Novel Magnetic Fe3O4/α-FeOOH Nanocomposites and Their Enhanced Mechanism for Tetracycline Hydrochloride Removal in the Visible Photo-Fenton Process

Magnetic Fe3O4/alpha-FeOOH heterojunction nanocomposites (denoted as Fe-NCs) have been synthesized by a fast one-pot hydrothermal method. The obtained Fe-NCs contain rich micropores with a high surface area of 135.15 m(2)/g. The different phases in the composites can efficiently enhance the visible-light absorption, improving the separation and transfer of photogenerated electron-hole pairs during the photocatalytic reaction. Thus, they show excellent degradation and mineralization of tetracycline (TC) over a wide pH range (5-9) in the visible photoFenton reaction. Especially, the catalyst exhibits the highest adsorption capacity toward TC at a neutral pH, which facilitates the surface reactions of TC with active species. Experiments evidence that the high production of photogenerated holes and superoxide radicals (O-2(center dot-)) in Fe-NCs are favorable to the high catalytic efficiency. Combined with liquid chromatography-mass spectrometry, the possible pathway toward TC degradation was proposed.