Ce-Fe-reduced graphene oxide nanocomposite as an efficient catalyst for sulfamethazine degradation in aqueous solution.

A heterogeneous Fenton catalyst Ce(0)-Fe(0)-reduced graphene oxide (Ce-Fe-RGO) was synthesized with chemical reduction methods and used for degradation of sulfamethazine. The introduction of Ce and graphene increased the dispersibility of iron particles which was confirmed by SEM and TEM. The results of VSM analysis showed good magnetism of Ce-Fe-RGO. The catalyst performance was compared with other kinds of catalysts (Fe(0) and Ce(0)-Fe(0)) for degradation of sulfamethazine. The results showed that Ce(0)-Fe-RGO had good catalytic performance and adsorption. X-ray diffraction showed the change of iron oxide on catalyst surface after use. The total sulfur (TS), total nitrogen (TN), total organic carbon (TOC), and intermediates, such as small organic molecular and anion ions, were analyzed by IC under different pH conditions. Finally, the possible catalytic mechanism was tentatively proposed based on inhibitor experimental results and XPS characterization. The main active species was hydroxyl radical on catalyst surface and the transition between Ce(3+) and Ce(4+) which enhanced the reduction from Fe(3+) to Fe(2+) and formation of ·OH and ·O2 (-).