Specific UV–vis absorbance changes of humic acid in the presence of clay particles during photocatalytic oxidation

Abstract

AbstractPhotocatalytic oxidation of humic acid (HA) in the presence of clay particles (montmorillonite [Mt] or kaolinite [Kt]) followed using specific UV–vis parameters (SUVA365, SUVA280, SUVA254, and SCoA) calculated by respective absorbance measurements through conversion to mass of carbon. Non-selective oxidative degradation of HA could be displayed by the observed changes in the UV–vis spectral features in accordance with the successful elimination of the dissolved organic carbon. It was previously reported that fractional UV–vis parameters (E254/E365, E254/E436, E280/E365, E280/E436, and E365/E436) could signify the removal of color forming groups in relation to the removal of UV absorbing centers revealing information on the different oxidation pathways through photocatalysis. Regarding the results attained in this study, with respect to the changes attained in the specific UV–vis parameters, it could be indicated that the photocatalytic oxidation mechanism was significantly different for HA in the ...