Humic-like substances from urban waste as auxiliaries for photo-Fenton treatment: a fluorescence EEM-PARAFAC study

SARA GARCÍA BALLESTEROS; MARIANA R. COSTANTE; R. VICENTE; M. MORA; A. M. AMAT; A. ARQUES; LUCIANO CARLOS; FERNANDO S. GARCÍA EINSCHLAG

Photochemical and Photobiological Sciences

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2017 vol. 16 p. 38 - 45

1474-905X

In this work, analysis of excitation-emission-matrices (EEM) has been employed to gain further insightinto the characterization of humic like substances (HLS) obtained from urban wastes (soluble bio-organicsubstances, SBOs). In particular, complexation of these substances with iron and changes along a photo-Fenton process have been studied. Recorded EEMs were decomposed by using parallel factor analysis(PARAFAC). Three fluorescent components were identified by PARAFAC modeling of the entire set of SBOsolutions studied. The EEM peak locations (λex/λem) of these components were 310?330 nm/400?420 nm (C1), 340/360 nm/450?500 nm (C2), and 285 nm/335?380 nm (C3). Slight variations ofthe maximum position of each component with the solution pH were observed. The interaction of SBOwith Fe(III) was characterized by determining the stability constants of the components with Fe(III) atdifferent pH values, which were in the order of magnitude of the ones reported for humic substances andreached their highest values at pH = 5. Photochemical experiments employing SBO and Fe(III), with andwithout H2O2, showed pH-dependent trends for the evolution of the modeled components, whichexhibited a strong correlation with the efficiency reported for the photo-Fenton processes in the presenceof SBO at different pH values.