A Comparative Study of Ozonation, Iron Coated Zeolite Catalyzed Ozonation and Granular Activated Carbon Catalyzed Ozonation of Humic Acid

Abstract

This study compares ozonation (O<inf>3</inf>), iron coated zeolite catalyzed ozonation (ICZ–O<inf>3</inf>) and granular activated carbon catalyzed ozonation (GAC–O<inf>3</inf>) for removal of humic acid from an aqueous solution. The results were evaluated by the removal of DOC that specifies organic matter, UV<inf>254</inf>absorbance, SUVA (Specific Ultraviolet Absorbance at 254 nm) and absorbance at 436 nm. When ozonation was used alone, DOC removal was 21.4% at an ozone concentration of 10 mg/L, pH 6.50 and oxidation time of 60 min. The results showed that the use of ICZ or GAC as a catalyst increased the decomposition of humic acid compared to ozonation alone. DOC removal efficiencies were 62% and 48.1% at pH 6.5, at a catalyst loading of 0.75 g/L, and oxidation time of 60 min for ICZ and GAC, respectively. The oxidation experiments were also carried out using <100 kDa and <50 kDa molecular size fractions of humic acid in the presence of ICZ or GAC. Catalytic ozonation also yielded better DOC and UV<inf>254</inf>reduction in both <50 kDa and <100 kDa fractions of HA compared to ozonation. © 2017 Elsevier Ltd