version ISSN 0718-0764
VALENCIA, Sergio H; MARIN, Juan M and RESTREPO, Gloria M. Effect of pH on the Photocatalytic Degradation of Natural Organic Matter. Inf. tecnol. [online]. 2011, vol.22, n.5, pp. 57-66. ISSN 0718-0764. doi: 10.4067/S0718-07642011000500008.
The effect of pH on the photocatalytic degradation of natural organic matter in water from a lentic ecosystem using commercial titanium dioxide in suspension and a solar UV simulator was studied. The degradation monitoring and natural organic matter characterization was followed by size exclusion chromatography with dissolved organic carbon and ultraviolet detection at wave length A=254 nm, and UV-Vis spectrophotometry. It was found that at pH below the isoelectric point of the photocatalyst, the kinetics of the reaction is high and with a pH above the isoelectric point the reaction kinetics decreases. Also, the photocatalysis is given by an alteration of the molecular weight distribution especially for the degradation of high molecular weight compounds to low molecular weight compounds, before their mineralization.
Keywords : natural organic matter; heterogeneous photocatalysis; titanium dioxide; chromatography.