Method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid

Abstract

The invention discloses a method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid, which adopts ion chromatography for determination and uses leacheate with a specific formula to realize effective separation of three ion chromatographic peaks, and the leacheate comprises Na2CO3, NaHCO3 and acetone; the method comprises the following steps: preparing leacheate; preparing a mixed standard solution of three target anions; leacheate is adopted as a mobile phase, and a standard curve is drawn through ion chromatography; pretreating a coke oven gas desulfurization liquid sample; and detecting the treated sample under the same chromatographic conditions as the previous steps, and calculating the content of each anion according to the standard curve. Compared with a chemical analysis method, the method has the advantages that pretreatment operations such as acid addition and alkali addition are not needed, rapid, synchronous and high-precision determination of three coexisting anions in the coke oven gas desulfurization liquid can be realized, the operation efficiency is greatly improved, the analysis time is obviously shortened, the efficiency is improved by 70% or above compared with that of a traditional chemical analysis method, and dangerous operation of the chemical method is avoided.

Description

Technical Field

[0001] This invention relates to the field of chemical testing technology, and more specifically, to a method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid. Background Technology

[0002] Coke oven gas is a combustible gas produced during the coking process, and its main components include methane, hydrogen, carbon monoxide, and carbon dioxide. Desulfurization liquid is a byproduct of the wet catalytic oxidation process for coke oven gas. Wet catalytic oxidation technology uses ammonia from coke oven gas as an alkali source. Ammonia reacts with pollutants such as hydrogen sulfide and hydrogen cyanide through complex chemical reactions to form complex salts; therefore, the SO4 in the desulfurization liquid... 2- SCN - S2O3 2- Anions coexist. Among them, SO42- 2- SCN - S2O3 2- They represent sulfate, thiocyanate, and thiosulfate ions, respectively.

[0003] Currently, existing technologies generally employ chemical methods to determine these three main anions in desulfurization solutions, including iodometric determination of S2O3 in the desulfurization solution. 2- Spectrophotometric determination of SCN - Determination of SO4 by EDTA titration or spectrophotometry 2- Because the desulfurization liquid has a complex composition, high turbidity, and deep color, interfering substances such as sulfur and phenols also significantly affect the accuracy of the measurement. The removal of interfering substances is cumbersome, requiring the addition of acid and alkali to the sample, which results in long analysis time, large human error, low analysis efficiency, and also limits the improvement of process production control efficiency.

[0004] For example, a spectrophotometric method for detecting sulfate in desulfurization liquid, as described in patent application number 202411075806.7, uses dilute acid as an interference remover, barium chloride as a precipitant, and potassium chromate as a colorimetric reagent. The sulfate concentration is calculated by measuring the remaining amount of chromate ions after the reaction using a spectrophotometer. This method uses many reagents, is relatively complex to operate, and can only detect sulfate ions in the desulfurization liquid, resulting in relatively low analytical efficiency.

[0005] For example, the invention patent application number 201510303798.1 describes a method for rapid determination of thiocyanate ions in coking desulfurization liquid. This invention is based on the reaction of thiocyanate ions with metal ions Fe. 3+The principle of colorimetric reaction involves adding excess metal ions to the test solution, then measuring the absorbance of the reaction solution at the maximum absorption wavelength using a 723 spectrophotometer. The thiocyanate ion content of the test solution is then calculated based on the absorbance curve of the standard solution. However, this method lacks an effective pretreatment method for desulfurization solutions, has low anti-interference capability, is complex to operate, and can only detect thiocyanates in liquids such as desulfurization solutions, resulting in relatively low analytical efficiency.

[0006] Therefore, the composition of coke oven gas desulfurization liquid is complex and subject to many interferences. Traditional methods require separate determination, which is cumbersome and inefficient. When existing ion chromatography methods are directly applied to the determination of desulfurization liquid samples, problems such as poor resolution, decreased column efficiency, and low accuracy exist.

[0007] In particular, no specific formulation of ion chromatography eluent combined with effective pretreatment methods has been found to address SO4 in this complex matrix. 2- SCN - S2O3 2- Reports on problems such as difficulty in separation and slow analysis speed.

[0008] In summary, current technologies lack a rapid, convenient, and accurate method for simultaneously analyzing the three coexisting anions, SO42-, in coke oven gas desulfurization liquid. 2- SCN - S2O3 2- The method. Summary of the Invention

[0009] The purpose of this invention is to overcome the aforementioned deficiencies in the prior art and provide a method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid. To address the interference from the complex matrix of the coke oven gas desulfurization liquid, ion chromatography is employed for determination, and a specifically formulated eluent is used to resolve SO4 content. 2- SCN - S2O3 2- This technology solves the problem of difficult peak separation in chromatographic analysis and addresses the challenge of rapidly and accurately determining SO4 in coke oven gas desulfurization liquid in existing technologies. 2- SCN - S2O3 2- Furthermore, it avoids the problems of long analysis time and low work efficiency. Compared with chemical analysis methods, it does not require pretreatment operations such as adding acid or alkali, which reduces resource consumption, environmental pollution and personnel injury risks, and significantly improves labor productivity.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows: A method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid, which addresses the interference from the complex matrix of coke oven gas desulfurization liquid, employs ion chromatography to determine the three coexisting anions in the coke oven gas desulfurization liquid, wherein the coexisting anions are SO42-. 2- SCN- S2O3 2- And use a specially formulated rinsing solution to address SO4. 2- SCN - S2O3 2- The specific steps to address the difficulty in separating chromatographic peaks are as follows: S1. Prepare the rinsing solution; The rinsing solution is prepared from Na2CO3, NaHCO3 and acetone; wherein the concentration of Na2CO3 in the rinsing solution is 3.2~4.5 mmol / L, the concentration of NaHCO3 is 0.85~1.15 mmol / L, and the concentration of acetone is 0~5% (v / v), preferably 1~5% (v / v), more preferably 2~5% (v / v); S2, Preparation of SO4 2- SCN - and S2O3 2- Mixed standard solutions; S3. Using the eluent as the mobile phase, a standard curve is plotted by ion chromatography. S4. Pre-treat the coke oven gas desulfurization liquid sample; S5. Detect the treated desulfurization liquid sample under the same chromatographic conditions as in step S3, and calculate the SO4 content in the desulfurization liquid sample according to the standard curve. 2- SCN - S2O3 2- The content of.

[0011] Specifically, in the eluent formulation, a specific concentration ratio of Na2CO3 and NaHCO3 can enhance the removal of SO4 in the desulfurization solution. 2- S2O3 2- The selectivity helps improve the separation degree and shorten the peak separation time; adding an appropriate amount of acetone to the eluent can enhance the SCN in the desulfurization solution. - S2O3 2- The separation degree is improved, the peak separation time is shortened, and SO4 is also improved. 2- S2O3 2- The separation effect is not significantly affected. Therefore, this eluent formulation can solve the problems of mutual interference of chromatographic peaks and poor selectivity of the three ions in coke oven gas desulfurization liquid during chromatographic analysis, and plays a key role in achieving rapid, synchronous, and high-precision chromatographic analysis of the three coexisting anions in coke oven gas desulfurization liquid. Using the eluent and method provided by this invention, SCN in coke oven gas desulfurization liquid can be separated. - With S2O3 2- SO4 2- With S2O3 2- The chromatographic peak resolution all reached above 1.5, ensuring accurate quantification.

[0012] Experiments have verified that when the Na₂CO₃ concentration is below 3.2 mmol / L or above 4.5 mmol / L, and the NaHCO₃ concentration is below 0.85 mmol / L or above 1.15 mmol / L, SCN... - With S2O3 2- The separation efficiency will decrease significantly (R<1.5), failing to meet the requirements for accurate quantification.

[0013] Optionally, in step S2, SO4 with different gradient concentrations is prepared. 2- SCN - and S2O3 2- The mixed standard solutions were prepared with gradient concentrations of 10 mg / L, 30 mg / L, 50 mg / L, 70 mg / L, and 100 mg / L.

[0014] Optionally, in step S2, SO4 is prepared. 2- SCN - and S2O3 2- The mixed standard solution comprises: weighing 0.1813 g of K2SO4, 0.1672 g of KSCN and 0.2212 g of Na2S2O35H2O solid analytical grade reagents respectively, placing them in a 1 L volumetric flask and diluting to 1 L with deionized water to prepare a mixed standard solution with a concentration of 100 mg / L; then measuring 10 ml, 30 ml, 50 ml and 70 ml of the mixed standard solution into four 100 ml volumetric flasks respectively, and diluting to 100 ml with deionized water to prepare mixed standard solutions with gradient concentrations of 10 mg / L, 30 mg / L, 50 mg / L, 70 mg / L and 100 mg / L respectively.

[0015] Optionally, in step S3, the mixed standard solution is analyzed by ion chromatography, and a standard curve is plotted with concentration as the abscissa and peak area as the ordinate.

[0016] Optionally, in steps S3 and S5, the conditions for the ion chromatography analysis are as follows: equipped with an anion exchange column and a guard column; anion exchange column: Metrosep A Supp 5-250 / 4.0; guard column: Metrosep A Supp 5 Guard / 4.0; using 5% H2SO4 as an inhibitor; the mobile phase is the eluent prepared in step S1; the eluent flow rate is 0.7 mL / min; the column temperature is 45℃; and the column pressure is 10.9 MPa.

[0017] Optionally, in step S4, the coke oven gas desulfurization liquid sample is filtered using quantitative filter paper, 1 mL of the filtrate is diluted to 1 L with deionized water, and then pretreated using a chromatographic solid-phase extraction pretreatment column; then, organic matter in the coke oven gas desulfurization liquid sample is removed using an ion chromatography column, and finally, microorganisms are removed using a needle filter; wherein, the pore size of the quantitative filter paper is 30~50 μm.

[0018] Optionally, in step S4, the pretreatment includes: diluting the filtered desulfurization liquid filtrate with deionized water at least 1000 times; preferably, the dilution ratio is 1000 to 1500 times.

[0019] Optionally, the determination of the sample in step S5 includes: adding the treated desulfurization liquid sample to the sample vial of the autosampler under the same chromatographic conditions and procedures as for plotting the standard curve; the sample entering the chromatographic column and being detected by a conductivity detector to generate an integrated spectrum and determine SO4. 2- SCN - and S2O3 2- The peak area of ​​SO4 in the treated desulfurization liquid sample was calculated using a program based on the standard curve established in S3. 2- SCN - S2O3 2- content.

[0020] Optional, SCN - With S2O3 2- Chromatographic peak resolution R ≥ 1.5, SO4 2- With S2O3 2- Chromatographic peak resolution R ≥ 1.5.

[0021] This invention solves the SO4 problem by creatively employing a carbonate leaching solution system containing a specific concentration of acetone. 2- SCN - S2O3 2- This addresses the challenges of separation and shortens retention time. Combined with a specific desulfurization liquid sample pretreatment method, it effectively removes interference from organic matter and particulate matter, protects the chromatographic column, and ultimately achieves rapid, accurate, and simultaneous determination using three ion chromatography methods.

[0022] Implementing the embodiments of the present invention will have the following beneficial effects: (1) The three ion SO4 in coke oven gas were realized 2- SCN - S2O3 2- Simultaneous determination: For the first time, SO4 in coke oven gas desulfurization liquid was determined using a single chromatographic method. 2- SCN - S2O3 2-- Rapid and simultaneous determination of three key anions overcomes the drawback of traditional methods that require separate detection.

[0023] (2) The analysis efficiency is greatly improved: the whole analysis time is shortened to about 45 minutes, which is more than 70% more efficient than the traditional chemical analysis method (about 180 minutes).

[0024] (3) The method is accurate and reliable: the provided special rinsing solution ensures that SO4 is contained. 2- SCN - S2O3 2- With the separation of difficult-to-separate ion pairs (R≥1.5), combined with effective pretreatment, the method precision (RSD<1.5%) and spike recovery (92-95%) are good.

[0025] (4) Safety and environmental protection: No dangerous chemical operations such as adding acid or alkali are required throughout the process, which reduces safety risks and environmental burden. Attached Figure Description

[0026] Fig. 1 S2O3 in Embodiment 1 of the present invention 2- Standard curve.

[0027] Fig. 2 The SCN of Embodiment 1 of the present invention - Standard curve.

[0028] Fig. 3 SO4 as described in Embodiment 1 of the present invention 2- Standard curve. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0030] This invention discloses a method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid, using ion chromatography to determine the SO42-3 coexisting anions in the coke oven gas desulfurization liquid. 2- SCN - S2O3 2- The specific steps for the measurement are as follows: S1. Preparation of the eluent; the eluent is prepared using Na2CO3, NaHCO3 and acetone; wherein the concentration of Na2CO3 in the eluent is 3.2~4.5mmol / L, the concentration of NaHCO3 is 0.85~1.15mmol / L, and the concentration of acetone is 0~5% (v / v).

[0031] Specifically, the eluent formulation provided by this invention can sequentially elute high-valence coexisting anions in a sample at a relatively low concentration. The acetone solution added to the eluent is an organic modifier that can reduce the SCN content in the desulfurization solution.- S2O3 2- The affinity with the stationary phase in the chromatographic column ensures the presence of SCN in the desulfurization solution. - With S2O3 2- A chromatographic peak resolution R ≥ 1.5 shortens the retention time in chromatographic analysis and reduces the likelihood of tailing peaks; simultaneously, it reduces SO4... 2- With S2O3 2- Effective separation of chromatographic peaks, enabling SO4 2- With S2O3 2- Chromatographic peak resolution R ≥ 1.5.

[0032] S2, Preparation of SO4 2- SCN - and S2O3 2- A mixed standard solution.

[0033] In one specific embodiment, in step S2, SO4 with different gradient concentrations is prepared. 2- SCN - and S2O3 2- The mixed standard solutions were prepared with gradient concentrations of 10 mg / L, 30 mg / L, 50 mg / L, 70 mg / L, and 100 mg / L.

[0034] In one specific embodiment, in step S2, SO4 is prepared. 2- SCN - and S2O3 2- The mixed standard solution comprises: weighing 0.1813 g of K2SO4, 0.1672 g of KSCN and 0.2212 g of Na2S2O3·5H2O solid analytical grade reagents respectively, placing them in a 1 L volumetric flask and diluting to 1 L with deionized water to prepare a mixed standard solution with a concentration of 100 mg / L; then measuring 10 ml, 30 ml, 50 ml and 70 ml of the mixed standard solution into four 100 ml volumetric flasks respectively, and diluting to 100 ml with deionized water to prepare mixed standard solutions with gradient concentrations of 10 mg / L, 30 mg / L, 50 mg / L, 70 mg / L and 100 mg / L respectively.

[0035] S3. Using the eluent as the mobile phase, a standard curve is plotted by ion chromatography.

[0036] In one specific embodiment, in step S3, the mixed standard solution is analyzed by ion chromatography, and a standard curve is plotted with concentration as the abscissa and peak area as the ordinate.

[0037] In one specific embodiment, in step S3, the conditions for ion chromatography analysis are as follows: equipped with an anion exchange column and a guard column; anion exchange column: Metrosep A Supp 5-250 / 4.0; guard column: Metrosep A Supp 5 Guard / 4.0; using 5% H2SO4 as an inhibitor; the mobile phase is the eluent prepared in step S1; the eluent flow rate is 0.7 mL / min; the column temperature is 45℃; and the column pressure is 10.9 MPa.

[0038] S4. Pre-treat the coke oven gas desulfurization liquid sample.

[0039] In one specific embodiment, the coking desulfurization liquid contains a large number of organic pollutants such as phenol, benzene, and arsenic. The purpose of pretreatment of the coking gas desulfurization liquid sample is to eliminate interfering components and protect the chromatographic separation column. In step S4, the coking gas desulfurization liquid sample is filtered using quantitative filter paper, and 1 mL of the filtrate is diluted to a 1 L volumetric flask with deionized water. Then, a chromatographic solid-phase extraction pretreatment column is used to remove particles and suspended solids from the desulfurization liquid. Next, an ion chromatography column is used to remove organic matter from the coking gas desulfurization liquid sample, and finally, a syringe filter is used to remove microorganisms.

[0040] In one specific embodiment, the pore size of the quantitative filter paper is 30~50μm.

[0041] In one specific embodiment, in step S4, the pretreatment includes: diluting the filtered desulfurization liquid filtrate with deionized water at least 1000 times.

[0042] S5. Detect the processed sample under the same chromatographic conditions as in step S3, and calculate the SO4 content in the desulfurization liquid sample based on the standard curve. 2- SCN - S2O3 2- The content of.

[0043] In one specific embodiment, the determination of the sample in step S5 includes: following the same chromatographic conditions and steps as for plotting the standard curve, calling the detection method, editing the measurement sequence, adding the treated desulfurization liquid sample to the sample vial of the autosampler, the sample entering the chromatographic column, being detected by a conductivity detector, forming an integrated spectrum, and measuring SO4. 2- SCN - and S2O3 2- The peak area of ​​SO4 in the treated desulfurization liquid sample was calculated using a program based on the standard curve established in S3. 2- SCN - S2O3 2- content.

[0044] In one specific embodiment, SCN -With S2O3 2- Chromatographic peak resolution R ≥ 1.5, SO4 2- With S2O3 2- Chromatographic peak resolution R ≥ 1.5.

[0045] The following are specific embodiments. Experimental instruments: The testing instrument used was a Metrohm ion chromatograph from Switzerland.

[0046] Example 1 This embodiment simultaneously measures three coexisting anions, SO4, in the desulfurization liquid of coke oven gas. 2- SCN - S2O3 2- The method used is ion chromatography to determine three coexisting anions in coke oven gas desulfurization liquid. The specific steps are as follows: S1. Prepare the chromatographic analysis eluent for desulfurization of coke oven gas; wherein the concentration of Na2CO3 in the eluent is 3.25 mmol / L, the concentration of NaHCO3 is 1.05 mmol / L, and the concentration of acetone is 4.50% (v / v).

[0047] S2, Preparation of SO4 2- SCN - and S2O3 2- Mixed standard solutions: Weigh 0.1813 g of K₂SO₄, 0.1672 g of KSCN, and 0.2212 g of Na₂S₂O₃·5H₂O (analytical grade) solid reagents, respectively, and add them simultaneously to the same 1 L volumetric flask. Dilute to 1 L with deionized water to prepare a mixed standard solution with a concentration of 100 mg / L. Then, pipette 10 ml, 30 ml, 50 ml, and 70 ml of the prepared 100 mg / L mixed standard solution into four 100 ml volumetric flasks, respectively. This will ultimately prepare mixed standard solutions with concentration gradients of 10 mg / L, 30 mg / L, 50 mg / L, 70 mg / L, and 100 mg / L.

[0048] S3. Construct a standard curve using ion chromatography: Analyze the mixed standard solution using ion chromatography, performing six determinations under the following experimental conditions to obtain quantitative parameters such as the linear equation, linear range, and correlation coefficient for each component. Plot concentration on the x-axis and peak area on the y-axis to obtain the following... Figs. 1-3The standard curve was obtained. The conditions for ion chromatography analysis were as follows: anion exchange column and guard column were used. Anion exchange column: Metrosep A Supp 5-250 / 4.0; guard column: Metrosep A Supp 5 Guard / 4.0; 5% H2SO4 was used as the inhibitor; the mobile phase was the eluent prepared in step S1; the eluent flow rate was 0.7 mL / min; the column temperature was 45℃; and the column pressure was 10.9 MPa. This resulted in a good chromatographic peak, SCN. - With S2O3 2- Resolution R = 1.6, SO4 2- With S2O3 2- The chromatographic peak resolution R = 1.55.

[0049] S4. Pretreatment of coke oven gas desulfurization liquid sample: Filter coke oven gas desulfurization liquid sample 1 using quantitative filter paper, take 1 mL of filtrate and dilute it to 1 L volumetric flask with deionized water, then pretreat it using a chromatographic IC-RP solid phase extraction pretreatment column to remove particles and suspended matter in the desulfurization liquid; then remove organic matter from the coke oven gas desulfurization liquid sample using an ion chromatography column, and finally remove microorganisms using a needle filter; wherein, the pore size of the quantitative filter paper is 40 μm.

[0050] S5. Following the same chromatographic conditions and steps as for plotting the standard curve, call the detection method, edit the measurement sequence, add the treated desulfurization liquid sample to the sample vial of the autosampler, and the sample enters the chromatographic column. Detected by a conductivity detector, an integrated spectrum is generated, and the SO4 content is measured. 2- SCN - and S2O3 2- The peak area of ​​SO4 in the treated desulfurization liquid sample can be calculated by the program based on the standard curve established in S3, as shown in Table 1. 2- SCN - S2O3 2- content.

[0051] Table 1

[0052] The pretreatment and chromatographic analysis of desulfurization liquid samples using the technical solution of this invention takes approximately 45 minutes.

[0053] The sample was simultaneously analyzed using chemical methods. The desulfurization liquid was pretreated by filtration with filter paper before analysis.

[0054] Table 2

[0055] As shown in Table 2, the analytical results of the chemical analysis method are similar to those of the chromatographic analysis method, with no significant difference.

[0056] When using chemical analysis methods, sample pretreatment and single-person analysis of the three ions takes approximately 180 minutes.

[0057] (1) Examination of linear relationships like Figs. 1-3 As shown, SO4 2- SCN - and S2O3 2- They all exhibit a good linear relationship, with a correlation coefficient R0. 2 All values ​​are greater than 0.99, indicating a wide linear range that meets detection requirements.

[0058] (2) Precision test The test was repeated 10 times under the above conditions. The test results are shown in Table 3. The relative standard deviations (RSD, n=10) were 1.23%, 1.51%, and 1.12%, respectively, indicating good precision.

[0059] Table 3

[0060] (3) Spike recovery rate investigation The spiked recovery results of Example 1 are shown in Table 4 below.

[0061] Table 4

[0062] Example 2 This embodiment simultaneously measures three coexisting anions, SO4, in the desulfurization liquid of coke oven gas. 2- SCN - S2O3 2- The method used is ion chromatography to determine three coexisting anions in coke oven gas desulfurization liquid. The specific steps are as follows: S1. Prepare the eluent; wherein the concentration of Na2CO3 in the eluent is 3.85 mmol / L, the concentration of NaHCO3 is 1.15 mmol / L, and the concentration of acetone is 4.85% (v / v).

[0063] S2. Prepare SO4 according to the method in Example 1. 2- SCN - and S2O3 2- A mixed standard solution.

[0064] S3. A standard curve was plotted using ion chromatography according to the method in Example 1. SCN - With S2O3 2- The chromatographic peak resolution R = 1.58, SO4 2- With S2O3 2-The chromatographic peak resolution R = 1.62.

[0065] S4. Pretreatment of coke oven gas desulfurization liquid sample: Filter coke oven gas desulfurization liquid sample 2 using quantitative filter paper, take 1 mL of filtrate and dilute it to 1 L volumetric flask with deionized water, then pretreat it using a chromatography IC-RP solid phase extraction pretreatment column to remove particles and suspended matter in the desulfurization liquid; then remove organic matter from the coke oven gas desulfurization liquid sample using an ion chromatography column, and finally remove microorganisms using a syringe filter; wherein, the pore size of the quantitative filter paper is 50 μm.

[0066] S5. Following the same chromatographic conditions and steps as for plotting the standard curve, call the detection method, edit the measurement sequence, add the treated desulfurization liquid sample to the sample vial of the autosampler, and the sample enters the chromatographic column. Detected by a conductivity detector, an integrated spectrum is generated, and the SO4 content is measured. 2- SCN - and S2O3 2- The peak area of ​​SO4 in the treated desulfurization liquid sample can be calculated by the program based on the standard curve established in S3, as shown in Table 5. 2- SCN - S2O3 2- content.

[0067] Table 5

[0068] The effect of this embodiment is the same as that of embodiment 1.

[0069] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid, characterized in that, Three coexisting anions in the desulfurization liquid of coke oven gas were determined by ion chromatography. The coexisting anions were SO42-. 2- SCN - S2O3 2- The specific steps are as follows: S1. Prepare the rinsing solution; The eluent is prepared from Na2CO3, NaHCO3 and acetone; wherein the concentration of Na2CO3 in the eluent is 3.2~4.5 mmol / L, the concentration of NaHCO3 is 0.85~1.15 mmol / L, and the concentration of acetone is 0~5% (v / v). S2, Preparation of SO4 2- SCN - and S2O3 2- Mixed standard solutions; S3. Using the eluent as the mobile phase, a standard curve is plotted by ion chromatography. S4. Pre-treat the coke oven gas desulfurization liquid sample; S5. Detect the treated desulfurization liquid sample under the same chromatographic conditions as in step S3, and calculate the SO4 content in the desulfurization liquid sample according to the standard curve. 2- SCN - S2O3 2- The content of.

2. The method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid according to claim 1, characterized in that, In step S2, SO4 with different gradient concentrations is prepared. 2- SCN - and S2O3 2- The mixed standard solutions were prepared with gradient concentrations of 10 mg / L, 30 mg / L, 50 mg / L, 70 mg / L, and 100 mg / L.

3. The method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid according to claim 1, characterized in that, In step S3, the mixed standard solution is analyzed by ion chromatography, and a standard curve is plotted with concentration on the x-axis and peak area on the y-axis.

4. The method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid according to claim 3, characterized in that, In steps S3 and S5, the conditions for the ion chromatography analysis are as follows: equipped with an anion exchange column and a guard column; anion exchange column: Metrosep A Supp 5-250 / 4.0; guard column: Metrosep A Supp 5 Guard / 4.0; using 5% H2SO4 as an inhibitor; the mobile phase is the eluent prepared in step S1; the eluent flow rate is 0.7 mL / min; the column temperature is 45℃; and the column pressure is 10.9 MPa.

5. The method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid according to claim 1, characterized in that, In step S4, the coke oven gas desulfurization liquid sample is filtered using quantitative filter paper. 1 mL of the filtrate is diluted to 1 L in a volumetric flask with deionized water, and then pretreated using a chromatographic solid-phase extraction pretreatment column. Organic matter in the coke oven gas desulfurization liquid sample is then removed using an ion chromatography column, and finally microorganisms are removed using a needle filter. The pore size of the quantitative filter paper is 30-50 μm.

6. The method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid according to claim 5, characterized in that, In step S4, the pretreatment includes diluting the filtered desulfurization liquid filtrate with deionized water at least 1000 times.

7. The method for simultaneously determining three coexisting anions in coke oven gas desulfurization liquid according to claim 1, characterized in that, The determination of the sample in step S5 includes: Following the same chromatographic conditions and procedures as for plotting the standard curve, the treated desulfurization liquid sample was added to the sample vial of the autosampler. The sample entered the chromatographic column, was detected by a conductivity detector, and an integrated spectrum was generated to determine SO4. 2- SCN - and S2O3 2- The peak area of ​​SO4 in the treated desulfurization liquid sample was calculated using a program based on the standard curve established in S3. 2- SCN - S2O3 2- content.

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