Method for removing pesticide pollutants in pesticide-containing wastewater

Abstract

The invention provides a method for removing pesticide pollutants in pesticide-containing wastewater, which comprises the following steps: adding sodium persulfate into the pesticide-containing wastewater, and uniformly mixing to obtain a solution to be irradiated; the addition amount of the sodium persulfate is 0.2-8 mmol / L; performing ionization irradiation treatment on the solution to be irradiated; wherein the irradiation absorbed dose of the ionization irradiation treatment is 0.2 to 2.0 kGy. According to the method, pesticide pollutants in pesticide-containing wastewater are removed in a sodium persulfate and ionization irradiation synergistic treatment mode. According to the method, the removal rate of pesticide pollutants in the pesticide-containing wastewater reaches 95% or above, and the removal rate is high; the treatment process is simple and can be carried out at normal temperature and normal pressure; in the ionization irradiation treatment process, the penetrability is good, the reaction is rapid, and the removal of pesticide pollutants can be promoted by matching with sodium persulfate; the method is good in safety and has a wide application prospect in the field of pesticide-containing wastewater treatment.

Description

Technical Field

[0001] The invention relates to the field of wastewater treatment, and in particular to a method for removing pesticide pollutants in pesticide-containing wastewater. Background Art

[0002] Organic pesticides are widely used in agriculture, forestry, animal husbandry and other fields in my country as an important means of preventing and controlling pests and diseases and regulating crop growth. As the world's largest producer and user of pesticides, my country's pesticide production capacity accounts for 1 / 4 of the world's total pesticide production. The production process of pesticides is complex and produces a large amount of wastewater. It is estimated that more than ten tons of pesticide wastewater will be produced for every ton of pesticide products produced. The annual discharge of pesticide wastewater in my country is about 1.5 billion tons. The pesticide synthesis processes used by different pesticide companies vary greatly, and the types of raw materials used are many, resulting in complex pesticide wastewater pollution components, which contain a variety of reaction intermediates and organic pollutants, and the water quality of pesticide wastewater is constantly changing, which makes pesticide wastewater highly toxic, with high pollutant concentrations and poor biodegradability. If not properly handled, the discharge of pesticide wastewater will cause serious harm to the ecological environment and human health.

[0003] At present, the treatment technologies for pesticide wastewater include three categories: physical, chemical, and biological methods. Physical methods mainly include adsorption, membrane separation, and ion exchange. Adsorption is the most commonly used physical treatment technology, which has the advantages of simple operation and good removal effect. However, the adsorbent used has the problem of difficulty in regeneration and high treatment cost. Biological methods can be divided into anaerobic treatment and aerobic treatment. The advantages of biological treatment are low cost and environmental friendliness. However, pesticide wastewater often has poor biodegradability, and it is difficult to guarantee the treatment effect by using biological methods. Chemical methods mainly include advanced oxidation technology. Advanced oxidation technology achieves the degradation and mineralization of difficult-to-degrade pollutants by catalyzing the decomposition of oxidants to produce active species with strong oxidizing ability. It has the advantages of fast reaction and good oxidation effect. However, in this process, a large amount of oxidants often need to be added, and sometimes complex and expensive catalysts need to be prepared. These defects limit the further application of advanced oxidation technology. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for removing pesticide pollutants in pesticide-containing wastewater, aiming to solve the problems of low removal rate of pesticide pollutants and complex treatment process in the prior art.

[0005] To achieve the above-mentioned object, the present invention provides a method for removing pesticide pollutants in pesticide-containing wastewater, comprising the steps of: adding sodium persulfate to the pesticide-containing wastewater and mixing to obtain a solution to be irradiated; the amount of sodium persulfate added is 0.2-8 mmol / L; and the solution to be irradiated is subjected to ionizing radiation treatment; wherein the radiation absorbed dose of the ionizing radiation treatment is 0.2-2.0 kGy.

[0006] Furthermore, the amount of sodium persulfate added is 1-4 mmol / L.

[0007] Furthermore, the absorbed radiation dose of the ionizing radiation treatment is 0.2 to 1.0 kGy.

[0008] Furthermore, the concentration of pesticide pollutants in the pesticide-containing wastewater is 1 to 100 mg / L.

[0009] Furthermore, the pesticide pollutants include one or more of organophosphorus pesticides, organochlorine pesticides, pyrethroids, carbamates, neonicotinoid pesticides and triazine herbicides.

[0010] Furthermore, the pesticide pollutants are triazine herbicides.

[0011] Furthermore, the pH of the pesticide-containing wastewater is 3.2 to 10.5.

[0012] Furthermore, the concentration of pesticide pollutants in the pesticide-containing wastewater is 5 to 20 mg / L.

[0013] Furthermore, the ionizing radiation treatment is carried out using gamma rays or high-energy electron beams; wherein the gamma rays are 60 Co or 137 The high-energy electron beam is produced by Cs decay; the high-energy electron beam is produced by an electron accelerator.

[0014] Furthermore, the mixing method includes vortexing the pesticide-containing wastewater after adding sodium persulfate for 2 to 10 minutes.

[0015] The beneficial effects achieved by the present invention are:

[0016] The method for removing pesticide-type pollutants from wastewater containing pesticides provided by the present invention removes pesticide-type pollutants from wastewater containing pesticides by a synergistic treatment method of sodium persulfate + ionizing radiation. The method has a removal rate of more than 95% for pesticide-type pollutants in wastewater containing pesticides, and a high removal rate; the treatment process is simple and can be carried out at room temperature and pressure; the ionizing radiation treatment process has good penetration and rapid reaction, which is conducive to the removal of pesticide-type pollutants in combination with sodium persulfate; the method has good safety and has broad application prospects in the field of pesticide-containing wastewater treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 It is a comparison chart of atrazine removal rate under different radiation absorbed doses in Example 1;

[0019] Figure 2 This is a comparison chart of atrazine removal rates before and after adding tert-butyl alcohol at different radiation absorption doses in Example 5;

[0020] Figure 3 It is a comparison chart of the experimental results of irradiation alone and irradiation + sodium persulfate in Example 6; wherein, (a) is a comparison chart of atrazine removal rate of irradiation alone at different irradiation absorbed doses and irradiation + sodium persulfate at different irradiation absorbed doses, and (b) is a comparison chart of TOC removal rate of TOC residual concentration of irradiation alone and irradiation + sodium persulfate.

[0021] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the implementation methods and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments rather than to limit the scope of protection of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used in the present invention are consistent with the prior art knowledge of those skilled in the art and the description of the present invention. The present invention can also be implemented using any methods, devices and materials in the prior art that are similar or equivalent to the methods, devices and materials described in the embodiments of the present invention.

[0025] When the embodiments give numerical ranges, it should be understood that unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. The test methods in the following embodiments without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturers. The materials or reagents required in the following embodiments are commercially available unless otherwise specified.

[0026] In order to solve the problems of low removal rate of pesticide pollutants and complex treatment process in the prior art, the present invention provides a method for removing pesticide pollutants in wastewater containing pesticides, comprising the steps of: adding sodium persulfate to the wastewater containing pesticides and mixing to obtain a solution to be irradiated; the amount of sodium persulfate added is 0.2-8 mmol / L; and the solution to be irradiated is subjected to ionizing radiation treatment; wherein the radiation absorbed dose of the ionizing radiation treatment is 0.2-2.0 kGy.

[0027] Specifically, the wastewater containing pesticides can be mixed with sodium persulfate and then placed in an irradiation container. At room temperature and pressure, the irradiation time is controlled to obtain an irradiation absorption dose of 0.2 to 2.0 kGy to treat the irradiated solution with ionizing radiation. Under ionizing radiation treatment, water molecules will undergo irradiation decomposition to produce a variety of active species, such as e aq - , ·OH, ·H, etc. (Reaction formula 1, the values ​​in brackets are the radiochemical yield G value of each active species). These active species will indiscriminately attack the pesticide pollutants contained in the pesticide wastewater, achieving the purpose of effectively removing pollutants and purifying water.

[0028] H2O→·OH(2.7)+e aq - (2.6)+·H(0.55)+H2(0.45)+H2O2(0.71)+H3O+ (2.6)(1)

[0030] Coupling ionizing radiation with persulfate can produce more active species with strong oxidative ability, further improving the degradation effect of pollutants (reaction 2-5).

[0031] S2O8 2- → 2SO4 ·- (2)

[0032] S2O8 2- + e aq - → SO4 ·- + SO4 2- (3)

[0033] S2O8 2- + ·H → SO4·- + SO4 2- + H + (4)

[0034] SO4 ·- + H2O → ·OH +SO4 2- +H + (5)

[0035] The method for removing pesticide-type pollutants from wastewater containing pesticides provided by the present invention removes pesticide-type pollutants from wastewater containing pesticides by a synergistic treatment method of sodium persulfate + ionizing radiation. The method has a removal rate of more than 95% for pesticide-type pollutants in wastewater containing pesticides, and a high removal rate; the treatment process is simple and can be carried out at room temperature and pressure; the ionizing radiation treatment process has good penetration and rapid reaction, which is conducive to the removal of pesticide-type pollutants in combination with sodium persulfate; the method has good safety and has broad application prospects in the field of pesticide-containing wastewater treatment.

[0036] Furthermore, the amount of sodium persulfate added is 1 to 4 mmol / L. Specifically, after adding 1 to 4 mmol / L sodium persulfate, the ionizing radiation coupled with the sodium persulfate system has the most significant improvement in the mineralization effect of atrazine. The TOC removal rate can reach 16.14%. The coupling of ionizing radiation and 1 to 4 mmol / L persulfate produces a large number of active species with strong oxidizing ability, which further significantly improves the degradation effect of organic pollutants (reaction formula 2-5).

[0037] Furthermore, the ionizing radiation treatment has an absorbed dose of 0.2 to 1.0 kGy. Specifically, when the absorbed doses are 0.2, 0.4, 0.6, 0.8, and 1 kGy, the removal rates of atrazine reach 68.47%, 86.6%, 96.26%, 98.71%, and 100%, respectively.

[0038] Furthermore, the concentration of pesticide pollutants in the pesticide-containing wastewater is 1 to 100 mg / L.

[0039] Furthermore, the pesticide pollutants include one or more of organophosphorus pesticides, organochlorine pesticides, pyrethroids, carbamates, neonicotinoid pesticides and triazine herbicides.

[0040] Furthermore, the pesticide pollutant is a triazine herbicide. Specifically, atrazine is a typical triazine herbicide. During the experiment, an atrazine solution can be used to simulate wastewater containing triazine herbicides.

[0041] Furthermore, the pH of the wastewater containing pesticides is 3.2 to 10.5. Specifically, when the pH is 3.2, 6.0, and 10.5, ionizing radiation can completely degrade atrazine at an absorbed dose of 1.0 kGy.

[0042] Furthermore, the concentration of pesticide pollutants in the pesticide-containing wastewater is 5 to 20 mg / L.

[0043] Furthermore, the ionizing radiation treatment is carried out using gamma rays or high-energy electron beams; wherein the gamma rays are 60 Co or 137 Cs decay; high-energy electron beams are produced by electron accelerators. Specifically, gamma rays and high-energy electron beams have the characteristics of high energy and good penetration. They can react quickly when acting on the irradiated solution, and synergistically improve the pollutant removal effect. If an electron accelerator is used to generate a high-energy electron beam for irradiation, no radioactive waste will be generated, and no radiation will be generated after power failure.

[0044] Furthermore, the mixing method includes vortexing the pesticide-containing wastewater after adding sodium persulfate for 2 to 10 minutes to make it evenly mixed.

[0045] For further understanding of the present invention, examples are given below:

[0046] Example 1

[0047] A certain amount of atrazine was dissolved in deionized water to obtain an atrazine solution, wherein the initial concentration of atrazine was 10 mg / L. The atrazine solution was placed in an irradiation container. 60 Coγ-ray irradiation is performed, and the required irradiation absorbed dose is obtained by controlling the irradiation time. After the irradiation, the residual concentration of atrazine under different irradiation absorbed doses is detected and the removal rate is calculated.

[0048] The concentration of atrazine was detected by high performance liquid chromatography. The instrument used was an Agilent 1200 high performance liquid chromatograph (Agilent 1200), the detector was an ultraviolet detector, the chromatographic column was an XBC-C18 reverse phase column, the column temperature was 30°C, the detection wavelength was 230nm, the mobile phase was acetonitrile and 0.1% formic acid / water solution, the mixing ratio was 70:30, and the flow rate was 1.0mL / min. TOC was determined by a TOC analyzer (multi N / C 2100) from Jena, Germany.

[0049] The degradation effect of atrazine under different radiation absorbed doses is shown in Figure 2. Figure 1When the initial concentration of atrazine was 10 mg / L and the irradiation absorbed dose was 0.2, 0.4, 0.6, 0.8, and 1.0 kGy, the removal rates of atrazine were 68.47%, 86.60%, 96.26%, 98.71%, and 100%, respectively.

[0050] Example 2

[0051] A certain amount of atrazine was dissolved in deionized water to obtain an atrazine solution with an initial concentration of 10 mg / L. The pH of the solution was not adjusted (pH = 6.0-6.5). One group used HCl to adjust the pH to 3.2, and one group used NaOH to adjust the pH to 10.5. The atrazine solution was placed in an irradiation container and 60 Coγ-ray irradiation was performed, and the required irradiation absorbed dose was obtained by controlling the irradiation time. After the irradiation, the residual concentration of atrazine at different pH values ​​was detected under different irradiation absorbed doses, and the removal rate was calculated. The results are shown in Table 1.

[0052] Table 1 Degradation efficiency of atrazine at different irradiation absorbed doses and different pH values

[0053]

[0054] It can be seen from the above table that ionizing irradiation can effectively remove atrazine, and can effectively remove atrazine contained in wastewater under acidic, neutral and alkaline conditions. When the irradiation absorbed dose is 2.0 kGy, atrazine in acidic, neutral and alkaline wastewater can be completely removed.

[0055] Example 3

[0056] A certain amount of atrazine was dissolved in deionized water to obtain atrazine solutions with initial concentrations of 5, 10, and 20 mg / L, respectively, without adjusting the solution pH (pH = 6.0 to 6.5). The atrazine solution was placed in an irradiation container. 60 Coγ-ray irradiation was performed, and the required irradiation absorbed dose was obtained by controlling the irradiation time. After the irradiation, the residual concentration of atrazine at different initial concentrations was detected under different irradiation absorbed doses, and the removal rate was calculated. The results are shown in Table 2.

[0057] Table 2 Degradation efficiency of atrazine at different irradiation absorbed doses and different initial concentrations

[0058]

[0059] It can be seen from the above table that ionizing radiation can effectively remove atrazine. When the initial concentration of atrazine is 5-20 mg / L, atrazine contained in wastewater can be effectively removed. When the irradiation absorbed dose reaches 1.0 kGy, atrazine with an initial concentration of 5-20 mg / L can be completely removed.

[0060] Example 4

[0061] A certain amount of atrazine was dissolved in deionized water to obtain an atrazine solution with an initial concentration of 10 mg / L, and the solution pH (pH = 6.0 to 6.5) was not adjusted. The atrazine solution was placed in a centrifuge tube, and a certain amount of sodium persulfate solution was added thereto to make its concentrations 1, 2, and 4 mM, respectively. Without irradiation, after standing for the same time as the irradiation treatment, the residual concentration of atrazine after different concentrations of sodium persulfate were detected, and the removal rate was calculated. The results showed that adding only sodium persulfate had no degradation effect on atrazine.

[0062] Example 5

[0063] A certain amount of atrazine was dissolved in deionized water to obtain an atrazine solution, with an initial atrazine concentration of 10 mg / L. One group was directly irradiated, and the other group was added with an appropriate amount of tert-butyl alcohol (100 mmol / L), vortexed for 5 minutes to mix evenly, and then the atrazine solution was placed in an irradiation container. 60 Coγ-ray irradiation was performed, and the required irradiation absorption dose was obtained by controlling the irradiation time. After the irradiation, the residual concentration of atrazine under different irradiation absorption doses was detected, and the removal rate was calculated. The results are as follows Figure 2 shown.

[0064] The results show that the irradiation degradation of atrazine was significantly inhibited after the addition of tert-butanol. When the irradiation absorbed dose was 1.0 kGy, direct irradiation could completely degrade atrazine in the wastewater without adding tert-butanol. After the addition of tert-butanol, the removal rate of atrazine dropped from 100% to 54.33%. Tert-butanol can quench the ·OH generated during the reaction, which indicates that ·OH plays a dominant role in the degradation of atrazine by ionizing radiation. However, the addition of tert-butanol did not completely stop the irradiation degradation reaction of atrazine, indicating that other active species (e aq - , ·H, etc.) also made a certain contribution to the irradiation degradation of atrazine.

[0065] Example 6

[0066] A certain amount of atrazine was dissolved in deionized water to obtain an atrazine solution, with an initial atrazine concentration of 10 mg / L. One group was directly irradiated, and the other group added an appropriate amount of sodium persulfate (1 mmol / L, 2 mmol / L, 4 mmol / L), vortexed for 5 minutes to mix evenly, and then the atrazine solution was placed in an irradiation container. 60 Coγ-ray irradiation was performed, and the required irradiation absorption dose was obtained by controlling the irradiation time. After irradiation, the residual concentration of atrazine under different irradiation absorption doses was detected and the removal rate was calculated. The residual concentration of TOC was detected and the mineralization rate was calculated. The results are shown in Figure 3 As shown. Among them, Figure 3 (a) is a comparison chart of atrazine removal rates of single irradiation at different irradiation absorbed doses and irradiation + sodium persulfate at different irradiation absorbed doses; Figure 3 (b) is a comparison chart of TOC removal rate of TOC residual concentration of single irradiation and irradiation + sodium persulfate. The atrazine degradation efficiency and mineralization efficiency of sodium persulfate with different concentrations (1mmol / L, 2mmol / L, 4mmol / L) under different irradiation absorbed doses are shown in Table 3 and Table 4, respectively.

[0067] Table 3 Degradation efficiency of atrazine at different irradiation absorbed doses and different concentrations of sodium persulfate

[0068]

[0069]

[0070] Table 4 Mineralization efficiency of atrazine at different irradiation absorbed doses and different concentrations of sodium persulfate

[0071]

[0072] The results showed that the irradiation degradation and mineralization effects of atrazine were significantly improved after the addition of sodium persulfate. When the irradiation absorbed dose was 0.2 kGy, the degradation rate of atrazine by irradiation alone was only 68.47%, while the degradation rate increased to 100% after the addition of sodium persulfate. When the irradiation absorbed dose was 2.0 kGy, the mineralization rate of atrazine by irradiation alone was only 6.48%, while the mineralization rate increased to 16.14% after the addition of sodium persulfate. This shows that ionizing irradiation coupled with sodium persulfate can significantly improve the degradation and mineralization effects of atrazine. Sodium persulfate + ionizing irradiation can remove pesticide pollutants from pesticide-containing wastewater through synergistic treatment.

[0073] In summary, the above technical solutions of the present invention are only preferred embodiments of the present invention, and the patent scope of the present invention is not limited thereto. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for removing pesticide pollutants from pesticide-containing wastewater, characterized in that: Includes steps: Adding sodium persulfate to the wastewater containing pesticides and mixing well to obtain a solution to be irradiated; the amount of sodium persulfate added is 0.2-8 mmol / L; The solution to be irradiated is subjected to ionizing radiation treatment; wherein the radiation absorption dose of the ionizing radiation treatment is 0.2 to 2.0 kGy.

2. The method according to claim 1, characterized in that The amount of sodium persulfate added is 1-4 mmol / L.

3. The method according to claim 1, characterized in that The radiation absorption dose of the ionizing radiation treatment is 0.2-1.0 kGy.

4. The method according to claim 1, characterized in that: The concentration of pesticide pollutants in the pesticide-containing wastewater is 1 to 100 mg / L.

5. The method according to claim 4, characterized in that The pesticide pollutants include one or more of organophosphorus pesticides, organochlorine pesticides, pyrethroids, carbamates, neonicotinoid pesticides and triazine herbicides.

6. The method according to claim 4, characterized in that The pesticide pollutants are triazine herbicides.

7. The method according to claim 1, characterized in that The pH of the pesticide-containing wastewater is 3.2-10.

5.

8. The method according to claim 1, characterized in that The concentration of pesticide pollutants in the pesticide-containing wastewater is 5 to 20 mg / L.

9. The method according to claim 1, characterized in that: The ionizing radiation treatment is carried out using gamma rays or high-energy electron beams; The gamma rays are 60 Co or 137 The high-energy electron beam is produced by Cs decay; the high-energy electron beam is produced by an electron accelerator.

10. The method according to claim 1, characterized in that The mixing method comprises vortexing the pesticide-containing wastewater after the addition of sodium persulfate for 2 to 10 minutes.

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