Removal of arsenic with zerovalent iron nanoparticles in the dark and under UV-vis light

I. K. LEVY; C. RAMOS; G. CUSTO; M. MIZRAHI; F. REQUEJO; M. LITTER

Bs.As.

Congreso; 5th International Congress on Arsenic in the Environment; 2014

ISGDS - CONICET

The zerovalent iron technology (ZVI) has been extensively applied to remediation of contaminants, especially toxic metallic pollutants. The primary advantages of ZVI are low cost, simplicity in handling and scalability. Different ZVI materials such as packing wire, iron powder and zerovalent iron nanoparticles (nZVI) have been tested for arsenic (As) treatment. In particular, As removal with nZVI has been extensively studied in dark conditions showing that nZVI are more efficient than the other ZVI material. As removal couldoccur by direct adsorption of As(III) on iron oxides (FeOx) and oxidation to As(V), which is also adsorbed on FeOx. Fresh oxides provide a high surface area for adsorption of As via surface complexes However, in order to understand the involved processes and to improve the efficiency of nZVI based removal processes, different reaction conditions should be investigated. In this work, removal of As(III) and As(V) from aqueous solutions using nZVI was studied at different As/Fe ratios, in the dark or under UV-vis irradiation, and in the presence of O2 or anoxic conditions. Solid products were analyzed by Mössbauer and XANES spectroscopies correlating As and Fe speciation with removal efficiency.