Correction method for turbidity influence during water quality COD detection by using ultraviolet-visible spectroscopy

Abstract

The invention relates to a correction method for turbidity influence during water quality COD detection by using ultraviolet-visible spectroscopy. The correction method comprises the following steps of: firstly, acquiring absorption spectrum data of a to-be-detected water sample and a plurality of turbidity standard solutions, and solving a turbidity influence matrix, wherein the concentrations ofthe turbidity standard solutions correspond to the concentration of the water sample to be detected; calculating an observation matrix and a sparse basis matrix through utilizing a compressed sensingtheory to obtain a turbidity influence factor; solving an optimal solution through using a norm to reconstruct a turbidity absorption spectrum influence matrix; and finally, deducting the turbidity absorption spectrum influence from the absorption spectrum data of the to-be-detected water sample to obtain the COD absorption spectrum. According to the correction method, under the condition that the ultraviolet absorption properties of the ultraviolet-visible spectroscopy is not influenced, turbidity correction of the ultraviolet-visible absorption spectrum of an actual water sample can be effectively realized, turbidity influence is deducted, the COD absorption spectrum of a detection result and the correlation coefficient of the actual water sample reach 0.9941, the root-mean-square erroris 0.0098, and an effective new method is provided for accurately realizing accurate calculation of the COD of the water quality.

Description

technical field [0001] The invention belongs to the technical field of using optical means to test or analyze materials in physical testing, and in particular relates to a method for correcting the influence of turbidity when detecting water quality COD by ultraviolet-visible spectroscopy. Background technique [0002] At present, the detection of water quality mainly adopts chemical method and spectroscopic analysis method. Although the traditional chemical method has high detection accuracy, the detection cycle is long and requires professional operation. The chemical reagents used are also prone to secondary pollution. [0003] Ultraviolet-visible spectroscopy is a method of analyzing and measuring by using the molecules of certain substances to absorb radiation in the 200-800nm ​​spectral region. It uses a spectrometer to connect to a computer for data processing and recording to complete and form an absorption spectrum. By establishing sample spectral information and it...

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Problems solved by technology

[0004] The detection of water quality COD by UV-visible spectroscopy also has the above advantages, but in turbid water, turbidity will cause a nonlinear rise in the overall UV-visible spectrum, thereby interfering with the direct measurement of COD by using UV-visible spectroscopy. This is also introduced in the existing published article: "Application of UV-Vis Spectroscopy in Water Quality Analysis"

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