Facile encapsulation of nano zero-valent iron with calcium carbonate: synthesis, characterization and application for iron remediation

In this study, CaCO3 was used as a modifier for nano zero-valent iron (nZVI) surface to prevent rapid aggregation and effectively utilized for iron remediation from aqueous solution. Surface chemistry and morphology of CaCO3 encapsulated nZVI (CaCO3–nZVI) before and after treatment of contaminant iron solution were characterized by scanning electron microscopy–energy dispersive X-ray (SEM–EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectros copy (XPS). The mechanisms of surface modification as well as iron remediation were well depicted with the help of these characterisation tools. Iron removal efficacy of 96.4% was achieved with 0.25 g/L adsorbent dose for an influent iron of 0.5 mg/L at pH 10 after a 3 h treatment process. When t he influent concentration was increased to 10 mg/L, the removal capacity decreased to 92.1%. The study demonstrates that CaCO3 and nZVI in the encapsulated nanoparticle have a significant synergistic effect. The pseudo-second- order reaction kinetics and Freundlich isotherm model correctly portrayed the experimental data for iron removal by CaCO3–nZVI. The CaCO3–nZVI is a viable option for iron removal from various aqueous media due to its facile preparation, high iron removal capability, and reusability.
Source: Journal of Environmental Health Science and Engineering - Category: Environmental Health Source Type: research