The functional kaolin-supported bimetallic Fe/Ni nanoparticles (K-Fe/Ni) were synthesized and applied in remediation of Direct Black G (DBG), where batch study showed that 99.97% of DBG was removed from aqueous solution using K-Fe/Ni, whereas only 95.89% and 13.34% were removed using Fe/Ni and kaolin, respectively. Kaolin-supported Fe/Ni led to decrease in aggregation of Fe/Ni nanoparticles, increase in adsorption of DBG onto the kaolin and enhanced reduction of DBG by Fe/Ni on K-Fe/Ni to form iron oxide, the functional K-Fe/Ni nanoparticles based on adsorption and reduction was confirmed by characterization using scanning electron microscopy (SEM) and X-ray diffraction (XRD). UV-Vis spectra showed that the DBG was degraded by the break in azo linkages, and Fourier infrared spectra (FTIR) shows that new bands appeared which corresponded to -N=N- after K-Fe/Ni reacted with DBG. Furthermore, kinetics studies showed that the degradation of DBG fitted well with the pseudo first-order model and the degradation pathways of DBG using K-Fe/Ni was proposed. Finally, K-Fe/Ni used for the degradation of DBG in wastewater was demonstrated as a potential technique for the remediation. (C) 2013 Elsevier B.V. All rights reserved.