electro-Fenton reaction device and the stirring process, and optimize the phosphorus form conversion process based on the operating efficiency.

[0017] Preferably, analyzing the absorption peak corresponding to the sediment spectrum, judging the degree of phosphorus decomposition according to the intensity change of the absorption peak, and combining the degree of decomposition with the phosphorus form content to verify the phosphorus form conversion efficiency includes: S431, obtaining a corresponding sediment spectrum curve based on the sediment spectrum diagram, and performing pre-processing on the sediment spectrum curve using a differential method, and determining a differential amount of the sediment spectrum curve after the pre-processing is completed; S432, generating a sediment spectrum differential curve using the differential component, and performing denoising and envelope processing on the sediment spectrum curve using the sediment spectrum differential curve to obtain an envelope-removed spectrum curve; S433, using a differential method to traverse the absorption peak value of the de-envelope spectrum curve, determine the intensity change of the absorption peak value, and analyze the decomposition degree of phosphorus according to the intensity change; S434. The decomposition degree and phosphorus form content are combined to evaluate the balance of phosphorus form conversion, and based on the balance, the ratio of phosphorus form converted from the initial form to the target form is analyzed to obtain the phosphorus form conversion efficiency.

[0018] The beneficial effects of the present invention are: The present invention improves the conversion efficiency of phosphorus forms in dredged sludge, so that the organic phosphorus form is converted to the inorganic phosphorus form, and the apatite phosphorus form is converted to the non-apatite phosphorus form. The above phosphorus form conversion results show that the phosphorus form in the dredged sludge is more conducive to the form conversion of phosphorus resource recycling, and promotes the recycling of phosphorus resources in the dredged sludge. 2+ The concentration of Fe 2+ The cathode reduction improves the efficiency of the Fenton reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 According to an embodiment of the present invention, a MoS2 / Fe 2+Flow chart of the method for transforming phosphorus forms in dredged river and lake sediments using an enhanced electro-Fenton reaction device; Figure 2 It is a common treatment route for dredged sludge in the prior art; Figure 3 According to the embodiment of the present invention, MoS2 / Fe 2+ IP morphology percentage content diagram after enhanced electro-Fenton treatment and traditional electro-Fenton EF treatment; Figure 4 According to the embodiment of the present invention, MoS2 / Fe 2+ OP morphology percentage content diagram after enhanced electro-Fenton treatment and traditional electro-Fenton EF treatment; Figure 5 According to the embodiment of the present invention, MoS2 / Fe 2+ Fe-P form percentage content diagram after enhanced electro-Fenton treatment and traditional electro-Fenton EF treatment; Figure 6 According to the embodiment of the present invention, MoS2 / Fe 2+ Ca-P form percentage content diagram after enhanced electro-Fenton treatment and traditional electro-Fenton EF treatment; Figure 7 According to the embodiment of the present invention, MoS2 / Fe 2+ Fe after enhanced electro-Fenton treatment and traditional electro-Fenton EF treatment 2+ and Fe 3+ Concentration comparison chart. DETAILED DESCRIPTION

[0021] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments. They can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in this field should be able to understand other possible implementation methods and advantages of the present invention.

[0022] According to an embodiment of the present invention, a MoS2 / Fe 2+ A method for transforming phosphorus forms in dredged river and lake sediments using an enhanced electro-Fenton reaction device.

[0023] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1 As shown, according to the embodiment of the present invention, based on MoS2 / Fe 2+ A method for transforming phosphorus forms in river and lake dredged sludge using an enhanced electro-Fenton reaction device, the method comprising: S1. Adjusting the pH of the original dredged sludge, and after the adjustment, selecting a preset number of compounds and mixing them with the original dredged sludge to obtain the dredged sludge to be treated.

[0024] In one embodiment, the pH of the original dredged sludge is adjusted, and after the adjustment is completed, a preset number of compounds are selected and mixed with the original dredged sludge to obtain the dredged sludge to be treated, which includes: S11. Selecting alkaline and acidic substances according to the initial pH value of the original dredged sludge, and adjusting the pH of the original dredged sludge to a preset range; S12, compounding each type of compound according to preset requirements to obtain compound materials of corresponding mass fractions, marking the compound materials and sending them into a stirring device for stirring to obtain a mixed compound; S13, mixing the mixed compound with the original dredged sludge and sending them into a stirring device for stirring to obtain a mixture, and collecting the motion state of the stirring blades in the stirring device in real time during the stirring process; S14. Analyze the mixing condition of the mixture in the stirring device according to the motion state, obtain the uniformity test result of the mixed stirring, and adjust the driving state of the stirring device based on the uniformity test result, and obtain the dredged sludge to be processed after the uniformity reaches the mixing requirement.

[0025] Among them, each category of compounds includes soluble sodium salts, soluble iron salts and molybdenum disulfide; the soluble sodium salt includes at least one of sodium sulfate, sodium nitrate, sodium chloride and sodium perchlorate; the soluble iron salt includes at least one of ferrous sulfate, ferric sulfate, ferric chloride, ferrous chloride, ferric nitrate and ferrous nitrate, the molybdenum disulfide is commercial molybdenum disulfide, the preset range of pH adjustment is 3~9; the preferred pH is 7.

[0026] Specifically, the mixing state of the mixture in the stirring device is analyzed according to the motion state, the uniformity test result of the mixing is obtained, and the driving state of the stirring device is adjusted based on the uniformity test result. After the uniformity meets the mixing requirements, the dredged sludge to be processed is obtained, including: S141, analyzing a change in stirring speed of the stirring device during the stirring process based on the motion state, and obtaining a change in temperature of the mixture in the stirring device according to the change in speed; S142, calculating a real-time stirring efficiency coefficient of the stirring device based on the speed change and the temperature change, and comparing the real-time stirring efficiency coefficient with a standard efficiency coefficient range; S143, analyzing the uniformity of the mixture in the stirring device according to the comparison result, and matching the uniformity detection result with the adjustment rule to adjust the driving state of the stirring device; S144. Continue stirring the mixture according to the adjustment result of the stirring equipment, and obtain the dredged sludge to be processed after the uniformity reaches the mixing requirement.

[0027] The expression of stirring efficiency coefficient is: ; In the formula, γ i represents the stirring efficiency coefficient at the i-th moment, Δθ i represents the change in stirring speed at the i-th moment, Δθ0 represents the change in standard stirring speed, and Δζ i represents the temperature change at the i-th moment, Δζ0 represents the standard temperature change, and α represents Δθ i The preset weight coefficient corresponding to the ratio of Δθ0, β represents Δζ i The preset weight coefficient corresponding to the ratio of Δζ0.

[0028] It should be noted that when analyzing the uniformity of the mixture in the stirring device according to the comparison results, and matching the uniformity test results with the adjustment rules to adjust the driving state of the stirring device, when the real-time stirring efficiency coefficient is within the standard efficiency coefficient range, it means that the mixing result of the mixture in the stirring device meets the requirements; When the real-time stirring efficiency coefficient is less than the standard efficiency coefficient range, it means that the current stirring equipment is inefficient and the stirring rate of the stirring blade needs to be increased; when the real-time stirring efficiency coefficient is greater than the standard efficiency coefficient range, it means that the current stirring equipment is efficient and the stirring rate of the stirring blade needs to be reduced.

[0029] S2. Select a preset number of compounds to prepare an overlying solution, and immerse the cathode plate and the anode plate into the overlying solution and the dredged sludge to be treated respectively.

[0030] The sodium sulfate added to the contaminated sediment and the overlying solution is 20mmol / L to 50mmol / L, preferably 30mmol / L, the ferrous sulfate is 1mmol / L to 4mmol / L, preferably 1mmol / L, and the molybdenum disulfide is 0.1~1.5g / L, preferably 0.6g / L.

[0031] S3, connecting the cathode plate and the anode plate, connecting to the power supply to perform enhanced electro-Fenton phosphorus form conversion operation on the dredged sludge to be treated, and determining the phosphorus form content in the dredged sludge to be treated after the conversion.

[0032] In one embodiment, the cathode plate and the anode plate are connected, and a power source is connected to perform an enhanced electro-Fenton phosphorus form conversion operation on the dredged sludge to be treated, and the phosphorus form content in the dredged sludge to be treated after the conversion is determined, including: S31, use titanium wire to connect the power supply to the cathode plate and the anode plate respectively, adjust the voltage and current according to the reaction amount of the dredged mud to be treated, and then turn on the power supply to run the MoS2 / Fe 2+ Enhanced electro-Fenton reaction device; S32, using MoS2 / Fe 2+The enhanced electro-Fenton reaction device starts the anode reaction and the cathode reaction to release hydrogen ions and hydroxide ions, and generates hydroxyl radicals based on ferrous ions and hydrogen peroxide during the cathode region reaction process; S33. Based on the hydroxyl radical oxidation of phosphorus forms, an enhanced electro-Fenton phosphorus form conversion operation is performed in the dredged sediment to be treated. After the conversion is completed, samples are weighed and combined with the phosphorus form graded extraction method to determine the phosphorus form content in the dredged sediment to be treated after the conversion.

[0033] The distance between the cathode plate and the anode plate is 10 cm to 15 cm, and the operating range of the current is 20 mA to 150 mA.

[0034] S4. Combine the phosphorus form content with infrared spectroscopy technology to analyze the decomposition degree of phosphorus in the dredged mud after the form conversion, and verify the balance of phosphorus form conversion based on the decomposition degree to obtain the form conversion efficiency.

[0035] In one embodiment, the phosphorus form content is combined with infrared spectroscopy technology to analyze the decomposition degree of phosphorus in the dredged sediment after the form conversion, and the balance of phosphorus form conversion is verified according to the decomposition degree to obtain the form conversion efficiency, including: S41, weighing a preset mass of a test product from the converted dredged sediment, and drying, crushing and sieving the test product to obtain a sediment sample; S42, combining the sediment sample with the potassium chloride mixture to prepare a potassium chloride tablet, and measuring the potassium chloride tablet using an infrared spectrometer to obtain a sediment spectrum; S43, analyzing the absorption peak corresponding to the sediment spectrum, judging the degree of phosphorus decomposition according to the intensity change of the absorption peak, and verifying the phosphorus form conversion efficiency by combining the decomposition degree with the phosphorus form content; S44. Evaluation of MoS2 / Fe based on phosphorus form conversion efficiency 2+ Enhance the operating efficiency of the electro-Fenton reaction device and the stirring process, and optimize the phosphorus form conversion process based on the operating efficiency.

[0036] Among them, the absorption peak corresponding to the sediment spectrum is analyzed, the degree of phosphorus decomposition is judged according to the intensity change of the absorption peak, and the decomposition degree is combined with the phosphorus form content to verify the phosphorus form conversion efficiency, including: S431, obtaining a corresponding sediment spectrum curve based on the sediment spectrum diagram, and performing pre-processing on the sediment spectrum curve using a differential method, and determining a differential amount of the sediment spectrum curve after the pre-processing is completed; S432, generating a sediment spectrum differential curve using the differential component, and performing denoising and envelope processing on the sediment spectrum curve using the sediment spectrum differential curve to obtain an envelope-removed spectrum curve; S433, using a differential method to traverse the absorption peak value of the envelope spectrum curve, determine the intensity change of the absorption peak value, and analyze the decomposition degree of phosphorus according to the intensity change; S434. The decomposition degree and phosphorus form content are combined to evaluate the balance of phosphorus form conversion, and based on the balance, the ratio of phosphorus form converted from the initial form to the target form is analyzed to obtain the phosphorus form conversion efficiency.

[0037] Embodiment 1 In this embodiment, the basic physical and chemical properties of the bottom mud in the anode area are the total phosphorus content: 3±463.13mg / kg, alkaline nitrogen content 203.5±5.5mg / kg, pH 7.5±0.18, organic matter content 1.80±0.55%, water content 71.2±12.6%, sulfide 54.74±44.89mg / kg.

[0038] Step 1: Use sulfuric acid and sodium hydroxide to adjust the pretreated dredged mud to a pH of about 7, add ferrous sulfate, sodium sulfate and molybdenum disulfide to the mud after adjusting the pH, so that the concentration of ferrous sulfate in the dredged mud is 1 mmol / L, the concentration of sodium sulfate is 30 mmol / L, and the concentration of molybdenum disulfide is 0.6 g / L, stir evenly, add about 190 mL of the above-mentioned mud sample to the anode area; place the anode plate in the dredged mud so that it is completely immersed in the mud.

[0039] Step 2: The overlay solution in this embodiment is composed of 1mmol / L ferrous sulfate, 30mmol / L sodium sulfate, and 0.6g / L molybdenum disulfide solution. The overlay solution is adjusted to a pH of about 7 with sulfuric acid and sodium hydroxide. The configured overlay solution is added to the cathode region and the cathode plate is completely placed in the overlay solution. The volume of the overlay solution in this embodiment is about 120mL. In actual use, the overlay solution is generally about 2 / 3 of the volume of the cathode region. The size of the body can be adjusted according to actual needs, and the corresponding body thickness, anode plate size, cathode plate size, anode separator size, cathode separator size, etc. can be adjusted accordingly.

[0040] Step 3: The distance between the anode plate and the cathode plate is 15 cm. Use titanium wire to connect the cathode area, the anode area and the power supply respectively. Turn on the power supply and monitor the current change of its circuit. In this embodiment, the power supply is a constant voltage DC power supply, model APS3005DM, and the current in this embodiment is set to 100 milliamperes (mA). In actual use, the current size can also be adjusted according to the specific situation or other power supply models can be replaced to implement this solution.

[0041] Step 4: Run MoS2 / Fe according to the above steps 2+ Strengthen the electro-Fenton reaction device and start MoS2 / Fe 2+Enhanced electro-Fenton treatment of phosphorus form transformation in dredged sediment, the experiment was stopped after 4 to 12 hours, and the MoS2 / Fe 2+ After the enhanced electro-Fenton reaction, the dredged sludge was sampled and the changes in phosphorus forms before and after the reaction were determined by referring to the phosphorus form fractionation extraction method based on the chemical sequential extraction scheme (SMT scheme) of phosphorus in freshwater sediments.

[0042] After the electro-Fenton treatment of dredged mud phosphorus content experiment according to the above steps ( Figures 3 to 6 MoS2 / Fe 2+ The percentage content of different forms of phosphorus after enhanced electro-Fenton treatment and traditional electro-Fenton EF treatment. The three groups of columns in the figure are EF, Mo-EF and CF from left to right, and the horizontal axis represents time), with a reaction time of 4h to 2h; The IP (inorganic phosphorus) content increased from 849.71±12.34 mg / kg to 974.63±16.77 mg / kg, the OP (organic phosphorus) content decreased from 505.11±12.23 mg / kg to 359.31±15.54 mg / kg, the Fe-P (iron-bound phosphorus) content increased from 391.60±14.23 mg / kg to 652.71±15.77 mg / kg, and the Ca-P (calcium-bound phosphorus) content decreased from 319.56±13.79 mg / kg to 108.13±13.88 mg / kg.

[0043] Comparative Example 1 was carried out simultaneously with Example 1, and the steps were as follows: Comparative Example 1 Step 1: Same as step 1 of Example 1, adjusting the pH of the sludge to about 7 with sulfuric acid and sodium hydroxide, and then adding ferrous sulfate to a concentration of 1 mmol / L and sodium sulfate to a concentration of 30 mmol / L to the sludge, respectively, stirring evenly to obtain the contaminated dredged sludge with a pre-treated pH of about 7, adding about 190 mL of the above sludge sample to the anode area; placing the anode plate in the sludge so that it is completely immersed in the sludge.

[0044] Step 2: The overlying solution consists of 1mmol / L ferrous sulfate and 30mmol / L sodium sulfate solution. The overlying water is adjusted to a pH of about 3 with sulfuric acid and sodium hydroxide. The prepared overlying solution is added to the cathode area and the cathode plate is completely placed in the overlying solution. The volume of the overlying solution is about 125mL. In actual use, the overlying solution is generally about 2 / 3 of the volume of the cathode area. The distance between the anode plate and the cathode plate is 15cm. The positive and negative electrodes are connected respectively by titanium wire and the power is turned on.

[0045] Step 3: Run the experimental reaction device according to the above steps, run for 9-12 hours under the same conditions as in Example 1, stop the experiment, sample the sludge after the electro-Fenton reaction, and determine the change in phosphorus form content before and after the reaction by referring to the SMT phosphorus form fractionation extraction method.

[0046] According to the above steps, the conventional electro-Fenton treatment of dredged mud phosphorus content experiment was carried out and the results were ( Figures 3 to 6 MoS2 / Fe 2+ The percentage content of different forms of phosphorus after enhanced electro-Fenton treatment and traditional electro-Fenton EF treatment. In the figure, a, b, and c are the results of variance analysis. The same letters indicate that there is no significant difference in the results. The three groups of columns from left to right are EF: electro-Fenton treatment experimental group, Mo-EF: MoS2 / Fe 2+ Enhanced electro-Fenton treatment group and CF: electrification treatment group), after 4-12h, IP content increased from 849.71±12.34mg / kg to 924.13±19.44mg / kg, and OP content decreased from 505.11±12.23 to 423.74±13.65mg / kg; The Fe-P content increased from 391.60±14.23mg / kg to 593.92±16.88mg / kg, and the Ca-P content decreased from 209.30±13.79mg / kg to 113.40±14.45mg / kg.

[0047] Comparing the phosphorus form transformation changes in Implementation 1 and Comparative Example 1, the results show that after 4 to 12 hours, the IP content increased by 15% on average, the OP content decreased by 40% on average, the Fe-P content increased by 68% on average, and the Ca-P content decreased by 54% on average.

[0048] Figure 7 MoS2 / Fe 2+ Fe after enhanced electro-Fenton treatment and traditional electro-Fenton EF treatment 2+ and Fe 3+ Concentration comparison chart, at the same initial Fe 2+ Under the dosage, MoS2 / Fe 2+ Electro-Fenton enhanced system and Fe in EF system 2+ / Fe 3+ Cycle, for the EF system, except for the Fe 3+ Concentration higher than Fe 2+ Except for the rest of the time, Fe 2+ Dominant, MoS2 / Fe 2+ Enhanced Fe in the electro-Fenton system 2+ The concentrations of MoS2 in the enhanced electro-Fenton system are higher than those in the conventional EF system. 2+ / Fe 3 Cycle plays an important role in promoting Fe 2+ The cathode reduction reduces the generation of iron sludge and improves the efficiency of the Fenton reaction.

[0049] In general, this embodiment is mainly to transform the P form in the polluted sediments of rivers and lakes, so that some organic P (OP) is transformed into inorganic P (IP), or apatite P (inorganic P related to Ca, Ca-P) is transformed into non-apatite P (inorganic P form related to Fe), thereby realizing the recovery of P resources. The implementation results of this embodiment also show that some OP is transformed into IP form, while Ca-P is transformed into Fe-P form. The transformation of P into IP and Fe-P can achieve the expected goal and realize the recovery of P resources. Ordinary electro-Fenton treatment only focuses on the change of total phosphorus, but does not care about the transformation of P form. Moreover, the present invention also solves the problem that the traditional electro-Fenton catalyst Fe under neutral and alkaline conditions 2+ To solve the problems of easy passivation and narrow pH application range, a MoS2 / Fe 2+ Strengthening the electro-Fenton method; found that the presence of MoS2 promoted Fe 2+ The reduction of P improves the conversion of P forms in dredged mud, which is particularly beneficial to the conversion of P forms under neutral conditions, and is significantly better than the conversion effect of traditional methods under pH conditions of 3 to 5. The treated dredged mud is convenient for the subsequent recycling of P resources.

[0050] It should be explained that electro-Fenton (EF) is widely used in the field of environmental pollutant treatment due to its relatively low operating cost, high mineralization efficiency and easy-to-control degradation kinetics. EF can produce H2O2 (O2+2H + +2e – →H2O2), avoiding the transportation risk of H2O2 and reducing its economic cost. At the same time, the whole reaction process is clean and green. In addition to producing H2O2, Fe 2+ / Fe 3+ The circulating catalyst is another important factor in maintaining the EF system. 3+ Can be reduced by cathode to regenerate Fe 2+ , which ensures the continuous generation of ·OH and reduces the generation of iron sludge, thus promoting the iron salt catalyst (Fe 2+ / Fe 3+ ) recycling can not only accelerate the formation of oxidants, but also reduce the consumption of catalysts. It is a key step in the EF process. 2+ / Fe 3+ By formula (Fe 2+ +H2O2→Fe 3+ + OH+OH − and Fe 3+ +e – →Fe 2+ ) recycling, Fe 2+It can also be achieved through the Fenton reaction (Fe 3+ +H2O2+H + →Fe 2+ +H + +·OH2) slowly regenerates. However, due to Fe 2+ / Fe 3+ The cycle reaction is not fast enough (Fe 2+ +H2O2→Fe 3+ + OH+OH − and Fe 3+ +e – →Fe 2+ ), and Fe 3+ The reduction reaction rate (Fe 3+ +H2O2+H + →Fe 2+ +H + +·OH2) is much slower than Fe 2+ Oxidation (Fe 2+ +H2O2→Fe 3+ + OH+OH − ), resulting in Fe 3+ The accumulation of sludge and the consumption of H2O2 affect the yield of ·OH. Therefore, although the EF reaction process is efficient, rapid and simple, its practical application is limited by its shortcomings such as the difficulty in reusing the catalyst and the deactivation of iron ions. It is still urgent to improve the EF process to overcome the Fe 2+ / Fe 3+ To solve the problem of low conversion efficiency, metal sulfides (such as MoS2) have been proven to be an excellent co-catalyst, which can improve the decomposition efficiency of H2O2 and significantly reduce the reaction between H2O2 and Fe. 2+ H2O2 can be consumed by the exposed Mo 4+ Active sites promote Fe 3+ Reduction to Fe 2+ (Mo 4+ +Fe 3+ →Mo 6+ +Fe 2+ ), significantly promoting Fe 3+ Reduction to Fe 2+ and through the formula (Mo 6+ +H2O2→Mo 4+ +H2O+O2) will generate Mo 6+ Further reduction to Mo 4+ , completing the cycle process and significantly improving the decomposition efficiency of H2O2.

[0051] At present, the electro-Fenton method is mainly used in the field of sewage treatment, and is rarely used in the treatment of dredged sludge. The main target pollutants are heavy metals or organic pollutants. There are even fewer studies on the transformation of P forms in dredged sludge. Due to the passivation of the catalyst under neutral and alkaline conditions, the traditional electro-Fenton method has a poor effect on the removal of pollution. Therefore, the optimal pH range for the application of the traditional electro-Fenton method is 3~5, which greatly limits the application of the electro-Fenton technology. In summary, it is necessary to construct a method suitable for overcoming Fe under neutral or alkaline conditions. 2+ / Fe 3+ Therefore, it is necessary to enhance the electro-Fenton treatment of dredged sludge with low conversion efficiency.

[0052] In summary, with the aid of the above technical solution of the present invention, the present invention improves the conversion efficiency of phosphorus forms in dredged sludge, so that the organic phosphorus form is converted to the inorganic phosphorus form, and the apatite phosphorus form is converted to the non-apatite phosphorus form. The above results of phosphorus form conversion show that the phosphorus form in the dredged sludge is more conducive to the form conversion of phosphorus resource recycling and utilization, and promotes the recycling of phosphorus resources in the dredged sludge. At the same time, Fe 2+ The concentration of Fe 2+ The cathode reduction improves the efficiency of the Fenton reaction.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A MoS2 / Fe-based 2+ The method for transforming phosphorus forms in river and lake dredged mud using an enhanced electro-Fenton reaction device is characterized in that: The phosphorus form transformation methods of river and lake dredged mud include: S1. Adjusting the pH of the original dredged sludge, and after the adjustment is completed, selecting a preset number of compounds and mixing them with the original dredged sludge to obtain the dredged sludge to be treated; S2, selecting a preset number of compounds to prepare an overlying solution, and immersing the cathode plate and the anode plate into the overlying solution and the dredged sludge to be treated respectively; S3, connecting the cathode plate and the anode plate, connecting to the power supply to perform enhanced electro-Fenton phosphorus form conversion operation on the dredged sludge to be treated, and measuring the phosphorus form content in the dredged sludge to be treated after the conversion; S4. Combine the phosphorus form content with infrared spectroscopy technology to analyze the decomposition degree of phosphorus in the dredged mud after the form conversion, and verify the balance of phosphorus form conversion based on the decomposition degree to obtain the form conversion efficiency.

2. A method based on MoS2 / Fe according to claim 1 2+ The method for transforming phosphorus forms in river and lake dredged mud using an enhanced electro-Fenton reaction device is characterized in that: The step of adjusting the pH of the original dredged sludge and, after the adjustment is completed, selecting a preset number of compounds and mixing them with the original dredged sludge to obtain the dredged sludge to be treated comprises: S11. Selecting alkaline and acidic substances according to the initial pH value of the original dredged sludge, and adjusting the pH of the original dredged sludge to a preset range; S12, compounding each type of compound according to preset requirements to obtain compound materials of corresponding mass fractions, marking the compound materials and sending them into a stirring device for stirring to obtain a mixed compound; S13, mixing the mixed compound with the original dredged sludge and sending them into a stirring device for stirring to obtain a mixture, and collecting the motion state of the stirring blades in the stirring device in real time during the stirring process; S14. Analyze the mixing condition of the mixture in the stirring device according to the motion state, obtain the uniformity test result of the mixed stirring, and adjust the driving state of the stirring device based on the uniformity test result, and obtain the dredged sludge to be processed after the uniformity meets the mixing requirements.

3. A method based on MoS2 / Fe according to claim 2 2+ The method for transforming phosphorus forms in river and lake dredged mud using an enhanced electro-Fenton reaction device is characterized in that: The various types of compounds include soluble sodium salts, soluble iron salts and molybdenum disulfide; The soluble sodium salt includes at least one of sodium sulfate, sodium nitrate, sodium chloride and sodium perchlorate; the soluble iron salt includes at least one of ferrous sulfate, ferric sulfate, ferric chloride, ferrous chloride, ferric nitrate and ferrous nitrate.

4. A method based on MoS2 / Fe according to claim 3 2+ The method for transforming phosphorus forms in river and lake dredged mud using an enhanced electro-Fenton reaction device is characterized in that: The method of analyzing the mixing state of the mixture in the stirring device according to the motion state, obtaining the uniformity detection result of the mixing and stirring, and adjusting the driving state of the stirring device based on the uniformity detection result, and obtaining the dredged sludge to be processed after the uniformity reaches the mixing requirement includes: S141, analyzing a change in stirring speed of the stirring device during the stirring process based on the motion state, and obtaining a change in temperature of the mixture in the stirring device according to the change in speed; S142, calculating a real-time stirring efficiency coefficient of the stirring device based on the speed change and the temperature change, and comparing the real-time stirring efficiency coefficient with a standard efficiency coefficient range; S143, analyzing the uniformity of the mixture in the stirring device according to the comparison result, and matching the uniformity detection result with the adjustment rule to adjust the driving state of the stirring device; S144. Continue stirring the mixture according to the adjustment result of the stirring equipment, and obtain the dredged sludge to be processed after the uniformity reaches the mixing requirement.

5. A method based on MoS2 / Fe according to claim 4 2+ The method for transforming phosphorus forms in river and lake dredged mud using an enhanced electro-Fenton reaction device is characterized in that: The expression of the stirring efficiency coefficient is: ； In the formula, γ i represents the stirring efficiency coefficient at the i-th moment, Δθ i represents the change in stirring speed at the i-th moment, Δθ0 represents the change in standard stirring speed, and Δζ i represents the temperature change at the i-th moment, Δζ0 represents the standard temperature change, and α represents Δθ i The preset weight coefficient corresponding to the ratio of Δθ0, β represents Δζ i The preset weight coefficient corresponding to the ratio of Δζ0.

6. A method based on MoS2 / Fe according to claim 5 2+ The method for transforming phosphorus forms in river and lake dredged mud using an enhanced electro-Fenton reaction device is characterized in that: When the uniformity of the mixture in the stirring device is analyzed according to the comparison result, and the driving state of the stirring device is adjusted by matching the uniformity detection result with the adjustment rule, when the real-time stirring efficiency coefficient is within the standard efficiency coefficient range, it means that the mixing result of the mixture in the stirring device meets the requirements; When the real-time stirring efficiency coefficient is less than the standard efficiency coefficient range, it means that the current stirring equipment is inefficient and the stirring speed of the stirring blade needs to be increased; When the real-time stirring efficiency coefficient is greater than the standard efficiency coefficient range, it means that the current stirring equipment is highly efficient and the stirring rate of the stirring blades needs to be reduced.

7. The method for phosphorus form conversion of river and lake dredged mud based on MoS2 / Fe2+ enhanced electro-Fenton reaction device according to claim 1 is characterized in that: The connecting of the cathode plate and the anode plate, connecting to a power source to perform an enhanced electro-Fenton phosphorus form conversion operation on the dredged sludge to be treated, and determining the phosphorus form content in the dredged sludge to be treated after the conversion comprises: S31, use titanium wire to connect the power supply to the cathode plate and the anode plate respectively, adjust the voltage and current according to the reaction amount of the dredged mud to be treated, and then turn on the power supply to run the MoS2 / Fe 2+ Enhanced electro-Fenton reaction device; S32, using MoS2 / Fe 2+ The enhanced electro-Fenton reaction device starts the anode reaction and the cathode reaction to release hydrogen ions and hydroxide ions, and generates hydroxyl radicals based on ferrous ions and hydrogen peroxide during the cathode region reaction process; S33. Based on the hydroxyl radical oxidation of phosphorus forms, an enhanced electro-Fenton phosphorus form conversion operation is performed in the dredged sediment to be treated. After the conversion is completed, samples are weighed and combined with the phosphorus form graded extraction method to determine the phosphorus form content in the dredged sediment to be treated after the conversion.

8. A method based on MoS2 / Fe according to claim 7 2+ The method for transforming phosphorus forms in river and lake dredged mud using an enhanced electro-Fenton reaction device is characterized in that: The distance between the cathode plate and the anode plate is 10 cm to 15 cm, and the operating range of the current is 20 mA to 150 mA.

9. A method based on MoS2 / Fe according to claim 1 2+ The method for transforming phosphorus forms in river and lake dredged mud using an enhanced electro-Fenton reaction device is characterized in that: The method of combining the phosphorus form content with infrared spectroscopy technology to analyze the decomposition degree of phosphorus in the dredged sediment after the form conversion, and verifying the balance of phosphorus form conversion according to the decomposition degree to obtain the form conversion efficiency includes: S41, weighing a preset mass of a test product from the converted dredged sediment, and drying, crushing and sieving the test product to obtain a sediment sample; S42, combining the sediment sample with the potassium chloride mixture to prepare a potassium chloride tablet, and measuring the potassium chloride tablet using an infrared spectrometer to obtain a sediment spectrum; S43, analyzing the absorption peak corresponding to the sediment spectrum, judging the degree of phosphorus decomposition according to the intensity change of the absorption peak, and combining the degree of decomposition with the phosphorus form content to verify the phosphorus form conversion efficiency; S44. Evaluation of MoS2 / Fe based on phosphorus form conversion efficiency 2+ Enhance the operating efficiency of the electro-Fenton reaction device and the stirring process, and optimize the phosphorus form conversion process based on the operating efficiency.

10. A method based on MoS2 / Fe according to claim 9. 2+ The method for transforming phosphorus forms in river and lake dredged mud using an enhanced electro-Fenton reaction device is characterized in that: The analysis of the absorption peak corresponding to the sediment spectrum, judging the degree of phosphorus decomposition according to the intensity change of the absorption peak, and combining the degree of decomposition with the phosphorus form content to verify the phosphorus form conversion efficiency includes: S431, obtaining a corresponding sediment spectrum curve based on the sediment spectrum diagram, and pre-processing the sediment spectrum curve using a differential method, and determining a differential amount of the sediment spectrum curve after the pre-processing is completed; S432, generating a sediment spectrum differential curve using the differential component, and performing denoising and envelope processing on the sediment spectrum curve using the sediment spectrum differential curve to obtain an envelope-removed spectrum curve; S433, using a differential method to traverse the absorption peak value of the envelope spectrum curve, determine the intensity change of the absorption peak value, and analyze the decomposition degree of phosphorus according to the intensity change; S434. The decomposition degree and phosphorus form content are combined to evaluate the balance of phosphorus form conversion, and based on the balance, the ratio of phosphorus form converted from the initial form to the target form is analyzed to obtain the phosphorus form conversion efficiency.

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