Abstract
In the present study, simulation of hexavalent chromium (Cr(VI)) removal from saturated porous media using stabilized zero-valent iron nanoparticles (ZVIN) was carried out under different experimental conditions such as ZVIN concentration, initial Cr(VI) concentration, geochemistry of groundwater, and pore water velocity. In this regards, stabilized ZVIN was synthesized with two different stabilizers namely sepiolite and polyacrylic acid (PAA). The aims of this study were twofold: (1) a comparison between the efficiency of mineral-stabilized and polymer-stabilized ZVINs in Cr(VI) removal and (2) the simulation of the experimental data of Cr(VI) removal in a simulated groundwater system. The experimental data were interpreted using the convection–dispersion equation via the CXTFIT software. The colloidal stability of sepiolite-stabilized zero-valent iron nanoparticles (S-ZVIN) compared to PAA-stabilized zero-valent iron nanoparticles (PAA-ZVIN) was apparently high. Additionally, the results of reductive transport experiments showed that Cr(VI) removal had a direct relationship with ZVIN and chloride ion (Cl−) concentrations, while an indirect relationship was observed with removal efficiency of Cr(VI) by initial Cr(VI) concentration and pore water velocity. Obtained simulated parameters (i.e. mass destruction term (μ) and retardation factor (R)) also confirmed the experimental results. Findings of both experimental and simulation studies indicated that clay mineral was absolutely more suitable than polymers as a stabilizer of ZVIN for reactive site treatment.
Published Version
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