Influence of temperature and turbidity on water COD detection by UV absorption spectroscopy

Zhou, Kunpeng; Bi, Weihong; Zhang, Qihang; Fu, Xinghu; Wu, Guozhong

doi:10.1007/s11801-016-6178-z

Cited by 13 publications

(8 citation statements)

References 9 publications

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“…The ultraviolet full-spectrum method is based on Lambert-Beer's law [9], which states that absorbance is proportional to the concentration of the substance and the absorption layer thickness, and the transmission intensity is inversely proportional to the absorption intensity. It can be described using Equation (1), as shown in Figure 2.…”

Section: Principle Of Uv Full-spectrum Analysismentioning

confidence: 99%

Study on nitrate detection method in water using UV full-spectrum combined with PCA-BPNN

Geng,

Zhang,

Yuan

et al. 2023

3rd International Conference on Laser, Optics, and Optoelectronic Technology (LOPET 2023)

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In recent years, the increasingly serious problem of marine pollution has raised high concern about environmental issues among people, which in turn has promoted rapid development of marine pollution detection technology. UV fullspectrum analysis is a nitrate detection method based on characteristics such as no reagents required, convenient and fast, and high detection accuracy. This article takes nitrate standard solution prepared with potassium nitrate as the experimental object, collects UV full-spectrum from 0 to 7mg/L standard solutions, uses the Savitzky-Golay (SG) smoothing algorithm to remove noise from the original nitrate full-spectrum data, processes the UV full-spectrum data using principal component analysis (PCA) algorithm, extracts characteristic bands, and uses BP neural network modeling for the screened bands. The results show that within the spectral range of 201-207nm, the prediction model achieves the highest coefficient of determination, with an R 2 of 0.99997, and the smallest root mean square error, with an RMSE of 0.11149, and all performance indicators are superior to those of the UV full-spectrum modeling method.

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Section: Principle Of Uv Full-spectrum Analysismentioning

confidence: 99%

Study on nitrate detection method in water using UV full-spectrum combined with PCA-BPNN

Geng,

Zhang,

Yuan

et al. 2023

3rd International Conference on Laser, Optics, and Optoelectronic Technology (LOPET 2023)

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“…The COD solution (100 mg/L) was prepared by dissolving 0.02125 g potassium hydrogen phthalate in deionized water and diluting to 250 mL. COD standard solutions whose values were 1, 2, 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31, and 32 mg/L, and were prepared by appropriate dilution. In addition, the NTU (nephelometric turbidity unit) standard (7027-1984 ISO) was used to determine the water turbidity.…”

Section: Samples Preparation and The Measurement Of Uv-vis Absorbance...mentioning

confidence: 99%

A Novel Hybrid Strategy for Detecting COD in Surface Water

Gui-ping

et al. 2020

Applied Sciences

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The prediction of chemical oxygen demand (COD) by ultraviolet–visible absorption spectrum is a common method. Many researchers use the absorbance at the characteristic wavelength to establish COD prediction models. However, selecting the characteristic wavelength is a problem. In this paper, the extreme values of absorption spectrum change rate, was proposed as a new characteristic parameter to determine the characteristic wavelengths. On this basis, a novel hybrid strategy for detecting COD in surface water was proposed. We first proposed to combine the first derivative method with the permutation entropy method (FDPE) to determine the characteristic wavelengths. Then we used partial least square (PLS) to establish a COD prediction model. Experimental results demonstrated the linear correlation coefficient (R2) of the FDPE_PLS was above 0.99 without turbidity interference. Secondly, a dual-wavelength method (DWM) was proposed to determine the turbidity values. The DWM used slopes of absorbance values at 400 nm and 600 nm to predict the turbidity values. Compared with the single-wavelength method, the DWM improves the measurement accuracy of turbidity. Finally, a new turbidity compensation method was proposed to compensate for the interference in the first derivative spectrum. After compensation, FDPE_PLS can predict COD concentrations accurately, whose R2 was 0.99.

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“…Water quality analysis is an important task of environmental monitoring. The chemical oxygen demand (COD) describes the concentration of reducing substances in water, which is an important parameter for evaluating the organic pollution and quality of water [1][2][3]. Generally, there are two methods for measuring the COD: chemical method and optical method.…”

Section: Introductionmentioning

confidence: 99%

“…At present, the optical method mainly includes absorbance spectrophotometry, hyperspectral analysis [1,2] and fluorescence spectroscopy. The absorbance spectrophotometry can be further divided into single-wavelength measurement method, doublewavelength measurement method, multi-wavelength measurement method and broad-spectrum measurement method.…”

Section: Introductionmentioning

confidence: 99%

Research on chemical oxygen demand based on laser Fluorescence-Raman spectroscopy

Che

Tian²,

Sun³

et al. 2022

Front. Phys.

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In this invited paper, a novel water chemical oxygen demand (COD) detection method based on laser spectroscopy is proposed, and the COD value is obtained according to the intensity ratio of laser Fluorescence-Raman signal produced by laser incident into water. Based on the laser Fluorescence-Raman ratio (LFRR) method, we design a portable water quality measurement system. In which, a 405 nm semiconductor laser is used as the light source. The laser is coupled into the delivering port of Y-type fiber and then transmitted into water. The generated Mie scattered light, water Raman light and corresponding fluorescence are received and transmitted into spectrometer through the detecting port of Y-type fiber, and the COD value can be obtained by analyzing the LFRR of water spectra. The mixed solution of sodium humate and glucose is used as the COD standard solution to calibrate the designed system. The experiment results show that the optimal volume ratio of the two solutions is 1:29. When the COD of standard solutions is in the 1–12 mg/L concentration range, a good linear relationship can be found between the COD value and LFRR value with a correlation coefficient of 0.974. In addition, the COD of natural water samples are measured with LFRR method, the results of which are consistent with COD values obtained by rapid digestion spectrophotometry. Meanwhile, experimental results prove that the COD detection method proposed in this paper has the advantages of high sensitivity, high precision, high detection speed and simplicity, which can be widely used in various water areas for real-time COD monitoring.

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Influence of temperature and turbidity on water COD detection by UV absorption spectroscopy

Cited by 13 publications

References 9 publications

Study on nitrate detection method in water using UV full-spectrum combined with PCA-BPNN

Study on nitrate detection method in water using UV full-spectrum combined with PCA-BPNN

A Novel Hybrid Strategy for Detecting COD in Surface Water

Research on chemical oxygen demand based on laser Fluorescence-Raman spectroscopy

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