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A rapid extraction method of different forms of arsenic and selenium in fly ash

An extraction method and morphological technology, applied in the field of analytical chemistry, which can solve problems such as long cycle

Active Publication Date: 2021-05-14
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the traditional Wenzel extraction method is oscillating extraction, and the cycle is long, so it is urgent to find a method for rapid and stable extraction of arsenic and selenium in fly ash. This method is still a hot and frontier topic in the field of analytical chemistry.

Method used

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  • A rapid extraction method of different forms of arsenic and selenium in fly ash

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] A fly ash sample from a power plant in Hebei was collected. The fly ash sample was ground and then freeze-dried at low temperature for 24 hours, and then passed through a 200-mesh sieve with the help of an automatic horizontal reciprocating oscillating sieving machine. The obtained sample was balanced under the conditions specified in GB / T 32722. The working parameters of the ultrasonic instrument are determined as follows: the working frequency is 40kHz, the power is 250W, and the volume of the soaking liquid in the water tank is 5.5L.

[0033] Extraction of non-specifically adsorbed arsenic: Weigh 1g of the fly ash sample after balance treatment into a 50mL polyethylene centrifuge tube, add 25mL, 0.05M ammonium sulfate solution to fully mix the fly ash sample and the extract, put the centrifuge tube into Put the beaker in a beaker filled with 400mL ultrapure water, and place it in an ultrasonic instrument for ultrasonication. Ultrasound is divided into 4 times, with a ...

Embodiment 2

[0040] A fly ash sample from a power plant in Shanxi was collected, and the sample treatment was the same as in Example 1.

[0041] Extraction of non-specifically adsorbed arsenic and selenium: the extraction method and process are the same as in Example 1, and the average concentrations of arsenic and selenium in the non-specific adsorbed state (form 1) obtained by detection and analysis are 3.62±0.37 mg / kg and 2.98±0.22 mg / kg respectively , the average concentrations of non-specifically adsorbed arsenic and selenium extracted by traditional Wenzel method were 3.91±0.62 mg / kg and 2.86±0.42 mg / kg, respectively. The average recovery rates of ultrasonic-assisted extraction of non-specifically adsorbed arsenic and selenium by the method of the present invention are respectively 92.6% and 104.2% of those of traditional vibration extraction.

[0042] Extraction of specifically adsorbed arsenic and selenium: the extraction method and process are the same as in Example 1, and the ave...

Embodiment 3

[0048] The national standard substance GBW08401 was collected as a fly ash sample, and the sample treatment was the same as in Example 1.

[0049] Extraction of non-specifically adsorbed arsenic and selenium: the extraction method and process are the same as in Example 1, and the average concentrations of arsenic and selenium in the non-specific adsorbed state (form 1) obtained by detection and analysis are 4.12±0.62 mg / kg and 0.26±0.03 mg / kg respectively , the measured average concentrations of non-specifically adsorbed arsenic and selenium extracted by traditional Wenzel shaking were 4.55±0.52 mg / kg and 0.27±0.04 mg / kg, respectively. The average recoveries of ultrasonic-assisted extraction of non-specifically adsorbed arsenic and selenium by the method of the present invention are respectively 90.5% and 96.3% of those of traditional vibration extraction.

[0050] Extraction of specifically adsorbed arsenic and selenium: the extraction method and process are the same as in Exam...

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Abstract

A rapid extraction method for different forms of arsenic and selenium in fly ash, comprising the following steps: pre-treatment of fly ash samples; extraction of arsenic and selenium in non-specific adsorption state (form 1); extraction of arsenic and selenium in specific adsorption state (form 2) ; The extraction of arsenic and selenium in the bonded state of amorphous and weakly crystalline iron-aluminum hydrated oxides (form 3); the extraction of arsenic and selenium in the bonded state of fully crystalline iron-aluminum oxides (form 4); the extraction of arsenic and selenium in the residue state (form 5), The ultrasonic extraction time required for different forms of arsenic and selenium is different. The ultrasonic extraction time of form 1, form 2 and form 3 arsenic is 11-13min, 23-25min, 2-3min respectively; the ultrasonic extraction of form 1, form 2 and form 3 selenium The time is 9-11min, 19-21min and 27-29min respectively. Compared with the traditional oscillation extraction scheme, the method of the invention greatly shortens the extraction time, has stable results, and presents high repeatability and reproducibility.

Description

technical field [0001] The invention relates to a rapid extraction method for different forms of arsenic and selenium in fly ash, belonging to the technical field of analytical chemistry. Background technique [0002] In the global coal consumption, nearly 50% of the coal consumption is used in the power industry, and a large amount of coal combustion has caused extremely serious trace element (TEs) emission problems. Current studies have shown that fly ash has a significant enrichment effect on arsenic and selenium. It is inaccurate to evaluate the environmental effect solely by the concentration of arsenic and selenium in fly ash. There is a close relationship between arsenic and selenium in different occurrence states and bioavailability, toxicity and mobility. At present, most speciation analysis studies are based on the Tessier method, and the EU-certified BCR method was subsequently developed, but its extraction efficiency for arsenic and selenium is not satisfactory....

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N1/34
CPCG01N1/34
Inventor 苑春刚何楷强史孟丹
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)