Enhanced Cr() removal by hierarchical CoFeO@SiO-NH reduction and adsorption processes

In order to realize the highly effective removal of toxic Cr( vi ), 3D porous CoFe 2 O 4 @SiO 2 -NH 2 has been successfully fabricated. As expected, the saturated adsorption capacity of the resulting CoFe 2 O 4 @SiO 2 -NH 2 composite towards Cr( vi ) can reach up to 126.8 mg g −1 , superior to most Fe-containing adsorbents. In addition, the obtained CoFe 2 O 4 @SiO 2 -NH 2 exhibits excellent Cr( vi ) removal performance after four consecutive adsorption-desorption cycles. The exceptional Cr( vi ) removal performance can be ascribed to its excellent electrostatic effect as well as the reduction process originating from the -CH group. Therefore, the hierarchically porous CoFe 2 O 4 @SiO 2 -NH 2 is expected to be highly applicable in Cr( vi )-contaminated water remediation. CoFe 2 O 4 @SiO 2 -NH 2 shows excellent removal performance towards Cr( vi ) due to its excellent electrostatic effect as well as the reduction process originating from the -CH group.