A kind of on-line detection device and detection method of thallium in water

Abstract

The present invention relates to an online detection device and method for thallium in water, and belongs to the technical field of heavy metal detection. It comprises a water sample container, an eluent container, a dilute nitric acid container, a filtering unit, an enriching and eluting unit, a liquid electrode glow detection unit and a liquid sampling control unit; the water sample in the water sample container enters the filtering unit, and the filtering unit is used to filter the entering water sample; the filtered water sample enters the enriching and eluting unit, and the enriching and eluting unit is used to enrich the filtered water sample, and the eluent is used to elute the enriched water sample; the liquid sampling control unit is used to control the water sample to flow out of the enriching and eluting unit, and is also used to control the dilute nitric acid in the dilute nitric acid container to mix with the water sample to adjust the acidity; the liquid electrode glow detection unit is used to analyze and detect the water sample. Highly sensitive field on-line analysis of thallium in water and emergency analysis of thallium pollution are realized. The detection limit of thallium in water by this method is lower than 0.1 μg / L.

Description

Technical Field

[0001] The invention relates to an online detection device and a detection method for thallium in water, belonging to the technical field of heavy metal detection. Background Art

[0002] Thallium is a heavy metal element with strong toxicity and very low content in the earth's crust. In recent years, with the development of mining and metallurgical industries, the release of thallium into the environment and regional thallium pollution in water environments have become more serious. Moreover, thallium can be significantly enriched in human tissues and organs through the food chain. When the intake of thallium exceeds a certain limit, it will cause great harm to the human body. The "GB 5749-2006 Drinking Water Hygiene Standard" requires that the standard limit of thallium is 0.1μg / L. Therefore, it is of great significance to carry out on-site online monitoring of thallium in environmental water bodies. By realizing online monitoring of thallium pollution risks in water bodies, the risk of thallium poisoning incidents can be effectively reduced.

[0003] At present, the detection of thallium mainly adopts atomic spectroscopy techniques such as atomic absorption spectroscopy and inductively coupled plasma-atomic emission spectroscopy. "HJ 748-2015 Determination of Thallium in Water Quality by Graphite Furnace Atomic Absorption Spectrophotometry" can meet the requirements of "GB 5749-2006 Drinking Water Hygiene Standard" through complex offline precipitation and enrichment operations, but for graphite furnace atomic absorption spectroscopy, the matrix interference is serious and the analysis efficiency is low; inductively coupled plasma-atomic emission spectroscopy technology has serious spectral interference and relatively poor sensitivity. Inductively coupled plasma-mass spectrometry technology has also been applied to the analysis of thallium. This technology has good analytical sensitivity, but the analysis operation of this technology is complicated and the instrument analysis cost is high. In addition, the above methods all require the use of gas cylinders, and it is difficult to achieve the portability of the instrument, which cannot meet the requirements of field on-line testing. Although electrochemical techniques such as anodic dissolution and polarographic analysis have been applied to the offline and online analysis of thallium in water, and have shown good detection limits and portability, the matrix interference is serious, the electrode treatment is cumbersome, and toxic reagents such as mercury need to be used, which poses a certain risk of environmental pollution. Liquid cathode glow discharge-atomic emission spectrometry has been applied to the analysis of heavy metal elements such as Pb, Cd, Cu and Hg. However, due to the extremely low level of thallium in water, it is difficult to achieve high-sensitivity online analysis and detection of thallium using existing methods. Summary of the invention

[0004] In view of this, an object of the present invention is to provide an online detection device and method for thallium in water.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows.

[0006] An online detection device for thallium in water, comprising a water sample container, an eluent container, a dilute nitric acid container, a filtering unit, an enrichment and elution unit, a liquid electrode glow detection unit and a liquid sampling control unit;

[0007] The liquid sampling control unit is used to control the water sample in the water sample container to enter the filtering unit, and the filtering unit is used to filter the entering water sample;

[0008] The liquid injection control unit is used to control the filtered water sample to enter the enrichment and elution unit, and the enrichment and elution unit is used to enrich the thallium in the filtered water sample. The liquid injection control unit controls the eluent in the eluent container to enter the enrichment and elution unit, and the eluent is used to elute the enriched thallium;

[0009] The liquid injection control unit is used to control the eluted water sample to flow out of the enrichment and elution unit. The liquid injection control unit is also used to control the dilute nitric acid in the dilute nitric acid container to mix with the outflowing water sample to adjust the acidity;

[0010] The liquid electrode glow detection unit is used to detect water samples after acidity adjustment.

[0011] Furthermore, the liquid injection control unit includes a first reversing valve, a peristaltic pump, a three-way pipe fitting and a second reversing valve; the first reversing valve is provided with two inlets and one outlet, the peristaltic pump is provided with two connecting pipes, and the second reversing valve is provided with one inlet and two outlets; the two inlets of the first reversing valve are respectively connected to the water sample container and the eluent container, the outlet of the first reversing valve is connected to the inlet of the filtration unit, the two ends of one connecting pipe on the peristaltic pump are respectively connected to the outlet of the filtration unit and the inlet of the enrichment and elution unit, the outlet of the enrichment and elution unit is connected to the inlet of the second reversing valve, the two ends of the other connecting pipe are respectively connected to the dilute nitric acid container and one port of the three-way pipe fitting, the other two ports of the three-way pipe fitting are respectively connected to the liquid glow detection unit and one outlet of the second reversing valve, and the other outlet of the second reversing valve is used to discharge the waste liquid after enrichment and elution.

[0012] Furthermore, the liquid injection control unit includes a peristaltic pump, a three-way pipe fitting, a second reversing valve, a multi-channel valve and an injection pump. The peristaltic pump is provided with two connecting pipes, the second reversing valve is provided with an inlet and two outlets, and the multi-channel valve is respectively connected to the filtration unit, the enrichment and elution unit, the eluent container and the injection pump; the two ends of one connecting pipe on the peristaltic pump are respectively connected to the water sample container and the inlet of the filtration unit, and the two ends of the other connecting pipe are respectively connected to the dilute nitric acid container and a port of the three-way pipe fitting; the other two ports of the three-way pipe fitting are respectively connected to the liquid glow detection unit and an outlet of the second reversing valve, and the other outlet of the second reversing valve is used to discharge the waste liquid after enrichment and elution.

[0013] Furthermore, the filtration unit includes a filter, and the enrichment and elution unit includes an enrichment column.

[0014] Furthermore, the liquid electrode glow detection unit includes a liquid cathode glow discharge spectrometer.

[0015] A method for online detection of thallium in water, the method steps are as follows:

[0016] (1) The water sample in the water sample container is controlled by the liquid sampling control unit to enter the filtering unit for filtration to obtain a filtered water sample;

[0017] (2) the filtered water sample is controlled by a liquid sampling control unit to enter an enrichment and elution unit for enrichment to obtain an enriched water sample;

[0018] (3) the liquid injection control unit controls the eluent in the eluent container to enter the enrichment and elution unit to elute the enriched water sample;

[0019] (4) the eluted water sample is controlled by the liquid injection control unit to enter the three-way pipe fitting, and at the same time, the liquid injection control unit controls the dilute nitric acid with a mass fraction of 1.5% in the dilute nitric acid container to enter the three-way pipe fitting to mix with the eluted water sample, and the acidity is controlled to be equivalent to the acidity of the dilute nitric acid with a mass fraction of 1.5%, thereby obtaining a mixed solution;

[0020] (5) The mixed solution is sent to a liquid electrode glow detection unit to detect thallium using liquid cathode glow discharge-atomic emission spectrometry.

[0021] Furthermore, in step (2), sulfur-functionalized manganese-based metal organic framework materials (terephthalic acid as a ligand is reacted with manganese ions to obtain a manganese-based metal organic framework material, and then reacted with disulfide hydrazone to obtain a sulfur-functionalized manganese-based metal organic framework material) and ion exchange resins are used as fillers to enrich thallium in the filtered water sample. The sulfur-functionalized manganese-based metal organic framework material has a large specific surface area and a large adsorption capacity, and is relatively suitable for the enrichment of thallium at a higher concentration (μg / L level or higher); ion exchange resins are relatively more suitable for the enrichment of thallium at a lower concentration (10 -1 μg / L level or lower) thallium enrichment, but the adsorption capacity of relatively high concentration thallium is limited and easily saturated. Therefore, mixing or using the two as fillers in series can expand the scope of water sample analysis while ensuring satisfactory adsorption efficiency, meeting the enrichment needs of thallium samples with different concentrations.

[0022] Furthermore, the ion exchange resin is tributyl phosphate leaching resin or Dowex 50WX8 type cation exchange resin.

[0023] Furthermore, in step (3), the eluent is dilute nitric acid, and the eluent flow rate is 3 mL / min.

[0024] Furthermore, in step (5), the detection wavelength is 535 nm, the electrode spacing is 3 mm, the voltage is greater than or equal to 800 V, and the current is greater than or equal to 40 mA.

[0025] Beneficial Effects

[0026] The invention realizes highly sensitive field online analysis of thallium in water, with a detection limit of less than 0.1 μg / L and a repeatability of less than 5%, meeting the detection limit requirement of thallium in GB 5749-2006 Drinking Water Hygiene Standard. In addition, except for using dilute acid and a small amount of specific non-toxic elution reagent, the method does not need to use toxic reagents, effectively avoiding secondary pollution of the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the structure of the device described in Example 1 of the present invention;

[0028] Figure 2 Schematic diagram of the structure of the device described in Example 2 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with specific embodiments.

[0030] An online detection device for thallium in water comprises a water sample container 1, an eluent container 2, a dilute nitric acid container 3, a filtering unit, an enrichment and elution unit, a liquid glow detection unit 10 and a liquid sampling control unit;

[0031] The liquid sampling control unit is used to control the water sample in the water sample container 1 to enter the filtering unit, and the filtering unit is used to filter the entering water sample;

[0032] The liquid injection control unit is used to control the filtered water sample to enter the enrichment and elution unit, and the enrichment and elution unit is used to enrich the thallium in the filtered water sample. The liquid injection control unit controls the eluent in the eluent container 2 to enter the enrichment and elution unit, and the eluent is used to elute the enriched thallium;

[0033] The liquid injection control unit is used to control the eluted water sample to flow out of the enrichment and elution unit. The liquid injection control unit is also used to control the dilute nitric acid in the dilute nitric acid container 3 to mix with the outflowing water sample to adjust the acidity;

[0034] The liquid glow detection unit 10 is used to analyze and detect the water sample after the acidity is adjusted.

[0035] Example 1

[0036] like Figure 1As shown, the liquid injection control unit described in this embodiment includes a first reversing valve 4, a peristaltic pump 6, a three-way pipe fitting 8 and a second reversing valve 9; the first reversing valve 4 is provided with two inlets and one outlet, the peristaltic pump 6 is provided with two connecting pipes, and the second reversing valve 9 is provided with one inlet and two outlets; the two inlets of the first reversing valve 4 are respectively connected to the water sample container 1 and the eluent container 2, the outlet of the first reversing valve 4 is connected to the inlet of the filtration unit, the two ends of one connecting pipe on the peristaltic pump 6 are respectively connected to the outlet of the filtration unit and the inlet of the enrichment and elution unit, the outlet of the enrichment and elution unit is connected to the inlet of the second reversing valve 9, the two ends of the other connecting pipe are respectively connected to the dilute nitric acid container 3 and one port of the three-way pipe fitting 8, the other two ports of the three-way pipe fitting 8 are respectively connected to the liquid electrode glow detection unit 10 and one outlet of the second reversing valve 9, and the other outlet of the second reversing valve 9 is used to discharge the waste liquid after enrichment and elution.

[0037] The filter unit comprises a filter 5, which is a cartridge structure, and the filter core is a sieve plate, which can filter impurities and particles in the water sample and the eluent.

[0038] The enrichment and elution unit includes an enrichment column 7, the diameter of the enrichment column 7 is 1.35 cm, the length 6 is cm, the inner diameter of the inlet and outlet is 2 mm, and the outer diameter of the inlet and outlet is 4 mm; two sieve plates are arranged in the enrichment column, one of which is filled with 1.5 g of sulfur-functionalized manganese-based metal organic framework material, and the other is filled with 1.5 g of tributyl phosphate leaching resin.

[0039] The liquid electrode glow detection unit 10 includes a liquid cathode glow discharge spectrometer, which includes a power supply 11, a tungsten anode 12, a liquid cathode 13, a graphite auxiliary electrode 14, a waste liquid pool 16 and an optical fiber spectrometer 16, wherein the liquid cathode 13 is arranged in the waste liquid pool 16, the tungsten anode 12 is located above the liquid cathode 13, the liquid cathode 13 is a glass tube, the glass tube is open at one end toward the tungsten anode, and the glass tube is covered with a graphite auxiliary electrode 14, the tungsten anode 12 and the graphite auxiliary electrode 14 are respectively connected to the positive and negative electrodes of the power supply 11, and the graphite auxiliary electrode 14 is also connected to a ground wire, the distance between the tungsten anode 12 and the liquid cathode 13 is 3 mm, and the liquid cathode glow discharge area is between the tungsten anode 12 and the liquid cathode 13, the probe of the optical fiber spectrometer 16 is located outside the glow discharge area, and the distance between the probe and the glow discharge area is 6 cm, the detection wavelength of the optical fiber spectrometer 16 is 535 nm, the power supply voltage is 800 V, and the current is 40 mA.

[0040] A method for online detection of thallium in water, the method steps are as follows:

[0041] (1) The first reversing valve 4 is connected to the water sample container 1, and 200 mL of environmental water sample is injected into the filtration unit at a flow rate of 3 mL / min via the peristaltic pump 6 for online filtration;

[0042] (2) the filtered water sample is controlled by a peristaltic pump 6 to enter the enrichment and elution unit at a flow rate of 3 mL / min for enrichment to obtain enriched thallium;

[0043] (3) The first reversing valve 4 is connected to the water sample container 1 and the eluent container 2, and 10 mL of the eluent (dilute nitric acid with a mass fraction of 1.5%) is injected into the enrichment and elution unit at a flow rate of 3 mL / min to elute the enriched thallium;

[0044] (4) The second reversing valve 9 is switched to the three-way pipe fitting 8, and the eluted water sample enters the three-way pipe fitting 8. At the same time, the peristaltic pump 6 controls the diluted nitric acid with a mass fraction of 1.5% in the diluted nitric acid container 3 to enter the three-way pipe fitting 8 and mix with the eluted water sample, and the acidity is controlled to be equivalent to the acidity of the diluted nitric acid with a mass fraction of 1.5%, thereby obtaining a mixed solution;

[0045] (5) The mixed solution is sent to the liquid glow detection unit 10 to analyze and detect thallium using liquid cathode glow discharge-atomic emission spectrometry. The corresponding emission spectrum of thallium element is collected at 535nm, and the peak height or peak area reading is used to quantitatively obtain the thallium content in the water sample based on the standard curve method.

[0046] Example 2

[0047] like Figure 2 As shown, the liquid injection control unit described in this embodiment includes a peristaltic pump 6, a three-way pipe fitting 8, a second reversing valve 9, a multi-channel valve 17 and an injection pump 18. The peristaltic pump 6 is provided with two connecting pipes, the second reversing valve 9 is provided with an inlet and two outlets, and the multi-channel valve 17 is respectively connected to the filtration unit, the enrichment and elution unit, the eluent container 2 and the injection pump 18; the two ends of one connecting pipe on the peristaltic pump 6 are respectively connected to the water sample container 1 and the inlet of the filtration unit, and the two ends of the other connecting pipe are respectively connected to the dilute nitric acid container 3 and a port of the three-way pipe fitting 8; the other two ports of the three-way pipe fitting 8 are respectively connected to the liquid glow detection unit 10 and an outlet of the second reversing valve 9, and the other outlet of the second reversing valve 9 is used to discharge the waste liquid after enrichment and elution.

[0048] The filter unit comprises a filter 5, which is a cartridge structure, and the filter core is a sieve plate, which can filter impurities and particles in the water sample and the eluent.

[0049] The enrichment and elution unit includes an enrichment column 7, the diameter of the enrichment column 7 is 1.35 cm, the length 6 is cm, the inner diameter of the inlet and outlet is 2 mm, and the outer diameter of the inlet and outlet is 4 mm; two sieve plates are arranged in the enrichment column, and the filling material on the sieve plates is a mixture of 1.0 g of sulfur-functionalized manganese-based metal organic framework material and 1.0 g of Dowex 50WX8 type cation exchange resin.

[0050] The liquid glow detection unit 10 includes a liquid cathode glow discharge spectrometer, which includes a power supply 11, a tungsten anode 12, a liquid cathode 13, a graphite auxiliary electrode 14, a waste liquid pool 16 and an optical fiber spectrometer 16, wherein the liquid cathode 13 is arranged in the waste liquid pool 16, the tungsten anode 12 is located above the liquid cathode 13, the liquid cathode 13 is a glass tube, the glass tube is open at one end toward the tungsten anode, and the glass tube is covered with a graphite auxiliary electrode 14, the tungsten anode 12 and the graphite auxiliary electrode 14 are respectively connected to the positive and negative electrodes of the power supply 11, and the graphite auxiliary electrode 14 is also connected to a ground wire, the distance between the tungsten anode 12 and the liquid cathode 13 is 3 mm, and the liquid cathode glow discharge area is between the tungsten anode 12 and the liquid cathode 13, the probe of the optical fiber spectrometer 16 is located outside the glow discharge area, and the distance between the probe and the glow discharge area is 6 cm, the detection wavelength of the optical fiber spectrometer 16 is 535 nm, the power supply voltage is 800 V, and the current is 40 mA.

[0051] A method for online detection of thallium in water, the method steps are as follows:

[0052] (1) 200 mL of environmental water sample is injected into the filtration unit at a flow rate of 3 mL / min via a peristaltic pump 6 for online filtration;

[0053] (2) The multi-channel valve 17 connects the filtration unit and the enrichment and elution unit, and the filtered water sample is controlled by the peristaltic pump 6 to enter the enrichment and elution unit at a flow rate of 3 mL / min for enrichment to obtain enriched thallium;

[0054] (3) The multi-channel valve 17 connects the eluent container 2 and the injection pump 18, 10 mL of the eluent (dilute nitric acid with a mass fraction of 1.5%) is sucked into the injection pump 18, the multi-channel valve 17 connects the enrichment and elution unit and the injection pump 18, and the injection pump 18 injects the eluent into the enrichment and elution unit at a flow rate of 3 mL / min to elute the enriched thallium;

[0055] (4) The second reversing valve 9 is switched to the three-way pipe fitting 8, and the eluted water sample enters the three-way pipe fitting 8. At the same time, the peristaltic pump 6 controls the diluted nitric acid with a mass fraction of 1.5% in the diluted nitric acid container 3 to enter the three-way pipe fitting 8 and mix with the eluted water sample, and the acidity is controlled to be equivalent to the acidity of the diluted nitric acid with a mass fraction of 1.5%, thereby obtaining a mixed solution;

[0056] (5) The mixed solution is sent to the liquid glow detection unit 10 to analyze and detect thallium using liquid cathode glow discharge-atomic emission spectrometry. The corresponding emission spectrum of thallium element is collected at 535nm, and the peak height or peak area reading is used to quantitatively obtain the thallium content in the water sample based on the standard curve method.

[0057] In summary, the invention includes but is not limited to the above embodiments. Any equivalent substitution or partial improvement made under the spirit and principle of the invention shall be deemed to be within the protection scope of the invention.

Claims

1. A method for online detection of thallium in water using an online detection device for thallium in water, characterized in that: The on-line detection device for thallium in water comprises a water sample container (1), an eluent container (2), a dilute nitric acid container (3), a filtering unit, an enrichment and elution unit, a liquid electrode glow detection unit (10) and a liquid sampling control unit; The liquid sampling control unit is used to control the water sample in the water sample container (1) to enter the filtering unit, and the filtering unit is used to filter the entering water sample; The liquid injection control unit is used to control the filtered water sample to enter the enrichment and elution unit, and the enrichment and elution unit is used to enrich thallium in the filtered water sample. The liquid injection control unit controls the eluent in the eluent container (2) to enter the enrichment and elution unit, and the eluent is used to elute the enriched thallium; The liquid injection control unit is used to control the eluted water sample to flow out of the enrichment and elution unit. The liquid injection control unit is also used to control the dilute nitric acid in the dilute nitric acid container (3) to mix with the outflowing water sample to adjust the acidity. The liquid electrode glow detection unit (10) is used to detect the water sample after the acidity is adjusted; The method steps are as follows: (1) The water sample in the water sample container (1) is controlled by the liquid sampling control unit to enter the filtering unit for filtration to obtain a filtered water sample; (2) The filtered water sample is controlled by the liquid injection control unit to enter the enrichment and elution unit for enrichment to obtain an enriched water sample; (3) The liquid injection control unit controls the eluent in the eluent container (2) to enter the enrichment and elution unit to elute the enriched water sample; (4) The eluted water sample is controlled by the liquid injection control unit to enter the three-way pipe fitting (8), and at the same time, the liquid injection control unit controls the diluted nitric acid with a mass fraction of 1.5% in the diluted nitric acid container (3) to enter the three-way pipe fitting (8) to mix with the eluted water sample, and the acidity is controlled to be equivalent to the acidity of the diluted nitric acid with a mass fraction of 1.5%, thereby obtaining a mixed solution; (5) sending the mixed solution into a liquid electrode glow detection unit (10) to analyze and detect thallium using liquid cathode glow discharge-atomic emission spectrometry; In step (2), sulfur-functionalized manganese-based metal organic framework material and ion exchange resin are used as fillers to enrich thallium in the filtered water sample; the ion exchange resin is tributyl phosphate leaching resin or Dowex 50WX8 type cation exchange resin.

2. A method for online detection of thallium in water as claimed in claim 1, characterized in that: The liquid injection control unit comprises a first reversing valve (4), a peristaltic pump (6), a three-way pipe fitting (8) and a second reversing valve (9); the first reversing valve (4) is provided with two inlets and one outlet, the peristaltic pump (6) is provided with two connecting pipes, and the second reversing valve (9) is provided with one inlet and two outlets; the two inlets of the first reversing valve (4) are respectively connected to the water sample container (1) and the eluent container (2), the outlet of the first reversing valve (4) is connected to the inlet of the filtration unit, the peristaltic pump (6) is provided with two connecting pipes, and the second reversing valve (9) is provided with one inlet and two outlets. The two ends of the upper connecting pipe are respectively connected to the outlet of the filtration unit and the inlet of the enrichment and elution unit, the outlet of the enrichment and elution unit is connected to the inlet of the second reversing valve (9), the two ends of the other connecting pipe are respectively connected to the dilute nitric acid container (3) and one opening of the three-way pipe fitting (8), the other two openings of the three-way pipe fitting (8) are respectively connected to the liquid electrode glow detection unit (10) and one outlet of the second reversing valve (9), and the other outlet of the second reversing valve (9) is used to discharge the waste liquid after enrichment and elution.

3. A method for online detection of thallium in water as claimed in claim 1, characterized in that: The liquid injection control unit comprises a peristaltic pump (6), a three-way pipe fitting (8), a second reversing valve (9), a multi-channel valve (17) and an injection pump (18). The peristaltic pump (6) is provided with two connecting pipes, the second reversing valve (9) is provided with an inlet and two outlets, and the multi-channel valve (17) is respectively connected to the filtration unit, the enrichment and elution unit, the eluent container (2) and the injection pump (18); the two ends of one connecting pipe on the peristaltic pump (6) are respectively connected to the water sample container (1) and the inlet of the filtration unit, and the two ends of the other connecting pipe are respectively connected to the dilute nitric acid container (3) and one opening of the three-way pipe fitting (8); the other two openings of the three-way pipe fitting (8) are respectively connected to the liquid electrode glow detection unit (10) and one outlet of the second reversing valve (9), and the other outlet of the second reversing valve (9) is used to discharge the waste liquid after enrichment and elution.

4. A method for online detection of thallium in water as claimed in claim 1, characterized in that: The filtration unit comprises a filter (5), and the enrichment and elution unit comprises an enrichment column (7).

5. A method for online detection of thallium in water as claimed in claim 1, characterized in that: The liquid electrode glow detection unit (10) comprises a liquid cathode glow discharge spectrometer.

6. A method for online detection of thallium in water as claimed in claim 1, characterized in that: In step (3), the eluent is dilute nitric acid, and the eluent flow rate is 3 mL / min.

7. A method for online detection of thallium in water as claimed in claim 1, characterized in that: In step (5), the detection wavelength is 535 nm, the electrode spacing is 3 mm, the voltage is greater than or equal to 800 V, and the current is greater than or equal to 40 mA.

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