Evaluation of natural organic matter changes from聽Lake Hohloh by three-dimensional excitation-emission matrix fluorescence spectroscopy during TiO₂/UV process

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• 作者：Sergio Valencia ; Juan M. Mar铆n ; Gloria Restrepo ; Fritz H. Frimmel
• 关键词：Natural organic matter ; Heterogeneous photocatalysis ; Fluorescence spectroscopy ; Excitation&ndash ; emission matrix
• 刊名：Water Research
• 出版年：15 March, 2014
• 年：2014
• 卷：51
• 期：Complete
• 页码：124-133
• 全文大小：2370 K

文摘

This study shows the changes of natural organic matter (NOM) from Lake Hohloh, (Black Forest, Germany) during heterogeneous photocatalysis with TiO₂ (TiO₂/UV). The effect of pH on the adsorption of NOM onto TiO₂ in the dark and TiO₂/UV degradation of NOM was followed using three-dimensional excitation-emission matrix (EEM) fluorescence. At pH values between 4 and 9, the NOM was adsorbed onto TiO₂ in the dark with a greater decrease in the fluorescence intensity and in the spectral shapes, especially under acidic pH conditions. However, at pH聽=聽10 there was not adsorption on NOM which led to a negligible changes the fluorescence intensity. A significant high linear correlation was observed between the DOC adsorption onto TiO₂ and the maximum fluorescence intensity. Additionally, the NOM adsorption onto TiO₂ and its TiO₂/UV degradation shifted the fluorescence maxima toward shorter wavelengths in the EEM contour plots, with a decrease in aromaticity. These changes were accompanied by a substantial decrease in the organically bound halogens adsorbable on activated carbon (AOXFP) and the trihalomethane formation potential (THMFP). Thus, the decrease in maximum fluorescence intensity can be used as an indicator of AOXFP and TTHMFP removal efficiency. Therefore, fluorescence spectroscopy is a robust analytical technique for evaluate TiO₂/UV removal of NOM.