Enhanced photo-Fenton degradation of rhodamine B using graphene oxide–amorphous FePO4 as effective and stable heterogeneous catalyst

Abstract

A series of graphene oxide (GO)–FePO4 composites with different GO weight ratios (2.5%, 5%, 10%, w/w) were prepared using a simple precipitation process and were firstly used as heterogeneous photo-Fenton catalysts. FESEM images prove the loose structure of the 5GO–FePO4 composite. UV–vis analysis demonstrates that the introduction of GO could enhance solar energy utilization of the composites. Under visible light irradiation, the degradation rate of rhodamine B (RhB) by the 5GO–FePO4 composite was 2.87 times more than that by the pure FePO4 in the presence of hydrogen peroxide. The composite was highly effective for the degradation of RhB in a wide pH range of 2.18–10.40 with negligible iron leaching. Moreover, the composite still showed high catalytic activity after six cycles, which makes it a promising heterogeneous catalyst for wastewater treatment. The introduction of GO promotes the photo-Fenton reaction of GO–FePO4 via three roles: offering more active sites, increasing adsorption capacity and accelerating the Fe3+/Fe2+ cycle by improving the utilization of solar energy. Our work may provide new insights for the development of new effective heterogeneous photo-Fenton catalyst.