Kinetic evaluation of graphene oxide based heterogenous catalytic ozonation for the removal of ibuprofen.

In this study, the performance of graphene oxide (GO) in ozonation process was kinetically evaluated using the modified R concept since GO may act as initiator, promoter and inhibitor in ozone radical chain reaction. The applicability of the modified R concept was demonstrated using different GO suspensions (GO alone, GO/TiO, GO/FeO, GO/TiO/FeO) in ozonation process. Results showed that ozone exposure and •OH exposure were found to be higher for GO/FeO and GO/TiO/FeO compared to other GO suspensions, which was almost equivalent to O/HO process. The determined initiation and inhibition rate constants of GO alone, were 1 fold higher than GO/FeO and GO/TiO/FeO, since the GO alone suspension possesses higher O decomposition but lower organic degradation because that GO does not yield •OH. Moreover, GO/FeO suspension, along with natural organic matter (NOM), was proven to be helpful in degrading ibuprofen in ozonation process, but the effect was minimal when compared to O/HO process. These results exhibited that the surface modified GO suspensions could be utilized as future alternative AOPs.