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Characterization of DOM adsorption of CNTs by using excitation–emission matrix fluorescence spectroscopy and multiway analysis

Peng, Mingguo, Li, Huajie, Li, Dongdong, Du, Erdeng, Li, Zhihong
Environmental technology 2017 v.38 no.11 pp. 1351-1361
adsorbents, adsorption, carbon nanotubes, environmental technology, fluorescence, fluorescence emission spectroscopy, models, sorption isotherms, temperature, thermodynamics
Carbon nanotubes (CNTs) were utilized to adsorb DOM in micro-polluted water. The characteristics of DOM adsorption on CNTs were investigated based on UV ₂₅₄, TOC, and fluorescence spectrum measurements. Based on PARAFAC (parallel factor) analysis, four fluorescent components were extracted, including one protein-like component (C4) and three humic acid-like components (C1, C2, and C3). The adsorption isotherms, kinetics, and thermodynamics of DOM adsorption on CNTs were further investigated. A Freundlich isotherm model fit the adsorption data well with high values of correlation. As a type of macro-porous and meso-porous adsorbent, CNTs preferably adsorb humic acid-like substances rather than protein-like substances. The increasing temperature will speed up the adsorption process. The self-organizing map (SOM) analysis further explains the fluorescent properties of water samples. The results provide a new insight into the adsorption behaviour of DOM fluorescent components on CNTs.