Method for measuring chemical oxygen requirement and its apparatus

A technology of chemical oxygen demand and determination method, which is applied in the field of chemical oxygen demand determination and its device, and can solve the problem of high chemical oxygen demand measurement value

Inactive Publication Date: 2002-10-16
IIJIMA ELECTRONICS CORP
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In this case, when the sample to be tested contains halogens, especially chloride ions, the chloride ions are also oxidized, making the measured value of chemical oxygen demand higher

Method used

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  • Method for measuring chemical oxygen requirement and its apparatus
  • Method for measuring chemical oxygen requirement and its apparatus

Examples

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Embodiment 1

[0034] The structural flow diagram of the assay device used in this embodiment is shown in figure 1 . The periphery of the cylindrical reaction vessel 1 is equipped with a heater 2, and the top cover 3 is equipped with a sample and reagent solution conduit 4, a washing water and nitrogen conduit 5, a nitrogen conduit and a drain pipe 9, an exhaust pipe 10, and a pair of coulometric titration pipes. Use electrode 6.

[0035]A quantitative pump 7 and a reagent solution switching valve 8 in front of the sample conduit 4 are connected to the sample, distilled water, sulfuric acid, oxidant solution of standard concentration, and reagent solution for reduction, and the necessary specified amount is measured and injected. reaction vessel. Nitrogen is introduced into reaction vessel 1 through washing water and nitrogen conduit 5 or through nitrogen conduit and drain pipe 9. When heating to remove chlorine ions and carry out coulometric titration, the nitrogen is used to stir the sol...

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PUM

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Abstract

PURPOSE: To provide an apparatus for measuring chemical oxygen demand and a method therefor which generate no measurement errors by halide ions simpler and easy to process without using mercury nitrate, silver nitrate, and the like. CONSTITUTION: According to the method for measuring chemical oxygen demand and the apparatus for carrying out the measurement method, a fixed amount of a sample whose chemical oxygen demand is to be measured is collected. A predetermined amount of sulfuric acid is added to the sample, which is heated under an inert ambience to remove dissolved chloride ions present in the sample as a hydrogen chloride. Then, a fixed amount of an oxidation reagent for oxidizing the sample is added and heated, whereby a substance to be oxidized in the sample is oxidized. The residual oxidation reagent is coulometric titrated by a reagent solution for reduction. An amount of the residual excessive oxidation reagent is measured. An amount of the oxidation reagent consumed for oxidizing the substance to be oxidized of the sample is measured from the fixed amount of the oxidation reagent added beforehand. The chemical oxygen demand is calculated from the volume of the sample, and the measured value of the oxidation reagent consumed for oxidizing the substance to be oxidized in the sample.

Description

technical field [0001] The present invention relates to the improvement of the chemical oxygen demand (Chemical Oxygen Demand, sometimes abbreviated as COD hereinafter) measuring method, especially relates to the measuring method and the device thereof which weaken the influence of halide ions existing in the sample. Background technique [0002] So far, the determination method of chemical oxygen demand relies on oxidizing agents such as potassium permanganate and potassium dichromate to detect oxidizable substances in the sample to be tested. In this case, when the sample to be tested contains halogens, especially chloride ions, the chloride ions are also oxidized, making the measured value of chemical oxygen demand higher. Therefore, before COD is quantified, a substance that reacts with existing halide ions to form a soluble complex is added to the sample to inhibit the oxidation of halide ions. [0003] Such substances that form soluble complexes...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N33/18C02F1/00G01N27/26G01N27/416G01N27/42
CPCG01N27/423G01N27/44G01N33/1806
Inventor 饭屿茂定北河慎哉福屿康雄
Owner IIJIMA ELECTRONICS CORP
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