An Experimental Investigation of In-situ Chromate Remediation by Bimetallic Iron/Nickel Nano Particles

In this study, application of nano zero valent iron/nickel particles for Cr (VI) removal in porous media was studied. First, stabilized nano Fe/Ni particles were prepared. Then, experiments were conducted in batch and continuous configurations. The continuous experiments were repeated in real groundwater conditions. Based on the batch experiments, corresponding reaction kinetics were in good agreement with the pseudo-second-order adsorption model and reaction rate ranged from 0.001 to 0.03 g/mg/min depending on solution pH and molar ratio of Fe/Cr. Continuous experiments showed that chromate remediation was mostly influenced by seepage velocity, quantity and freshness of nano particles and grain size of porous media. Higher Cr (IV) removal rate in sand rather than glass beads was the result of further surface absorption of nano Fe/Ni particles in sand grain. The maximum Cr (VI) removal rate in batch, lab and bench-scale model were 99%, 70% and 85%, respectively. Finally, in bench-scale model under 15g S-nZVI loading, 118 Lit. treated water with 80% removal efficiency was obtained.