Method for rapidly detecting arsenic content in chemical wastewater

Abstract

The invention relates to a method for rapidly detecting arsenic content in chemical wastewater, which comprises the following steps: S1, sample pretreatment optimization: taking a chemical wastewater vulcanized liquid sample, and filtering to obtain a sample to be detected; s2, debugging parameters of an energy dispersive X-ray luminoscope: setting an energy detection interval of the luminoscope according to the characteristic X-ray energy range of the arsenic element, and determining an optimal detection time parameter; s3, establishing a standard curve: collecting a plurality of groups of chemical wastewater standard samples with known arsenic content, detecting by adopting an energy dispersion X luminoscope, and drawing and fitting to obtain the standard curve; s4, actual sample detection: putting a to-be-detected sample into the debugged energy dispersive X-ray luminoscope, and obtaining the arsenic element characteristic X-ray intensity of the to-be-detected sample; and substituting the intensity value into a standard curve, and calculating to obtain the content of arsenic in the sample to be detected. According to the method, the operation process is simplified, the labor cost and the error risk are reduced, and efficient and accurate detection of the arsenic content in the chemical wastewater is realized.

Description

Technical Field

[0001] This invention relates to the field of water quality testing technology, and in particular to a method for rapidly detecting arsenic content in chemical wastewater. Background Technology

[0002] In chemical production processes, especially in copper-related chemical plants, wastewater containing sulfides is generated. The arsenic content in this wastewater is a crucial indicator for process control and environmental monitoring. As a toxic and harmful element, excessively high levels of arsenic can not only affect the stability of subsequent production processes but also cause serious environmental pollution. Therefore, accurate and timely detection of arsenic content in chemical wastewater is essential.

[0003] Currently, the analysis of arsenic content in sulfidation liquid samples from chemical plants commonly employs a method of "sample nitric acid acidification pretreatment + spectroscopic analysis." This method involves steps such as filtration, acidification, separation, detection, and data uploading, with a single sample analysis time reaching up to 2 hours. In actual production, process control requires timely parameter adjustments based on arsenic content detection results to ensure stable production and avoid waste. However, the 2-hour detection cycle is insufficient to meet the timeliness requirements of process control, potentially leading to process deviations due to the inability to obtain arsenic content data promptly, increasing production waste and environmental risks. Furthermore, the nitric acid acidification pretreatment step in this traditional method is not only time-consuming but also complex to operate, prone to introducing human error, and the use of nitric acid increases detection costs and environmental treatment pressure.

[0004] Therefore, there is an urgent need to develop a method for detecting arsenic content in chemical wastewater that can shorten detection time, simplify operation procedures, and ensure detection accuracy. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a simple, accurate and rapid method for detecting arsenic content in chemical wastewater.

[0006] To address the above problems, the present invention provides a method for rapid detection of arsenic content in chemical wastewater, comprising the following steps: S1 Sample Pretreatment Optimization: Take a sample of sulfidated liquid from chemical wastewater and filter it using a filter membrane with a pore size of 0.45~0.8μm to obtain the sample to be tested. S2 Energy Dispersive X-ray Fluorometer Parameter Adjustment: Based on the characteristic X-ray energy range of arsenic, the energy detection range of the instrument is set; while ensuring that the detection sensitivity can accurately identify minute changes in arsenic content of 0.01 mg / L and below, the instrument detection time is adjusted to determine the optimal detection time parameter; S3 establishes a standard curve: Multiple sets of standard samples of chemical wastewater with known arsenic content were collected. The energy dispersive X-ray fluorescence spectrometer calibrated in step S2 was used to perform three parallel tests on each set of standard samples. The corresponding characteristic X-ray intensity data were recorded, and the average value of the characteristic X-ray intensity was taken as the corresponding intensity data of the set of standard samples. Then, the arsenic content of the standard samples was plotted as the abscissa and the corresponding average value of the characteristic X-ray intensity was plotted as the ordinate, and the standard curve was obtained by fitting it using the linear regression method. S4 Actual Sample Testing: The sample to be tested obtained in step S1 is placed in a calibrated energy dispersive X-ray fluorescence spectrometer and detected according to the optimal detection time parameters to obtain the characteristic X-ray intensity of arsenic in the sample to be tested; then the intensity value is substituted into the standard curve established in step S3 to calculate the arsenic content in the sample to be tested.

[0007] In step S2, the characteristic X-ray energy range of arsenic is set to 10.5~11.5 keV.

[0008] The optimal detection time parameter in step S2 is determined to be 3 to 5 minutes.

[0009] In step S3, 5 to 8 groups of standard samples of chemical wastewater with known arsenic content are set up. The arsenic content of each group of standard samples covers 0.01 to 10 mg / L, and the concentration gradient is uniform.

[0010] The linear correlation coefficient R of the standard curve in step S3 2 ≥0.999.

[0011] Step S4 also includes a test result verification step: the same sample to be tested is tested in parallel using the traditional nitric acid acidification pretreatment + spectrometer analysis method, and the test results of the two methods are compared. If the deviation is less than 5%, the test result of this method is determined to be valid.

[0012] Compared with the prior art, the present invention has the following advantages: 1. Significantly improved timeliness: This invention simplifies the sample pretreatment process (omitting the nitric acid acidification step and retaining only the filtration operation) and optimizes the instrument detection time, reducing the detection time for a single sample from 2 hours in the traditional method to 40 minutes (of which the pretreatment time is 5-10 minutes, the instrument detection time is 3-5 minutes, and the data calculation and output time is 2-3 minutes). It can quickly provide feedback on arsenic content data, allowing the branch plant process control to adjust production parameters in a timely manner based on the detection results, reducing process deviations and production waste caused by detection delays.

[0013] 2. Reliable accuracy and stability: This invention effectively eliminates interference from other common elements in chemical wastewater by precisely setting the instrument's energy detection range (specifically targeting the characteristic X-ray energy of arsenic); simultaneously, it establishes a linear correlation coefficient R using multiple sets of gradient standard samples. 2 A standard curve with a value of ≥0.999, combined with parallel verification of actual samples and traditional methods (deviation <5%), ensures the accuracy and stability of the detection results, thereby meeting the process control requirements for the accuracy of arsenic content detection.

[0014] 3. Simple operation and reduced cost: This invention omits the complex nitric acidification pretreatment step in traditional methods, reducing operational difficulty and human error. Simultaneously, it reduces the use of chemical reagents such as nitric acid, lowering testing costs and the environmental burden of subsequent chemical waste treatment. Furthermore, the shortened testing time reduces manpower investment in sample processing and testing, further lowering the company's operating costs.

[0015] 4. Positive social benefits: This invention can efficiently and accurately monitor the arsenic content of chemical wastewater, helping enterprises to strictly control wastewater discharge indicators, fulfill their environmental responsibilities, reduce pollution to the surrounding environment, and establish a good corporate environmental image. At the same time, it provides a feasible solution for upgrading wastewater detection technology for similar chemical enterprises (such as metallurgical, chemical, and pharmaceutical companies that generate arsenic-containing wastewater), which helps to promote the progress of detection technology and the improvement of environmental protection level in the entire industry. Detailed Implementation

[0016] A rapid method for detecting arsenic content in chemical wastewater includes the following steps: S1 Sample Pretreatment Optimization: A sample of sulfidated chemical wastewater is taken and filtered using a membrane with a pore size of 0.45~0.8μm to remove large particulate impurities, thus avoiding interference with subsequent instrument detection signals and preventing arsenic loss. This yields the sample to be tested. This step omits the nitric acid acidification treatment in traditional methods, directly obtaining the sample and significantly shortening the pretreatment time while reducing the use of chemical reagents and the risk of error.

[0017] S2 Energy Dispersive X-ray Fluorometer Parameter Adjustment: Based on the characteristic X-ray energy range of arsenic, the energy detection range of the instrument is precisely set to ensure that the instrument can efficiently capture the characteristic signal of arsenic and eliminate the interference of characteristic X-rays of other elements (such as sulfur, copper and other elements commonly found in chemical wastewater). Under the premise of ensuring that the detection sensitivity can accurately identify minute changes in arsenic content of 0.01 mg / L and below, the instrument detection time is adjusted to determine the optimal detection time parameter.

[0018] Energy-dispersive X-ray fluorescence spectrometers are based on the principle of X-ray fluorescence analysis. Different elements, when excited, produce characteristic X-rays with specific energies. By detecting the energy and intensity of these characteristic X-rays, the type and content of the element can be determined. The characteristic X-ray energy range for arsenic is set to 10.5–11.5 keV to exclude interference from characteristic X-rays of other elements.

[0019] Through multiple experiments and adjustments to the detection time, the optimal detection time parameter was finally determined to be 3-5 minutes. Within this time range, the detection sensitivity can meet the process control requirements for identifying minute changes in arsenic content, while maximizing detection efficiency.

[0020] S3 establishes a standard curve: Multiple sets of standard samples of chemical wastewater with known arsenic content were collected. Each set of standard samples was analyzed three times in parallel using an energy-dispersive X-ray fluorescence spectrometer (EDXRF) calibrated in step S2. The corresponding characteristic X-ray intensity data were recorded, and the average value of the characteristic X-ray intensity was taken as the corresponding intensity data for that set of standard samples. Then, a standard curve was plotted with the arsenic content of the standard samples as the x-axis and the average value of the corresponding characteristic X-ray intensity as the y-axis. A linear regression method was used to fit the curve to obtain a standard curve. The linear correlation coefficient R0 of the standard curve was calculated. 2 A value ≥0.999 ensures the accuracy and reliability of the standard curve, providing a basis for subsequent quantitative analysis of unknown samples.

[0021] Among them, 5 to 8 groups of standard samples of chemical wastewater with known arsenic content were set up. The arsenic content of each group of standard samples covered 0.01 to 10 mg / L, so as to cover the concentration range that may occur in actual chemical wastewater production (the common range of arsenic content in actual chemical wastewater production), and the concentration gradient was uniform (such as 0.01 mg / L, 0.1 mg / L, 1 mg / L, 2 mg / L, 5 mg / L, 8 mg / L, 10 mg / L) to ensure the fitting accuracy of the standard curve.

[0022] S4 Actual Sample Testing: The sample to be tested obtained in step S1 is placed in a calibrated energy dispersive X-ray fluorescence spectrometer and detected according to the optimal detection time parameters to obtain the characteristic X-ray intensity of arsenic in the sample to be tested; then the intensity value is substituted into the standard curve established in step S3 to calculate the arsenic content in the sample to be tested.

[0023] To verify the accuracy of the test results, a test result verification step is also included: the same sample to be tested is tested in parallel using the traditional nitric acid acidification pretreatment + spectrometer analysis method, and the test results of the two methods are compared. If the deviation is less than 5%, the test results of this method are determined to be valid and can be used for process control and environmental monitoring.

[0024] Example 1 Take 10 ml of sulfidated chemical wastewater sample and filter it using a filter membrane with a pore size of 0.45~0.8 μm to obtain the sample to be tested. Take 1 ml of the filtered sample into a 100 ml volumetric flask and place the samples to be tested in ascending order of sample tray numbering on the autosampler. Adjust the X-ray energy range to 11 keV, click "Sample" or "Detection" in the "Sample Test List" column to enter the sample information editing interface, edit the sample information, and then click the "Start" button to begin the sample measurement. Simultaneously, atomic fluorescence spectrometry is used for comparative detection.

[0025] The results of ten sample tests are shown in Table 1 below.

[0026] Table 1 Comparison of Detection Results of Energy Dispersion Method and Atomic Fluorescence Method for Chemical Sulfation Wastewater Example 2: Take 10 ml of wastewater sample from chemical treatment and filter it using a filter membrane with a pore size of 0.45~0.8 μm to obtain the sample to be tested. Take 10 ml of the filtered sample into a 100 ml volumetric flask and place the samples to be tested in ascending order of sample tray numbering on the autosampler. Adjust the X-ray energy range to 11 keV, click "Sample" or "Detection" in the "Sample Test List" column to enter the sample information editing interface, edit the sample information, and then click the "Start" button to begin the sample measurement. Simultaneously, atomic fluorescence spectrometry is used for comparative detection.

[0027] The results of ten sample tests are shown in Table 2 below.

[0028] Table 2 Comparison of Detection Results of Energy Dispersion Method and Atomic Fluorescence Method for Chemically Treated Wastewater In summary, the method of the present invention can achieve accurate detection of arsenic content in chemical wastewater.

Claims

1. A method for rapid detection of arsenic content in chemical wastewater, comprising the following steps: S1 Sample Pretreatment Optimization: Take a sample of sulfidated liquid from chemical wastewater and filter it using a filter membrane with a pore size of 0.45~0.8μm to obtain the sample to be tested. S2 Energy Dispersive X-ray Fluorometer Parameter Adjustment: The energy detection range of the instrument is set according to the characteristic X-ray energy range of arsenic. Under the premise of ensuring that the detection sensitivity can accurately identify minute changes in arsenic content of 0.01 mg / L and below, the instrument detection time is adjusted to determine the optimal detection time parameter; S3 establishes a standard curve: Multiple sets of standard samples of chemical wastewater with known arsenic content were collected. The energy dispersive X-ray fluorescence spectrometer calibrated in step S2 was used to perform three parallel tests on each set of standard samples. The corresponding characteristic X-ray intensity data were recorded, and the average value of the characteristic X-ray intensity was taken as the corresponding intensity data of the set of standard samples. Then, the arsenic content of the standard samples was plotted as the abscissa and the corresponding average value of the characteristic X-ray intensity was plotted as the ordinate, and the standard curve was obtained by fitting it using the linear regression method. S4 Actual Sample Testing: The sample to be tested obtained in step S1 is placed in the calibrated energy dispersive X-ray fluorescence spectrometer and tested according to the optimal detection time parameters to obtain the characteristic X-ray intensity of arsenic in the sample to be tested. Then, the intensity value is substituted into the standard curve established in step S3 to calculate the arsenic content in the sample to be tested.

2. The method for rapid detection of arsenic content in chemical wastewater as described in claim 1, characterized in that: In step S2, the characteristic X-ray energy range of arsenic is set to 10.5~11.5 keV.

3. The method for rapid detection of arsenic content in chemical wastewater as described in claim 1, characterized in that: The optimal detection time parameter in step S2 is determined to be 3-5 minutes.

4. The method for rapid detection of arsenic content in chemical wastewater as described in claim 1, characterized in that: In step S3, 5 to 8 groups of standard samples of chemical wastewater with known arsenic content are set up. The arsenic content of each group of standard samples covers 0.01 to 10 mg / L, and the concentration gradient is uniform.

5. The method for rapid detection of arsenic content in chemical wastewater as described in claim 1, characterized in that: The linear correlation coefficient R of the standard curve in step S3 2 ≥0.

999.

6. The method for rapid detection of arsenic content in chemical wastewater as described in claim 1, characterized in that: Step S4 also includes a test result verification step: the same sample to be tested is tested in parallel using the traditional nitric acid acidification pretreatment + spectrometer analysis method, and the test results of the two methods are compared. If the deviation is less than 5%, the test result of this method is determined to be valid.

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