Method for catalyzing oxidation degradation of pollutants in soil by using tungsten disulfide activated amorphous manganese dioxide to catalyze chlorine dioxide

Abstract

The invention relates to a method for degrading pollutants in soil by activating amorphous manganese dioxide through tungsten disulfide to catalyze chlorine dioxide oxidation, which comprises the following steps: mixing a catalyst, an activating agent and an oxidizing agent with the polluted soil, and carrying out remediation treatment; wherein the catalyst is amorphous manganese dioxide, the oxidizing agent is chlorine dioxide, the activating agent is tungsten dioxide, and the polluted soil is soil polluted by polycyclic aromatic hydrocarbon pollutants. Compared with the prior art, the catalyst with tungsten disulfide as the activating agent and amorphous manganese dioxide as the active component catalyzes chlorine dioxide to oxidize and degrade polycyclic aromatic hydrocarbon in polluted soil, the degradation efficiency of chlorine dioxide on polycyclic aromatic hydrocarbon is effectively improved, and meanwhile, amorphous manganese dioxide is rich in reserves in the natural environment, low in price and easy to obtain; the method does not cause secondary pollution to soil, is cleaner and more environment-friendly, and greatly reduces the cost due to the fact that tungsten disulfide can be recycled.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of soil remediation, in particular to a method for degrading pollutants in soil by catalyzing chlorine dioxide oxidation with tungsten disulfide activated amorphous manganese dioxide. BACKGROUND

[0002] With the rapid development of industrialization, the enrichment of polycyclic aromatic hydrocarbons (PAHs) in industrial soil is becoming increasingly serious, and effective remediation measures are urgently needed. As a kind of persistent organic pollutants with carcinogenic, teratogenic and mutagenic effects, polycyclic aromatic hydrocarbons not only have large emission, but also are difficult to be degraded in the natural environment. Due to their significant lipophilicity and hydrophobicity, as well as high chemical stability, these compounds can be long-term retained in the soil-crop system. Studies have shown that more than 90% of polycyclic aromatic hydrocarbons in the environment are ultimately accumulated in soil media. Due to their high hydrophobic coefficient, low vapor pressure and extremely low water solubility, polycyclic aromatic hydrocarbons will quickly bind to soil particles and continuously accumulate, eventually forming a significant biological enrichment effect in the soil ecosystem. Crops absorb polycyclic aromatic hydrocarbons in the soil through the root system and enrich them in the body, and then transmit them through the food chain, eventually posing a serious threat to human health.

[0003] Currently, the remediation technologies for polycyclic aromatic hydrocarbon contaminated soil mainly include three types: physical remediation, biological remediation and chemical remediation. Although physical remediation technologies (such as steam extraction, supercritical fluid extraction and thermal desorption) are simple to operate, they can only achieve the transfer or phase change of pollutants, and often require subsequent treatment. Biological remediation technology realizes the transformation or degradation of pollutants through plant absorption or microbial metabolism, and has the advantages of environmental friendliness and low cost, but its remediation effect is easily affected by soil properties and environmental conditions, and its treatment capacity for high-concentration pollutants is limited, and the required remediation period is long. In comparison, chemical remediation technology (including photocatalytic degradation and advanced oxidation process) has the characteristics of high degradation efficiency and short treatment period.

[0004] Patent publication No. CN117840201A discloses a method for degrading pollutants in soil by catalyzing chlorine dioxide oxidation with sodium bicarbonate activated amorphous manganese dioxide. The oxidizing agent chlorine dioxide solution, the catalytic agent amorphous manganese dioxide and the activator sodium bicarbonate are mixed with the contaminated soil for degradation and remediation treatment. Although the degradation rate has reached a high level, sodium bicarbonate as an activator will be consumed during the reaction process and cannot be recovered. And with the consumption of sodium bicarbonate, its stabilizing effect may be weakened, which may affect the long-term stability of the catalytic efficiency to some extent, and further improvement is needed. SUMMARY

[0005] The present application aims to overcome the defects of the existing sodium bicarbonate activation system, such as non-recyclable activator, high cost, and possible long-term stability of catalytic efficiency, and provide a method for degrading pollutants in soil by catalytic oxidation of chlorine dioxide with tungsten disulfide activated amorphous manganese dioxide, which is more cost-effective, recyclable, and has more stable and persistent catalytic efficiency. The method uses tungsten disulfide as an activator and amorphous manganese dioxide as an active component to catalyze the oxidation of polycyclic aromatic hydrocarbons in contaminated soil by chlorine dioxide, ensuring degradation efficiency while improving long-term stability of catalytic efficiency. Amorphous manganese dioxide is abundant in natural environment and inexpensive, and does not cause secondary pollution to the soil, making it more environmentally friendly. Tungsten disulfide is reusable, greatly reducing costs.

[0006] The object of the present application can be achieved by the following technical solutions: A method for degrading pollutants in soil by catalytic oxidation of chlorine dioxide with tungsten disulfide activated amorphous manganese dioxide, which mixes catalysts, activators, oxidants, and contaminated soil for remediation treatment. The catalyst is amorphous manganese dioxide, the oxidant is chlorine dioxide, the activator is tungsten dioxide, and the contaminated soil is contaminated by polycyclic aromatic hydrocarbons.

[0007] Further, the total amount of polycyclic aromatic hydrocarbon pollutants in the contaminated soil is 1-2000 mg kg -1 The method has a more significant degradation effect on industrial polycyclic aromatic hydrocarbon soil with a concentration of 2000 mg kg -1 The total amount of detected polycyclic aromatic hydrocarbon pollutants can be 1, 10, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000 mg kg -1 .

[0008] Further, the polycyclic aromatic hydrocarbons in the contaminated soil are extracted with an extraction solvent, which is n-hexane and / or dichloromethane.

[0009] Further, the contaminated soil is crushed and sieved before extraction.

[0010] Further, the contaminated soil is crushed and sieved to a particle size of ≤0.25 mm before extraction.

[0011] Further, the polycyclic aromatic hydrocarbons are one or more of naphthalene, acenylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene, or benzo[g,h,i]perylene.

[0012] Further, the ratio of the sum of the oxidizing agent and the catalyst, the activator, and the mass of the polycyclic aromatic hydrocarbon pollutants in the contaminated soil is 1-25:2-20:1, preferably 1.68-22.68:3.36-13.45:1.

[0013] Further, in the specific operation process, the ratio of the added oxidizing agent, catalyst, and activator should be linearly increased or decreased according to the measured concentration of polycyclic aromatic hydrocarbon pollutants.

[0014] Further, in the specific operation process, according to the detected total mass of polycyclic aromatic hydrocarbons in the contaminated soil, the addition amount of the sum of the oxidizing agent and the catalyst is linearly increased or decreased within the range of 1-25:1, and the addition amount of the activator is linearly increased or decreased within the range of 2-20:1.

[0015] Further, the mass ratio of the oxidizing agent to the catalyst is 5-15:1, preferably 6.25-12.5:1.

[0016] Further, in the degradation and repair process of the contaminated soil, the chlorine dioxide exists in the form of a solution, with a concentration of 1000-2000 mg kg -1 , and the solvent is water.

[0017] Further, in the degradation and repair process of the contaminated soil, the amorphous manganese dioxide and tungsten dioxide exist in the form of a powder.

[0018] Further, in the degradation and repair process of the contaminated soil, the pH of the reaction system is 3-6, preferably 6, because too high acidity can easily lead to soil acidification.

[0019] Further, the mixing method of the oxidizing agent, catalyst, and activator with the contaminated soil is one or a combination of spraying, drip irrigation, stirring mixing, and oscillation mixing.

[0020] Further, the method comprises the following steps: S1: sampling the contaminated soil containing polycyclic aromatic hydrocarbons, crushing, sieving, extracting, and detecting the total amount of polycyclic aromatic hydrocarbons; S2: configuring the oxidizing agent chlorine dioxide, the activator amorphous manganese dioxide, and the catalyst tungsten dioxide according to the detected concentration of polycyclic aromatic hydrocarbons. S3: applying the oxidant chlorine dioxide, the catalyst amorphous manganese dioxide and the activator tungsten dioxide to the contaminated soil containing polycyclic aromatic hydrocarbons, to carry out soil degradation repair.

[0021] Compared with the prior art, the present application has the following advantages: (1) Chlorine dioxide as a green and efficient oxidant has been used in the degradation of polycyclic aromatic hydrocarbons, but the degradation efficiency of chlorine dioxide alone on polycyclic aromatic hydrocarbons is only about 70%, which cannot meet the actual use requirements, so it is necessary to add a catalyst and an activator to improve the degradation efficiency. Tungsten disulfide has a positive effect on the catalytic activity of amorphous manganese dioxide. The current research shows that free radicals play an important role in promoting the reaction rate. Mn(III) in amorphous manganese dioxide is unstable and prone to disproportionation, generating Mn(II) and Mn(IV). W(IV) and W(VI) produced by tungsten disulfide in the reaction can effectively promote the self-cycling between Mn(IV) and Mn(II), thereby promoting the generation of more free radicals, such as hydroxyl radicals and superoxide radicals. Compared with different crystal forms of manganese dioxide such as alpha-MnO2 and beta-MnO2, amorphous manganese dioxide has more oxygen vacancies, and the existence of oxygen vacancies is beneficial to the exposure of Mn(III), providing more active sites for the degradation of pollutants. The average oxidation state (AOS) plays an important role in catalytic reactions. Compared with different crystal forms of manganese dioxide, the AOS of amorphous manganese dioxide is the lowest, and thus it has the highest Mn(III), which plays an important role in the reaction.

[0022] (2) The mechanism of sodium bicarbonate in patent publication CN117840201A is to prevent the loss of Mn(III), which is a defensive strategy. The present application promotes the valence state cycle of manganese by WS2, which is a self-sustaining positive promotion mechanism. The presence of WS2 enables the manganese catalytic cycle to be more efficient, providing more stable and longer-lasting catalytic degradation efficiency, and solving the higher demand for long-term stability of degradation efficiency. The free radicals (·OH and ·O2 - ) generated by WS2 can more effectively attack pollutant molecules, and the method of the present application can effectively ensure the degradation rate while providing a more efficient solution.

[0023] (3) The present application uses the activator tungsten disulfide, and W(IV) plays an activating role therein. Tungsten disulfide itself can be recycled and has stable properties, and can be separated and recovered from the treated soil by a simple method, and still maintains good activity after multiple recoveries, greatly reducing the reaction cost and successfully solving the problem of non-recyclable activator and high single-use cost in the prior art.

[0024] (4) The chlorine dioxide used in the present application is a green and efficient strong oxidant, and the natural reserves of amorphous manganese dioxide are large, cheap and easy to obtain, green and environmentally friendly, no toxic by-products are generated in the repair process, which can effectively reduce the secondary pollution to the soil, and the oxidation characteristics of single electron transfer of chlorine dioxide make the present method not produce toxic by-products, and the operation process is simple. DETAILED DESCRIPTION

[0025] The present application will be described in detail below in conjunction with specific embodiments. The present embodiment is implemented on the premise of the technical scheme of the present application, and gives a detailed implementation manner and specific operation process, but the protection scope of the present application is not limited to the following examples. Based on the given examples, all other examples obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0026] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present application are conventional reagents, methods, instruments and equipment in the art. The amorphous manganese dioxide used in the present application has a CAS number of 1313-13-9, a specific surface area of 5.78 m 2 / g, a spherical shape, and is purchased from Shanghai Liang Tian Nanometer Material Co., Ltd.

[0027] The preparation processes of α-MnO2, β-MnO2, γ-MnO2 and δ-MnO2 are as follows: (1) 0.658 g of KMnO4 was added to 75 mL of deionized water, and 1.5 mL of HCl solution (36 wt.%) was added dropwise. The obtained suspension was subjected to hydrothermal reaction at 150°C for 10 h, and the precipitate was washed with deionized water for 5 times. Finally, the obtained sample was dried at 80°C for 12 h, and was denoted as α-MnO2.

[0028] (2) 0.2528 g of KMnO4 and 0.475 g of MnCl2 were added to 10 mL of deionized water, respectively. After the obtained suspension was stirred for 60 min, it was subjected to hydrothermal reaction at 180°C for 48 h, and the precipitate was washed with deionized water for 5 times. The obtained sample was dried at 80°C for 12 h, and was denoted as β-MnO2.

[0029] (3) 1.715 g of KMnO4 and 4.25 g of MnSO4·H2O were dissolved in 100 mL of deionized water at the same time, and 50 mL of H2SO4 (1 M) was added dropwise and continuously stirred. After reaction at room temperature for 20 h, the sample was collected and washed with deionized water for 5 times. Finally, the sample was dried at 70°C overnight. The obtained sample was denoted as γ-MnO2.

[0030] (4) Dissolve 9.5 g of KMnO4 in 150 mL of deionized water, boil and stir in an oil bath at 135 °C for 20 min, and then add 27 mL of 6 mol L⁻¹ water dropwise at a rate of one drop every 7-8 s using a constant pressure separatory funnel. −1 After the hydrochloric acid solution was added dropwise, the mixture was allowed to react for at least 30 minutes. The generated Cl₂ was removed using a 0.3 M sodium thiosulfate solution. After the reaction was complete, the mixture was aged at 60°C for 12 hours. After 12 hours, the mixture was removed, centrifuged, and the solid product was filtered off. The product was washed with deionized water until the conductivity of the filtrate was less than 10 μS / cm. −1 The sample was freeze-dried at -60℃ in a freeze dryer and then ground in a ball mill for later use. The obtained sample was δ-MnO2.

[0031] Example 1 The method for activating amorphous manganese dioxide with tungsten disulfide to catalyze the oxidation and degradation of pollutants in soil by chlorine dioxide in this embodiment specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the contents, including 16 polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, acenaphthene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, α, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indo[1,2,3cd]pyrene, dibenzo[a,h]anthracene, or benzo[g,h,i]perylene, were contained in a 40 mL light-proof brown glass bottle.

[0032] 2. Add amorphous manganese dioxide catalyst, tungsten disulfide activator, and chlorine dioxide solution as oxidant to a glass bottle. The mass of amorphous manganese dioxide catalyst is 0.0016 g, and the mass of tungsten disulfide activator is 0.0032 g. The final concentration of chlorine dioxide solution (solvent is water) in the reaction system is 2000 mg L⁻¹ (the mass ratio of chlorine dioxide solution as oxidant, amorphous manganese dioxide catalyst, and tungsten disulfide activator to polycyclic aromatic hydrocarbons in the contaminated soil is 21:1.68:3.36:1). Adjust the pH of the reaction system to 6. The total volume of the solution in the system is 10 mL.

[0033] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0034] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0035] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 470.5 mg kg-1 This oxidative degradation system can remediate 75.29% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 4.9 mg kg -1 It can remediate 96.34% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0036] Example 2 The method for activating amorphous manganese dioxide with tungsten disulfide to catalyze the oxidation and degradation of pollutants in soil by chlorine dioxide in this embodiment specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (particle size 0.25 mm, polycyclic aromatic hydrocarbon content 1904 mg kg-1, including 16 kinds of polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) into a 40 mL light-proof brown glass bottle.

[0037] 2. Add amorphous manganese dioxide catalyst, tungsten disulfide activator, and chlorine dioxide solution as oxidant to a glass bottle. The mass of amorphous manganese dioxide catalyst is 0.0016 g, and the mass of tungsten disulfide activator is 0.0064 g. The final concentration of chlorine dioxide solution (solvent is water) in the reaction system is 2000 mg L⁻¹ (the mass ratio of chlorine dioxide solution as oxidant, amorphous manganese dioxide catalyst, and tungsten disulfide activator to polycyclic aromatic hydrocarbons in the contaminated soil is 21:1.68:6.72:1). Adjust the pH of the reaction system to 6. The total volume of the solution in the system is 10 mL.

[0038] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0039] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0040] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 408.2 mg kg -1 This oxidative degradation system can remediate 78.56% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 3.9 mg kg -1 It can remediate 97.03% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0041] Example 3 The method for activating amorphous manganese dioxide with tungsten disulfide to catalyze the oxidation and degradation of pollutants in soil by chlorine dioxide in this embodiment specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0042] 2. Add amorphous manganese dioxide catalyst, tungsten disulfide activator, and chlorine dioxide solution as oxidant to a glass bottle. The mass of amorphous manganese dioxide catalyst is 0.0016 g, and the mass of tungsten disulfide activator is 0.0128 g. The final concentration of chlorine dioxide solution (solvent is water) in the reaction system is 2000 mg L⁻¹ (the mass ratio of chlorine dioxide solution as oxidant, amorphous manganese dioxide catalyst, and tungsten disulfide activator to polycyclic aromatic hydrocarbons in the contaminated soil is 21:1.68:13.45:1). Adjust the pH of the reaction system to 6. The total volume of the solution in the system is 10 mL.

[0043] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0044] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0045] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 243.5 mg kg -1 This oxidative degradation system can remediate 87.21% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 2.1 mg kg -1 It can remediate 98.43% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0046] Example 4 The method for activating amorphous manganese dioxide with tungsten disulfide to catalyze the oxidation and degradation of pollutants in soil by chlorine dioxide in this embodiment specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0047] 2. Add amorphous manganese dioxide (a catalyst), tungsten disulfide (an activator), and chlorine dioxide solution (an oxidant) to a glass bottle. The mass of amorphous manganese dioxide is 0.0016 g, the mass of tungsten disulfide is 0.0032 g, and the final concentration of chlorine dioxide solution (water as solvent) in the reaction system is 1000 mg / L. -1 (The mass ratio of oxidant chlorine dioxide solution, catalyst amorphous manganese dioxide, activator tungsten disulfide to polycyclic aromatic hydrocarbons in contaminated soil is 10.5:1.68:3.36:1). The pH of the reaction system is adjusted to 6, and the total volume of the solution in the system is 10 mL.

[0048] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0049] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0050] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 549.9 mg kg -1 This oxidative degradation system can remediate 71.12% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 6.0 mg kg -1 It can remediate 95.54% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0051] Example 5 The method for activating amorphous manganese dioxide with tungsten disulfide to catalyze the oxidation and degradation of pollutants in soil by chlorine dioxide in this embodiment specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0052] 2. Add amorphous manganese dioxide catalyst, tungsten disulfide activator, and chlorine dioxide solution as oxidant to a glass bottle. The mass of amorphous manganese dioxide catalyst is 0.0016 g, and the mass of tungsten disulfide activator is 0.0064 g. The final concentration of chlorine dioxide solution (solvent is water) in the reaction system is 2000 mg L⁻¹ (the mass ratio of chlorine dioxide solution as oxidant, amorphous manganese dioxide catalyst, and tungsten disulfide activator to polycyclic aromatic hydrocarbons in the contaminated soil is 21:1.68:6.72:1). Adjust the pH of the reaction system to 3. The total volume of the solution in the system is 10 mL.

[0053] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0054] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0055] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 327.3 mg kg -1 This oxidative degradation system can remediate 82.81% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 3.6 mg kg -1 It can remediate 97.29% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0056] Comparative Example 1 The method for activating amorphous manganese dioxide with tungsten disulfide to catalyze the oxidation and degradation of pollutants in soil using chlorine dioxide in this comparative example specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0057] 2. Add amorphous manganese dioxide (MANG) catalyst and chlorine dioxide solution (COD) oxidant to a glass bottle. The mass of the amorphous manganese dioxide catalyst is 0.0016 g, and the final concentration of the COD solution (water as solvent) in the reaction system is 2000 mg / L. -1 (The mass ratio of the oxidizing agent chlorine dioxide solution, the catalyst amorphous manganese dioxide, and the mass of polycyclic aromatic hydrocarbons in the contaminated soil is 21:1.68:1). The pH of the reaction system is adjusted to 6, and the total volume of the solution in the system is 10 mL.

[0058] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0059] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0060] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 617.8 mg kg -1 This oxidative degradation system can remediate 67.55% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 13.9 mg kg -1 It can remediate 89.62% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0061] Comparative Example 2 The method for activating amorphous manganese dioxide with tungsten disulfide to catalyze the oxidation and degradation of pollutants in soil using chlorine dioxide in this comparative example specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0062] 2. Add the catalyst amorphous manganese dioxide to a glass bottle, wherein the mass of the catalyst amorphous manganese dioxide is 0.0016 g (the mass ratio of the catalyst amorphous manganese dioxide to the polycyclic aromatic hydrocarbons in the contaminated soil is 1.68:1), adjust the pH of the reaction system to 6, and the total volume of the solution in the system is 10 mL.

[0063] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0064] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0065] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 1201.0 mg kg -1This oxidative degradation system can remediate 36.92% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 52.8 mg kg -1 It can remediate 60.71% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0066] Comparative Example 3 The method for activating amorphous manganese dioxide with tungsten disulfide to catalyze the oxidation and degradation of pollutants in soil using chlorine dioxide in this comparative example specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0067] 2. Add chlorine dioxide, an oxidizing agent, to a glass bottle. The concentration of chlorine dioxide as an oxidizing agent is 2000 mg / L. -1 (The mass ratio of oxidant chlorine dioxide to polycyclic aromatic hydrocarbons in contaminated soil is 21:1). The pH of the reaction system is adjusted to 6, and the total volume of the solution in the system is 10 mL.

[0068] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0069] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0070] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 746.2 mg kg -1 This oxidative degradation system can remediate 60.81% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 21.2 mg kg -1 It can remediate 84.21% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0071] Comparative Example 4 The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated manganese dioxide crystals in this comparative example includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0072] 2. Add catalyst α-MnO2 to a glass bottle, wherein the mass of catalyst α-MnO2 is 0.0016 g (the mass ratio of catalyst α-MnO2 to polycyclic aromatic hydrocarbons in contaminated soil is 1.68:1), adjust the pH of the reaction system to 6, and the total volume of the solution in the system is 10 mL.

[0073] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0074] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0075] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 853.2 mg kg -1 This oxidative degradation system can remediate 55.21% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 43.7 mg kg -1 It can remediate 67.51% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0076] Comparative Example 5 The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated manganese dioxide crystals in this comparative example includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0077] 2. Add catalyst β-MnO2 to a glass bottle, wherein the mass of catalyst β-MnO2 is 0.0016 g (the mass ratio of catalyst β-MnO2 to polycyclic aromatic hydrocarbons in contaminated soil is 1.68:1), adjust the pH of the reaction system to 6, and the total volume of the solution in the system is 10 mL.

[0078] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0079] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0080] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 910.3 mg kg -1 This oxidative degradation system can remediate 52.21% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 44.9 mg kg -1 It can remediate 66.64% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0081] Comparative Example 6 The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated manganese dioxide crystals in this comparative example includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0082] 2. Add catalyst γ-MnO2 to a glass bottle, wherein the mass of catalyst γ-MnO2 is 0.0016 g (the mass ratio of catalyst γ-MnO2 to polycyclic aromatic hydrocarbons in contaminated soil is 1.68:1), adjust the pH of the reaction system to 6, and the total volume of the solution in the system is 10 mL.

[0083] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0084] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0085] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 877.2 mg kg -1 This oxidative degradation system can remediate 53.95% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg.-1 and 46.3 mg kg -1 It can remediate 65.54% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0086] Comparative Example 7 The method for activating amorphous manganese dioxide with tungsten disulfide to catalyze the oxidation and degradation of pollutants in soil using chlorine dioxide in this comparative example specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0087] 2. Add catalyst δ-MnO2 to a glass bottle, wherein the mass of catalyst δ-MnO2 is 0.0016 g (the mass ratio of catalyst δ-MnO2 to polycyclic aromatic hydrocarbons in contaminated soil is 1.68:1), adjust the pH of the reaction system to 6, and the total volume of the solution in the system is 10 mL.

[0088] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0089] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0090] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 821.9 mg kg -1 This oxidative degradation system can remediate 56.85% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 42.9 mg kg -1 It can remediate 68.08% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0091] Comparative Example 8 The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated manganese dioxide crystalline chlorine dioxide oxidation in this embodiment specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0092] 2. Add catalyst α-MnO2, activator tungsten disulfide, and oxidant chlorine dioxide solution to a glass bottle. The mass of catalyst α-MnO2 is 0.0016 g, the mass of activator tungsten disulfide is 0.0064 g, and the final concentration of chlorine dioxide solution (solvent is water) in the reaction system is 2000 mg / L. -1 (The mass ratio of oxidant chlorine dioxide solution, catalyst α-MnO2, activator tungsten disulfide to polycyclic aromatic hydrocarbons in contaminated soil is 21:1.68:6.72:1). The pH of the reaction system is adjusted to 6, and the total volume of the solution in the system is 10 mL.

[0093] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0094] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0095] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 832.4 mg kg -1 This oxidative degradation system can remediate 56.3% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 47.9 mg kg -1 It can remediate 64.40% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0096] Comparative Example 9 The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated manganese dioxide crystalline chlorine dioxide oxidation in this embodiment specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0097] 2. Add catalyst β-MnO2, activator tungsten disulfide, and oxidant chlorine dioxide solution to a glass bottle. The mass of catalyst β-MnO2 is 0.0016 g, the mass of activator tungsten disulfide is 0.0064 g, and the final concentration of chlorine dioxide solution (solvent is water) in the reaction system is 2000 mg / L. -1(The mass ratio of oxidant chlorine dioxide solution, catalyst β-MnO2, activator tungsten disulfide to polycyclic aromatic hydrocarbons in contaminated soil is 21:1.68:6.72:1). The pH of the reaction system is adjusted to 6, and the total volume of the solution in the system is 10 mL.

[0098] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0099] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0100] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 694.8 mg kg -1 This oxidative degradation system can remediate 63.52% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 41.3 mg kg -1 It can remediate 69.27% ​​of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0101] Comparative Example 10 The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated manganese dioxide crystalline chlorine dioxide oxidation in this embodiment specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0102] 2. Add catalyst γ-MnO2, activator tungsten disulfide, and oxidant chlorine dioxide solution to a glass bottle. The mass of catalyst γ-MnO2 is 0.0016 g, the mass of activator tungsten disulfide is 0.0064 g, and the final concentration of chlorine dioxide solution (solvent is water) in the reaction system is 2000 mg / L. -1 (The mass ratio of oxidant chlorine dioxide solution, catalyst γ-MnO2, activator tungsten disulfide to polycyclic aromatic hydrocarbons in contaminated soil is 21:1.68:6.72:1). The pH of the reaction system is adjusted to 6, and the total volume of the solution in the system is 10 mL.

[0103] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0104] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0105] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 614.9 mg kg -1 This oxidative degradation system can remediate 67.72% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 40.8 mg kg -1 It can remediate 69.69% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0106] Comparative Example 11 The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated manganese dioxide crystalline chlorine dioxide oxidation in this embodiment specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0107] 2. Add catalyst δ-MnO2, activator tungsten disulfide, and oxidant chlorine dioxide solution to a glass bottle. The mass of catalyst δ-MnO2 is 0.0016 g, the mass of activator tungsten disulfide is 0.0064 g, and the final concentration of chlorine dioxide solution (water as solvent) in the reaction system is 2000 mg / L. -1 (The mass ratio of oxidant chlorine dioxide solution, catalyst δ-MnO2, activator tungsten disulfide to polycyclic aromatic hydrocarbons in contaminated soil is 21:1.68:6.72:1). The pH of the reaction system is adjusted to 6, and the total volume of the solution in the system is 10 mL.

[0108] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0109] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0110] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 623.9 mg kg -1This oxidative degradation system can remediate 67.25% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 40.7 mg kg -1 It can remediate 69.75% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0111] Comparative Example 12 The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated manganese dioxide crystalline chlorine dioxide oxidation in this embodiment specifically includes the following steps: 1. Weigh 0.5 g of contaminated soil containing polycyclic aromatic hydrocarbons (PAHs) after crushing and sieving (particle size 0.25 mm, PAH content 1904 mg / kg). -1 The contents of the sample (including 16 polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene and benzo[a]pyrene) were placed in a 40 mL light-proof brown glass bottle.

[0112] 2. Add catalyst MnO2, activator sodium bicarbonate, and oxidant chlorine dioxide solution to a glass bottle. The mass of catalyst MnO2 is 0.0016 g, the mass of activator sodium bicarbonate is 0.0128 g, and the final concentration of chlorine dioxide solution (solvent is water) in the reaction system is 2000 mg / L. -1 (The mass ratio of oxidant chlorine dioxide solution, catalyst MnO2, activator sodium bicarbonate to the mass of polycyclic aromatic hydrocarbons in the contaminated soil is 21:1.68:13.45:1). The pH of the reaction system is adjusted to 6, and the total volume of the solution in the system is 10 mL.

[0113] 3. Place the reaction system in a shaker, protect from light, and react at 180 rpm and 25°C for 12 h.

[0114] 4. After the reaction is complete, place the mixture in a centrifuge and centrifuge at 3500 rpm for 20 min. Discard the supernatant. The resulting soil is the remediated soil.

[0115] The total content of polycyclic aromatic hydrocarbons in the contaminated soil before and after treatment was measured to be 1904 mg kg. -1 and 457.0 mg kg -1 This oxidative degradation system can remediate 76.00% of polycyclic aromatic hydrocarbons in contaminated soil (see Table 1 for details). The content of benzo[a]pyrene in the contaminated soil before and after treatment was 134.5 mg / kg. -1 and 15.0 mg kg -1 It can remediate 88.81% of benzo[a]pyrene in contaminated soil, as detailed in Table 2.

[0116] Table 1 shows the polycyclic aromatic hydrocarbon content and remediation effect of the contaminated soil before and after treatment in Examples 1-5 and Comparative Examples 1-12. Table 2 shows the benzo[a]pyrene content and remediation effect of the contaminated soil before and after treatment in Examples 1-5 and Comparative Examples 1-12.

[0117] Table 1. Polycyclic aromatic hydrocarbon (PAH) content and remediation effect of contaminated soil before and after treatment in Examples 1-5 and Comparative Examples 1-12. Table 2. Benzo[a]pyrene content and remediation effect of contaminated soil before and after treatment in Examples 1-5 and Comparative Examples 1-12. Examples 1-3 show that activator WS2 has a positive effect on the catalytic activity of amorphous manganese dioxide. Within a certain range, increasing the amount of activator WS2 has a positive effect on the degradation of polycyclic aromatic hydrocarbons. Tungsten disulfide plays a role in the reaction, with both sulfur and tungsten contributing. Sulfur vacancies are generated during the reaction, which facilitates the production of tetravalent tungsten ions. These tetravalent tungsten ions can promote the self-circulation between manganese of different valence states through electron transfer, thereby increasing the catalytic rate.

[0118] As can be seen from the examples and comparative examples 1-3, by adding tungsten disulfide to activate the amorphous manganese dioxide catalyst, the chlorine dioxide oxidation degradation of polycyclic aromatic hydrocarbons in polluted soil can be effectively catalyzed. Only a small amount of tungsten disulfide is needed to effectively improve the catalytic activity of manganese dioxide, thereby improving the performance of chlorine dioxide oxidation degradation of polycyclic aromatic hydrocarbons in polluted soil. Moreover, the degradation effect on benzo[a]pyrene, a common polycyclic aromatic hydrocarbon, is particularly outstanding.

[0119] As can be seen from the examples and comparative examples 4-7 and 8-9, the activator WS2 has a positive effect on the catalytic activity of amorphous manganese dioxide, but no positive effect on crystalline manganese dioxide such as α-MnO2, β-MnO2, γ-MnO2, and δ-MnO2. The degradation rates of cyclic aromatic hydrocarbons and benzo[a]pyrene using crystalline manganese dioxide, chlorine dioxide, and WS2 are consistent with those using crystalline manganese dioxide and chlorine dioxide.

[0120] As can be seen from Examples 1 and 4, the amount of chlorine dioxide added as an oxidant is one of the important factors affecting the degradation effect.

[0121] Examples 2 and 5 show that acidic conditions are conducive to the degradation of polycyclic aromatic hydrocarbons (PAHs). PAHs, as persistent organic pollutants in soil, have carcinogenic, teratogenic, and mutagenic effects, posing a significant threat to the environment and are difficult to degrade. This system primarily relies on the oxidizing effect of chlorine dioxide. However, the aqueous solution of chlorine dioxide is acidic, and the resulting reactive species such as hypochlorous acid are important factors affecting the reaction rate and degradation efficiency. Under alkaline conditions, hydroxide ions in the system consume chlorine dioxide and hypochlorous acid, thus affecting the final degradation effect. Since excessive acidity can easily lead to soil acidification, a pH of 6 is preferred.

[0122] Compared with Comparative Example 12, the addition of activator WS2 significantly improved the degradation capacity of polycyclic aromatic hydrocarbons (PAHs). Compared with NaHCO3, WS2 enabled a more efficient manganese catalytic cycle, providing more stable and sustained catalytic degradation efficiency, thus addressing the higher demand for long-term stability of degradation efficiency. WS2 promotes the generation of free radicals (·OH and ·O2). - This invention can more effectively attack pollutant molecules, and its method can provide a more efficient solution while effectively ensuring the degradation rate. The manganese dioxide, chlorine dioxide, and tungsten disulfide selected in this invention are all environmentally friendly agents that will not cause secondary pollution to the soil. Manganese dioxide is inexpensive and readily available, while tungsten disulfide is recyclable and retains good activity even after multiple recycling cycles, significantly reducing degradation costs. W(Ⅳ) in tungsten disulfide can undergo electron transfer with Mn(Ⅲ), increasing the Mn(Ⅲ) / Mn(Ⅳ) conversion rate. Furthermore, tungsten disulfide generates S vacancies during the reaction, which helps expose the active sites of W(Ⅳ) and promotes the reaction. Reference (Zhao T, Zhang P, Ma L, et al. Synergistic catalysis of tungsten disulfide and manganese ions for the degradation of dimethyldisulfide using chlorine dioxide[J]. Separation and Purification Technology,2025, 352: 127886.) also demonstrates that the activator tungsten disulfide is recyclable and retains significant catalytic effects after repeated use. In practical applications, recyclability greatly reduces costs.

[0123] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for the catalytic degradation of pollutants in soil by tungsten disulfide-activated amorphous manganese dioxide-catalyzed chlorine dioxide oxidation, characterized in that, The catalyst, activator, and oxidant are mixed with the contaminated soil for decontamination and remediation treatment; The catalyst is amorphous manganese dioxide, the oxidant is chlorine dioxide, the activator is tungsten dioxide, and the contaminated soil is soil contaminated by polycyclic aromatic hydrocarbons.

2. The method for the oxidative degradation of pollutants in soil by tungsten disulfide-activated amorphous manganese dioxide catalyzing chlorine dioxide oxidation according to claim 1, characterized in that, Before the degradation and remediation treatment, samples of the contaminated soil were taken, and the total amount of polycyclic aromatic hydrocarbon pollutants contained therein was measured to be 1–2000 mg / kg. -1 .

3. The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated amorphous manganese dioxide catalysis of chlorine dioxide oxidation according to claim 2, characterized in that, Polycyclic aromatic hydrocarbons in contaminated soil were extracted and detected using an extraction solvent, which was n-hexane and / or dichloromethane.

4. The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated amorphous manganese dioxide oxidation according to claim 1, characterized in that, The polycyclic aromatic hydrocarbons are naphthalene, acenaphthene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, etc. One or more of benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indo[1,2,3-cd]pyrene, dibenzo[a,h]anthene, or benzo[g,h,i]perylene.

5. The method for the oxidative degradation of pollutants in soil by tungsten disulfide-activated amorphous manganese dioxide catalyzing chlorine dioxide oxidation according to claim 1, characterized in that, The ratio of the sum of the oxidant and catalyst, the activator, and the mass of polycyclic aromatic hydrocarbon pollutants in the contaminated soil is 1–25:2–20:

1.

6. The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated amorphous manganese dioxide catalysis of chlorine dioxide oxidation according to claim 1, characterized in that, The mass ratio of the oxidant to the catalyst is 5 to 15:

1.

7. The method for the oxidative degradation of pollutants in soil by tungsten disulfide-activated amorphous manganese dioxide catalyzing chlorine dioxide oxidation according to claim 1, characterized in that, In the degradation and remediation process of contaminated soil, the chlorine dioxide exists in solution form with a concentration of 1000–2000 mg / kg. -1 The solvent is water.

8. The method for the oxidative degradation of pollutants in soil by tungsten disulfide-activated amorphous manganese dioxide catalyzing chlorine dioxide according to claim 1, characterized in that, During the degradation and remediation of contaminated soil, the amorphous manganese dioxide and tungsten dioxide exist in powder form.

9. The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated amorphous manganese dioxide catalysis of chlorine dioxide oxidation according to claim 1, characterized in that, During the degradation and remediation of contaminated soil, the pH of the reaction system is 3–6.

10. The method for catalytic degradation of pollutants in soil by tungsten disulfide-activated amorphous manganese dioxide catalysis of chlorine dioxide oxidation according to claim 1, characterized in that, The oxidant, catalyst and activator are mixed with the contaminated soil by one or more of the following methods: spraying, drip irrigation, stirring, and shaking.

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