The effect of photocatalytic oxidation on molecular size distribution profiles of humic acid. Issue 3 (11th November 2014)

• Record Type: Journal Article
• Authors: Bekbolet, M.; Sen-Kavurmaci, S.
• Is Part Of: Photochemical & photobiological sciences. Volume 14:Issue 3(2015:Mar.)
• Page Start: 576
• Page End: 582
• Publication Date: 2014-11-11
• Subjects: Photochemistry -- Periodicals; Photobiology -- Periodicals; 541.35
• DOI: 10.1039/c4pp00262h
• Languages: English
• ISSNs: 1474-905X

Abstract

Abstract : Photocatalytic oxidation leads to a drastic change in excitation emission matrix (EEM) fluorescence features of humic acid molecular size fractions. Abstract : The influence of photocatalytic degradation on molecular size fractionation (0.45 μm filtered, 100 kDa, 30 kDa and 3 kDa) of humic acid as a model compound of natural organic matter was investigated. The results were evaluated using UV-vis parameters, dissolved organic carbon (DOC) and excitation emission matrix (EEM) fluorescence spectral features. EEM fluorescence signatures displayed an irradiation period dependent transformation of humic-like fluorophores to fulvic-like fluorophores in accordance with the photocatalytic mineralization of HA. Molecular size distribution profiles expressed the formation of lower molecular size (<3 kDa) fractions through oxidative degradation of humic acid of higher molecular size fractions (100 kDa and 30 kDa fractions). The fluorescence-derived index (fluorescence intensity (FI), represented by the ratio of the emission intensity at λ emis = 450 nm to that at λ emis = 500 nm, following the excitation at λ exc = 370 nm) was also investigated. The use of EEM features has proven to be a useful tool for monitoring the effect of photocatalytic degradation on the structure and molecular size distribution profile of HA.