The removal of Cr(VI) from aqueous and saturated porous media by nanoscale zero-valent iron stabilized with flaxseed gum extract: Synthesis by continuous flow injection method

다국어 초록 (Multilingual Abstract)

Recently, the in-situ removal of contaminants by iron nanoparticles has been considered due to their nontoxicity,abundance, ease of production, and cost-effectiveness, which can be accomplished by injecting them underground.
In this study, nZVI was synthesized using a novel continuous synthesis method using flaxseed glaze as a green,non-toxic, and low-priced coating. The produced nanoparticles were characterized by dynamic diffraction analysis(DLS), field electron microscopy (FE-SEM), X-ray spectroscopy (EDX), and infrared spectroscopy (FTIR) spectroscopy.
Batch experiments were conducted to evaluate the effect of Cr(VI) concentration, FG-nZVI dosage, pH, and coexistingcomponents (Total dissolved solids, Humic acid, and NO3) on Cr(VI) removal. Results of the characterization andidentification, and stability tests indicated that nanoparticles synthesized by using this continuous synthesis system weresmaller and more regular shaped than those prepared by conventional synthesis. According to the results, the Cr(VI)residual level increased by increasing the initial Cr(VI) concentration and decreased by increasing the nZVI coatedwith flaxseed glaze (FG-nZVI) dosage. At the Cr(VI) initial concentration of 4mg L1, the Cr(VI) was removed entirelyat almost all dosages of FG-nZVI. Optimal amount of FG-nZVI was 62.73mg L1 when applied at 4mg L1 of Cr(VI)at optimum pH 6.64, resulting in the Cr(VI) residual concentration of 0.05mg L1. The results of saturated porousmedia showed that injection background solutions enhanced the transfer of nanoparticles in the porous medium, resultingin the adequate removal along the desired radius. The results illustrated that using FG-nZVI can be effective forpractical groundwater remediation.