Turbidity Disturbance Compensation for UV-VIS Spectrum of Waterbody Based on Mie Scattering

Decao, 吴德操 Wu; Biao, 魏彪 Wei; Ge, 汤 戈 Tang; Peng, 冯 鹏 Feng; Yuan, 唐 媛 Tang; Juan, 刘娟 Liu; Shuangfei, 熊双飞 Xiong

doi:10.3788/aos201737.0230007

Cited by 8 publications

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“…(4) , resulting in compensated absorption spectra, as shown in Figure 4B . Other turbidity compensation models, such as the Lambert-Beer law-based (LBL) and multiple-scattering cluster (MSC) models mentioned in the literature, were also examined for comparison with the exponential model presented here ( Wu et al, 2017 ; Li et al, 2019 ; Chen et al, 2021 ). The compensated spectra from the LBL and MSC models are shown in Figures 4C , D , respectively.…”

Section: Resultsmentioning

confidence: 99%

“…UV-vis spectroscopy is widely utilized for COD measurement due to its rapid measurement time, lack of secondary pollution, reagent-free nature, and ability to provide real-time determination ( Carré et al, 2017 ; Ma et al, 2018 ). However, UV-vis spectroscopy is typically limited by the interference of suspended particles; thus, effective methods must be adopted to suppress the influence of interfering factors and improve prediction accuracy ( Wu et al, 2017 ; Chen et al, 2021 ). Turbidity compensation has become a research focus in the area of COD measurement based on UV-vis spectroscopy ( Hu et al, 2016 ; Li et al, 2019 ; Hu et al, 2020 ; Kang et al, 2022 ; Zhang et al, 2022 ).…”

Section: Introductionmentioning

confidence: 99%

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A straightforward approach utilizing an exponential model to compensate for turbidity in chemical oxygen demand measurements using UV-vis spectrometry

et al. 2023

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Recently, ultraviolet-visible (UV-vis) absorption spectrometry has garnered considerable attention because it enables real-time and unpolluted detection of chemical oxygen demand (COD) and plays a crucial role in the early warning of emerging organic contaminants. However, the accuracy of detection is inevitably constrained by the co-absorption of organic pollutants and turbidity at UV wavelengths. To ensure accurate detection of COD, it is necessary to directly subtract the absorbance caused by turbidity from the overlaid spectrum using the principle of superposition. The absorbance of COD is confined to the UV range, whereas that of turbidity extends across the entire UV-vis spectrum. Therefore, based on its visible absorbance, the UV absorbance of turbidity can be predicted. In this way, the compensation for turbidity is achieved by subtracting the predicted absorbance from the overlaid spectrum. Herein, a straightforward yet robust exponential model was employed based on this principle to predict the corresponding absorbance of turbidity at UV wavelengths. The model was used to analyze the overlaid absorption spectra of synthetic water samples containing COD and turbidity. The partial least squares (PLS) method was employed to predict the COD concentrations in synthetic water samples based on the compensated spectra, and the corresponding root mean square error (RMSE) values were recorded. The results indicated that the processed spectra yielded a considerably lower RMSE value (9.51) than the unprocessed spectra (29.9). Furthermore, the exponential model outperformed existing turbidity compensation models, including the Lambert-Beer law-based model (RMSE = 12.53) and multiple-scattering cluster method (RMSE = 79.34). Several wastewater samples were also analyzed to evaluate the applicability of the exponential model to natural water. UV analysis yielded undesirable results owing to filtration procedures. However, the consistency between the compensated spectra and filtered wastewater samples in the visible range demonstrated that the model is applicable to natural water. Therefore, this proposed method is advantageous for improving the accuracy of COD measurement in turbid water.

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Section: Resultsmentioning

confidence: 99%