Spectrofluorometric Characterization of Adsorption of Different Molecular Size Fractions of Humic Acid onto Anion-Doped TiO2 Specimens

Abstract

In this study, excitation-emission matrix (EEM) fluorescence spectral features were evaluated for the elucidation of surface interactions among diverse molecular size fractions of humic acid (0.45 µm filtered fraction, 100 kDa fraction and 30 kDa fraction) and bare as well as anion-doped TiO 2 specimens (Evonik P-25 and Hombikat UV-100). EEM constitute fluorescence spectra at many different excitation wavelengths providing a general point of view related to all features of organic matter within a particular spectral range. The objective of the present research was to compare the similarities and differences of the origin of different molecular size fractions of humic acid in the presence of bare and anion doped TiO 2 (Evonik P-25 and Hombikat UV-100) specimens by excitation-emission matrix (EEM) fluorescence spectral properties.