Turbidity compensation method for COD detection based on spectrometry

Abstract

The invention discloses a turbidity compensation method for COD detection based on spectrometry. The method comprises the following steps: (1) acquiring the absorption spectrum of a to-be-measured liquid; (2) calculating the absorption spectrum of the to-be-measured liquid in the step (1) under the action of current turbidity; and (3) carrying out peak drop correction on the absorption spectrum of the to-be-measured liquid in the step (1). The turbidity compensation method introduces an impact factor KN(lambda) to characterize influence of turbidity substances on the light absorption effect of organic molecules and establishes a KN(lambda) model by using an approximate linear relation between KN(lambda) and the absorbance of a standard COD liquid and a negative exponential relation between the valley value of KN(lambda) and turbidity so as to correct and directly deduct peak drop in a turbidity baseline compensation method; and the established model has environmental adaptability, so precision and flexibility of COD measurement are improved.

Description

technical field [0001] The invention relates to the technical field of water quality detection, in particular to a turbidity compensation method based on spectral COD detection. Background technique [0002] In water environment monitoring, COD (chemical oxygen demand) is an important water quality index, which reflects the pollution degree of water body by reducing organic matter. In national standards such as "Environmental Quality Standards for Surface Water" (GB3838-2002), "Water Quality Standards for Drinking Water Sources" (CJ3020-93), "Hygienic Standards for Drinking Water" (GB5749-2006) and other national standards, COD concentration limits are set. Therefore, the accurate, convenient and rapid detection of COD is very important. [0003] At present, COD detection methods include chemical methods and physical methods, among which the chemical methods are mainly dichromate method (GB11914-89) and permanganate method (GB11892-89), these methods have the disadvantages ...

AI Technical Summary

Problems solved by technology

Although the first method is simple, it does not fundamentally eliminate the influence of turbidity but only considers the numerical mapping relationship, and requires a large number of test experiments and data support

For the second type of method, most of the current methods are just simple mathematical calculations, without considering the interaction mechanism of the composition of substances in water, so there is still a large deviation between the compensation result and the absorption spectrum curve of the actual turbidity-free solution

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