Solid Phase Catalytic Ozonation Process for the Destruction of a Model Pollutant

Pure metal oxides, mixed metal oxides, and platinum metals were evaluated as ozonation catalysts. Batch reactor experiments were performed using deionized water at pH 7 and semi-continuous ozonation experiments were performed using a natural water. p-Chlorobenzoic acid (pCBA), a non-adsorbing model micropollutant that does not react directly with molecular ozone, was included in both solution matrixes. Titanium dioxide, cobalt oxide, nickel oxide, copper oxide, and a mixed metal oxide comprised of copper, zinc, and aluminum did not accelerate the removal pCBA in deionized water. However, cobalt oxide and the mixed metal oxide catalyst were effective at accelerating the removal of pCBA in a natural water matrix. The mixed metal oxide catalyst may have the most potential as an ozonation catalyst because it also was very stable (i.e., low solubility). A ruthenium / alumina catalyst also increased the removal of pCBA, but this metal may follow a different reaction mechanism than the metal oxide catalysts.