Method for degrading polycyclic aromatic hydrocarbon by organic matter reinforced persulfate system

Abstract

The invention relates to a method for degrading polycyclic aromatic hydrocarbon by an organic matter reinforced persulfate system, persulfate and an alkali activator are added into polycyclic aromatic hydrocarbon polluted soil and heated to form an advanced oxidation system, the removal efficiency of polycyclic aromatic hydrocarbon in the polluted soil is enhanced by adding organic matter, and the degradation rate of polycyclic aromatic hydrocarbon can reach 95% or above. Compared with the prior art, the problems that mass transfer of a persulfate system is limited, instability is caused by interference of influence factors in soil and the like can be solved, meanwhile, the degradation rate of polycyclic aromatic hydrocarbon is further increased, the added organic matter is safe and non-toxic, secondary pollution to the environment is avoided, and the polycyclic aromatic hydrocarbon degradation agent can be applied to organically-polluted soil. And high-efficiency removal of polycyclic aromatic hydrocarbon pollution is realized.

Description

Technical Field

[0001] The present invention belongs to the field of soil pollution remediation and relates to a method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system. Background Art

[0002] Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic, teratogenic, and mutagenic organic pollutants with high toxicity and environmental persistence. They are commonly found in industrial contaminated sites, such as those at the petrochemical and coking gas sites. PAHs enter soil and groundwater through natural sedimentation and migration, with concentrations in soil far exceeding those in groundwater, posing a serious threat to environmental safety and human health. Therefore, a green, efficient, and safe remediation method is urgently needed to degrade PAH contaminants in sites.

[0003] In recent years, persulfate (PS) has gradually developed into a mainstream oxidant in advanced oxidation processes due to its high chemical stability, low storage and transportation risks, and economic cost advantages. Thermal activation achieves targeted cleavage of peroxide bonds in persulfate through controllable temperature rise, and has shown unique advantages in soil pollution control due to its adaptability to in situ remediation. This process does not require the introduction of exogenous chemical reagents, and can avoid the potential risk of metal ion dissolution during transition metal activation, as well as the inherent defects of carbon-based material systems such as difficult material recovery and low reuse rate. The alkali-activated persulfate system consumes the H generated by the decomposition of persulfate through a neutralization reaction. + , which can effectively inhibit environmental risks such as impaired microbial activity and heavy metal ion dissolution caused by excessive soil acidification, and also has the potential for application as an in-situ remediation technology. Therefore, the combined action of thermal activation and alkaline activation can fully leverage their respective advantages to achieve better degradation results. It is a simple, environmentally friendly, and highly practical treatment technology. However, its implementation currently faces many challenges, such as strong dependence on activation conditions, mass transfer limitations and free radical quenching, and energy consumption and economic bottlenecks.

[0004] CN111940485A discloses a chemical oxidation remediation agent for organically contaminated soil, comprising the following components by weight: 2 parts oxidant, 4 parts activator, wherein the oxidant is one or more of sodium persulfate, ammonium persulfate, and potassium persulfate, and the activator is one or more of calcium oxide and soda lime. The method for using the chemical oxidation remediation agent includes the following steps: 1) crushing and screening the organically contaminated soil to obtain a pretreated soil sample; 2) mixing the pretreated soil sample with the chemical oxidation remediation agent and stirring uniformly to obtain a mixed soil sample; 3) adding sufficient water to the original mixed soil sample and stirring uniformly until water precipitates to obtain a medicated slurry; and 4) curing the medicated slurry in a dark place. However, after using this chemical oxidation remediation agent, problems such as long reaction time and high oxidant and activator dosages are still present.

[0005] Therefore, it is necessary to provide a method for strengthening the combined activation of hot alkali persulfate system, which can maintain a high removal rate of PAHs in complex soil media, while reducing the amount of activator and oxidant, lowering energy consumption and cost to ensure the greenness and economy of the persulfate system for PAHs degradation. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system. By using an organic matter-enhanced persulfate system to degrade polycyclic aromatic hydrocarbons, combined with the combined effects of thermal activation and alkali activation, the activation effect of persulfate can be improved, and polycyclic aromatic hydrocarbon pollution can be efficiently repaired. The method is simple to operate, has a high degradation rate, a wide range of applications, and can be applied to the repair of high-concentration polycyclic aromatic hydrocarbon pollution.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The object of the present invention is to provide a method for degrading polycyclic aromatic hydrocarbons by an organic matter-enhanced persulfate system, the method comprising the following steps:

[0009] S1. Adding an oxidant, an activator, and deionized water to a polycyclic aromatic hydrocarbon-contaminated soil sample to obtain a mixed sample, and mixing the mixed sample uniformly to obtain a soil system to be reacted, wherein the oxidant is persulfate and the activator is calcium oxide;

[0010] S2. Adding organic matter to the soil system to be reacted obtained in step S1, mixing evenly, and heating the system to degrade polycyclic aromatic hydrocarbons in the soil.

[0011] Furthermore, in step S1, the pollutants in the polycyclic aromatic hydrocarbons-contaminated soil sample are high-concentration polycyclic aromatic hydrocarbons, and the total concentration of polycyclic aromatic hydrocarbons is 300 mg / kg.

[0012] Furthermore, in step S1, the persulfate is sodium persulfate or potassium persulfate.

[0013] Furthermore, in step S1, the dosage of the persulfate is 1-20 mmol.

[0014] Further preferably, in step S1, the dosage of the persulfate is 10 mmol.

[0015] Furthermore, in step S1, the molar ratio of persulfate to calcium oxide is 1:0.1-1:1.

[0016] Further preferably, in step S1, the molar ratio of persulfate to calcium oxide is 1:1.

[0017] Furthermore, in step S2, the heating temperature is 60-80°C.

[0018] More preferably, in step S2, the heating temperature is 60°C.

[0019] Furthermore, in step S2, the organic matter is humus material.

[0020] Furthermore, the humus material is added at a concentration of 1-5 g / kg.

[0021] Furthermore, the humus material is one of humic acid, biogenic fulvic acid and mineral-derived fulvic acid.

[0022] Furthermore, the polycyclic aromatic hydrocarbons-contaminated soil, organic matter, calcium oxide, persulfate and deionized water form an oxidation system, and the water-soil ratio of the oxidation system is 2:1.

[0023] Compared with the prior art, the present invention has the following characteristics:

[0024] 1) The present invention provides a method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system, which uses humic material as a reinforcing agent to help the persulfate system accelerate the degradation of organic pollutants.

[0025] 2) The persulfate used in the present invention has stable physical and chemical properties, high removal efficiency for polycyclic aromatic hydrocarbons, no secondary pollution, and is environmentally friendly.

[0026] 3) The method provided by the present invention for degrading polycyclic aromatic hydrocarbons using an organic matter-enhanced persulfate system is green and safe, and no toxic or harmful byproducts are generated during the removal process. It is applicable to soil contaminated with high concentrations of polycyclic aromatic hydrocarbons, and the degradation rate can reach over 95%.

[0027] 4) The method provided by the present invention for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system has low cost, high economic applicability, is applicable to various complex site environments, is less affected by the environmental matrix, and has high stability.

[0028] 5) The present invention provides a method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system. By using an organic matter-enhanced persulfate system to degrade polycyclic aromatic hydrocarbons, combined with the combined effects of thermal activation and alkaline activation, the activation effect of persulfate can be improved, and polycyclic aromatic hydrocarbon pollution can be efficiently degraded. This method is simple to operate, has high treatment efficiency, a wide range of applications, and can be applied to the remediation of high-concentration polycyclic aromatic hydrocarbon pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the effect of the persulfate concentration of Comparative Examples 1 to 5 of the present invention on the degradation of polycyclic aromatic hydrocarbons in the system.

[0030] Figure 2 The figure shows the effect of the molar ratio of CaO to PS dosage on the degradation of polycyclic aromatic hydrocarbons in the system in Comparative Examples 6 to 10 of the present invention and the blank control group.

[0031] Figure 3 This is Example 1 of the present invention, which shows the effects of different humus material dosages on the degradation of polycyclic aromatic hydrocarbons in simulated contaminated soil.

[0032] Figure 4 This is Example 2 of the present invention, which shows the effects of different humus material dosages on the degradation of polycyclic aromatic hydrocarbons in contaminated soil at an actual site. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the accompanying drawings and the following embodiments are intended only to illustrate the present invention and are not intended to limit the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the scope of the present invention. Such modifications and improvements are all within the scope of protection of the present invention.

[0034] Any features such as preparation methods, materials, structures or composition ratios that are not clearly described in this technical solution shall be deemed to be common technical features disclosed in the prior art.

[0035] The present invention relates to a method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system. Persulfate (sodium persulfate) and an alkaline activator (calcium oxide) are added to polycyclic aromatic hydrocarbon contaminated soil and heated (40-80°C) to form an advanced oxidation system. The removal rate of polycyclic aromatic hydrocarbons in the contaminated soil is enhanced by adding organic matter, and the degradation rate of polycyclic aromatic hydrocarbons can reach more than 95%. The present invention can overcome the problems of limited mass transfer and instability caused by interference from influencing factors in the soil in the persulfate system, while further improving the degradation rate. The added organic material is safe and non-toxic, will not cause secondary pollution to the environment, and can be applied to soil contaminated by organic pollutants. Efficient removal of polycyclic aromatic hydrocarbon pollution is achieved.

[0036] In the present invention, the applicant proposes a method for degrading polycyclic aromatic hydrocarbons using an organic matter-enhanced persulfate system, which can be directly applied to in-situ remediation of sites. Thermally activated persulfate does not require the addition of an additional catalyst, has a wide pH range of application, and does not suffer from secondary pollution caused by metal ion leaching, difficulty in catalyst recovery, and poor reusability. Alkali-activated persulfate (calcium oxide-activated persulfate is used in the present invention) can effectively neutralize the H generated by the decomposition of persulfate. + , avoiding excessive acidification of the soil, and is also suitable for in-situ remediation of the soil. Therefore, the combined action of thermal activation and alkaline activation can give full play to their respective advantages to achieve a better degradation effect. It is a treatment technology that is simple to operate, environmentally friendly and highly practical, and can effectively treat difficult-to-degrade organic pollutants in the soil. Adding organic matter (humic acid or fulvic acid) to the persulfate system, because the quinone functional group structure in the organic matter can activate persulfate to produce new active species (singlet oxygen), can strengthen the persulfate oxidation system, improve the degradation rate of PAHs by the persulfate system, and overcome the challenges of the combined activation system, such as strong dependence on activation conditions, limited mass transfer and easy quenching of free radicals, energy consumption and economic bottlenecks.

[0037] Specific embodiment 1: This embodiment provides a method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system, which is accomplished by the following steps:

[0038] 1. adding an oxidant, an activator, and deionized water to the polycyclic aromatic hydrocarbon-contaminated soil and uniformly mixing them with the soil sample to be treated, wherein the oxidant is persulfate and the catalyst is calcium oxide (CaO);

[0039] 2. Add organic matter to the soil to be treated, mix it thoroughly, and then heat the mixed contaminated soil to efficiently degrade polycyclic aromatic hydrocarbons in the soil.

[0040] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the persulfate in step 1 is potassium persulfate or sodium persulfate. The other steps are the same as those in specific embodiment 1.

[0041] Specific embodiment three: The difference between this embodiment and specific embodiments one to two is that the concentration of polycyclic aromatic hydrocarbons contained in the contaminated soil in step one is 300 mg / kg, and the other steps are the same as specific embodiments one to two.

[0042] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the dosage of persulfate in step 1 is 10 mmol. The other steps are the same as those of specific embodiments 1 to 3.

[0043] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the activator in step 1 is calcium oxide and the molar ratio of persulfate to calcium oxide is 1:1. The other steps are the same as specific embodiments 1 to 4.

[0044] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the heating temperature in step 1 is 60° C. The other steps are the same as those in specific embodiments 1 to 5.

[0045] Specific embodiment 7: This embodiment differs from Specific embodiments 1 to 6 in that the PAH-contaminated soil sample, organic matter, calcium oxide, and persulfate form an oxidation system with a water-to-soil ratio of 2:1. The other steps are the same as Specific embodiments 1 to 6.

[0046] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that the organic matter in step 2 is one of humic acid, biogenic fulvic acid, or mineral-derived fulvic acid, and the added amount is 1-5 g / kg. The other steps are the same as specific embodiments 1 to 7.

[0047] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the reaction time in step 2 is 12 hours. The other steps are the same as those in specific embodiments 1 to 8.

[0048] In the following examples, the raw materials used can be purchased commercially.

[0049] Among them, humic acid (Shanghai Aladdin Biochemical Technology Co., Ltd., CAS: 1415-93-6), bio-source fulvic acid (Beijing Bowei Shennong Technology Co., Ltd., 95% biochemical fulvic acid), and mineral-source fulvic acid (Beijing Bowei Shennong Technology Co., Ltd., 85% mineral-source fulvic acid).

[0050] The persulfate (PS) solution is 1 mol / L sodium persulfate solution and the solvent is deionized water.

[0051] The first set of experiments

[0052] Comparative Example 1

[0053] This comparative example provides a method for degrading polycyclic aromatic hydrocarbons using a persulfate system.

[0054] The above method comprises the following steps:

[0055] Weigh 10g of simulated polycyclic aromatic hydrocarbon contaminated soil into a 100mL glass conical flask, add 10mL of 1mol / L PS solution, 10mmol of calcium oxide (CaO) and 10mL of deionized water. Then seal the conical flask with tin foil and place it in a heat-collecting constant temperature heating magnetic stirrer (100rpm) that has been pre-heated to 60°C for reaction. After the required reaction time (2h, 4h, 6h, 8h, 10h, 12h) is reached, remove the conical flask and immediately add 5mL of sodium thiosulfate solution (2mol / L) to terminate the reaction. The total residual PAHs content is determined by GC-MS. The results are shown in Figure 2. Figure 1 .

[0056] The simulated contaminated soil was prepared on our own. Testing revealed initial pollutant contents of: naphthalene (Nap) 58.732±1.645 mg / kg, fluorene (FLR) 76.624±2.537 mg / kg, phenanthrene (PHE) 82.427±1.361 mg / kg, and fluoranthene (FLT) 81.865±1.763 mg / kg, totaling approximately 300 mg / kg. The organic matter content was 10.3 g / kg.

[0057] Comparative Example 2

[0058] Compared with Comparative Example 1, the only difference is that the amount of PS added is 1 mmol.

[0059] Comparative Example 3

[0060] Compared with Comparative Example 1, the only difference is that the amount of PS added is 3 mmol.

[0061] Comparative Example 4

[0062] Compared with Comparative Example 1, the only difference is that the amount of PS added is 5 mmol.

[0063] Comparative Example 5

[0064] Compared with Comparative Example 1, the only difference is that the amount of PS added is 20 mmol, and no deionized water is added.

[0065] Depend on Figure 1As can be seen, the degradation rate of PAHs increases with increasing PS concentration. At a dosage of 10 mmol, PAHs can be degraded by over 90% within 12 hours. After the PS dosage exceeds 10 mmol, the PAH degradation rate stabilizes, with little change in the increase. This indicates that increasing the oxidant dosage within a certain range can improve the pollutant degradation rate, but beyond a critical value (10 mmol), further increases in oxidant concentration have little effect on pollutant degradation. This is closely related to the dynamic equilibrium mechanism of free radical generation and consumption.

[0066] The second set of experiments

[0067] Comparative Example 6

[0068] This comparative example provides a method for degrading polycyclic aromatic hydrocarbons using a persulfate system.

[0069] The above method comprises the following steps:

[0070] Weigh 10g of PAHs simulated contaminated soil into a 100mL glass conical flask, and add 10mL of 1mol / L PS solution, 10mmol of calcium oxide (CaO), and 10mL of deionized water. Then seal the conical flask with tin foil and place it in a heat-collecting constant-temperature heating magnetic stirrer (100rpm) heated to 60°C for reaction. After the desired reaction time (2h, 4h, 6h, 8h, 10h, 12h) is reached, remove the conical flask and immediately add 5mL of sodium thiosulfate solution (2mol / L) to terminate the reaction. The total residual PAHs content is determined by GC-MS. The results are shown in Figure 2. Figure 2 .

[0071] Comparative Example 7

[0072] Compared with Comparative Example 6, the only difference is that the molar ratio of CaO to PS is 0.1:1.

[0073] Comparative Example 8

[0074] Compared with Comparative Example 6, the only difference is that the molar ratio of CaO to PS is 0.3:1.

[0075] Comparative Example 9

[0076] Compared with Comparative Example 6, the only difference is that the molar ratio of CaO to PS is 0.5:1.

[0077] Comparative Example 10

[0078] Compared with Comparative Example 6, the only difference is that the molar ratio of CaO to PS is 0.7:1.

[0079] Blank control group

[0080] Compared with Comparative Example 6, the only difference is that no CaO is added.

[0081] Depend on Figure 2 It can be seen that compared with the blank control group without CaO, the degradation rate of PAHs was significantly improved after adding CaO, indicating that the degradation effect of the persulfate system activated by hot alkali is better than that of the system activated by heat alone. When the molar ratio of CaO to PS increased from 0.1:1 to 1:1, the degradation rate of PAHs also gradually increased. This shows that higher concentrations of CaO activated PS can produce more SO4 - ·, and SO4 - · will be converted into ·OH, both of which participate in the degradation process and promote the degradation of PAHs.

[0082] The third group of experiments

[0083] Example 1

[0084] The experimental group of this embodiment provides a method for degrading PAHs in simulated contaminated soil by using an organic matter-enhanced persulfate system.

[0085] Based on the first and second groups of experiments, a persulfate oxidation system was constructed with the following reaction conditions: PS = 10 mmol, CaO = 10 mmol, water-soil ratio = 2:1, and reaction temperature = 60°C. Different types and contents of humus materials (i.e., organic matter) were added to the simulated contaminated soil to achieve enhanced organic matter remediation. Different addition methods were set:

[0086] 1) 5g / kg humic acid / biosource fulvic acid / mineral source fulvic acid (PS-free system).

[0087] 2) 0g / kg humic acid / biosource fulvic acid / mineral source fulvic acid + PS system.

[0088] 3) 1g / kg humic acid / biosource fulvic acid / mineral source fulvic acid + PS system.

[0089] 4) 2g / kg humic acid / biosource fulvic acid / mineral source fulvic acid + PS system.

[0090] 5) 3g / kg humic acid / biosource fulvic acid / mineral source fulvic acid + PS system.

[0091] 6) 5g / kg humic acid / biosource fulvic acid / mineral source fulvic acid + PS system.

[0092] The method of this embodiment specifically includes the following steps:

[0093] S1. Add 10 mL of 1 mol / L PS solution, 10 mmol of CaO, and 10 mL of deionized water to the simulated contaminated soil and mix well to obtain the treated soil (for the above-mentioned addition method 1, this is actually a comparative example, in which no PS solution and CaO are added);

[0094] S2. Add organic matter to the soil to be treated obtained in step S1 (for the above-mentioned addition method 2, it is actually a comparative example, and no organic matter is added). After mixing evenly, the mixed contaminated soil is placed in a heat-collecting constant temperature heating magnetic stirrer (100 rpm) heated to 60° C. and reacted for 12 hours to degrade polycyclic aromatic hydrocarbons in the soil.

[0095] Depend on Figure 3 As can be seen, when only organic materials were added to the system without PS, the PAH degradation rate was low, below 10%, indicating that the physical adsorption or complexation of organic materials alone contributed only limitedly to the oxidative degradation of PAHs. However, after the organic materials were introduced into the PS system, the PAH degradation rate increased to varying degrees compared to the PS system alone. When humic acid, biogenic fulvic acid, and mineral-derived fulvic acid were added at a dosage of 5g / kg, the PAH degradation rates were 98.29%, 96.32%, and 97.67%, respectively, representing increases of 6.62%, 4.64%, and 6.01%, respectively, compared to the absence of humic acid. This demonstrates that the low-concentration addition of humic materials can enhance the degradation efficiency of the persulfate oxidation system for PAHs.

[0096] The fourth set of experiments

[0097] Example 2

[0098] The experimental group of this example provides a method for degrading PAHs in real-world contaminated soil using an organic matter-enhanced persulfate system. The real-world contaminated soil was collected from a coking plant in Shaanxi Province at a depth of 0-1 m. It was transported to the laboratory frozen and stored at 4°C in the dark. Testing revealed an organic matter content of 6.92 g / kg, a pH of 8.13, and a moisture content of 10.7%. After pretreatment with a 20-mesh sieve, the initial PAH concentration in the soil was determined (as shown in Table 1).

[0099] Table 1 PAHs content in contaminated soil at actual site

[0100]

[0101]

[0102] A persulfate oxidation system was constructed with the following reaction conditions: PS = 10 mmol, CaO = 10 mmol, water-soil ratio = 2:1, and reaction temperature = 60°C. Different types and contents of humus materials were added to the contaminated soil at the actual site to achieve enhanced organic matter remediation. Different addition methods were set:

[0103] 1) 5g / kg humic acid / biosource fulvic acid / mineral source fulvic acid (PS-free system).

[0104] 2) 0g / kg humic acid / biosource fulvic acid / mineral source fulvic acid + PS system.

[0105] 3) 1g / kg humic acid / biosource fulvic acid / mineral source fulvic acid + PS system.

[0106] 4) 2g / kg humic acid / biosource fulvic acid / mineral source fulvic acid + PS system.

[0107] 5) 3g / kg humic acid / biosource fulvic acid / mineral source fulvic acid + PS system.

[0108] 6) 5g / kg humic acid / biosource fulvic acid / mineral source fulvic acid + PS system.

[0109] The method of this embodiment specifically includes the following steps:

[0110] S1. Add 10 mL of 1 mol / L PS solution, 10 mmol of CaO, and 10 mL of deionized water to the actual contaminated soil at the site and mix them evenly to obtain the soil to be treated (for the above-mentioned addition method 1, this is actually a comparative example, in which no PS solution and CaO are added);

[0111] S2. Add organic matter to the soil to be treated obtained in step S1 (for the above-mentioned addition method 2, it is actually a comparative example, and no organic matter is added). After mixing evenly, the mixed contaminated soil is placed in a heat-collecting constant temperature heating magnetic stirrer (100 rpm) heated to 60° C. and reacted for 12 hours to degrade polycyclic aromatic hydrocarbons in the soil.

[0112] Depend on Figure 4 It can be seen that after the introduction of organic materials into the PS system, the degradation rate of PAHs increased to varying degrees compared with the single PS system. Compared with the absence of humic substances, the PAHs degradation rate increased by 11.50%, 10.54% and 11.72% after adding 5g / kg of humic materials. This synergistic effect may be due to the following mechanism: the persistent free radicals generated during the decomposition of organic matter can form electron transfer complexes with PS, promoting the degradation of SO4 -At the same time, the aldehyde functional group structure in organic matter can activate persulfate to produce new active species (singlet oxygen), thereby strengthening the persulfate oxidation system and improving the degradation efficiency of the persulfate system for PAHs.

[0113] The present invention provides a method for using humus materials to strengthen the persulfate oxidation system, thereby accelerating the degradation of PAHs in the soil. Compared with existing PAHs pollution remediation technologies, this method is highly economical, green and harmless, and has a wide range of applications.

[0114] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

[0115] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system, characterized in that: The method comprises the following steps: S1. Adding an oxidant, an activator, and deionized water to a polycyclic aromatic hydrocarbon-contaminated soil sample to obtain a mixed sample, and mixing the mixed sample uniformly to obtain a soil system to be reacted, wherein the oxidant is persulfate and the activator is calcium oxide; S2. Adding organic matter to the soil system to be reacted obtained in step S1, mixing evenly, and heating the mixed contaminated soil to degrade polycyclic aromatic hydrocarbons.

2. The method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system according to claim 1, wherein: In step S1, the pollutants in the polycyclic aromatic hydrocarbons-contaminated soil sample are high-concentration polycyclic aromatic hydrocarbons, and the total concentration of polycyclic aromatic hydrocarbons is 300 mg / kg.

3. The method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system according to claim 1, wherein: In step S1, the persulfate is sodium persulfate or potassium persulfate.

4. The method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system according to claim 1, wherein: In step S1, the dosage of the persulfate is 1-20 mmol; In step S1, the molar ratio of persulfate to calcium oxide is 1:0.1-1:

1.

5. The method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system according to claim 4, wherein: In step S1, the dosage of the persulfate is 10 mmol; In step S1, the molar ratio of persulfate to calcium oxide is 1:

1.

6. The method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system according to claim 1, wherein: In step S2, the heating temperature is 40-80°C.

7. The method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system according to claim 6, characterized in that: In step S2, the heating temperature is 60°C.

8. The method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system according to claim 1, characterized in that: In step S2, the organic matter is humus material; The added amount of the humus material is 1-5 g / kg.

9. The method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system according to claim 8, characterized in that: The humic material is one of humic acid, biogenic fulvic acid and mineral-derived fulvic acid.

10. The method for degrading polycyclic aromatic hydrocarbons by using an organic matter-enhanced persulfate system according to claim 1, characterized in that: The polycyclic aromatic hydrocarbon-contaminated soil, organic matter, calcium oxide, persulfate and deionized water form an oxidation system, and the water-soil ratio of the oxidation system is 2:1.

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