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A kinetic approach on hexavalent chromium removal with metallic iron
- Gheju, M., Balcu, I., Enache, A., Flueras, A.
- Journal of environmental management 2017 v.203 pp. 937-941
- adsorption, anions, chemical reduction, chlorides, chromium, iron, kinetics, models, reducing agents, sulfates, temperature
- This paper examines the mechanism of Cr(VI) removal with Fe(0), and the possible effect of various experimental parameters, from a kinetic perspective. The experimental data was analyzed using five different kinetic models: three for chemical reactions and two for adsorption processes. It was found that the process fitted well to the zero-order kinetic model for all investigated systems, excepting experiments conducted at 6 °C and those with nano-Fe(0), when the process followed the Ho's pseudo second-order model. Therefore, even though, under acidic conditions, chemical reduction can be generally considered as the main mechanism of Cr(VI) removal with Fe(0), under some experimental conditions (e.g. when working with nano-Fe(0) or at low temperatures), adsorption seems to be the dominant removal path. The enhanced Cr(VI) removal noticed in co-presence of SO4²⁻ and Cl⁻ anions reiterates the significance of the secondary reductant Fe(II) within the process of Cr(VI) removal with Fe(0).