Bimetallic FeNi Alloy Nanoparticles Grown on Graphene for Efficient Removal of Congo Red From Aqueous Solution

Nano zero-valent iron (nZVI) is an effective material for dye wastewater treatment, but excessive agglomeration and oxidation greatly limit its application. Herein, graphene (GR) supported FeNi bimetallic nanoparticles (FeNi@GR) are prepared by alloying and carrier supported dispersion for efficient removal of azo dyes from water. Not only can it effectively solve the problem of excessive agglomeration and oxidation of nZVI, but also the synergistic effect of bimetallic coordination formation and the excellent electron transfer ability of graphene are beneficial to enhance the reactivity of FeNi@GR. The optimal FeNi@GR is prepared by adjusting the content of GR and the removal of Congo red (CR) by FeNi@GR-10% reached 625 mg g(-1) within 150 min at pH = 7.0. Higher temperature and lower pH favor the removal of CR azo dye. The action mechanisms of FeNi@GR presumably involve the transfer of active hydrogen atoms and the transfer of electrons generated by Fe-0 and Ni-0. Besides, the saturation magnetization (Ms) of FeNi@GR is 68.15 emu g(-1), which has excellent magnetic response performance. This work not only provides a simple and efficient method to stabilize nZVI, but also reveals that using FeNi@GR is a promising approach for the remediation of water pollution.