Removal of hexavalent chromium from aqueous solution by iron nanoparticles.

Groundwater remediation by nanoparticles has received increasing interest in recent years. This report presents a thorough evaluation of hexavalent chromium removal in aqueous solutions using iron (Fe^o) nanoparticles. Cr(VI) is a major pollutant of groundwater. Zero-valent iron, an important natural reductant of Cr(VI), is an option in the remediation of contaminated sites, transforming Cr(VI) to essentially nontoxic Cr(III). At a dose of 0.4 g/L, 100% off Cr(VI) (20 mg/L) was degraded. The Cr(VI) removal efficiency decreased significantly with increasing initial pH. Different Fe^o type was compared in the same conditions. The reactivity was in the order starch-stabilized Fe^o nanoparticles>Fe^o nanoparticles>Fe^o powder>Fe^o filings. Electrochemical analysis of the reaction process led to the conclusion that Cr(OH)₃ should be the final product of Cr(VI). Iron nanoparticles are good choice for the remediation of heavy metals in groundwater. [ABSTRACT FROM AUTHOR]