Optical study of the reduction of hexavalent chromium by iron-based nanoparticles

In this paper, a simple method was presented to measure the concentration change in the Cr(VI)-contained waste water during treatment by nanoparticles, based on its optical absorption spectral evolution which exhibits a good linear relationship between the absorbance of the peak at 348 nm and Cr6+ ion concentration. The iron and Fe/Pd bimetal nanoparticles were prepared and used for removal of Cr6+ in waste water. It has been found that presented method for concentration determination based on optical spectral evolution is effective and flexible. The nanoparticles have higher efficiency than normal iron powders and Fe/Pd bimetallic nanoparticles show faster removal of the Cr6+ than iron nanoparticles. The study is of importance in environmental remediation or pollution treatment of heavy metal ions in water and even soil.