Graphene oxide in the remediation of norfloxacin from aqueous matrix: simultaneous adsorption and degradation process

In the present study, the simultaneous adsorption degradation of norfloxacin (NOR) by graphene oxide from aqueous matrix was verified. Graphene oxide (GO, similar to 8 layers) was prepared using modified Hummers method through the oxidation/exfoliation of expanded graphite. Spectroscopic techniques confirmed the NOR adsorption onto GO surface and the partial antibiotic degradation promoted by hydroxyl radicals derived from GO. Furthermore, the mass spectra after the adsorption-degradation processes showed NOR degradation intermediates that was compared and confirmed by other studies. The nanomaterial showed a removal capacity of 374.9 +/- 29.8 mg g(-1), observing greater contribution from the NOR in the zwitterionic form and removals up to 94.8%. The intraparticle diffusion process, assessed by Boyd's model and Fick's law, presented a greater contribution in the removal process, reaching the equilibrium 30 min after the beginning. In addition, the temperature increase would disadvantage the process, which was considered thermodynamically viable throughout the evaluated temperature range. Finally, the process was scaled-up in a single stage batch adsorber considering a NOR removal efficiency of 95%. This resulted in mass requirement of 63.6 g of GO in order to treat 0.5 m(3)of contaminated water. In general, the simultaneous adsorption-degradation process was considered innovative and promising in pharmaceutical compounds remediation.