FeOOH modified carbon doped TiO2 p-n heterojunction wrapped Fe3O4 for highly efficient removal of As(III) through photocatalytic oxidation and adsorption

Arsenic pollution control of wastewater is still a difficult problem in environmental governance. In this paper, a bifunctional p-n heterojunction for removing As(III) has been constructed by FeOOH modifying carbon-doped TiO2, 2 , which can achieve highly efficient photocatalytic oxidation of As(III) and synchronous adsorption of the generated As(V). Furthermore, the Fe3O4 3 O 4 cores were wrapped by the p-n heterojunction (FeOOH@C/TiO2@- 2 @- Fe3O4) 3 O 4 ) to realize the recycling of photocatalysts through magnetic separation. A series of characterizations showed that carbon doping and FeOOH modifying could promote the light energy utilization of TiO2 2 and boost the separation efficiency of photogenerated carriers through interfacial chemical bonds and built-in electric fields, facilitating the visible photocatalytic oxidation of As(III). Simultaneously, the presence of FeOOH on the surface of heterojunction can efficiently adsorb the generated As(V) through forming Fe- O- As bonds. As a result, the FeOOH@C/TiO2@Fe3O4 2 @Fe 3 O 4 heterojunction (20 mg) can completely remove 10,000 mu g & sdot;L-1 & sdot; L- 1 (40 mL) of As (III) from water within 12 min. Additionally, The reusability of FeOOH@C/TiO2@Fe3O4 2 @Fe 3 O 4 is outstanding, maintaining 100 % As(III) removal even after 5 cycles without significant changes in its crystal structure. The superior photocatalytic oxidation and adsorption properties of FeOOH@C/TiO2@Fe3O4 2 @Fe 3 O 4 indicate that it is an effective approach to remove arsenic by constructing bi-functional heterojunction.