Montmorillonite-supported Fe/Ni bimetallic nanoparticles for removal of Cr(VI) from wastewater

Abstract

Cr(VI) is one of the most dangerous heavy metal contaminants and its removal is a great challenge throughout the world. With a nanometer length scale (1-100nm) and large specific surface area, higher reducing ability and activity, stronger adsorption property, better mobility than bulk or microscale iron particles, nanoscale zerovalent iron (nZVI) has shown great promise for removal of Cr(VI) from wastewater. Despite its merits, resulting from large specific surface area and intrinsic magnetic interaction, high reduction ability as well as ultrafine size, nZVI is troubled by aggregation and oxidation from the degraded system, reducing its reduction ability and limiting its application. To overcome these drawbacks, Fe/Ni bimetallic nanoparticles were synthesized by classic sodium borohydride solution reduction method to enhance the reactivity of nZVI. Furthermore, montmorillonite (Mt), which is often used as an effective protective reagent and support as well, was used to achieve well disperse of nZVI. The preparation of the composites was achieved by a simple route. This study has shown that for Mt-supported Fe/Ni bimetallic nanoparticles are promising materials for removal of Cr(VI) from wastewater.