Oxidation of Ibuprofen in the Presence of Iron Species

Thousands of tons of ibuprofen are produced and disposed of worldwide on an annual basis. Its impact on the environment is rarely studied; however some research has begun to demonstrate its negative impacts. Considering the amount consumed annually worldwide, it is crucial that alternative methods are found to treat waste water containing IBP and its metabolites. The objective of this project was to investigate the removal of ibuprofen in the presence of three oxidants; hydrogen peroxide, sodium persulfate and ozone. Furthermore, these oxidation experiments were carried out in the presence of three iron species; Fe 2+, Fe3O4 and Fe 2+ amended Fe3O4. First, magnetite (Fe 3O4) was characterized using Brunauer Emmett Teller, X-Ray Diffraction, Transmission Electron Microscope and Scanning Electron Microscope. Furthermore, the adsorption isotherm and edge sorption were plotted and it was concluded that IBP has little affinity to Fe3O4 at the concentrations and pH at which the experiments took place. During the oxidative treatments almost no removal was observed for H2O 2 and Na2S2O8 alone or in the presence of Fe3O4. By adding Fe2+ this removal increased to 95% and 63% respectively. In the case when only O3 was used, a removal of 28% was observed and the presence of Fe2+ hindered the oxidation of IBP (16% removal). Magnetite had shown very little or no effect during oxidation. Furthermore, second order rate constants were determined for H2O2 and Na2S2O 8 in the presence of magnetite and for Na2S2O 8 alone. The results showed that in the presence of magnetite the rate constant was slightly higher for H2O2 (k=3.0*10 -3 M-1 s-1) than Na2S 2O8 (k=1.59*10-3 M-1 s -1). Finally, several degradation products were detected by the different treatment methods; these include oxalic acid, 4-acetylbenzoic acid and oxo-ibuprofen. Based on these results it can be concluded that the best oxidative approaches amongst the ones studied were the use of hydrogen peroxide and persulfate activated by Fe2+. Therefore these should be considered as alternative methods to treat ibuprofen-containing wastes. These results also demonstrated the potential of using alternative oxides and magnetite for the treatment of pharmaceutical wastes.