Precise quantification method of quenchers in advanced oxidation processes for wastewater treatment

Abstract

The present application relates to the precise quantitative method of quenching agent in advanced oxidation treatment of sewage, comprising the following steps: S1: using the standard substance of the to-be-treated pollutant to prepare the to-be-tested pollutant mother liquor; S2: taking several portions of the to-be-tested pollutant mother liquor with the same volume, respectively adding different volumes of the quenching agent, and then forming several portions of the first to-be-tested liquid after constant volume; S3: taking the same volume of sample from the several portions of the first to-be-tested liquid for detection, and determining the maximum volume fraction of the quenching agent ensuring the detection accuracy; S4: taking several portions of the to-be-tested pollutant mother liquor with the same volume, respectively adding different volumes of the quenching agent, adding the catalyst and the oxidant, and then forming several portions of the second to-be-tested liquid after reaction; S5: controlling the sampling volume, determining the minimum volume fraction of the quenching agent required for terminating the oxidation reaction within the range of the maximum volume fraction of the quenching agent; and S6: actual sewage oxidation experiment, determining the addition amount of the quenching agent according to the maximum volume fraction of the quenching agent and the minimum volume fraction of the quenching agent.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a precise quantitative method for quenching agents in advanced oxidation treatment of wastewater. Background Technology

[0002] Advanced oxidation processes (AEs) are an important water treatment technology. During treatment, they generate highly oxidizing free radicals that can chemically react with recalcitrant organic pollutants, degrading them into smaller molecules or short-chain organic compounds, thus improving biodegradability. The reactions are rapid, and the treatment effects are excellent. Currently, AEs typically require the addition of quenchers to stop the free radicals from degrading the pollutants, allowing for the acquisition of degradation data at a specific point in time. Alternatively, quenchers are added near the end of the treatment process to terminate the reaction. Commonly used organic quenchers include methanol, ethanol, tert-butanol, and ascorbic acid, while inorganic quenchers mainly include sodium sulfite, sodium thiosulfate, hydroxylamine hydrochloride, and sodium nitrite.

[0003] Currently, in practice, excessive quenchers are often added to ensure the quenching reaction is achieved, with a common addition ratio of 1:1 or even higher than the reaction liquid volume. This not only wastes quenchers but also affects the accurate determination of subsequent pollutant concentrations. For example, when testing certain pollutants in water using gas chromatography, organic solvents are required for extraction. If the pollutant to be tested is dissolved in ethanol, and ethanol is used as the quencher, the extraction rate will be affected, resulting in a lower measured concentration of the pollutant. Similarly, when testing certain pollutants using spectrophotometry, adding excessive quenchers can hinder the colorimetric reaction, or the quencher itself may have strong absorbance at the test wavelength, leading to either an overestimation or underestimation of the measured value. Therefore, determining the accurate dosage of quenchers at the end of advanced oxidation treatment is crucial for avoiding quencher waste and accurately detecting pollutant degradation rates. Summary of the Invention

[0004] To address the above problems, this invention provides a precise quantitative method for quenching agents in advanced oxidation treatment of wastewater, comprising the following steps:

[0005] S1: Prepare a stock solution of the pollutant to be tested at a certain concentration using the standard of the pollutant to be treated;

[0006] S2: Take several portions of the same volume of the mother liquor of the pollutant to be tested, and add different volumes of quencher to each portion. Then, make up the same volume of the several portions of the solution to form several portions of the first test solution.

[0007] S3: Take samples of the same volume from several portions of the first test solution, perform tests, obtain the effect of different quencher volume fractions on the test values, and determine the maximum quencher volume fraction under the premise of ensuring test accuracy;

[0008] S4: Take several portions of the same volume of the mother liquor of the pollutant to be tested, and add different volumes of quencher to each portion. Then add the same amount of catalyst solution and the same amount of oxidant solution to each portion to trigger the oxidation reaction. After the reaction is completed, several portions of the second test solution are formed.

[0009] S5: By controlling the sampling volume within the range of the maximum volume fraction of the quencher determined in step S3, the quenching effect of the quencher on the advanced oxidation reaction system is verified, and the minimum volume fraction of the quencher required to terminate the oxidation reaction is determined.

[0010] S6: Conduct an actual wastewater oxidation degradation experiment. The concentration of the pollutants to be treated in the wastewater is known. Take a certain volume of reaction solution, which includes wastewater, catalyst, and oxidant solution. Determine the amount of quencher to be added based on the maximum volume fraction of the quencher determined in step S3 and the minimum volume fraction of the required quencher determined in step S5.

[0011] Optionally, in step S1, a sample solution of the pollutant to be tested with a concentration of M is prepared using ultrapure water and a standard of the pollutant to be treated, where M is 100-900 μmol / L.

[0012] Optionally, in step S2, take several portions of the mother liquor of the pollutant to be tested with a volume of V1 and add them into several volumetric flasks with a volume of V2, where V1 < V2.

[0013] Add different volumes of quencher to several volumetric flasks;

[0014] Then, ultrapure water was used to dilute several volumetric flasks to form several portions of the first test solution with a volume of V2.

[0015] Optionally, in step S2, the concentration of the pollutant to be tested in each sample of the first test solution is M×(V1 / V2), and the volume fraction of the quencher in each sample of the first test solution is v. i / V2, v i v is the volume of quencher in the corresponding first test solution; i is the number of portions of the first test solution; v i The value is 0-50 mL.

[0016] Optionally, step S3 includes the following steps:

[0017] (1) Take a sample with a volume of V3 from several portions of the first test solution and test it;

[0018] (2) The contaminant concentration detection values ​​of several samples of the first test solution were m. 1i When m 1i When ≥a×M×(V1 / V2), the corresponding v of the first test solution i / V2 is the maximum volume fraction of quencher while ensuring detection accuracy, denoted as v. j / V2.

[0019] Further optional, in step (2), press v i / V2 is detected in ascending or descending order, and the detection method depends on the specific substances of the pollutant and quencher to be treated;

[0020] When m 1i When ≥a×M×(V1 / V2), m 1i The amount of quencher added to the first test solution and below that amount are used to ignore the influence of the quencher on the test results, and a is 0.90-0.99.

[0021] Optionally, in step S4, take several portions of the mother liquor of the pollutant to be tested with a volume of V4, add them to several reaction flasks respectively, and then add different volumes of quencher to each flask.

[0022] Then, ultrapure water is added to make the liquid volumes of several reaction flasks equal. Then, the same amount of catalyst solution and the same amount of oxidant solution are added to trigger the oxidation reaction. After the oxidation reaction is completed, several portions of the second test solution with a volume of V5 are formed, where V4 < V5.

[0023] Optionally, the concentration of the analyte in each sample of the second test solution is M(V4 / V5), and the volume fraction of the quencher in each sample of the second test solution is t. i / V5,t i The corresponding quencher volume in the second test solution; the quantity of the second test solution is the same as the quantity of the first test solution in step S2, t i The value is 0-50 mL.

[0024] Optional, in step S5, for v j / V2≥t i The second test solution of / V5 ignores the influence of quencher on the detection results. The sampling volume of the second test solution is V3, so that the amount of quencher does not exceed the maximum amount that affects the detection accuracy of the pollutant.

[0025] Press t i / V5 is tested in ascending or descending order of concentration, and the contaminant concentration of several samples of the second test solution is measured as m. 2i When m 2i When ≥b×M×(V4 / V5), the corresponding t of the second test solution i / V5 is the minimum volume fraction of quencher required to terminate the oxidation reaction, denoted as t. j / V5.

[0026] Optional, in step S5, for vj / V2<t i The second test solution (V5) has a quencher that affects the test results. The sampling volume of this second test solution is V3 × (v j / V2) / (t i / V5), then dilute with ultrapure water to a final volume of V3, ensuring that the amount of quencher does not exceed the maximum amount that would affect the detection accuracy of the pollutant to be tested;

[0027] Press t i / V5 is tested in ascending or descending order of concentration, and the contaminant concentration of several samples of the second test solution is measured as m. 2i When m 2i ×(v j / V2) / (t i When / V5)≥b×M×(V4 / V5), the corresponding t of the second test solution i / V5 is the minimum volume fraction of quencher required to terminate the oxidation reaction, denoted as t. j / V5.

[0028] Further optionally, b is 0.90-0.99.

[0029] Optionally, step S6 includes the following steps:

[0030] (3) The concentration of the pollutant to be treated in the actual wastewater is C. Add the same amount of catalyst solution and oxidant solution as in step S4 to the actual wastewater, mix them evenly, and form a reaction solution.

[0031] (4) The sampling volume of the reaction solution is V6, and the amount of quencher to be added is V6 × t. j / (V5-t j And V6 must satisfy V6×t j / (V5-t j )≤(v j / V2)×V3 and V6+V6×t j / (V5-t j )≤V3.

[0032] Optionally, when V6+(v j / V2)×V3<V3, use ultrapure water to dilute the sample solution of the reaction solution to V3, and then perform the test. Detailed Implementation

[0033] The precise quantitative method for quenching agents in advanced oxidation treatment of wastewater provided in this embodiment, taking the degradation of phenol in water using a Fenton oxidation system and the termination of the reaction using methanol as a quenching agent, includes the following steps:

[0034] S1: Prepare a 400 μmol phenol stock solution using ultrapure water and phenol standard;

[0035] S2: Take eight portions of phenol stock solution with a volume of V1 = 1.25 mL and add them to eight volumetric flasks with a volume of V2 = 50 mL. Add different volumes of methanol to the volumetric flasks, with volumes of 0 mL, 0.5 mL, 1.0 mL, 2.5 mL, 5.0 mL, 10 mL, 20 mL, and 25 mL, respectively. Then, dilute the eight portions of solution to 50 mL with ultrapure water to form eight portions of the first test solution.

[0036] The concentration of the analyte in each sample of the first test solution is M(V1 / V2) = 10 μmol, and the volume fraction of the quencher in each sample of the first test solution is v. i / V2, respectively 0%, 1%, 2%, 5%, 10%, 20%, 40%, 50%;

[0037] S3: Take a sample with a volume of V3 = 5 mL from each of the eight test solutions and use the 4-aminoantipyrine method to detect it. Obtain the effect of different quencher volume fractions on the detection value and determine the maximum quencher volume fraction under the premise of ensuring detection accuracy.

[0038] Contaminant concentration values ​​(m) of eight test samples 1i The concentrations are 10.29 μM, 10.23 μM, 9.91 μM, 9.44 μM, 8.48 μM, 8.05 μM, 5.32 μM, and 3.22 μM, respectively. Taking a = 0.95, then a × M × (V1 / V2) = 0.95 × 10 = 9.5, m 1i ≥9.5, corresponding to the first test liquid with i=3, then the maximum volume fraction v of the quencher under the premise of ensuring detection accuracy. j / V2 = 2%;

[0039] S4: Take eight portions of phenol stock solution with a volume of V4 = 25 mL and add them to eight reaction flasks respectively. Then add different volumes of quencher, with volumes of 0 mL, 1.0 mL, 2.0 mL, 5.0 mL, 10.0 mL, 20 mL, 40 mL, and 50 mL respectively. Then add ultrapure water so that the liquid volume of each of the eight reaction flasks is 80 mL.

[0040] Then, 10 mL of 10 mM ferrous sulfate solution and 10 mL of 50 mM hydrogen peroxide were added to trigger the oxidation reaction. The reaction was stopped after 30 min, resulting in eight second test solutions, each with a volume of V5 = 100 mL.

[0041] The concentration of the analyte in each sample of the second test solution is M(V4 / V5) = 100 μmol, and the volume fraction of the quencher in each sample of the second test solution is t.i / V5, respectively 0%, 1%, 2%, 5%, 10%, 20%, 40%, 50%;

[0042] S5: By controlling the sampling volume within the range of the maximum volume fraction of the quencher determined in step S3, the quenching effect of the quencher on the advanced oxidation reaction system is verified, and the minimum volume fraction of the quencher required to terminate the oxidation reaction is determined.

[0043] S6: Conduct an actual wastewater oxidation degradation experiment. The concentration of phenol in the wastewater is 100 μM. Take a certain volume of reaction solution, which includes wastewater, catalyst, and oxidant solution. Determine the amount of quencher to be added based on the maximum volume fraction of the quencher determined in step S3 and the minimum volume fraction of the required quencher determined in step S5.

[0044] In step S5, for v j / V2(=2%)≥t i The second test solution of / V5, i.e., the first three portions of the second test solution (t of methanol) i / V5 is 0%, 1%, 2%), ignoring the influence of quencher on the test results, the sampling volume of the first three second test solutions is V3 = 5mL;

[0045] For v j / V2<t i / V5 is the second test solution, that is, the last five portions of the second test solution (t of methanol). i / V5 is 5%, 10%, 20%, 40%, 50%), the quencher affects the test results, the sampling volume of the last five second test solutions is V3×(v j / V2) / (t i / V5), respectively 2mL, 1mL, 0.5mL, 0.25mL, 0.2mL, and then diluted with ultrapure water to a final volume of V3 = 5mL;

[0046] The contaminant concentration detection value of the eight second test solutions was m. 2i The concentrations are 14.74 μM, 91.79 μM, 96.19 μM, 96.30 μM, 97.65 μM, 97.82 μM, 98.74 μM, and 99.61 μM, respectively. Taking b = 0.95, then b × M × (V4 / V5) = 0.95 × 100 = 95, m 2i For a sample solution with a volume fraction ≥95 corresponding to i=3, the minimum volume fraction t of the quencher required to terminate the oxidation reaction is... j / V5 = 2%.

[0047] In step S6, the same amount of catalyst solution and oxidant solution as in step S4 are added to the actual wastewater and mixed evenly to form a reaction solution.

[0048] The sample volume of the reaction solution is V6 = 4.9 mL, and the amount of quencher to be added is V6 × t. j / (V5-t j )=4.9×2 / (100-2)=0.1mL, and V6 must satisfy V6×t j / (V5-t j )=(v j / V2)×V3 and V6+V6×t j / (V5-t j =V3, no need to use ultrapure water to make up the volume for testing.

Claims

1. A precise quantitative method for quenching agents in advanced oxidation treatment of wastewater, characterized in that, Includes the following steps: S1: Prepare a stock solution of the pollutant to be tested at a certain concentration using the standard of the pollutant to be treated; S2: Take several portions of the same volume of the mother liquor of the pollutant to be tested, and add different volumes of quencher to each portion. Then, make up the same volume of the several portions of the solution to form several portions of the first test solution. S3: Take samples of the same volume from several portions of the first test solution, perform tests, obtain the effect of different quencher volume fractions on the test values, and determine the maximum quencher volume fraction under the premise of ensuring test accuracy; S4: Take several portions of the same volume of the mother liquor of the pollutant to be tested, and add different volumes of quencher to each portion. Then add the same amount of catalyst solution and the same amount of oxidant solution to each portion to trigger the oxidation reaction. After the reaction is completed, several portions of the second test solution are formed. S5: By controlling the sampling volume within the range of the maximum volume fraction of the quencher determined in step S3, the quenching effect of the quencher on the advanced oxidation reaction system is verified, and the minimum volume fraction of the quencher required to terminate the oxidation reaction is determined. S6: Conduct an actual wastewater oxidation degradation experiment. The concentration of the pollutants to be treated in the wastewater is known. Take a certain volume of reaction solution, which includes wastewater, catalyst and oxidant solution. Determine the amount of quencher to be added based on the maximum volume fraction of the quencher determined in step S3 and the minimum volume fraction of the required quencher determined in step S5. In step S3, when the detected value of the pollutant concentration in the first test liquid is not less than 90% of the concentration of the pollutant in the first test liquid, the corresponding quencher volume fraction in the first test liquid is the maximum quencher volume fraction under the premise of ensuring detection accuracy. In step S5, if the quencher volume fraction of the second test liquid is not greater than the maximum quencher volume fraction, the influence of the quencher on the detection result is ignored. The sampling volume of the second test liquid is the same as the sampling volume of the first test liquid in step S3, so that the amount of quencher does not exceed the maximum amount that affects the detection accuracy of the pollutant. The second test liquid is tested in order of quencher volume fraction from small to large or from large to small. When the pollutant concentration detection value of the second test liquid is not less than 90% of the concentration of the pollutant in the second test liquid, the corresponding quencher volume fraction of the second test liquid is the minimum volume fraction of quencher required to terminate the oxidation reaction. In step S5, if the volume fraction of the quencher in the second test solution is greater than the maximum volume fraction of the quencher, then the quencher will affect the detection result. The sampling volume of the second test solution is the product of the sampling volume of the first test solution in step S3 and the maximum volume fraction of the quencher, divided by the volume fraction of the quencher in the second test solution. Then, it is diluted with ultrapure water to the sampling volume of the first test solution, so that the amount of quencher does not exceed the maximum amount that affects the detection accuracy of the pollutant. The second test solution is tested in order of increasing or decreasing quencher volume fraction. When the detected value of the pollutant concentration in the second test solution is not less than 90% of the concentration of the pollutant in the second test solution and the product of the sampling volume of the second test solution in this step, then the corresponding volume fraction of the quencher in the second test solution is the minimum volume fraction of the quencher required to terminate the oxidation reaction. In step S6, the volume fraction of the quencher in the sample of the reaction solution is made equal to the minimum volume fraction, thereby determining the amount of quencher to be added. At the same time, the sum of the sample volume and the volume of the added quencher is not greater than the sampling volume of the first test solution in step S3, and the amount of quencher added is not greater than the product of the sampling volume of the first test solution in step S3 and the maximum volume fraction of the quencher.

2. The precise quantitative method for quenching agents in advanced oxidation treatment of wastewater according to claim 1, characterized in that, In step S2, take several portions of the mother liquor of the pollutant to be tested with a volume of V1 and add them into several volumetric flasks with a volume of V2 respectively; add different volumes of quencher to the several volumetric flasks respectively; Then, ultrapure water was used to dilute several volumetric flasks to form several portions of the first test solution with a volume of V2.

3. The precise quantitative method for quenching agents in advanced oxidation treatment of wastewater according to claim 2, characterized in that, The concentration of the analyte in each first test solution is M(V1 / V2), where M is the concentration of the analyte in the mother liquor; the volume fraction of the quencher in each first test solution is v. i / V2, v i v is the volume of quencher in the corresponding first test solution; i is the number of portions of the first test solution; v i The value is 0-50 mL.

4. The precise quantitative method for quenching agents in advanced oxidation treatment of wastewater according to claim 3, characterized in that, Step S3 includes the following steps: (1) Take a sample with a volume of V3 from several portions of the first test solution and perform the test; (2) The contaminant concentration detection value of several samples of the first test solution is m 1i When m 1i When ≥a×M×(V1 / V2), the corresponding v of the first test solution i / V2 is the maximum volume fraction of quencher while ensuring detection accuracy, denoted as v. j / V2, a is 0.90-0.

99.

5. The precise quantitative method for quenching agents in advanced oxidation treatment of wastewater according to claim 4, characterized in that, In step (2), press v i / V2 is detected in ascending or descending order, when m 1i When ≥a×M×(V1 / V2), m 1i The effect of the quencher on the test results is ignored for the amount of quencher added to the first test solution and below that amount.

6. The precise quantitative method for quenching agents in advanced oxidation treatment of wastewater according to claim 5, characterized in that, In step S4, take several portions of the mother liquor of the pollutant to be tested with a volume of V4, add them to several reaction flasks respectively, and then add different volumes of quencher to each flask. Then, ultrapure water is added to make the liquid volumes of several reaction flasks equal. Then, the same amount of catalyst solution and the same amount of oxidant solution are added to trigger the oxidation reaction. After the oxidation reaction is completed, several portions of the second test solution with a volume of V5 are formed, where V4 < V5.

7. The precise quantitative method for quenching agents in advanced oxidation treatment of wastewater according to claim 6, characterized in that, The concentration of the analyte in each sample of the second test solution is M(V4 / V5), and the volume fraction of the quencher in each sample of the second test solution is t. i / V5,t i This represents the volume of the quencher in the corresponding second test solution; The quantity of the second test solution is the same as the quantity of the first test solution in step S2, t i The value is 0-50 mL.

8. The method for precise quantification of quencher in advanced oxidation treatment of wastewater according to claim 7, characterized in that, In step S5, for v j / V2≥t i The second test solution of / V5 ignores the influence of quencher on the detection results. The sampling volume of the second test solution is V3, so that the amount of quencher does not exceed the maximum amount that affects the detection accuracy of the pollutant. Press t i / V5 is tested in ascending or descending order of concentration, and the contaminant concentration of several samples of the second test solution is measured as m. 2i When m 2i When ≥b×M×(V4 / V5), the corresponding t of the second test solution i / V5 is the minimum volume fraction of quencher required to terminate the oxidation reaction, denoted as t. j / V5, b is 0.90-0.

99.

9. The method for precise quantification of quencher in advanced oxidation treatment of wastewater according to claim 7, characterized in that, In step S5, for v j / V2<t i The second test solution (V5) has a quencher that affects the test results. The sampling volume of this second test solution is V3 × (v j / V2) / (t i / V5), then dilute with ultrapure water to a final volume of V3, ensuring that the amount of quencher does not exceed the maximum amount that would affect the detection accuracy of the pollutant to be tested; Press t i / V5 is tested in ascending or descending order of concentration, and the contaminant concentration of several samples of the second test solution is measured as m. 2i When m 2i / [V3×(v j / V2) / (t i When / V5)]≥b×M×(V4 / V5), the corresponding t of the second test liquid i / V5 is the minimum volume fraction of quencher required to terminate the oxidation reaction, denoted as t. j / V5, b is 0.90-0.

99.

10. The method for precise quantification of quencher in advanced oxidation treatment of wastewater according to claim 8 or 9, characterized in that, Step S6 includes the following steps: (3) The concentration of the pollutant to be treated in the actual wastewater is C. Add the same amount of catalyst solution and oxidant solution as in step S4 to the actual wastewater, mix them evenly, and form a reaction solution. (4) The sampling volume of the reaction solution is V6, and the amount of quencher to be added is V6×t. j / (V5-t j And V6 must satisfy V6×t j / (V5-t j )≤(v j / V2)×V3 and V6+V6×t j / (V5-t j )≤V3.