Efficient Removal of Cr(VI) from Aqueous Solution with Fe@Fe₂O₃ Core−Shell Nanowires

Abstract

The batch removal of Cr(VI) from simulated wastewater with Fe@Fe2O3 core-shell nanowires (FCSNs) was investigated in this study. Itwas found that each gram of the FCSNs could remove 7.78 mg of Cr(VI) from simulated wastewater containing 8.0 mg L(-1) of Cr(VI) with an initial pH of 6.5 at room temperature. The Freundlich adsorption isotherm was applicable to describe the removal processes. Kinetics of the Cr(VI) removal was found to follow pseudo-second-order rate equation. Furthermore, the as-prepared and Cr(VI)-adsorbed FCSNs were carefully examined by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopic analysis (XPS). The characterization results suggested that the adsorbed Cr(VI) was partially reduced to Cr(lll) in Cr2O3/Cr(OH)3 on the FCSNs. The possible mechanism of removal of Cr(VI) on FCSNs was proposed, which involved the dominant Cr(VI) adsorption, followed by the partial reduction of Cr(VI) to Cr(III) (chromium(III) oxyhydroides) on the surface of FCSNs. These Fe@Fe2O3 core-shell nanowires with high specific surface area and strong magnetic property are very attractive for the removal of Cr(VI) from wastewater.

Progress in Understanding the Mechanism of CrVI Removal in Fe0-Based Filtration Systems

“…Even though reduction of Cr VI at the surface of secondary mineral layers was initially believed to be slow [88], recent studies revealed that, actually, Cr VI may be rapidly sequestrated at the surface of Fe II -bearing minerals containing structural Fe II and/or Fe II impurities, following an adsorption-reduction mechanism [96,97]. Cr VI adsorption onto positively charged iron and/or chromium oxyhidroxide layers surrounding Fe 0 particles was regarded not only as an intermediate step, but also as an important Cr VI removal mechanism by itself [98][99][100][101]. It has been shown that adsorption processes may contribute not only to the removal of Cr VI , but also to the removal of the resulted Cr III [61,86,92].…”

Chromium(VI) Removal by Fe(III)-loaded Succinylated Mercerized Cellulose from Aqueous Solution

“…However, the use of costly chemicals and poor removal capacity limit the application of these treatments (Park et al 2005;Park et al 2007). Therefore, researchers have investigated a variety of sorbents for the removal of chromium(VI) from water (Bai and Deng 2004;Mohanty et al 2005;Abdel-Halim et al 2006;Park et al 2006a,b;Zubair et al 2008;Zhang et al 2008;Gurgel et al 2009;Lo and Mak 2011).…”

A novel method for synthesis of nano-γ-Al2O3: study of adsorption behavior of chromium, nickel, cadmium and lead ions

“…Most of these methods require either high energy or large quantities of chemicals. Adsorption method is very popular due to its simplicity and low cost (Ahn et al 2009;Gurgel et al 2009), and it is known to be more effective and versatile technique for heavy metal removal from aqueous solutions, especially when combined with an appropriate desorption method (Ai et al 2008). Certain properties, such as high mechanical and thermal stability and high sorption capacity, should be considered for the adsorbent.…”