Removal Mechanism of Natural Organic Matter and Organic Acid by Ozone in the Presence of Goethite

ABSTRACT

The oxidations of natural organic matter (NOM) and a model compound (p-chlorobenzoic acid) were characterized using ozonation and catalytic ozonation processes. In general, the catalytic ozonation showed better performance in the removal of organics tested in the study. The hydrophobic, transphilic, and hydrophilic NOM fractions were isolated using XAD-8 and -4 resins to evaluate the reaction characteristics. The catalytic ozonation in the presence of goethite accomplished the higher removal of NOM with simultaneous reduction of the three fractions than the ozonation which removed the hydrophobic portion only. The analysis of discrete size distributions of NOM revealed that ozonation yielded a removal of >1,000MW and an increase of <1,000MW, whereas all molecular weight fractions reduced after catalytic ozonation. The concentrations of model compound and aqueous and gaseous ozone were monitored during the oxidations, and efficiencies were compared for cases in the absence and presence of iron oxide (FeOOH).

Keywords:

• Ozone
• Catalytic Oxidation
• Natural Organic Matter
• p-Chlorobenzoic Acid
• Goethite
• Iron Oxide

ACKNOWLEDGMENT

This research was supported in part by a grant (4–1–1) from the Sustainable Water Resources Research Center (SWRRC) of the twenty first century frontier R&D program through the Water Reuse Technology Center (WRTC) at Kwangju Institute of Science and Technology (K-JIST) and by a grant from the Green Korea 21 program at Korea Institute of Science and Technology (KIST).