Method for removing refractory organic matters in wastewater

Abstract

The invention provides a method for removing refractory organic matters in wastewater, which comprises the following steps: adding periodate into the wastewater, and uniformly mixing to obtain a solution to be irradiated; the addition amount of the periodate is 1-4 mM; performing ionization irradiation treatment on the solution to be irradiated; wherein the irradiation absorbed dose of the ionization irradiation treatment is 0.2 to 3.0 kGy. According to the method, the degradation rate and mineralization rate of the ionization irradiation technology on refractory organic pollutants are improved; the irradiation absorbed dose required by degradation and mineralization of refractory organic pollutants is reduced, and the reaction time is short; degradation and mineralization of refractory pollutants can be realized at normal temperature and normal pressure, and the operation is simple and convenient; the catalyst has no selectivity for degradation-resistant organic pollutants, and is suitable for a relatively wide pH range; the method has a wide application prospect in the field of environmental protection.

Description

Technical Field

[0001] The invention relates to the field of wastewater treatment, and in particular to a method for removing refractory organic matter in wastewater. Background Art

[0002] Water resources are the basic material basis for the survival of human society. my country is short of water resources, with uneven temporal and spatial distribution and scarce freshwater resources. Data show that my country's per capita freshwater resources are only 1 / 4 of the world's per capita amount, and it is one of the 13 water-poor countries in the world. With the development of my country's economy and society, the water pollution problem has become increasingly serious. A large number of difficult-to-degrade organic pollutants, such as pesticides, persistent organic pollutants, endocrine disruptors, pharmaceuticals and personal care products, are discharged into various water bodies, posing a serious threat to the water ecological environment and human health. These organic pollutants are generally low in concentration and relatively stable in chemical properties, and traditional sewage treatment technologies are difficult to effectively remove.

[0003] Ionizing radiation technology is a type of advanced oxidation technology that uses gamma rays or high-energy electron beams to achieve efficient degradation and removal of difficult-to-degrade organic pollutants. At present, ionizing radiation technology has been widely used in the field of water treatment. Studies have shown that ionizing radiation technology can degrade a variety of organic pollutants, such as dyes, antibiotics, endocrine disruptors, etc. Although ionizing radiation technology can effectively degrade organic pollutants in water, it has defects such as low mineralization efficiency and high radiation absorption dose required for complete degradation of pollutants, which affects the further application of ionizing radiation technology. Summary of the invention

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

[0005] To achieve the above-mentioned purpose, the present invention provides a method for removing refractory organic matter in wastewater, comprising the steps of: adding periodate to the wastewater and mixing to obtain a solution to be irradiated; the amount of periodate added is 1 to 4 mM; 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 to 3.0 kGy.

[0006] Furthermore, the amount of periodate added is 1-2 mM.

[0007] Furthermore, the absorbed radiation dose of the ionizing radiation treatment is 0.2 to 1.5 kGy.

[0008] Furthermore, the ionizing radiation treatment is carried out using gamma rays or high-energy electron beams; wherein the gamma rays are 60 Co or 137The high-energy electron beam is produced by Cs decay; the high-energy electron beam is produced by an electron accelerator.

[0009] Furthermore, the irradiation time of the gamma ray is 2 to 25 minutes.

[0010] Furthermore, the periodate is sodium periodate, potassium periodate, barium periodate, periodic acid or trisodium periodate.

[0011] Furthermore, the wastewater is one or more of pharmaceutical wastewater, pesticide wastewater, and effluent from a municipal sewage treatment plant.

[0012] Furthermore, the concentration of the refractory organic matter in the wastewater is 1 to 100 mg / L; and the pH of the wastewater is 3.1 to 10.8.

[0013] Furthermore, the difficult-to-degrade organic matter is an antibiotic.

[0014] Furthermore, the concentration of refractory organic matter in the wastewater is 5 to 20 mg / L.

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

[0016] The method for removing refractory organic matter in wastewater provided by the present invention utilizes ionizing radiation in conjunction with periodate to remove refractory organic pollutants in wastewater, and has the following advantages: (1) the degradation rate and mineralization rate of refractory organic pollutants by ionizing radiation technology can be improved; (2) the radiation absorption dose required for degradation and mineralization of refractory organic pollutants is reduced, and the reaction time is short; (3) the degradation and mineralization of refractory pollutants can be achieved at room temperature and pressure, and the operation is simple; (4) there is no selectivity for refractory organic pollutants, and it is applicable to a wider pH range; the method has broad application prospects in the field of environmental protection. 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 1The experimental results of sulfonamide degradation by irradiation alone, ionizing irradiation combined with sodium persulfate (irradiation + persulfate), and ionizing irradiation in coordination with periodate (irradiation + periodate) in Example 1 are compared; wherein (a) is a comparison of the removal rates of sulfonamide by irradiation alone at different irradiation absorbed doses, irradiation + persulfate at different irradiation absorbed doses, and irradiation + periodate at different irradiation absorbed doses, and (b) is a comparison of the TOC removal rates of the residual TOC concentrations of irradiation + persulfate and irradiation + periodate;

[0019] Figure 2 It is a comparison chart of the experimental results of the degradation of sulfathiazole by irradiation alone, ionizing irradiation combined with sodium persulfate (irradiation + persulfate), and ionizing irradiation synergistically with periodate (irradiation + periodate) in Example 2; wherein, (a) is a comparison chart of the removal rates of sulfathiazole by irradiation alone at different irradiation absorbed doses, irradiation + persulfate at different irradiation absorbed doses, and irradiation + periodate at different irradiation absorbed doses, and (b) is a comparison chart of the TOC removal rates of the TOC residual concentrations of irradiation + persulfate and irradiation + periodate.

[0020] 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

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] In order to solve the problems of low removal rate of refractory organic matter and complicated treatment process in the prior art, the present invention provides a method for removing refractory organic matter in wastewater, comprising the steps of: adding periodate to the wastewater and mixing to obtain a solution to be irradiated; the amount of periodate added is 1 to 4 mM; 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 to 3.0 kGy.

[0026] Specifically, 1 to 4 mM periodate can be added to the wastewater, and then vortexed for 2 to 10 minutes to obtain the irradiated solution. The irradiated solution is subjected to ionizing radiation treatment with an absorbed dose of 0.2 to 3.0 kGy. Periodate is coupled with ionizing radiation, and ionizing radiation can activate periodate to produce a variety of active species with strong oxidizing ability (such as ·OH, O2 ·- , 1O2, IO3 · 、O( 3 P) etc.), to achieve efficient degradation of difficult-to-degrade organic pollutants.

[0027] The method for removing refractory organic matter in wastewater provided by the present invention utilizes ionizing radiation in conjunction with periodate to remove refractory organic pollutants in wastewater, and has the following advantages: (1) the degradation rate and mineralization rate of refractory organic pollutants by ionizing radiation technology can be improved; (2) the radiation absorption dose required for degradation and mineralization of refractory organic pollutants is reduced, and the reaction time is short; (3) the degradation and mineralization of refractory pollutants can be achieved at room temperature and pressure, and the operation is simple; (4) there is no selectivity for refractory organic pollutants, and it is applicable to a wider pH range; the method has broad application prospects in the field of environmental protection.

[0028] Furthermore, the amount of periodate added is 1-2 mM. Specifically, when 1 mM, 2 mM, and 4 mM periodate are added, the degradation rates of sulfathiazole, a difficult-to-degrade organic matter, are 94.10%, 96.41%, and 96.72% respectively when the absorbed dose is 0.2 kGy.

[0029] Furthermore, the radiation absorption dose of the ionizing radiation treatment is 0.2 to 1.5 kGy. Specifically, when the refractory organic matter is sulfonamide, when the absorption doses are 0.2 kGy, 0.4 kGy, 0.6 kGy, 1.0 kGy, and 1.5 kGy, the removal rates of sulfonamide are 43.68%, 73.08%, 82.67%, 97.78%, and 100%, respectively.

[0030] 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 generated by electron accelerators. In an optional embodiment, high-energy electron beams can be used for ionizing irradiation. At this time, the electron accelerator as a source for generating high-energy electron beams has good safety, is environmentally friendly and reliable, does not generate any radioactive waste, does not generate radiation after power failure, and the shielding device can effectively shield radiation.

[0031] Furthermore, the irradiation time of gamma rays is 2 to 25 minutes. Preferably, the dose rate is 120 Gy / min.

[0032] Furthermore, the periodate is sodium periodate, potassium periodate, barium periodate, periodic acid or trisodium periodate. Preferably, the periodate can be sodium periodate. Ionizing radiation can activate sodium periodate to produce a variety of active species with strong oxidizing ability (such as OH, O2 ·- , 1O2, IO3 · 、O( 3 P) etc.), to achieve efficient degradation of difficult-to-degrade organic pollutants.

[0033] Furthermore, the wastewater is one or more of pharmaceutical wastewater, pesticide wastewater, and effluent from a municipal sewage treatment plant. Specifically, the main pollutants in pharmaceutical wastewater are sulfonamide antibiotics; the main pollutants in pesticide wastewater are triazine herbicides; and the main pollutants in a municipal sewage treatment plant are medicines and personal care products.

[0034] Furthermore, the concentration of refractory organic matter in the wastewater is 1 to 100 mg / L, and the pH of the wastewater is 3.1 to 10.8. Specifically, within the pH range of 3.1 to 10.8, when the absorbed dose reaches 1.5 kGy, the pollutants can be completely removed.

[0035] Furthermore, refractory organic matter is used as antibiotics. Ionizing radiation can cleave water molecules to produce a variety of active species (such as ·OH, ·H, eaq - etc.), to achieve efficient degradation of antibiotics.

[0036] Furthermore, the concentration of the refractory organic matter in the wastewater is 5 to 20 mg / L. Specifically, when the concentration is 5 to 20 mg / L, when the absorbed dose is 3.0 kGy, the pollutants can be completely degraded and removed.

[0037] For further understanding of the present invention, examples are given below:

[0038] Example 1

[0039] The difficult-to-degrade organic pollutant treated in this embodiment is sulfonamide antibiotics. A certain amount of sulfonamide antibiotics is dissolved in deionized water to obtain a sulfonamide solution with an initial concentration of 10 mg / L to simulate pharmaceutical wastewater.

[0040] A certain amount of sodium periodate was added to the sulfonamide solution to make the concentration 2mmol / L, and vortexed for 5 minutes to mix it evenly. Then the mixed sulfonamide solution was transferred to the irradiation room and 60 Coγ-ray irradiation was performed, and the irradiation time was adjusted to control the irradiation absorbed dose to 0.2, 0.4, 0.6, 1.0, and 1.5 kGy. Sulfonamide was irradiated alone without adding sodium periodate, and irradiated after adding sodium persulfate (2 mmol / L) for comparison. After each reaction was completed, the residual concentration of sulfonamide treated in three different ways under different irradiation doses was detected, and the removal rate was calculated. The results are as follows Figure 1 (a) As shown. The TOC residual concentration of sulfonamide irradiated without sodium periodate, irradiated after adding sodium persulfate, and irradiated after adding sodium periodate was tested, and the mineralization rate was calculated. The results are shown in Figure 1 (b) as shown.

[0041] Among them, a high performance liquid chromatography analyzer (Shimadzu LC-20A) was used to detect the concentration of sulfonamide. The detector was a photodiode array detector, the chromatographic column was a WondaSil C18 reverse phase column, the column temperature was 25°C, the detection wavelength was 265nm, the mobile phase was acetonitrile and 0.1% formic acid / water solution, the mixing ratio was 90:10, and the flow rate was 1.0mL / min. TOC was measured using a TOC analyzer (multi N / C 2100) from Jena, Germany.

[0042] Specifically, without adding sodium periodate, the removal rates of sulfonamide were 43.68%, 73.08%, 82.67%, 97.78% and 100% when the absorbed doses were 0.2 kGy, 0.4 kGy, 0.6 kGy, 1.0 kGy and 1.5 kGy, respectively. The removal rates of sulfonamide were 49.59%, 75.43%, 88.64% and 100% when the absorbed doses were 0.2 kGy, 0.4 kGy, 0.6 kGy and 1.0 kGy, respectively. The removal rates of sulfonamide were 66.99% and 100% when the absorbed doses were 0.2 kGy and 0.4 kGy, respectively, when the ionizing radiation was synergistic with periodate.

[0043] pass Figure 1 (a) The results show that the radiation absorbed dose required for complete removal of sulfonamide from water by irradiation alone is 1.5 kGy. After adding persulfate, the removal effect of sulfonamide was significantly improved, and the radiation absorbed dose required for complete degradation was reduced to 1.0 kGy. The combination of ionizing radiation and periodate can significantly improve the degradation effect of sulfonamide, and only 0.4 kGy of absorbed dose is required to completely degrade sulfonamide.

[0044] according to Figure 1 (b) It can be seen that the TOC removal rates of irradiation alone, irradiation combined with persulfate, and irradiation combined with periodate are 19.51%, 25.57%, and 79.19%, respectively, indicating that irradiation combined with periodate can significantly improve the degradation and mineralization of sulfonamide.

[0045] Example 2

[0046] The difficult-to-degrade organic pollutant treated in this embodiment is sulfathiazole. A certain amount of sulfathiazole is dissolved in deionized water to obtain a sulfathiazole solution with an initial concentration of 10 mg / L to simulate pharmaceutical wastewater.

[0047] A certain amount of sodium periodate was added to the sulfathiazole solution to make the concentration 1mmol / L, and vortexed for 5 minutes to mix it evenly. Then the mixed sulfathiazole solution was transferred to the irradiation room and 60 Coγ-ray irradiation was performed, and the irradiation time was adjusted to control the irradiation absorbed dose to 0.2, 0.4, 0.6, 1.0, and 1.5 kGy. Sodium periodate was not added for irradiation alone, and sodium persulfate (1 mmol / L) was added for irradiation for comparison. After each reaction was completed, the residual concentration of sulfathiazole treated in three different ways under different irradiation doses was detected, and the removal rate was calculated. The results are as follows Figure 2 (a) As shown. The TOC residual concentration of sulfathiazole irradiated without sodium periodate, irradiated after adding sodium persulfate, and irradiated after adding sodium periodate was detected, and the mineralization rate was calculated. The results are shown in Figure 2(b) as shown.

[0048] Among them, a high performance liquid chromatography analyzer (Shimadzu LC-20A) was used to detect the concentration of sulfonamide. The detector was a photodiode array detector, the chromatographic column was a WondaSil C18 reverse phase column, the column temperature was 25°C, the detection wavelength was 284nm, the mobile phase was acetonitrile and 0.1% formic acid / water solution, the mixing ratio was 20:80, and the flow rate was 1.0mL / min. TOC was measured using a TOC analyzer (multi N / C 2100) from Jena, Germany.

[0049] Specifically, without adding sodium periodate, the removal rates of sulfathiazole were 46.30%, 84.14%, 97.05% and 100% when the absorbed doses were 0.2kGy, 0.4kGy, 0.6kGy, 1.0kGy and 2.0kGy, respectively. The removal rates of sulfathiazole were 50.42%, 89.43% and 100% when the absorbed doses were 0.2kGy, 0.6kGy and 1.0kGy, respectively when the ionizing radiation was combined with sodium persulfate. The removal rates of sulfathiazole were 94.10% and 100% when the absorbed doses were 0.2kGy and 0.6kGy, respectively when the ionizing radiation was combined with sodium periodate.

[0050] pass Figure 2 (a) The results show that the radiation absorbed dose required for complete removal of sulfathiazole in water by irradiation alone is 2.0 kGy. After adding persulfate, the removal effect of sulfathiazole was significantly improved, and the radiation absorbed dose required for complete degradation was reduced to 1.0 kGy. The combination of ionizing radiation and periodate can significantly improve the degradation effect of sulfathiazole, and only 0.6 kGy of absorbed dose is required to completely degrade sulfathiazole.

[0051] according to Figure 2 (b) It can be seen that the TOC removal rates of irradiation alone, ionizing irradiation combined with persulfate, and ionizing irradiation synergistic with periodate are 22.62%, 45.41%, and 60.24%, respectively. This indicates that irradiation combined with periodate can significantly improve the degradation and mineralization of sulfathiazole.

[0052] Example 3

[0053] The refractory organic pollutant treated in this embodiment is sulfadiazine. A certain amount of sulfadiazine is dissolved in deionized water to obtain a sulfadiazine solution with an initial concentration of 10 mg / L to simulate pharmaceutical wastewater.

[0054] The samples were divided into three groups: one group did not adjust the pH (6.5-7.0), one group adjusted the pH to 5.0 with HCl, and one group adjusted the pH to 10.0 with NaOH. An appropriate amount of sodium periodate was added to each group to make the concentration 1mmol / L, and the mixture was vortexed for 5 minutes to mix well. The mixed sulfadiazine solution was then transferred to the irradiation room and 60 Coγ-ray irradiation was performed, and the irradiation time was adjusted to control the irradiation absorbed dose to 0.1, 0.2, 0.4, 0.6, and 1.0 kGy. Sulfadiazine was irradiated alone without adding sodium periodate for comparison. After each reaction was completed, the residual concentration of sulfadiazine under different irradiation doses was detected, and the removal rate was calculated. The results are shown in Table 1.

[0055] Among them, a high performance liquid chromatography analyzer (Shimadzu LC-20A) was used to detect the concentration of sulfadiazine. The detector was a photodiode array detector, the chromatographic column was a WondaSil C18 reverse phase column, the column temperature was 25°C, the detection wavelength was 270nm, the mobile phase was acetonitrile and 0.1% formic acid / water solution, the mixing ratio was 30:70, and the flow rate was 1.0mL / min.

[0056] Table 1 Comparison of the degradation efficiency of sulfadiazine by irradiation alone and ionizing radiation in combination with periodate at different absorbed radiation doses and different pH values

[0057]

[0058] As can be seen from the table above, ionizing radiation combined with periodate can effectively degrade the difficult-to-degrade organic pollutants in wastewater under acidic, neutral and alkaline conditions (pH 5.0-10.0), and the degradation effect is better than that of irradiation alone.

[0059] 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 refractory organic matter from wastewater, characterized in that: Includes steps: Adding periodate to wastewater and mixing evenly to obtain a solution to be irradiated; the amount of periodate added is 1 to 4 mM; 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 3.0 kGy.

2. The method according to claim 1, characterized in that The amount of periodate added is 1-2 mM.

3. The method according to claim 1, characterized in that The radiation absorption dose of the ionizing radiation treatment is 0.2-1.5 kGy.

4. 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.

5. The method according to claim 4, characterized in that The irradiation time of the gamma ray is 2 to 25 minutes.

6. The method according to claim 1, characterized in that The periodate is sodium periodate, potassium periodate, barium periodate, periodic acid or trisodium periodate.

7. The method according to claim 1, characterized in that The wastewater is one or more of pharmaceutical wastewater, pesticide wastewater, and effluent from a municipal sewage treatment plant.

8. The method according to claim 1, characterized in that The concentration of the refractory organic matter in the wastewater is 1-100 mg / L; the pH of the wastewater is 3.1-10.

8.

9. The method according to claim 8, characterized in that The difficult-to-degrade organic matter is an antibiotic.

10. The method according to claim 1, characterized in that The concentration of the refractory organic matter in the wastewater is 5-20 mg / L.

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