JPS626523Y2 - - Google Patents

Description

[Detailed description of the invention] Atomic absorption spectrometry is generally used to detect trace amounts of mercury. In other words, if the sample is a gas, the gas is sent to the mercury collection section to collect metallic mercury as an amalgam, and the amalgam is thermally decomposed and the released metallic mercury is sent to an absorption cell to detect the spectral lines of mercury. Observe the decay.
If the sample is liquid, solid, or molecular mercury that has formed a compound, it is heated to evaporate, decompose, or burnt to obtain atomic metallic mercury, which is then collected as an amalgam as described above. was. Conventionally, when detecting mercury contained in a compound, the compound was decomposed and then collected as an amalgam, so when atomic metal mercury and molecular compound mercury coexist in a sample, it is difficult to detect them. It was not possible to separate and detect. The present invention eliminates these drawbacks and provides an atomic absorption spectrometer that can separate and detect molecular mercury and metallic mercury with a simple configuration.

FIG. 1 shows an embodiment of the present invention, in which a molecular mercury collection unit 1 is constructed by filling a heat-resistant tube such as quartz with powder of a heat-resistant porous material such as diatomaceous earth, and The heating means 2 is provided by winding a heating wire around the heating wire, and the powder of the heat-resistant porous material is not coated with a metal film. The gas inlet of this molecular mercury collection unit 1 is connected to the gas intake 4 for which mercury is to be detected and the dehumidifier 5 by an electromagnetic three-way switching valve 3,
The air intake port of the dehumidifier is opened to the atmosphere through an activated carbon filter 6. In addition, the metal mercury collection unit 7 forms a gold coating on powder of the heat-resistant porous material as described above, and fills a heat-resistant tube such as quartz with this.
A heating means 8 is provided by winding a heating wire around the outside of a heat-resistant tube. The gas inlet of this metal mercury trapping section 7 is connected to the gas outlet of the molecular mercury trapping section 1, and they are connected in series, and the electromagnetic three-way switching valve 9
The gas outlet of the metal mercury collection section 7 is connected to the gas inlet and outlet of the spectral line absorption cell 10, and the cell is connected through a filter 11 for absorbing harmful substances such as mercury. The outlet of 10 is connected to the inlet of pump 12. A sampling needle valve 13, a measuring needle valve 14, and an electromagnetic three-way switching valve 15 are connected to the discharge port of this pump 12.
A flow meter 16 is connected through the flow meter, and the gas outlet of the flow meter is opened to the atmosphere.

In the above-mentioned apparatus, first, the intake port 4 of the gas whose mercury is to be detected is connected to the collection section 1 by the valve 3, and the outlet of the collection section 7 is connected to the filter 11 by the valve 9. At the same time, the needle valve 13 is connected to the flow meter 16 by the switching valve 15. That is, in this state, a flow path as shown in FIG. is set to an appropriate value by Therefore, by continuing the above-mentioned state for a desired period of time, the total amount of gas flowing through the collection sections 1 and 7 is regulated. When molecular mercury made of a mercury compound and metallic mercury made of mercury atoms are present in the gas, the molecular mercury is almost completely adsorbed to the porous material of the collection section 1, and the metallic mercury is absorbed into the porous material. The gold is fed into the collecting section 7 without being adsorbed to the porous material, and forms amalgam with gold that adheres to the porous material. That is, molecular mercury is captured in the collection section 1, and metallic mercury is captured in the collection section 7.

Next, the valves 3 and 15 are switched to connect the inlet of the collecting section 1 to the dehumidifier 5 and the needle valve 14 to the flow meter 16 as shown in FIG. 2b. Therefore, clean air flows through the collection parts 1 and 7 as shown by the arrows through the filter 6 and the dehumidifier 5, and exhausts the sample gas remaining inside these parts or in the filter 11, pump 12, etc. do. After performing this operation, the valve 9 is switched and the collection part 7 is opened as shown in Fig. 2c.
A spectral line absorption cell 10 is inserted between the gas outlet of the filter 11 and the filter 11, and the air that has passed through the collection parts 1 and 7 is made to flow through the cell 10, and the flow rate is adjusted in advance to an appropriate level using the needle valve 14. Adjust it.

After the above-described operations are completed, the heating means 8 is connected to a power source and the temperature of the metal mercury collecting section 7 is rapidly raised to, for example, about 600°C. As the amalgam in the collection section 7 is decomposed by this heating, the metallic mercury captured as amalgam in the collection section is liberated and flows through the cell 10 together with the inhaled air. Therefore, metal mercury contained in the sample gas is detected by atomic absorption spectrometry. The measured value quickly reaches a maximum value and returns to zero when the amalgam is completely decomposed, but the amount of metallic mercury can be determined, for example, from the integral value of this curve. Next, the heating means 2 is further connected to the power source while the collecting section 7 is kept at a high temperature, and the molecular mercury collecting section 1 is
Heat rapidly to about ℃. Due to this temperature rise, molecular mercury, which is a compound adsorbed on the porous material of the collection section 1, is liberated, and together with the carrier air, the molecular mercury is released into the collection section 7.
sent to. Therefore, a part of the liberated molecular mercury is decomposed in the collection section 1, but the molecular mercury sent to the collection section 7 without being decomposed is completely decomposed here and converted into atomic metal. It becomes mercury. Since the metallic mercury is sent into the cell 10, its amount can be measured by atomic absorption spectrometry as described above. Further, when this measurement is completed, the power to the heating means 2 and 8 is cut off, and if necessary, the collection sections 1 and 7 are cooled with a fan, so that the next measurement operation can be started immediately.

As explained above in the embodiments, the present invention consists of a molecular mercury collection section filled with a heat-resistant porous material that is not coated with any metal that would form an amalgam with mercury, and a porous layer that is coated with gold that forms an amalgam. A collection part for metallic mercury made of a material is connected in series in this order, and a spectral line absorption cell is connected to the gas outlet.As mentioned above, the metallic mercury and molecular mercury contained in the gas It is possible to separate them and measure their contents separately. In other words, when the two types of collection sections described above are connected in series and sample gas is passed through them, molecular mercury is almost completely adsorbed to the porous material in the previous collection section, but metallic mercury is almost completely adsorbed. It is sent to the subsequent collection section without being adsorbed and forms an amalgam. Therefore, by using the latter collecting section as a decomposition furnace for molecular mercury, it is possible to separate and detect molecular mercury and metallic mercury as described above.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the configuration of an embodiment of the present invention, Figure 2 is a diagram showing the configuration of an embodiment of the present invention.
The figures are diagrams showing various states of the apparatus shown in Fig. 1 during use. In the figure, 1 is a molecular mercury collection section, 7 is a metal mercury collection section, 2 and 8 are heating means,
10 is a spectral line absorption cell; 3, 9, and 15 are electromagnetic three-way switching valves; 12 is a pump; 13 and 14 are needle valves; 6 and 11 are filters; 4 is a sample intake port;
5 is a dehumidifier, and 16 is a flow meter.

Claims (1)

[Scope of utility model registration request] A molecular mercury collection unit provided with a heating means for filling a heat-resistant tube without adhering metal to the heat-resistant porous material and liberating molecular mercury adsorbed on the porous material, and a heat-resistant porous material. Metal mercury collection in which a heat-resistant tube is filled with gold coated on a material, and a heating means is provided to liberate the metal mercury that has formed an amalgam with the gold again, and to decompose molecular mercury to obtain metal mercury. An apparatus for separating and detecting molecular mercury and metallic mercury, comprising: a mercury mercury collecting section connected in series with a mercury spectral line absorption cell connected to a gas outlet of the metallic mercury collecting section.