Method for removing polycyclic aromatic hydrocarbon in underground water by activating persulfate with boron-reinforced ferric iron

Abstract

The invention relates to the technical field of water treatment, and provides a method for removing polycyclic aromatic hydrocarbon in underground water by activating persulfate with boron-reinforced ferric iron, which comprises the following steps: adding PS solid powder with a relative pollutant molar ratio of 20: 1-120: 1 into an underground water solution polluted by polycyclic aromatic hydrocarbon, and then adding B and ferric iron as a reinforcing system, in-situ production of ferrous iron is realized by slowly releasing Fe (II), and the system is intensively activated. The Fe (III) iron source can slowly release Fe (II) into the environment in the reducing atmosphere, compared with a traditional method of directly adding Fe (II), PS cannot be consumed rapidly, self-cleaning can be avoided, and efficient utilization of an oxidizing agent can be achieved; the added Fe (III) reducing agent B is cheap and easy to obtain, Fe (III) is continuously reduced and converted into Fe (II) in the reaction process, the utilization efficiency of the oxidizing agent and the catalyst is improved, and efficient and lasting treatment of pollutants is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental treatment, relates to groundwater treatment technology, and specifically relates to a method for removing polycyclic aromatic hydrocarbons in groundwater by activating persulfate with boron-enhanced trivalent iron. Background Art

[0002] With the acceleration of urbanization and industrial transfer in my country, some traditional industries have begun to move to the central and western regions, releasing land and other resource elements. At the same time, in order to achieve the "dual carbon" goal, high-energy-consuming industries are orderly transferring and gathering to the central and western regions. The process of industrial adjustment has led to the emergence of a large number of industrial legacy pollution sites in and around cities. The 2021 Ecological Environment Bulletin pointed out that the soil risks of land used by enterprises in key industries across the country cannot be ignored. In a survey of 277 organic pollution sites across the country in 2022, polycyclic aromatic hydrocarbons (PAHs) pollution sites accounted for the largest proportion. In recent years, due to the urgent need for redevelopment of industrial pollution sites in my country, a large number of projects have a short restoration cycle. Therefore, in order to achieve a rapid reduction in the total amount and concentration of groundwater pollution, high-intensity restoration measures such as extraction-treatment, advanced oxidation technology, and water-stopping curtain + excavation are widely used.

[0003] Advanced oxidation technology is based on chemical oxidation. It uses strong oxidizing free radicals to decompose highly resistant and highly toxic organic matter into less harmful mineralized products, showing good results in the control of persistent organic pollution. Among them, in-situ chemical oxidation (ISCO) is an important means of soil and groundwater remediation. It has the advantages of small site disturbance and low cost. It has great advantages in the remediation of contaminated areas in confined areas. The oxidants commonly used in ISCO technology are mainly potassium permanganate (KMnO 4 ), ozone, hydrogen peroxide (H 2 O 2 ), persulfate (PS), etc. In KMnO 4 In the technology, manganese dioxide is an intermediate substance in the reaction, which may reduce the permeability of the bottom layer, affect the mass transfer process of the oxidant and inhibit the degradation of pollutants. The traditional Fenton reaction refers to H 2 O 2 Hydroxyl radicals (HO·) are generated under the catalysis of ferrous ions (Fe(II)). HO· can react non-selectively with most organic pollutants. However, due to high concentrations of H 2 O 2 It is unstable, reacts quickly, and produces a large amount of gas and heat, which poses a great safety hazard when used on site.

[0004] PS oxidation technology has the advantages of fast reaction rate, wide application range and mild reaction conditions, and therefore has attracted widespread attention. However, traditional PS technology requires Fe(II) activation to achieve the purpose of pollutant degradation. During the reaction, a large amount of trivalent iron (Fe(III)) will be produced. At the same time, the reduction of Fe(III) is very slow, so it is easily converted into Fe(OH) in the groundwater environment. 3 At the same time, traditional Fe(II) will quickly activate PS to produce a large number of free radicals in a short time. These free radicals will not only react with pollutants, but also scavenge oxidants or self-scavenge, resulting in waste of oxidants and reducing the utilization efficiency of oxidants.

[0005] Boron (B) has many properties similar to carbon and can act as an electron donor to play the role of a reducing agent. During the reaction, Fe(III) can be reduced and converted into Fe(II), thereby promoting the Fenton-like reaction. Therefore, it is theoretically valuable to replace Fe(II) with Fe(III) that can slowly release iron. The present invention aims to utilize the reducing properties of B to enhance the Fe(III) activation of PS to degrade polycyclic aromatic hydrocarbons, so as to overcome the above-mentioned shortcomings. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of existing advanced oxidation technologies in the practice of contaminated groundwater remediation, and to provide a method for removing polycyclic aromatic hydrocarbons in groundwater by Fe(III) activated PS under boron reduction, thereby achieving efficient and lasting treatment of pollutants and reducing the cost of groundwater remediation in contaminated sites.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] The technical scheme provided by the present invention for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced trivalent iron is as follows: PS solid powder having a relative molar ratio of 20:1 to 120:1 to the pollutant is added to the groundwater solution contaminated by polycyclic aromatic hydrocarbons, and then B and trivalent iron are added as an enhanced system, and divalent iron is generated in situ by slowly releasing Fe(II), and the system is enhanced and activated.

[0009] Preferably, the polycyclic aromatic hydrocarbons are one or more of fluoranthene (FLT), naphthalene (NAP) and phenanthrene (PHE). Further, the concentration ranges of fluoranthene, naphthalene and phenanthrene in the contaminated water suitable for treatment by the method are 0.0001-0.001 mmol / L, 0.01-0.05 mmol / L and 0.1-1 mg·L, respectively. -1 .

[0010] Preferably, the molar ratio of PS solid powder to ferric iron is 3 to 10:1, and the molar ratio of B to ferric iron is 7 to 20:1. Furthermore, the dosage of ferric iron added is 0.01 to 0.1 mmol / L, and the dosage of B added is 0.002 to 0.008 g·L -1 The PS dosage added is 0.1~1.0mmol / L.

[0011] Preferably, the pH value of the PAH-contaminated groundwater solution is adjusted to 3 to 5 before treatment. Experimental results show that the degradation effect of the system of the present invention on FLT, NAP and PHE is significantly improved under acidic and weakly acidic conditions compared with alkaline and neutral environments.

[0012] Preferably, the reaction conditions of the present invention are as follows: the reaction temperature is controlled to be 20±0.5°C, and stirring is performed during the reaction. Conventional stirring can be used for stirring. The stirring method used in the experimental process of the present invention is magnetic stirring, and the speed is 550-650r·min -1 .

[0013] Preferably, the trivalent iron is one or more of ferric sulfate, ferric chloride and ferric nitrate.

[0014] Preferably, the PAH-contaminated groundwater solution can contain one or both of inorganic anions and humic acid. - ), sulfate ion (SO 4 2- ) and nitrate ions (NO 3 - ), and humic acid was added to simulated polluted water in another experiment. The results showed that the technology of the present invention has a good adaptability to inorganic anions and humic acid in aqueous solution and does not affect the effective removal of polycyclic aromatic hydrocarbons.

[0015] The beneficial protection and effects of the present invention are as follows:

[0016] Compared with the prior art, the present invention has the following positive effects: ① The present invention uses Fe(III) as an iron source, which can slowly release Fe(II) into the environment under a reducing atmosphere. Compared with the traditional direct addition of Fe(II), it will not quickly consume PS, and can avoid self-cleaning to achieve efficient utilization of the oxidant; ② The added Fe(III) reducing agent B is cheap and easy to obtain, and continuously reduces Fe(III) to Fe(II) during the reaction process, thereby improving the utilization efficiency of the oxidant and the catalyst, achieving efficient and lasting treatment of pollutants, and helping to reduce the cost of drug use. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the XPS characterization diagram of B before and after the reaction in Example 1;

[0018] Figure 2 This is a graph showing the change in removal rate of FLT over time in different systems in a simulated groundwater environment in Example 2;

[0019] Figure 3 This is a graph showing the change in removal rate of FLT over time in simulated groundwater environments with different initial pH values ​​in Example 3;

[0020] Figure 4 This is a graph showing the change in removal rate of FLT over time in a simulated groundwater environment containing different anions in Example 4;

[0021] Figure 5 This is a graph showing the change in removal rate of FLT over time in a simulated groundwater environment containing humic acid in Example 5;

[0022] Figure 6 is a graph showing the change in removal rate of FLT in an actual groundwater environment over time in Example 6;

[0023] Figure 7 It is a graph showing the change of removal rate of NAP and PHE in a simulated groundwater environment over time in Example 7;

[0024] Figure 8 This is a graph showing the change in removal rate of NAP and PHE over time in an actual groundwater environment in Example 8. DETAILED DESCRIPTION

[0025] The implementation of the present invention is described in detail below in conjunction with the embodiments of the present invention. The following embodiments are implemented on the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following embodiments.

[0026] Example 1

[0027] A method for removing fluoranthene from groundwater by activating PS with boron-reduced iron catalyst, comprising PS, Fe(III), B and FLT, wherein the dosage ratio of PS, Fe(III) and FLT is 60 / 20 / 1, and the dosage of B is 0.002 g·L -1 250 mL of simulated groundwater solution with an initial FLT concentration of 0.001 mM was prepared, and a certain dose of B, trivalent iron and oxidant PS were added to the solution in sequence. The solution was fully stirred during the chemical oxidation process. The reaction temperature was controlled at 20 ± 0.5 °C, the total reaction time was 120 min, and the magnetic stirring speed was 550-650 r·min -1 After the reaction, the B was collected by vacuum filtration, ultrapure water washing, vacuum drying and other steps, and the Fe valence state and content changes on the surface of B were analyzed by X-ray photoelectron spectroscopy.

[0028] The results are as follows Figure 1 As shown, the binding energy peaks at 711.49eV and 725.35eV belong to Fe(III); the binding energy peaks at 710.09eV and 724.1eV belong to Fe(II); and there are two Fe2P 3 / 2 Satellite peaks correspond to Fe(II) and Fe(III), respectively; the other two Fe2P 1 / 2 Satellite peaks appear at 730.41eV and 735.30eV. After integrating and calculating the area of ​​the peaks corresponding to Fe(II) and Fe(III), the proportion of Fe in different valence states on the surface of B after the reaction can be obtained, of which Fe(II) accounts for 47.77% and Fe(III) accounts for 52.23%, indicating that during the degradation of FLT by the PS / Fe(III) / B system, a reduction reaction of Fe(III) regenerating into Fe(II) occurred on the surface of B. The experimental results prove the feasibility of the technology of the present invention to use B to strengthen the reduction of iron-based catalysts to activate PS.

[0029] Example 2

[0030] A method for removing fluoranthene from groundwater by activating PS with boron-reduced iron catalyst, comprising PS, Fe(III), Fe(II), B and FLT, wherein the molar ratio of PS, Fe(III) and FLT is 60 / 20 / 1, the molar ratio of PS, Fe(II) and FLT is 60 / 20 / 1, and the dosage of B is 0.002 g·L -1 250 mL of simulated groundwater solution with an initial FLT concentration of 0.001 mM was prepared, and a certain dose of B, iron-based catalyst (ferrous iron, ferric iron) and oxidant PS were added to the solution in sequence. The solution was fully stirred during the chemical oxidation process. The reaction temperature was controlled at 20 ± 0.5 °C, the total reaction time was 120 min, and the magnetic stirring speed was 550-650 r·min -1 , samples were taken at 0, 2, 5, 15, 30, 60, and 120 min, and the reaction was quenched with an equal volume of methanol. The FLT concentration in the samples was then analyzed by liquid chromatography.

[0031] The experimental results are as follows Figure 2 As shown in the figure, the removal effect of single or combined technology of PS and B on FLT is not obvious. After 120 minutes, the technology of the present invention has a better removal effect than PS / Fe(II), PS / Fe(II) / B and PS / Fe(III) technologies. Without adding B, the removal rate of FLT by PS / Fe(II) / FLT system is 59.5%, and the removal rate of FLT by PS / Fe(III) / FLT system is 24.4%. When 0.002 g L-1 Under the condition of B, the removal rate of FLT by PS / Fe(II) / FLT system is 92.1%, and the removal rate of FLT by PS / Fe(III) / FLT system is 100%, which indicates that the technology of the present invention has a good promoting effect on the removal of FLT, and compared with the PS / Fe(II) / B / FLT system, the PS / Fe(III) / B / FLT system can achieve a higher FLT removal rate, which proves that the addition of B enhances the ability of Fe(III) to catalyze PS to degrade FLT.

[0032] Example 3

[0033] A method for removing fluoranthene from groundwater by activating PS with boron-reduced iron catalyst, comprising PS, Fe(III), B and FLT, wherein the dosage ratio of PS, Fe(III) and FLT is 60 / 20 / 1, and the dosage of B is 0.002 g·L -1 250 mL of simulated groundwater solution with an initial FLT concentration of 0.001 mM was prepared. The initial pH of the FLT solution was adjusted to 3.0, 5.0, 7.0, 9.0 and 11.0 with sulfuric acid solution (1 M) or sodium hydroxide solution (0.1 M) in advance. Then, a certain dose of B, trivalent iron and oxidant PS were added in sequence. The dosage of B was 0.002 g·L -1 The PS / Fe(III) / FLT molar ratio is 60 / 20 / 1. The chemical oxidation process is fully stirred, and the reaction temperature is controlled at 20±0.5℃, the total reaction time is 120min, and the magnetic stirring speed is 550~650r·min -1 , sampled at 120 min and quenched the reaction with an equal volume of methanol, and then the FLT concentration in the sample was analyzed by liquid chromatography.

[0034] The experimental results are as follows Figure 3 As shown, when the initial pH of the solution was 3.0, 5.0, 7.0, 9.0 and 11.0, the removal rates of FLT were 96.0%, 75.9%, 38.7%, 11.6% and 8.5%, respectively. The results showed that the degradation effect of the PS / Fe(III) system on FLT decreased with the increase of the solution pH, and the degradation effect of FLT was good under acidic and weakly acidic conditions, indicating that the technology of the present invention has a good removal effect on FLT in a simulated groundwater environment under acidic conditions.

[0035] Example 4

[0036] A method for removing fluoranthene from groundwater by activating PS with boron-reduced iron catalyst, comprising PS, Fe(III), B and FLT, wherein the molar ratio of PS, Fe(III) and FLT is 60 / 20 / 1, and the dosage of B is 0.002 g·L -1250 mL of simulated groundwater solution with an initial FLT concentration of 0.001 mM was prepared, and common anion sodium salts were added in advance to prepare a series of anion solutions with a concentration gradient, where the anion refers to chloride ions (Cl - ), sulfate ion (SO 4 2- ) and nitrate ions (NO 3 - ), with three concentrations of 1, 5, and 50 mM. Then, a certain amount of B, trivalent iron, and oxidant PS were added in sequence, with the amount of B added being 0.002 g·L -1 The PS / Fe(III) / FLT molar ratio is 60 / 20 / 1. The chemical oxidation process is fully stirred, and the reaction temperature is controlled at 20±0.5℃, the total reaction time is 120min, and the magnetic stirring speed is 550~650r·min -1 , sampled at 120 min and quenched the reaction with an equal volume of methanol, and then the FLT concentration in the sample was analyzed by liquid chromatography.

[0037] The experimental results are as follows Figure 4 As shown, when Cl - When the dosage was 1, 5 and 50 mM, the removal efficiency of FLT was 97.7%, 100% and 100% respectively. 4 2- When the dosage was 1, 5 and 50 mM, the removal efficiency of FLT was 97.1%, 98.5% and 95.2% respectively. 3 - When the dosage is 1, 5 and 50 mM, the removal rates of FLT are 97.3%, 90.5% and 90.2% respectively. The results show that the technology of the present invention has a good adaptability to anions in aqueous solution, indicating that the technology of the present invention has a good removal effect on FLT in a simulated groundwater environment containing inorganic anions.

[0038] Example 5

[0039] A method for removing fluoranthene from groundwater by activating PS with boron-reduced iron catalyst, comprising PS, Fe(III), B and FLT, wherein the dosage ratio of PS, Fe(III) and FLT is 60 / 20 / 1, and the dosage of B is 0.002 g·L -1 250 mL of simulated groundwater solution with an initial FLT concentration of 0.001 mM was prepared, and humic acid (HA) was added in advance and set to 1, 5, and 10 mg·L -1 These three concentration gradients were then added with a certain dose of B, trivalent iron and oxidant PS in sequence, where the dosage of B was 0.002 g·L -1The PS / Fe(III) / FLT molar ratio is 60 / 20 / 1. The chemical oxidation process is fully stirred, and the reaction temperature is controlled at 20±0.5℃, the total reaction time is 120min, and the magnetic stirring speed is 550~650r·min -1 , samples were taken at 0, 2, 5, 15, 30, 60, and 120 min, and the reaction was quenched with an equal volume of methanol, and then the FLT concentration in the samples was analyzed by liquid chromatography. The experimental results showed that ( Figure 5 ), when the concentration of HA was 1, 5 and 10 mg·L -1 When , the removal rates of FLT were 100%, 90.6% and 61.4% respectively. The results show that the technology of the present invention has a good removal effect on FLT in the simulated groundwater environment containing humic acid.

[0040] Example 6

[0041] A method for removing fluoranthene from groundwater by activating PS with a boron-reduced iron-based catalyst, comprising PS, Fe(III), B and FLT. The simulated groundwater environment in Example 2 is replaced with an actual groundwater environment, and the actual groundwater is collected from a well at a depth of about 15 m in Songjiang, Shanghai. 250 mL of actual groundwater solution with an initial FLT concentration of 0.001 mM is prepared, and a certain dose of B, trivalent iron and oxidant PS are added to the solution in sequence. The solution is fully stirred during the chemical oxidation process, and the reaction temperature is controlled at 20±0.5°C, the total reaction time is 120 min, and the magnetic stirring speed is 550-650 r·min -1 , sampled at 120 min and quenched the reaction with an equal volume of methanol, and then the FLT concentration in the sample was analyzed by liquid chromatography.

[0042] The experimental results are as follows Figure 6 As shown, when 0.002 g·L -1 In the case of B, when the molar ratio of PS / Fe(III) / FLT was 60 / 20 / 1, the removal efficiency of FLT was 14.7%. When the dosage of PS, Fe(III) and B increased by 1 and 3 times, the removal efficiency of FLT was 29.0% and 37.3%, respectively. When the initial pH of the actual groundwater was adjusted to 4.0 in advance, the removal efficiency of FLT was 14.7% when 0.002 g·L -1 Under the condition of B, when the molar ratio of PS / Fe(III) / FLT was 60 / 20 / 1, the removal rate of FLT was 96.9%. When the dosage of PS, Fe(III) and B increased by 1 and 3 times, the removal rates of FLT reached 100%, indicating that the pH buffering capacity of groundwater is the main factor inhibiting the effective removal of FLT by the PS / Fe(III) / B system. The results show that after acid adjustment, the technology of the present invention has a good removal effect on FLT in the actual groundwater environment, proving the feasibility of the technology of the present invention in practical applications.

[0043] Example 7

[0044] A method for removing other polycyclic aromatic hydrocarbons from groundwater by activating PS with boron-reduced iron catalysts, comprising PS, Fe(III), B, NAP and PHE. The initial concentrations of NAP and PHE were 0.02 mM and 1 mg·L -1 250mL simulated groundwater solution was added with a certain dose of B, trivalent iron and oxidant PS in sequence. The solution was fully stirred during the chemical oxidation process. The reaction temperature was controlled at 20±0.5℃, the total reaction time was 120min, and the magnetic stirring speed was 550-650r·min -1 , samples were taken at 0, 2, 5, 15, 30, 60, and 120 min, and the reaction was quenched with an equal volume of methanol. The concentrations of NAP and PHE in the samples were then analyzed by liquid chromatography.

[0045] The experimental results are as follows Figure 7 As shown, the dosages of PS, Fe(III) and B were 0.06 mM, 0.02 mM and 0.002 g·L, respectively. -1 When the dosage of PS, Fe(III) and B was 0.12 mM, 0.04 mM and 0.004 g·L -1 The removal rates of NAP and PHE were 92.8% and 98.5% respectively. The experimental results show that the technology of the present invention also has a good removal effect on NAP and PHE in the simulated groundwater system environment, proving the feasibility of the technology of the present invention to effectively remove other polycyclic aromatic hydrocarbons pollutants.

[0046] Example 8

[0047] A method for removing other polycyclic aromatic hydrocarbons in groundwater by activating PS with boron-reduced iron catalysts, comprising PS, Fe(III), B, NAP and PHE. The simulated groundwater environment in Example 8 was replaced with an actual groundwater environment, and the actual groundwater was collected from a well with a depth of about 15 m in Songjiang, Shanghai. The initial concentrations of NAP and PHE were prepared to be 0.02 mM and 1 mg·L -1 250mL actual groundwater solution was prepared, the initial pH of the solution was adjusted to 4, and then a certain amount of B, trivalent iron and oxidant PS were added to the solution in sequence. The solution was fully stirred during the chemical oxidation process. The reaction temperature was controlled at 20±0.5℃, the total reaction time was 120min, and the magnetic stirring speed was 550-650r·min -1 , samples were taken at 120 min and the reaction was quenched with an equal volume of methanol, and then the concentrations of NAP and PHE in the samples were analyzed by liquid chromatography.

[0048] Experimental Figure 8 As shown, when 0.002 g·L -1 In the case of B, when the PS / Fe(III) / FLT molar ratio was 60 / 20 / 1, the removal rates of NAP and PHE were 45.6% and 63.6%, respectively. When the dosage of PS, Fe(III) and B increased by 1 time, the removal rates of NAP and PHE were 67.2% and 87.0%, respectively. When the dosage of PS, Fe(III) and B increased by 3 times, the removal rates of NAP and PHE were 76.0% and 92.6%, respectively. When the dosage of PS, Fe(III) and B increased by 5 times, the removal rates of NAP and PHE were 76.0% and 92.6%, respectively. , the removal rates of NAP and PHE were 85.1% and 94.7%, respectively. When the dosage of PS, Fe(III) and B increased by 7 times, the removal rates of NAP and PHE were 95.8% and 100%, respectively, indicating that the pH buffering capacity of groundwater is the main factor inhibiting the effective removal of NAP and PHE by the PS / Fe(III) / B system. The results show that after acid adjustment, the technology of the present invention has a good removal effect on NAP and PHE in the actual groundwater environment, proving the feasibility of the technology of the present invention in practical applications.

[0049] From the above experimental results, it can be seen that compared with the PS / Fe(II) / B / FLT system, the PS / Fe(III) / B / FLT system can achieve a higher PAH removal rate; adjusting the pH of the contaminated water to be treated to acidic before treatment helps to enhance the treatment effect; at the same time, the technology of the present invention has a good adaptability to inorganic anions and humic acid in the aqueous solution, and does not affect the effective removal of PAHs.

[0050] The preferred embodiments of the present invention have been specifically described above, but the present invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced ferric iron, It is characterized in that PS solid powder with a relative pollutant molar ratio of 20:1-120:1 is added to the PAH-contaminated groundwater solution, and then B and trivalent iron are added as a strengthening system to realize the in-situ generation of divalent iron and strengthen the activation of the system.

2. The method for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced ferric iron according to claim 1, characterized in that: in, The polycyclic aromatic hydrocarbons are one or more of fluoranthene, naphthalene and phenanthrene.

3. The method for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced ferric iron according to claim 2, characterized in that: in, The concentration ranges of fluoranthene, naphthalene and phenanthrene were 0.0001-0.001mmol / L, 0.01-0.05mmol / L and 0.1-1mg·L, respectively. -1 .

4. The method for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced ferric iron according to claim 1, characterized in that: in, The molar ratio of PS solid powder to trivalent iron is 3 to 10:1, and the molar ratio of B to trivalent iron is 7 to 20:

1.

5. The method for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced ferric iron according to claim 1, characterized in that: in, The dosage of trivalent iron added is 0.01-0.1mmol / L, and the dosage of B added is 0.002-0.008g·L -1 The PS dosage added is 0.1~1.0mmol / L.

6. The method for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced ferric iron according to claim 1, characterized in that: in, Before treatment, the pH value of the PAH-contaminated groundwater solution is adjusted to 3-5.

7. The method for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced ferric iron according to claim 1, characterized in that: in, The reaction temperature was controlled at 20±5°C and stirring was performed during the reaction.

8. The method for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced ferric iron according to claim 7, characterized in that: in, The stirring method is magnetic stirring, and the speed is 550-650 r·min -1 .

9. The method for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced ferric iron according to claim 1, characterized in that: in, The trivalent iron is one or more of ferric sulfate, ferric chloride and ferric nitrate.

10. The method for removing polycyclic aromatic hydrocarbons from groundwater by activating persulfate with boron-enhanced ferric iron according to claim 1, characterized in that: in, PAH-contaminated groundwater may contain one or both of inorganic anions and humic acid.

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