Accurate, energy-saving and consumption-reduction method for measuring COD (chemical oxygen demand)

Abstract

The invention relates to an accurate, energy-saving and consumption-reduction method for measuring COD (chemical oxygen demand). The method comprises the following steps: preparing potassium dichromate standard solution with the concentration of 0.25mol / L; preparing ferroin indicator solution; preparing ammonium ferrous sulfate solution; preparing sulfuric acid-silver sulfate solution; calibrating the ammonium ferrous sulfate solution, namely, drawing 1mL of potassium dichromate standard solution, adding with water for dilution until reaching 20mL, adding with 3mL of concentrated sulfuric acid, adding with one drop of ferroin indicator solution, placing the ammonium ferrous sulfate solution into a seat type micro burette for titration; weighing 0.04g of mercury sulfate, adding into a HACH transparent threaded pipe, adding with 2mL of water sample, adding with 1mL of potassium dichromate standard solution and 3mL of sulfuric acid-silver sulfate solution simultaneously and placing into a HACH digestion apparatus; performing titration experiment, namely, cooling the solution in the HACH transparent threaded pipe to be at room temperature, transferring the solution into a 50mL conical flask and diluting to reach 20mL with deionized water, adding with one drop of ferroin indicator solution, and titrating with the seat type micro burette, therefore, the COD measurement can be finished. The method is accurate, convenient, safe and environmentally friendly.

Description

technical field [0001] The invention relates to a method for accurately saving energy and reducing consumption to measure COD, which belongs to a water quality monitoring method in the field of sewage treatment. Background technique [0002] At present, the COD (chemical oxygen demand) detection method often uses the traditional heating reflux method and HACH COD method. Among them, the former device has a large volume, a large amount of reagents, high cost, poor safety in the sample digestion process, and has certain limitations for the simultaneous determination of multiple groups of water samples. In the latter monitoring, it is necessary to purchase a special HACH reagent, that is, a HACH colorimeter, which is expensive, and the one-time use of the HACH colorimetric tube is seriously wasteful. If an alternative reagent is used instead of a special HACH reagent, the HACH transparent threaded tube is easy to wear during colorimetric measurement , will directly affect the ...

AI Technical Summary

Problems solved by technology

Among them, the former device has a large volume, a large amount of reagents, high cost, poor safety during sample digestion, and has certain limitations for the simultaneous determination of multiple groups of water samples.

In the latter monitoring, it is necessary to purchase a special HACH reagent, that is, a HACH colorimeter, which is expensive, and the one-time use of the HACH colorimetric tube is seriously wasteful. If an alternative reagent is used instead of a special HACH reagent, the HACH transparent threaded tube is easy to wear during colorimetric measurement , will directly affect the accuracy of the measurement results

[0003] It can be seen from the above that the conventional COD detection methods currently used have certain defects, so it is necessary to design an accurate method for measuring COD with energy saving and consumption reduction to overcome the above defects

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