Method for detecting heavy metal ions in chemical sewage

Abstract

The invention discloses a method for detecting heavy metal ions in chemical sewage. The method comprises the following steps: 1, collecting a sample; 2, sample pretreatment, precipitate removal and pH adjustment; step 3, separating and enriching the pretreated water sample by adopting a solid-phase extraction (SPE) technology, eluting heavy metal ions by using an eluting solvent, and collecting an eluent; and 4, modifying an electrode by using the functionalized nano material, preparing a heavy metal ion sensor, and reacting the enriched sample with the sensor to detect heavy metal ions. 5, meanwhile, adding a specific fluorescent probe into the enriched liquid, and reacting at a certain temperature to form a compound of heavy metal ions and generate a fluorescent signal; measuring the fluorescence intensity by using a fluorospectro photometer, and establishing a standard curve; according to the method disclosed by the invention, high sensitivity, selectivity and rapid detection of heavy metal ions are realized by combining solid-phase extraction, multiple reactions and an electrochemical sensor technology. The operation is simple, economical and practical.

Description

Technical Field

[0001] The invention relates to a method for detecting heavy metal ions in chemical wastewater, and belongs to the technical field of environmental monitoring. Background Art

[0002] Heavy metal pollution has a serious impact on aquatic ecosystems and human health. Although traditional detection methods such as atomic absorption spectroscopy (AAS) and inductively coupled plasma mass spectrometry (ICP-MS) have high accuracy, they have disadvantages such as complex operation and high cost. Therefore, it is of great practical significance to develop an efficient and economical method for heavy metal ion detection. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides a method for detecting heavy metal ions in chemical wastewater, thereby solving the above-mentioned technical problems.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: a method for detecting heavy metal ions in chemical wastewater, comprising the following steps: Step 1: Sample collection: Collect representative water samples from chemical wastewater, using clean sampling bottles to avoid contamination; Step 2: Sample pretreatment, precipitation removal: add an appropriate amount of sodium chloride NaCl to the water sample, stir and let it stand for a period of time to precipitate the suspended matter, and then filter; adjust pH: use hydrochloric acid HCl or sodium hydroxide NaOH to adjust the pH value of the water sample to ensure the effective progress of the subsequent reaction; Step 3: Using solid phase extraction (SPE) technology, the pretreated water sample is separated and enriched by a chromatographic column filled with a polymer adsorbent, and the heavy metal ions are eluted with an appropriate elution solvent, and the eluate is collected; Step 4: Use functionalized nanomaterials to modify the electrode, prepare a heavy metal ion sensor, react the enriched sample with the sensor, and detect the heavy metal ions using electrochemical methods.

[0005] Step 5: At the same time, add specific fluorescent probes to the enrichment solution, react at a certain temperature to form a complex of heavy metal ions and generate a fluorescent signal; use a fluorescence spectrophotometer to measure the fluorescence intensity and establish a standard curve.

[0006] Furthermore, in the step 2, a proper amount of sodium chloride NaCl is added to the water sample, stirred and then allowed to stand for 10 minutes to precipitate suspended matter, and then filtered and the pH value of the water sample is adjusted to 4-6 using hydrochloric acid HCl or sodium hydroxide NaOH.

[0007] Furthermore, in step three, the chromatographic column is made of polystyrene material.

[0008] Furthermore, in step three, the elution solvent is an ethanol-water solution.

[0009] Furthermore, in step 4, the functionalized nanomaterial is graphene oxide or metal nanoparticles, the enriched sample is reacted with the sensor, and the heavy metal ions are detected by cyclic voltammetry.

[0010] Furthermore, in step five, the main method of fluorescent labeling is to add modified fluorescent nanoparticles to the enrichment solution, react at a certain temperature for 30 minutes to form a complex of heavy metal ions and generate a fluorescent signal.

[0011] The beneficial effects of the present invention are as follows: the method of the present invention realizes high sensitivity, selectivity and rapid detection of heavy metal ions by combining solid phase extraction, multiple reactions and electrochemical sensor technology. The method is simple to operate, economical and practical, and is suitable for wide application in various environmental monitoring occasions. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail by examples below. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0013] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0014] A method for detecting heavy metal ions in chemical wastewater comprises the following steps: Step 1: Sample collection: Collect representative water samples from chemical wastewater, using clean sampling bottles to avoid contamination; Step 2: Sample pretreatment, precipitation removal: add an appropriate amount of sodium chloride NaCl to the water sample, stir and let it stand for a period of time to precipitate the suspended matter, and then filter; adjust pH: use hydrochloric acid HCl or sodium hydroxide NaOH to adjust the pH value of the water sample to ensure the effective progress of the subsequent reaction; Step 3: Using solid phase extraction (SPE) technology, the pretreated water sample is separated and enriched by a chromatographic column filled with a polymer adsorbent, and the heavy metal ions are eluted with an appropriate elution solvent, and the eluate is collected; Step 4: Use functionalized nanomaterials to modify the electrode, prepare a heavy metal ion sensor, react the enriched sample with the sensor, and detect the heavy metal ions using electrochemical methods.

[0015] Step 5: At the same time, add specific fluorescent probes to the enrichment solution, react at a certain temperature to form a complex of heavy metal ions and generate a fluorescent signal; use a fluorescence spectrophotometer to measure the fluorescence intensity and establish a standard curve.

[0016] Preferably, in step 2 of this embodiment, a proper amount of sodium chloride NaCl is added to the water sample, and the water sample is stirred and allowed to stand for 10 minutes to precipitate suspended matter, and then filtered and the pH value of the water sample is adjusted to 4-6 using hydrochloric acid HCl or sodium hydroxide NaOH.

[0017] Preferably, in step 3 of this embodiment, the chromatographic column is made of polystyrene material.

[0018] In this embodiment, preferably, in step 3, the elution solvent is ethanol-water solution.

[0019] Preferably, in step 4 of this embodiment, the functionalized nanomaterial is graphene oxide or metal nanoparticles, the enriched sample is reacted with the sensor, and the heavy metal ions are detected by cyclic voltammetry.

[0020] In this embodiment, in step five, the main method of fluorescent labeling is to add modified fluorescent nanoparticles to the enrichment solution, react at a certain temperature for 30 minutes to form a complex of heavy metal ions and generate a fluorescent signal. The following are three groups of embodiments: Example 1: Detection of lead ions (Pb²⁺) Sample source: Wastewater sample from a chemical plant. Sample volume: 100 mL. Pretreatment: Add 5 g of sodium chloride (NaCl), stir and let stand for 10 minutes to precipitate suspended matter. Use 0.1 M hydrochloric acid (HCl) to adjust the pH to 5.0. Solid phase extraction: Use polystyrene adsorbent for enrichment, the eluent volume is 10 mL, and the elution solvent is ethanol-water (3:1). Sensor reaction: In the electrochemical sensor, the cyclic voltammetry method measured the lead ion current peak value of 0.25 μA. Fluorescence labeling: Add specific fluorescent probe, and after 30 minutes of reaction, the fluorescence intensity is measured to be 1500 RFU (relative fluorescence unit). Quantitative results: Calculated by the standard curve, the lead ion concentration is 12.5 mg / L.

[0021] Example 2: Detection of Cadmium Ions (Cd²⁺) Sample source: another chemical plant wastewater sample. Sample volume: 150 mL. Pretreatment: Add 7 g of sodium chloride (NaCl), stir and let stand for 10 minutes to precipitate suspended matter. Use 0.1 M sodium hydroxide (NaOH) to adjust the pH to 6.0. Solid phase extraction: Use polyacrylamide adsorbent for enrichment, the eluent volume is 10 mL, and the elution solvent is ethyl acetate. Sensor reaction: In the electrochemical sensor, the cyclic voltammetry method measured the cadmium ion current peak value to be 0.15 μA. Fluorescent labeling: Add specific fluorescent probe, and after 30 minutes of reaction, the fluorescence intensity is measured to be 1200 RFU. Quantitative results: Calculated by the standard curve, the cadmium ion concentration is 8.0 mg / L.

[0022] Example 3: Detection of mercury ions (Hg²⁺) Sample source: A simulated chemical wastewater sample from a laboratory. Sample volume: 200 mL. Pretreatment: Add 10 g of sodium chloride (NaCl), stir and let stand for 10 minutes to precipitate suspended matter. Use 0.1 M hydrochloric acid (HCl) to adjust the pH to 4.5. Solid phase extraction: Use activated carbon adsorbent for enrichment, the eluent volume is 10 mL, and the elution solvent is methanol. Sensor reaction: In the electrochemical sensor, the cyclic voltammetry method measured the mercury ion current peak to be 0.30 μA. Fluorescent labeling: Add a specific fluorescent probe, and after 30 minutes of reaction, the fluorescence intensity is measured to be 1800 RFU. Quantitative results: Calculated by the standard curve, the mercury ion concentration is 5.5 mg / L.

[0023] The above examples demonstrate the effectiveness and sensitivity of the method of the present invention in detecting different heavy metal ions (lead, cadmium, mercury) in chemical wastewater, and prove the practicality and reliability of the method in environmental monitoring.

[0024] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting heavy metal ions in chemical wastewater, characterized in that: The following steps are involved: Step 1: Sample collection: Collect representative water samples from chemical wastewater, using clean sampling bottles to avoid contamination; Step 2: Sample pretreatment, precipitation removal: add an appropriate amount of sodium chloride NaCl to the water sample, stir and let it stand for a period of time to precipitate the suspended matter, and then filter; adjust pH: use hydrochloric acid HCl or sodium hydroxide NaOH to adjust the pH value of the water sample to ensure the effective progress of the subsequent reaction; Step 3: Using solid phase extraction (SPE) technology, the pretreated water sample is separated and enriched by a chromatographic column filled with a polymer adsorbent, and the heavy metal ions are eluted with an appropriate elution solvent, and the eluate is collected; Step 4: Use functionalized nanomaterials to modify the electrode to prepare a heavy metal ion sensor, react the enriched sample with the sensor, and detect the heavy metal ions using an electrochemical method; Step 5: At the same time, add specific fluorescent probes to the enrichment solution, react at a certain temperature to form a complex of heavy metal ions and generate a fluorescent signal; use a fluorescence spectrophotometer to measure the fluorescence intensity and establish a standard curve.

2. The method for detecting heavy metal ions in chemical wastewater according to claim 1, characterized in that: In the step 2, a proper amount of sodium chloride NaCl is added to the water sample, and the water sample is stirred and allowed to stand for 10 minutes to precipitate suspended matter, and then filtered and the pH value of the water sample is adjusted to 4-6 using hydrochloric acid HCl or sodium hydroxide NaOH.

3. The method for detecting heavy metal ions in chemical wastewater according to claim 1, characterized in that: In the step 3, the chromatographic column is made of polystyrene material.

4. The method for detecting heavy metal ions in chemical wastewater according to claim 1, characterized in that: In the step 3, the elution solvent is an ethanol-water solution.

5. The method for detecting heavy metal ions in chemical wastewater according to claim 1, characterized in that: In the step 4, the functionalized nanomaterial is graphene oxide or metal nanoparticles, the enriched sample is reacted with the sensor, and the heavy metal ions are detected by cyclic voltammetry.

6. The method for detecting heavy metal ions in chemical wastewater according to claim 1, characterized in that: In step five, the main method of fluorescent labeling is to add modified fluorescent nanoparticles to the enrichment solution, react at a certain temperature for 30 minutes, form a complex of heavy metal ions and generate a fluorescent signal.