Carbon disulfide removal by zero valent iron

The use of zero valent iron (Fe-0) for the remediation of water contaminated with carbon disulfide (CS2), a common groundwater contaminant, has been evaluated in this study. Mineralogical analysis of Fe-0 filings and polished Fe-0 cross-sections indicates that iron sulfide is formed due to the removal of carbon disulfide from solution by Fe-0. The kinetics of CS2 removal by Fe-0 was examined through both batch and column testing, and it is demonstrated that CS2 is removed rapidly from solution. A linear relationship was observed, through batch testing, between the pseudofirst-order rate constant (k(obs)) and the surface area concentration of Fe-0 (rho a). Data obtained from kinetic batch tests performed at four temperature levels conformed to the Arrhenius equation, anc the calculated apparent activation energy (E-a) was 37 +/- 2.3 kJ mol(-1), indicating that the kinetics of CS2 removal by Fe-0 is controlled by a chemical surface reaction. The temperature correction factors for CS2 from a reference of 25 degrees C were x 1.4 for 18 degrees C, x 1.7 for 15 degrees C, x 2.0 for 12 degrees C, and x 2.3 for 9 degrees C. Surface area normalization of kob, obtained through batch and column testing gives specific reaction rate constants (k(SA)) within 1 order of magnitude, indicating that kSA values are useful as a general descriptor of CS2-Fe-0 reaction kinetics and that these values provide a clear starting point for design calculations prior to commencing site-specific treatability studies for permeable reactive barrier design.