Fabrication of magnetic flower-shaped Fe3O4@In2S3 composite for efficient removal of aqueous Cr(VI)

The incorporation of semiconductor materials on Fe 3 O 4 has been demonstrated as an efficient way to promote the photocatalytic activity of Fe 3 O 4 . Therefore, we synthesized Fe 3 O 4 @In 2 S 3 composite by growing ultrathin In 2 S 3  nanosheets on the surface of Fe 3 O 4 using a simple one-pot water bath heating method. Fe 3 O 4 @In 2 S 3 exhibited high adsorption and photoreduction capacities for Cr(VI) under wide pH, as well as excellent magnetic separation property. Meanwhile, the adsorption and reduction ability of Fe 3 O 4 @In 2 S 3 towards Cr(VI) maintained high level in low-valent anions system, while it significantly declined with existence of high-valent anion (PO 4 3− ). A sharp contrast between the two situations manifested that the Fe 3 O 4 @In 2 S 3 has strong anti-interference in low-valent anions system. Furthermore, cyclic experiments revealed the admirable photocatalytic activity and reusability of Fe 3 O 4 @In 2 S 3 . According to the results of adsorption and cyclic experiments, a distinctly enhanced proportion of Cr on surface of Fe 3 O 4 @In 2 S 3 in the first cycle experiment was observed, which indicated that the photocatalytic reduction of Cr(VI) probably promoted the immobilization of Cr species on Fe 3 O 4 @In 2 S 3 . XPS analysis results suggested that the Cr(VI) loaded on Fe 3 O 4 @In 2 S 3 mostly reduced to Cr(III) via photocatalytic reduction process with In 2 S 3 , and Fe 3 O 4 partly contributed to its reduction. Finally, the enhanced adsorption and reduction capacity of Fe 3 O 4 @In 2 S 3 for Cr(VI) and its easy recycling feature make it has great application potential in Cr(VI) wastewater treatment.