Synthesis, characterization and application of zero valent iron nanoparticle for Cr(VI) removal

Abstract

Hexavalent chromium is a heavy metal used in a variety of industrial applications which is highly toxic to humans, animals, plants and microorganisms. Moreover, it is a well-established human Carcinogen by the inhalation route of exposure and by the oral route of exposure. Therefore, it should be removed from contaminated waters. Its reduction to trivalent chromium can be beneficial because a more mobile and more toxic chromium species is converted to a less mobile and less toxic form. The reduction of hexavalent chromium [Cr(VI)] by nanoscale zerovalent iron (nZVI) has received considerable attention in recent years because of large surface to volume ratio. A considerable volume of research has been carried out in order to investigate the mechanism and kinetics of Cr (VI) reduction with nZVI, as well as the influence of various parameters controlling the reduction efficiency. This paper aims at synthesising zero valent iron nano particles by chemical reduction method using FeCl .6H O with sodium borohydride (NaBH ) as a reducer. 3 2 4 The crystalline size of the nZVI particles was determined through XRD. Morphology of the particles was observed using SEM. The chromium stock solution was treated with nZVI by varying time and amount of nanoparticles in batch studies. And in the column studies, the chromium stock solution was treated with the scrap iron. The solution was then tested using UV-Vis spectrophotometer and the percentage removal of chromium was studied. The present experimental results revealed that Cr (VI) is considerably adsorbed on nZVI nanoparticles and it could be a cost effective method for the in situ remediation of Cr(VI).