Method for degrading agricultural non-point source organic pollutants by using ferroferric sulfide-peracetic acid system and application of method

Abstract

The invention discloses a method for degrading agricultural non-point source organic pollutants by utilizing a ferroferric sulfide-peracetic acid system and application of the method. The ferroferric sulfide adopted by the invention shows the efficient redox cycle characteristic of Fe (Fe < 2 + > / Fe < 3 + >) and S (S < 2-> / Sn < 2->), the cycle performance of the material is efficient, and the defects that the degradation of pollutants is not ideal and the pollutants are difficult to recover when the existing material is used for activating persulfate or peracetic acid in a water treatment technology are overcome; in addition, in the degradation process, the system has good anti-interference capability on common ions and organic matters in the environment. Peroxyacetic acid is used for adjusting the pH value, no extra acid or alkali needs to be added, and the application range is wide. The reaction can be carried out at normal temperature and normal pressure, and the method has a good application prospect in the field of water pesticide pollutant remediation.

Description

Technical Field

[0001] The invention belongs to the technical field of circulating water treatment, and particularly relates to a method for degrading agricultural non-point source organic pollutants by utilizing a ferrous tetrasulfide-peracetic acid system and an application thereof. Background Art

[0002] Pesticides, primarily herbicides and insecticides, are the most representative organic pollutants in agricultural non-point source pollution. Due to their widespread use, persistent residues, and potential ecotoxicity, pesticide pollution has become a global environmental problem. Isoproturon is a photosynthesis inhibitor widely used in weed control. It is absorbed by plant roots and leaves, causing weeds to chlorosis and die. However, due to its excessive use and long half-life, environmental residues can affect normal crop growth and significantly reduce yields. Of particular concern is the potential toxicity and carcinogenicity of isoproturon, which can accumulate through the food chain and threaten human health. It poses a moderate exposure risk to terrestrial organisms such as birds and rats, and exhibits acute toxicity to aquatic organisms such as fish. More seriously, isoproturon has a strong leaching property in soil and easily migrates to water bodies, causing widespread pollution and posing a serious threat to aquatic environmental safety.

[0003] Peracetic acid (PAA) is an alternative oxidant and disinfectant for water treatment, with a high redox potential (Eh0 = 1.96 V) and few disinfection byproducts. Due to its electrophilic nature, PAA readily attacks organic compounds containing electron-rich functional groups, such as isoproturon, which contains aromatic rings. However, due to its high selectivity, PAA alone is far from sufficient to decompose most molecularly complex pollutants. Furthermore, the peroxide bond energy of PAA is 159 kJ / mol, lower than that of H2O2 (213 kJ / mol) and PMS (317 kJ / mol), meaning that PAA can be activated with lower energy consumption. Furthermore, the ease of PAA activation is reflected in its lower unoccupied molecular orbital energy, which is lower for PAA (-0.25 eV) than for H2O2 (0.57 eV), indicating that PAA has a stronger electron-accepting capacity than H2O2, making it easier to activate. Therefore, peracetic acid-based advanced oxidation processes (PAA-AOPs) have attracted widespread attention due to their high reactivity towards organic pollutants and high selectivity in the presence of complex environmental matrices. The activation of PAA leads to the cleavage of the OO bond, generating strong oxidative free radicals such as various organic free radicals (RO·) and hydroxyl radicals (·OH), thereby effectively decomposing pollutants. Previous studies have proposed various activation methods, including external energy input (e.g., alkaline, thermal, ultraviolet, ultrasonic), electrochemistry, transition metal ion catalysis (e.g., and ) and metal-based materials (Fe3O4, FeS and nZVI), etc., however, low energy efficiency limits the development of these high-energy activation methods. Although homogeneous metal catalytic reactions show high reaction rates, their catalysts are difficult to effectively recover from treated water bodies, resulting in a significant increase in operating costs. In addition, most heterogeneous catalysts are susceptible to interference from environmental anions, thereby weakening their degradation efficiency for pollutants. Therefore, the development of heterogeneous catalytic materials with both high recyclability and excellent catalytic performance, the construction of an efficient peracetic acid activation system based on iron-based materials, and the ability to effectively resist the interference of complex water quality backgrounds have important scientific significance and practical application value for achieving efficient removal of difficult-to-degrade pesticide pollutants in water. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the object of the present invention is to provide a method for degrading agricultural non-point source organic pollutants using a ferrous sulfide-peracetic acid system.

[0005] Another object of the present invention is to provide an application of the above method.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for degrading agricultural non-point source organic pollutants using a ferrous sulfide-peracetic acid system comprises the following steps:

[0008] An oxidant is added to the polluted water body to adjust the pH, and then a metal-based catalyst is added to catalyze the degradation of agricultural non-point source organic pollutants in the polluted water body.

[0009] The oxidant comprises at least one of peracetic acid, hydrogen peroxide and peroxydisulfate.

[0010] The amount of the oxidant added is such that the final concentration is 0.2 to 1.5 mmol, preferably 0.2 to 0.6 mmol.

[0011] The pH is adjusted to 3-9, preferably to 3-5.

[0012] The metal-based catalyst includes at least one of ferroic sulfide, ferroic oxide, copper sulfide, ferrous sulfide, cuprous sulfide, and molybdenum disulfide; preferably ferroic sulfide.

[0013] The metal-based catalyst is added in an amount to a final concentration of 20 to 500 mg / L, preferably 20 to 150 mg / L.

[0014] The agricultural non-point source organic pollutants include one of isoproturon, imidacloprid, thiamethoxam and clothianidin.

[0015] The concentration of the agricultural non-point source organic pollutants is 5 to 500 mg / L, preferably 5 to 10 mg / L.

[0016] The preparation method of the iron tetrasulfide comprises the following steps:

[0017] Ferric chloride hexahydrate and thiourea are dissolved in ethylene glycol and stirred to dissolve. The solution is then transferred to a reactor and heated in an oven at 160-200° C. for 10-14 hours. The solid is collected magnetically, washed with ethanol and water, and then freeze-dried in a vacuum to obtain iron tetrasulfide.

[0018] The molar ratio of the ferric chloride hydrate to thiourea is 1:1 to 3, preferably 1:2.

[0019] Alternatively, the method for preparing the iron tetrasulfide comprises the following steps:

[0020] CTAB is dissolved in water, and then L-cysteine and ferrous chloride are added and magnetically stirred. The mixture is then transferred to a reactor and heated in an oven at 160-200° C. for 30-50 hours. The solid is collected by centrifugation, washed, and dried to obtain iron tetrasulfide.

[0021] The molar ratio of the CTAB, L-cysteine and ferrous chloride is 3:15:1.

[0022] The above method of using the ferrous sulfide-peracetic acid system to degrade agricultural non-point source organic pollutants is used in degrading agricultural non-point source organic pollutants in polluted water bodies.

[0023] The present invention has the following advantages over the prior art:

[0024] (1) In the present invention, by preparing a heterogeneous catalytic material, ferric tetrasulfide, agricultural non-point source organic pollutants in water bodies can be efficiently degraded. The pollutants are mainly isoproturon, imidacloprid, thiamethoxam, and clothianidin. The material is simple to prepare, the raw materials are easily available, it has a good catalytic effect, and it is easy to store. At present, no research or patent has been found on the use of ferric tetrasulfide to activate peracetic acid to degrade isoproturon. At the same time, in previous studies, there are few studies on the activation of peracetic acid to degrade organic pollutants in water bodies, which have high catalytic performance and recycling effects, as well as excellent adaptability and stability to environmental conditions containing different anions and organic matter.

[0025] (2) The present invention aims to propose a catalytic system based on nano-iron tetrasulfide, which can efficiently degrade isoproturon in water by activating peracetic acid. The system uses nano-iron tetrasulfide as a catalyst to activate peracetic acid, thereby achieving efficient degradation of various agricultural non-point source organic pollutants. Experimental results show that the system exhibits excellent degradation performance under the conditions of different anions, especially in the presence of sulfate ions, with a degradation rate of up to 0.370 min -1 Compared with the control group, the degradation rate increased by 1.85 times. In addition, by adjusting the pH value of the solution with peracetic acid, it can achieve efficient removal of pollutants without the need for additional acid or alkali, and has a wide range of applications.

[0026] The present invention has the following effects relative to the prior art:

[0027] (1) The present invention provides a novel method for treating isoproturon-contaminated water. Specifically, ferric sulfide and peracetic acid are added to the contaminated water and uniformly stirred to degrade the organic pesticide pollutants. The ferric sulfide is used as a catalyst and the peracetic acid is used as an oxidant to degrade the organic pollutants in the water. Within a 20-minute reaction time, the degradation rate of isoproturon can reach as high as 98%.

[0028] (2) The iron tetrasulfide used in the present invention shows Fe(Fe 2+ / Fe 3+ ) and S(S 2- / S n 2- ) Its efficient redox cycling properties can be used for the effective degradation of a variety of pesticides, such as isoproturon, imidacloprid, thiamethoxam, and clothianidin.

[0029] (3) The ferrous sulfide / peracetic acid system of the present invention can still maintain a high degradation rate in the presence of various anions and humic acid, especially in the presence of sulfate ions, which significantly accelerates the system's ability to degrade isoproturon, indicating that the system has good anti-interference ability against common ions and organic matter in the environment.

[0030] (4) The iron tetrasulfide used in the present invention can be used to recover materials using magnetic force. The separation of solid and liquid products after the degradation reaction is simple. In addition, the iron tetrasulfide has a long service life and still has efficient catalytic performance after multiple uses, which can activate oxidants to degrade agricultural non-point source organic pollutants.

[0031] (5) The ferrosulphide of the present invention does not require the provision of additional energy such as light, electricity, heat, or ultrasound, and the reaction can be carried out at room temperature and pressure, thus saving energy. Furthermore, the process is simple and easy to operate, making it easy to promote. It has a promising application prospect in the field of remediation of agricultural non-point source organic pollutants in water bodies.

[0032] (6) The method of the present invention uses peracetic acid to adjust the pH, and does not require the addition of additional acid or alkali, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is the XRD pattern of iron tetrasulfide (thiourea method) obtained by the present invention;

[0034] Figure 2 is the XRD pattern of iron tetrasulfide (L-Cys method) obtained in the present invention;

[0035] Figure 3 3 is the VSM diagram of iron tetrasulfide (thiourea method) obtained in the present invention;

[0036] Figure 4 This is a graph showing the degradation of isoproturon pollutants in Examples 2.1-2.3 within 20 minutes;

[0037] Figure 5 This is a comparison chart of the degradation of isoproturon pollutants in Example 2.4 within 20 minutes;

[0038] Figure 6 This is a graph showing the degradation of isoproturon pollutants in Example 3.1 within 20 minutes;

[0039] Figure 7 This is a comparison chart of the degradation of isoproturon pollutants in Example 3.2 within 20 minutes;

[0040] Figure 8 This is a comparison chart of the degradation of isoproturon pollutants in Example 3.3 within 20 minutes;

[0041] Figure 9 This is a comparison chart of the degradation of isoproturon pollutants in Example 3.4 within 20 minutes;

[0042] Figure 10 This is a comparison chart of the degradation of isoproturon pollutant in Example 4.1 within 20 minutes;

[0043] Figure 11 This is a comparison chart of the degradation of isoproturon pollutants in Example 4.2 within 20 minutes;

[0044] Figure 12 This is a comparison chart of the degradation of agricultural non-point source organic pollutants in Example 4.3 within 20 minutes;

[0045] Figure 13 This is a comparison chart of the degradation of isoproturon pollutants in Example 5 within 20 minutes;

[0046] Figure 14 These are photos of the experimental process in Example 2. DETAILED DESCRIPTION

[0047] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0048] In the embodiment of the present invention, isoproturon is used as a typical agricultural non-point source organic pollutant, and isoproturon is also a typical difficult-to-biodegrade organic pollutant. In addition, agricultural non-point source organic pollutants such as imidacloprid, thiamethoxam, and clothianidin are also included. Isoproturon, imidacloprid, thiamethoxam, and clothianidin agricultural non-point source organic pollutants are only used to illustrate the present invention, but the method is not limited to these four pollutants.

[0049] Example 1 Preparation and Characterization of Iron Tetrasulfide

[0050] 1.1 Preparation of Fe3S4 (Thiourea Method)

[0051] 3mmol of ferric chloride hexahydrate and 6mmol of thiourea were dissolved in 60ml of ethylene glycol and stirred magnetically until completely dissolved. The solution was then transferred to a stainless steel high-temperature reactor lined with polytetrafluoroethylene and heated in an oven at 180°C for 12 hours. The solid was collected magnetically, washed with anhydrous ethanol and ultrapure water, and then freeze-dried in a vacuum to obtain ferroferric sulfide (thiourea method).

[0052] 1.2 Preparation of FeS4 (L-Cys method)

[0053] Dissolve 0.6 mmol of hexadecyltrimethylammonium bromide (CTAB) in 35 mL of deoxygenated water. Then, add 3 mmol of L-cysteine (L-Cys) and 2 mmol of ferrous chloride. Stir magnetically for 10 minutes. The mixture is then transferred to a 75 mL stainless steel high-temperature reactor lined with polytetrafluoroethylene and heated in an oven at 165°C for 40 hours. The solid is collected by centrifugation, washed with anhydrous ethanol and ultrapure water, and then freeze-dried under vacuum to obtain ferroferric sulfide (L-Cys method).

[0054] 1.3 Characterization of FeS4

[0055] In order to verify the effect of the above preparation method, the synthesized product was characterized by XRD and VSM. Figures 1 to 3 As shown, Figure 1 is the XRD pattern of iron tetrasulfide (thiourea method), Figure 2 is the XRD pattern of iron tetrasulfide (L-Cys method), Figure 3 This is the VSM diagram of iron tetrasulfide (thiourea method).

[0056] Depend on Figure 1 and Figure 2 From the XRD patterns, we can see that both methods successfully synthesized FeS3; Figure 3It can be seen that the maximum saturation magnetization intensity value of iron tetrasulfide (thiourea method) is 31.80emu / g.

[0057] Example 2 Comparison of the effects of different systems and the ferrous sulfide-peracetic acid system

[0058] 2.1 Study on the efficiency of the ferrous tetrasulfide-peracetic acid (PAA) system in degrading isoproturon

[0059] In order to verify the effectiveness of the iron tetrasulfide-peracetic acid system in degrading isoproturon, a corresponding experiment was designed. The specific steps are as follows:

[0060] An aqueous solution containing 5 mg / L isoproturon was prepared to simulate contaminated water. Peracetic acid was added to the solution to a final concentration of 0.5 mmol, and 0.10 g / L of ferroferric sulfide (thiourea method) prepared in Example 1 was added. After the reaction started, samples were taken regularly to detect the concentration of isoproturon in the solution and recorded.

[0061] Depend on Figure 4 It can be seen that the ferrous sulfide (thiourea method) used in the present invention can quickly degrade isoproturon after activating peracetic acid, and the degradation rate of this pollutant can be as high as 98%.

[0062] 2.2 Comparison of the degradation of isoproturon by different oxidants activated by iron tetrasulfide (thiourea method)

[0063] The method of 2.1 of Example 2 was followed, except that peracetic acid was replaced with hydrogen peroxide or peroxydisulfate (PDS). The remaining steps and parameters were the same as those of 2.1 of Example 2.

[0064] Depend on Figure 4 It can be seen that when the oxidant is replaced by hydrogen peroxide and peroxydisulfate, the degradation efficiency of isoproturon is 100%, 98% and 86% respectively, and the degradation rate is 0.2953min -1 、0.1501min -1 and 0.1221min -1 , which reflects the superiority of the ferrous sulfide-peracetic acid system in degrading agricultural non-point source organic pollutants.

[0065] 2.3 Effect of FeS4 or Peracetic Acid on Degradation of Isoproturon

[0066] The method of 2.1 of Example 2 was followed, except that only ferroferric sulfide (thiourea method) or peracetic acid was added to the system. The remaining steps and parameters were the same as those of 2.1 of Example 2.

[0067] Depend on Figure 4 It can be seen that when iron tetrasulfide (thiourea method) or peracetic acid is added alone, the degradation rate of isoproturon is less than 2%.

[0068] 2.4 Comparison of the degradation of isoproturon by peracetic acid activated by different metal-based materials

[0069] The method in 2.1 of Example 2 was followed, except that ferroferric sulfide (thiourea method) was replaced with one of ferroferric oxide, copper sulfide, ferrous sulfide, cuprous sulfide, molybdenum disulfide and ferroferric sulfide (L-Cys method). The remaining steps and parameters were the same as those in 2.1 of Example 2.

[0070] Depend on Figure 5 It can be seen that the iron tetrasulfide (thiourea method) used to activate peracetic acid can rapidly degrade isoproturon within 20 minutes, with a degradation rate of 100%. However, the degradation rate of isoproturon using iron tetrasulfide (L-Cys method) is only 26%. The isoproturon degradation rate of peracetic acid activated by other different metal-based materials is less than 21%.

[0071] Example 3 Effect of the operating parameters of the ferrous sulfide-peracetic acid system on the efficiency of IPU degradation

[0072] 3.1 Effect of initial peracetic acid concentration

[0073] The method of 2.1 of Example 2 was followed, except that the concentration of peracetic acid was adjusted to 0.1 mM, 0.2 mM, 0.3 mM, 0.4 mM, 0.5 mM, and 0.6 mM. The remaining steps and parameters were the same as those of 2.1 of Example 2.

[0074] Depend on Figure 6 As the peracetic acid concentration increased, the degradation efficiency of isoproturon increased, significantly improving the degradation effect. After a 20-minute oscillation reaction, the degradation efficiency of isoproturon was 80%, 94%, 98%, 98%, 99%, and 98% at peracetic acid concentrations of 0.1mM, 0.2mM, 0.3mM, 0.4mM, 0.5mM, and 0.6mM, respectively.

[0075] 3.2 Influence of material dosage

[0076] The method in 2.1 of Example 2 was followed, except that the dosage of ferrosulphide (thiourea method) was adjusted to 0.02 g / L, 0.04 g / L, 0.06 g / L, 0.08 g / L, 0.10 g / L and 0.15 g / L. The remaining steps and parameters were the same as those in 2.1 of Example 2.

[0077] Depend on Figure 7It can be seen that with increasing the dosage of ferric sulfide (thiourea method), the degradation efficiency of isoproturon accelerated and the degradation effect was significantly improved. Within 20 minutes of oscillation reaction, when the dosage of ferric sulfide (thiourea method) was 0.02g / L, 0.04g / L, 0.06g / L, 0.08g / L, 0.10g / L, and 0.15g / L, the degradation efficiency of isoproturon was 54%, 81%, 97%, 99%, 99%, and 100%, respectively.

[0078] 3.3 Effect of pH adjustment after adding peracetic acid

[0079] The method of 2.1 of Example 2 was followed, except that after adding peracetic acid, 0.1 M H2SO4 and 0.1 M NaOH were used to adjust the pH of the solution to 3, 5, 7, and 9, respectively. The pH of the control group was not adjusted. The remaining steps and parameters were the same as those of 2.1 of Example 2.

[0080] Depend on Figure 8 It can be seen that the iron tetrasulfide (thiourea method) activated peracetic acid can effectively degrade isoproturon under acidic conditions.

[0081] 3.4 Effect of adding peracetic acid after pH adjustment

[0082] The method of 2.1 of Example 2 was followed, except that 0.1 M H2SO4 and 0.1 M NaOH were used to adjust the pH of the solution to 3, 5, 7, and 9, and then peracetic acid was added. The pH of the control group was not adjusted. The remaining steps and parameters were the same as those of 2.1 of Example 2.

[0083] Depend on Figure 9 It can be seen that the addition of peracetic acid can adjust the pH of the solution to acidic, so that ferric sulfide (thiourea method) can efficiently activate peracetic acid to degrade isoproturon. This system is suitable for a wide range of pH environmental conditions.

[0084] Example 4 Effect of Different Water Conditions on Isoproturon Degradation in the Iron Tetrasulfide-Peracetic Acid System

[0085] 4.1 Effects of coexisting anions and humic acid in common water bodies

[0086] The method of 2.1 of Example 2 was followed, except that 20 mg / L of sodium sulfate or humic acid, or 200 mg / L of sodium chloride or sodium nitrate was added to the reaction system to simulate natural water conditions. No anions or humic acid were added to the control group. The remaining steps and parameters were the same as those of Example 2.1.

[0087] Depend on Figure 10 As shown, the effect of ferrous sulfide (thiourea method) activated peracetic acid to degrade isoproturon in the presence of chloride ions, nitrate ions and humic acid still has a high isoproturon degradation efficiency.

[0088] 4.2 Effect of sulfate ions on degradation rate

[0089] Refer to the method in 2.1, except that 5, 10, and 20 mg / L of sodium sulfate were added to the reaction system, respectively. No sodium sulfate was added to the control group, and the other conditions were the same.

[0090] like Figure 11 As shown in the figure, the introduction of sulfate ions significantly enhanced the degradation rate of IPU by the system. After adding 5, 10, and 20 mg / L of sodium sulfate, the degradation rate increased from 0.2449 min in the control group to 0. -1 increased to 0.2707min respectively -1 、3197min -1 and 3699min -1 , which indicates that sulfate ions play a promoting role in the system and significantly increase the degradation rate of isoproturon.

[0091] 4.3 Degradation effect on different pollutants

[0092] The method of 2.1 of Example 2 was followed, except that the isoproturon-contaminated water was replaced with one of imidacloprid (IMI), thiamethoxam (THI), and clothianidin (CLO). The remaining steps and parameters were the same as 2.1 of Example 2, wherein the concentrations of imidacloprid, thiamethoxam, and clothianidin were 5 mg / L.

[0093] Depend on Figure 12 It can be seen that the ferric sulfide (thiourea method) activated peracetic acid used in the embodiment of the present invention can degrade a variety of agricultural non-point source organic pollutants, and the degradation efficiencies of imidacloprid, thiamethoxam and clothianidin reach 87%, 93% and 95%, respectively, reflecting the universality of the ferric sulfide-peracetic acid system.

[0094] Example 5 Reusability of FeS4

[0095] The method of 2.1 of Example 2 was followed, except that after each reaction for 20 min, the isoproturon was supplemented to a concentration of 5 mg / L, and then peracetic acid was supplemented at a concentration of 0.5 mmol. The iron tetrasulfide (thiourea method) was reused three times, and the concentration of isoproturon was measured at the 2nd minute, 4th minute, 6th minute, 8th minute, 10th minute, 12th minute, 15th minute, and 20th minute, respectively.

[0096] Depend on Figure 13It can be seen that the iron tetrasulfide (thiourea method) used in the embodiment of the present invention still maintains a high isoproturon degradation efficiency (over 86%) after three cycles. This shows that the iron tetrasulfide (thiourea method) used in the embodiment of the present invention has excellent reusability when activating peracetic acid to degrade isoproturon.

[0097] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for degrading agricultural non-point source organic pollutants using a ferrous sulfide-peracetic acid system, characterized in that The steps include: An oxidant is added to the polluted water body to adjust the pH, and then a metal-based catalyst is added to catalyze the degradation of agricultural non-point source organic pollutants in the polluted water body.

2. The method according to claim 1, wherein: The oxidant comprises at least one of peracetic acid, hydrogen peroxide and peroxydisulfate.

3. The method according to claim 1, wherein: The pH is adjusted to 3-9.

4. The method according to claim 1, wherein: The metal-based catalyst includes at least one of ferroferric sulfide, ferroferric oxide, copper sulfide, ferrous sulfide, cuprous sulfide, and molybdenum disulfide.

5. The method according to claim 1, wherein: The amount of the oxidant added is such that the final concentration is 0.2 to 1.5 mmol; The amount of the metal-based catalyst added is such that the final concentration reaches 20 to 500 mg / L.

6. The method according to claim 1, wherein: The agricultural non-point source organic pollutants include one of isoproturon, imidacloprid, thiamethoxam and clothianidin.

7. The method according to claim 1, wherein: The concentration of the agricultural non-point source organic pollutants is 5-500 mg / L.

8. The method according to claim 4, wherein: The preparation method of the iron tetrasulfide comprises the following steps: Ferric chloride hexahydrate and thiourea are dissolved in ethylene glycol and stirred to dissolve. The solution is then transferred to a reactor and heated in an oven at 160-200° C. for 10-14 hours. The solid is collected magnetically, washed with ethanol and water, and then freeze-dried in a vacuum to obtain iron tetrasulfide.

9. The method according to claim 8, characterized in that: The molar ratio of the ferric chloride hydrate to thiourea is 1:1-3.

10. Use of the method for degrading agricultural non-point source organic pollutants using the ferrous tetrasulfide-peracetic acid system according to any one of claims 1 to 9 in degrading agricultural non-point source organic pollutants in polluted water bodies.

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