title: Photoinductive activity of humic acid fractions with the presence of Fe(III): the role of aromaticity and oxygen groups involved in fractions.
abstract: Relationship between the photoinductive activity and the properties of humic acids (HA) fractions were investigated with and without Fe(III). Three fractions were separated based on the molecular weight (M(w)) and were obtained following the order of M(w): F(A)>F(B)>F(C). Compared to F(A) and F(B), photodegradation of atrazine under simulated sunlight was much faster in solution containing F(C), whose structure was dominated by greater aromaticity, more oxygen groups and fluorophores. The interaction of HA fractions and Fe(III) was studied using fluorescence spectrometry and F(C) had the largest quenching constant. The capacity of electron transfer, estimated from the amount of photoformed Fe(II), was also highest for F(C). Thus, the Fe(III)-F(C) complex was efficient in phototransformation of atrazine in nearly neutral aqueous solutions. These results suggest that the aromaticity and oxygen groups content of HA exert great influence on the binding ability of metals and on the fate of pollutants in natural waters.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024, China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Ou
authors.forename: Shuo
authors.initials: S
authors.lastname: Chen
authors.forename: Xie
authors.initials: X
authors.lastname: Quan
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhao
mesh_terms: D005591:Chemical Fractionation; D005290:Ferric Compounds / Q000737:chemistry*; D006812:Humic Substances; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D008027:Light; D010084:Oxidation-Reduction; D010777:Photochemistry; D017382:Reactive Oxygen Species / Q000737:chemistry*; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D006812:Humic Substances; D006841:Hydrocarbons, Aromatic; D017382:Reactive Oxygen Species; D012996:Solutions; D014874:Water Pollutants, Chemical