Method for removing organic pollutants

Abstract

The invention discloses a method for removing organic pollutants. The method comprises the following steps: S1, mixing sewage and a chlorine dioxide solution to obtain a mixed solution; s2, irradiating the mixed solution by using a 400-450 nm VIS-LED light source to react so as to remove pollutants in the sewage; the pollutants comprise altilol. Through the absorption characteristic of ClO2 under visible light, generation of active species is widened and promoted, degradation of pollutants is enhanced, and generation of disinfection by-products is inhibited.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly to a method for removing organic pollutants. Background Art

[0002] In recent years, with the progress of analytical techniques, the types and quantities of emerging organic contaminants (EOCs) detected in water sources have increased significantly. These contaminants include pharmaceuticals, personal care products, endocrine disruptors, etc., posing a serious threat to human health and the ecological environment. Although the concentrations of these emerging contaminants in water are usually low (in the range of ng / L to μg / L), their persistence, bioaccumulation, and potential toxicity make them difficult to be effectively removed by conventional water treatment processes. Traditional water treatment technologies (such as coagulation, sedimentation, filtration, etc.) have limited removal efficiency for these trace contaminants, and there is an urgent need to develop efficient and environmentally friendly advanced treatment technologies. Advanced oxidation processes (AOPs) have been widely used in the removal of organic pollutants in water because they can generate highly reactive free radicals (such as hydroxyl radicals HO·). Among them, chlorine-based advanced oxidation processes have received extensive attention due to their high efficiency and simplicity of operation. However, chlorine (Cl2) and chloramine (NH2Cl) widely used in traditional water treatment processes are prone to react with natural organic matter during oxidation to form toxic by-products such as trihalomethanes (THMs) and haloacetic acids (HAAs), posing potential risks to human health and environmental safety. With the continuous development of the preparation technology of chlorine dioxide (ClO2), ClO2, as a new type of disinfectant with low toxicity, broad spectrum, rapidity, and high efficiency, has gradually replaced chlorine and chloramine in traditional processes. ClO2 has significant advantages in the water treatment process: First, it hardly reacts with natural organic matter in water to form halogenated compounds, greatly reducing the generation of organic disinfection by-products; Second, ClO2 can maintain high oxidation activity in a wide pH range (pH 4 - 10), with strong adaptability. However, when ClO2 is used alone, there are problems such as high oxidation selectivity and insufficient degradation ability for some organic pollutants; In addition, trace amounts of chlorite (ClO2) and chlorate (ClO3 - ) may be generated during the process of removing organic pollutants by ClO2-based water treatment processes, and these by-products have potential hazards to human health. In the prior art, the ultraviolet (UV) activated ClO2 (UV / ClO2) process generates a large number of reactive species (such as ClO·, Cl·, O·, etc.) by photolyzing ClO2, significantly enhancing the oxidation ability and being able to effectively remove organic pollutants in water. Under UV irradiation, ClO2 photolyzes to generate chlorine oxygen radicals (ClO·) and oxygen atoms (O( 3P)), or generate the isomer ClOO, which rapidly decomposes into chlorine radicals (Cl·) and oxygen (O2). These radicals further react to form active species such as dichloride anion radicals (ClO2· - ), hydroxyl radicals (HO·), and ozone (O3), thereby enhancing the oxidation ability. However, typical UV light sources (such as mercury lamps) have disadvantages such as high energy consumption, poor penetration, and high environmental pollution risks, which limit their practical applications. Compared with traditional mercury lamps, new LED ultraviolet lamps have advantages such as safety, simple operation, long service life, and no need for preheating, but their cost is relatively high and the spectral range is limited.

[0003] In view of the above deficiencies of the prior art, the present invention provides an efficient method for removing organic pollutants in water. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and provides an efficient and energy-saving method for removing organic pollutants in water, which uses visible light to activate ClO2 to remove organic pollutants in water. Through the absorption characteristics of ClO2 in the visible light, the generation of active species is broadened and promoted, the degradation of pollutants is strengthened, and the generation of disinfection by-products is inhibited.

[0005] According to a first aspect of the present invention, a method for removing organic pollutants is provided, and the method includes the following steps:

[0006] S1. Mix sewage and a chlorine dioxide solution to obtain a mixed solution;

[0007] S2. Irradiate the mixed solution with a VIS-LED light source of 400 - 450 nm to react and remove pollutants in the sewage;

[0008] The pollutants include at least one of atenolol, carbamazepine, ibuprofen, and atrazine.

[0009] According to the first aspect of the present invention, it has at least the following beneficial effects:

[0010] The present invention innovatively introduces the technology of activating ClO2 with visible light (Vis-LED), breaking through the limitation of its oxidation selectivity. ClO2 has a large molar extinction coefficient in the visible light region (400 - 450 nm), can efficiently absorb light energy and undergo cleavage to generate highly active chlorine oxide radicals (ClO·), chlorine radicals (Cl·), and oxygen radicals (O· - ). These radicals further react with dissolved oxygen or pollutants to generate singlet oxygen ( 1 O2), superoxide radicals (O2· - ), etc. A variety of active species, forming a multi-path oxidation network, significantly enhancing the degradation efficiency of organic pollutants.

[0011] The specific implementation method of the present invention is as follows: Add ClO2 to the water source containing pollutants, and carry out stirring reaction under Vis-LED irradiation, so as to achieve the goal of Vis-LED enhanced ClO2 for removing organic pollutants in water. Among them, the ClO2 is prepared by gradually adding sulfuric acid (H2SO4) to sodium chlorite (NaClO2). The experimental results show that the method of using Vis425-LED to enhance ClO2 for removing organic pollutants in water has a 77.46% higher removal rate of pollutants compared with using ClO2 alone, significantly improving the treatment efficiency.

[0012] The method for removing organic pollutants of the present invention has:

[0013] 1. High efficiency: Activate ClO2 by Vis-LED to generate a variety of highly active free radicals, significantly enhancing the degradation efficiency of organic pollutants. 2. Environmental friendliness: ClO2 hardly generates chlorinated disinfection by-products during the reaction process, reducing environmental risks. 3. Energy saving: Use visible light to activate ClO2, reducing the high energy consumption problem of traditional ultraviolet light sources (such as mercury lamps), which conforms to the concept of green environmental protection. 4. Wide applicability: This method is applicable to the removal of a variety of organic pollutants, including drugs, personal care products, endocrine disruptors, etc., and has broad application prospects. The present invention activates ClO2 through V IS -LED to provide an efficient, safe and environmentally friendly method for removing organic pollutants in water, providing an innovative technical solution for solving problems in the water treatment field. Compared with the existing technology, the technology proposed by the present invention has characteristics such as higher efficiency, energy saving and safety. V IS -LED replaces the traditional ultraviolet light source, without complex power facilities, and is safer and more energy-saving; V IS -LED efficiently activates ClO2, promotes the generation of active species, and improves the removal efficiency of pollutants; the concentration of disinfection by-products after the reaction is far lower than the WHO drinking water guidelines; the applicable pH range is wide.

[0014] ClO2 may undergo a reduction reaction during the water treatment process to generate ClO2 - , ClO3 - :

[0015] For example: ClO2 + e- → ClO2 -

[0016] ClO2 + O2 → ClO3 -

[0017] After Vis-LED activates ClO2, ClO2 efficiently absorbs light energy and cleaves in the visible light region (400 - 450 nm) to generate highly active free radicals (such as ClO·, Cl·, O· -) These free radicals rapidly react with the pollutants, reducing the residual amount of ClO₂, thereby inhibiting the generation of ClO₂. - The generated active species (such as singlet oxygen 1 ¹O₂, superoxide radical O₂· - ) can further oxidize ClO₂ - and ClO₃ - , converting them into harmless chloride ions (Cl - ) or oxygen (O₂), specifically: Cl· + H₂O → ClOH· + H + (3); Cl· + OH - → ClOH· (4); ClOH· → OH· + Cl - (5); O( 3 ¹P) + O₂ → O₃ (7).

[0018] According to some embodiments of the present invention, the time of the reaction is 20 - 30 min.

[0019] According to some embodiments of the present invention, the concentration of the chlorine dioxide in the mixed solution is 90 - 100 μM.

[0020] According to some embodiments of the present invention, the preparation method of the chlorine dioxide includes: mixing and reacting sodium chlorite and sulfuric acid.

[0021] According to some embodiments of the present invention, the pH of the mixing reaction is 6 - 8.

[0022] According to some embodiments of the present invention, the reaction includes a stirring reaction, and the rotation speed of the stirring reaction is 600 - 800 r / min.

[0023] According to some embodiments of the present invention, the method includes the following steps:

[0024] S1. Mixing sewage and a chlorine dioxide solution to obtain a mixed solution;

[0025] S2. Irradiating the mixed solution with a VIS - LED light source at 420 - 430 nm to react and remove the pollutants in the sewage.

[0026] According to some embodiments of the present invention, the concentration of the chlorine dioxide in the mixed solution is 95 - 100 μM.

[0027] According to some embodiments of the present invention, the concentration of the pollutants is 5 - 10 μM.

[0028] According to some embodiments of the present invention, the pH of the reaction is 1 - 9.

[0029] Unless otherwise specified, the "about" in the present invention actually means that the allowable error is within the range of ±2%. For example, about 100 actually means 100 ± 2% × 100.

[0030] Unless otherwise specified, "between... and..." in the present invention includes the specified numbers. For example, "between 2 and 3" includes the endpoint values 2 and 3.

[0031] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. Detailed implementation manners

[0032] The following will clearly and completely describe the concept and technical effects generated by the present invention in combination with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of the present invention.

[0033] In the description of the present invention, the descriptions with reference to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0034] Embodiment 1

[0035] This example provides a method for removing organic pollutants, specifically including the following steps:

[0036] S1. Add 100 μM of ClO2 to a deionized water source containing 5 μM of atenolol and mix to obtain a mixed solution;

[0037] S2. Stir for 20 min under Vis 425 -LED irradiation to complete the removal of organic pollutants in water;

[0038] The ClO2 is prepared by gradually adding sulfuric acid to sodium chlorite, the pH of the reaction solution is 7, and the reaction stirring speed is 600 r / min.

[0039] This embodiment adds Vis 425- The removal rate of atenolol in the effluent after LED treatment is 93.04%, which is 77.46% higher than that of the single ClO2 process.

[0040] Example 2

[0041] This example provides a method for removing organic pollutants. The difference between this example and Example 1 is that the pH is 6, and the other conditions are the same. The removal rate of atenolol in this example is 94.6%.

[0042] Example 3

[0043] This example provides a method for removing organic pollutants. The difference between this example and Example 1 is that the pH is 8, and the other conditions are the same. The removal rate of atenolol in this example is 91.07%.

[0044] Comparative Example 1

[0045] This example provides a method for removing organic pollutants, which specifically includes the following steps:

[0046] Add 100 μM of ClO2 to a deionized water source containing 5 μM of atenolol and stir for 20 min to complete the removal of organic pollutants in the water;

[0047] The ClO2 is prepared by gradually adding sulfuric acid to sodium chlorite. The pH of the reaction solution is 7, and the reaction stirring speed is 600 r / min.

[0048] The removal rate of atenolol in the water in this comparative example is 15.58%.

[0049] Comparative Example 2

[0050] This example provides a method for removing organic pollutants. The difference between this comparative example and Example 1 is that it is a VIS-LED light source with a wavelength of 525 nm, and the specific steps are as follows:

[0051] S1. Add 100 μM of ClO2 to a deionized water source containing 5 μM of atenolol to obtain a mixed solution;

[0052] S2. Stir for 20 min under Vis 525 -LED irradiation to complete the removal of organic pollutants in the water;

[0053] The ClO2 is prepared by gradually adding sulfuric acid to sodium chlorite. The pH of the reaction solution is 7, and the reaction stirring speed is 600 r / min.

[0054] The removal rate of atenolol in the effluent after adding Vis 525 -LED in this example is 16.8%.

[0055] Comparative Example 3

[0056] This example provides a method for removing organic pollutants. The difference between this comparative example and Example 1 lies in the VIS-LED light source of 550 nm. The specific steps are as follows:

[0057] S1. Add 100 μM of ClO2 to a deionized water source containing 5 μM of atenolol and mix to obtain a mixed solution;

[0058] S2. Stir for 20 min under Vis 550 -LED irradiation to complete the removal of organic pollutants in water;

[0059] The ClO2 is prepared by gradually adding sulfuric acid to sodium chlorite, the pH of the reaction solution is 7, and the reaction stirring speed is 600 r / min.

[0060] After adding Vis 550 -LED in this example, the removal rate of atenolol in the effluent is 51.25%.

[0061] Comparative Example 4

[0062] This example provides a method for removing organic pollutants. The specific steps are as follows:

[0063] S1. Add 100 μM of ClO2 to a deionized water source containing 5 μM of atenolol and mix to obtain a mixed solution;

[0064] S2. Stir for 20 min under Vis 480 -LED irradiation to complete the removal of organic pollutants in water;

[0065] The ClO2 is prepared by gradually adding sulfuric acid to sodium chlorite, the pH of the reaction solution is 7, and the reaction stirring speed is 600 r / min.

[0066] After adding Vis 480 -LED in this comparative example, the removal rate of atenolol in the effluent is 58.9%.

[0067] Comparative Example 5

[0068] This example provides a method for removing organic pollutants. The specific steps are as follows:

[0069] S1. Add 100 μM of ClO2 to a deionized water source containing 5 μM of atenolol and mix to obtain a mixed solution;

[0070] S2. Stir for 20 min under Vis 505 -LED irradiation to complete the removal of organic pollutants in water;

[0071] The ClO2 therein is prepared by gradually adding sulfuric acid to sodium chlorite, the pH of the reaction solution is 7, and the stirring speed of the reaction is 600 r / min.

[0072] This comparative example adds Vis 505 - The removal rate of atenolol in the effluent after LED is 43.6%.

[0073] The above has been described in detail in conjunction with the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for removing organic pollutants, characterized in that, The method includes the following steps: S1. Mix sewage and a chlorine dioxide solution to obtain a mixed solution; S2. Irradiate the mixed solution with a V IS -LED light source at 400 - 450 nm to react and remove pollutants in the sewage; The pollutants include at least one of atenolol, carbamazepine, ibuprofen, and atrazine.

2. The method for removing organic pollutants according to claim 1, wherein The reaction time is 20 to 30 minutes.

3. The method for removing organic pollutants according to claim 1, wherein The concentration of chlorine dioxide in the mixed solution is 90 to 100 μM.

4. The method for removing organic pollutants according to claim 1, wherein The preparation method of the chlorine dioxide includes: mixing and reacting sodium chlorite and sulfuric acid.

5. The method for removing organic pollutants according to claim 1, characterized in that, The pH of the mixed reaction is 6 - 8.

6. The method for removing organic pollutants according to claim 4, characterized in that, The reaction includes a stirring reaction, and the rotation speed of the stirring reaction is 600 to 800 r / min.

7. The method for removing organic pollutants according to claim 1, characterized in that, The method includes the following steps: S1. Mix sewage and a chlorine dioxide solution to obtain a mixed solution; S2. Irradiate the mixed solution with a VIS - LED light source at 420 - 430 nm to react and remove the pollutants in the sewage.

8. The method for removing organic pollutants according to claim 7, wherein The concentration of chlorine dioxide in the mixed solution is 95 to 100 μM.

9. The method for removing organic pollutants according to claim 1, wherein The concentration of the pollutants is 5 to 10 μM.

10. The method for removing organic pollutants according to claim 1, wherein The pH of the reaction is 1 - 9.