CN114544744A - Rapid mercury measurement method - Google Patents

Abstract

The invention discloses a rapid measurement method of mercury, which is based on an ion mobility spectrometry detection unit, introduces gas enriched with mercury for detection, adds chloroform as a dopant, can realize rapid measurement of mercury, avoids the problem of data hysteresis, and provides scientific basis for monitoring and controlling mercury pollution; and since many volatile organic compounds, such as alcohols, amines, aldehydes, ketones, and alkanes do not ionize in the CD-IMS negative mode, these compounds do not interfere with the detection of Hg. The invention realizes the effective separation of the complex matrix and the element to be analyzed in the flue gas by means of the gold amalgam and realizes the direct detection of low-concentration mercury in the flue gas.

Description

A Quick Measurement Method for Mercury

technical field

The invention belongs to the field of environment, and in particular relates to a quick measurement method of mercury.

Background technique

Atomic absorption spectroscopy (AAS) and cold vapor atomic absorption spectroscopy (CV-AAS) are the main techniques used to detect and measure mercury in environmental samples. Cold Vapor Atomic Fluorescence Spectroscopy (CV-AFS) is also widely used to analyze mercury content in different samples such as water, food, fish and seafood, soil and ash. However, these techniques require multi-step preconcentration and sample preparation methods to achieve trace mercury determination in complex samples. Inductively coupled plasma mass spectrometry (ICP-MS) has been increasingly used as a fast method for the detection and measurement of mercury. However, there are certain positive and negative deviations in the quantitative analysis of Hg by ICP-MS, and it shows a memory effect.

The offline mercury measurement method can only obtain the average value of a period of time, cannot observe the mercury pollution in time, and takes a long time for sampling and analysis. It is very necessary to realize the rapid measurement of flue gas mercury.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above deficiencies, and to provide a quick measurement method for mercury, which can solve the problem of delay in mercury sampling and testing, and minimize the sampling and testing time.

In order to achieve the above-mentioned purpose, a kind of quick measurement method of mercury, comprises the following steps:

S1, using gold to capture mercury in flue gas, mercury and gold form gold amalgam, to achieve separation and enrichment of mercury with a concentration of not less than 0.01 μg/m ³ in flue gas;

S2, heating the gold amalgam to 850-1000°C to release the enriched mercury;

S3, the mercury-enriched gas is sent into the ion mobility spectrometry detection unit through the carrier gas, chloroform is added as a dopant, the ion mobility spectrometry detection unit is adjusted to the CD-IMS negative mode, and the mercury in the flue gas is detected, Get mercury test results.

When the enriched mercury is released, the gold amalgam is heated for 0.1 to 1 minute.

The mercury-enriched gas is sent into the ion mobility spectrometry detection unit through a carrier gas, and the flow rate of the carrier gas is 0.1-2 L/min.

In the negative mode of the ion mobility spectrometry detection unit, the peak at the drift time of 7.55ms is HgCl ^- , and the relative drift time of the HgCl ^- peak relative to the Cl ^- peak is 1.52.

The drift gas temperature is 160-180°C, and the drift gas flow rate is 50-1000mL/min.

Compared with the prior art, the present invention uses an ion mobility spectrometry detection unit as a basis, introduces mercury-enriched gas for detection, and adds chloroform as a dopant, which can realize the rapid measurement of mercury and avoid the problem of data hysteresis. Provide a scientific basis for monitoring and controlling mercury pollution; and since many volatile organic compounds such as alcohols, amines, aldehydes, ketones and alkanes do not ionize in CD-IMS negative mode, these compounds do not interfere with Hg detection. The invention realizes the effective separation of the complex matrix in the flue gas and the element to be analyzed by means of the gold amalgam, and realizes the direct detection of low-concentration mercury in the flue gas.

Description of drawings

1 is a system diagram of the present invention;

Among them, 1. Flue gas sampling probe, 2. Backflushing system, 3. Pretreatment system, 4. Oxygen sensor, 5. Mercury measurement system, 6. Calibration system, 7. Data acquisition and transmission system.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings.

A method for rapid measurement of mercury, comprising the following steps:

S1, using gold to capture mercury in flue gas, mercury and gold form gold amalgam, to achieve separation and enrichment of mercury with a concentration of not less than 0.01 μg/m ³ in flue gas;

S2, heating the gold amalgam to 850-1000°C for 0.1-1 minute to release the enriched mercury;

S3, the mercury-enriched gas is sent into the ion mobility spectrometry detection unit through the carrier gas, the flow rate of the carrier gas is 0.1-2 L/min, chloroform is added as a dopant, and the ion mobility spectrometry detection unit is adjusted to the CD-IMS negative mode The mercury in the flue gas is detected, the peak value at the drift time of 7.55ms is HgCl ^- , and the relative drift time of the HgCl ^- peak relative to the Cl ^- peak is 1.52. The temperature of the drift gas is 160-180° C., and the flow rate of the drift gas is 50-1000 mL/min to obtain the detection result of mercury.

Referring to Fig. 1, an on-line mercury measurement system is characterized in that it includes a flue gas sampling probe 1, the flue gas sampling probe 1 is inserted into the flue, the flue gas sampling probe 1 is connected to a pretreatment system 3, and the pretreatment system 3 is connected to mercury measurement System 5, an oxygen sensor 4 is provided on the connection pipeline between the pretreatment system 3 and the mercury measurement system 5. The oxygen sensor 4 is used to detect the oxygen concentration in the flue gas. The mercury measurement system 5 is connected to the data acquisition and transmission system 7, and the flue gas is sampled. The probe 1 is provided with a backflushing system 2 to solve the problem of clogging of the probe; the backflushing system 2 can also be used for the interface of the instrument calibration module. Both the mercury measurement system 5 and the flue gas sampling probe 1 are connected to a calibration system 6, and the calibration system 6 is used to provide mercury standard gas. The mercury standard gas can be passed into the flue gas sampling probe 1, and the air tightness test and instrument calibration of the entire sampling test system can be carried out to ensure the accuracy of the measurement data of the analysis system. The calibration system 6 can also send the mercury standard gas to the mercury measurement system 5, which is directly used for the calibration of the mercury analyzer.

The pretreatment system 3 is used to remove dust and water in the flue gas; the mercury measurement system 5 is used to heat the gold amalgam to 850-1000°C to release the enriched mercury; the mercury-enriched gas is sent into the ion through the carrier gas In the mobility spectrum detection unit, chloroform is added as a dopant, and the ion mobility spectrum detection unit is adjusted to CD-IMS negative mode to detect mercury in the flue gas, and the mercury detection result is obtained. The data acquisition and transmission system 7 is used to collect data from the mercury measurement system 5 . The data acquisition and transmission system 7 is used for the acquisition and transmission of the data of the mercury measurement system 5, and can use the communication bus or wireless transmission to transmit the data to the computer or mobile phone in real time.

Claims (5)

1. a fast measuring method of mercury, is characterized in that, comprises the following steps: S1, using gold to capture mercury in flue gas, mercury and gold form gold amalgam, to achieve separation and enrichment of mercury with a concentration of not less than 0.01 μg/m ³ in flue gas; S2, heating the gold amalgam to 850-1000°C to release the enriched mercury; S3, the mercury-enriched gas is sent into the ion mobility spectrometry detection unit through the carrier gas, chloroform is added as a dopant, the ion mobility spectrometry detection unit is adjusted to the CD-IMS negative mode, and the mercury in the flue gas is detected, Get the mercury concentration. 2 . The method for rapid measurement of mercury according to claim 1 , wherein when the enriched mercury is released, the gold amalgam is heated for 0.1 to 1 minute. 3 . 3 . The method for quickly measuring mercury according to claim 1 , wherein the mercury-enriched gas is fed into the ion mobility spectrometry detection unit through a carrier gas, and the flow rate of the carrier gas is 0.1-2 L/min. 4 . 4. the fast measuring method of a kind of mercury according to claim 1, is characterized in that, during ion mobility spectrum detection unit negative mode, drift time is that the peak value at 7.55ms is HgCl-, HgCl ^- peak is relative ^{to Cl- peak} The relative drift time of 1.52. 5 . The method for rapidly measuring mercury according to claim 1 , wherein the temperature of the drift gas is 160-180° C., and the flow rate of the drift gas is 50-1000 mL/min. 6 .

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