Issue 27, 2018

Efficient removal of hexavalent chromium from water by an adsorption–reduction mechanism with sandwiched nanocomposites

Abstract

Hexavalent chromium Cr(VI), one of the most toxic contaminants, is released in the environment due to various anthropogenic activities. This study presents a novel sandwiched nanocomposite synthesized using graphene oxide (GO), manganese dioxide (MnO2) nanowires, iron oxide (Fe3O4) nanoparticles and polypyrrole (PPy) to remove hexavalent chromium ion Cr(VI) from water by an adsorption–reduction mechanism. In the sandwiched nanocomposites, GO provided enough surface area, functional groups, and hydrophilic surface for efficient absorption. Fe3O4 nanoparticles with excellent magnetic properties make it easy to separate and recover from water. Under acidic conditions, MnO2 nanowires act as both template and oxidant to initiate the polymerization of pyrrole monomers on its freshly activated surface to obtain GO/MnO2/Fe3O4/PPy (designated as GMFP) nanocomposite. GMFP could effectively adsorb Cr(VI) through electrostatic attraction, and the adsorbed Cr(VI) ions were partly reduced to trivalent chromium Cr(III) (62%), resulting in the efficient adsorption and high removal of Cr(VI) from water. Hexavalent chromium adsorption by GMFP is strongly pH dependent and the adsorption kinetics followed the pseudo-second-order model. The Langmuir isothermal model described the adsorption isotherm data well and the maximum adsorption capacity was up to 374.53 mg g−1 at pH 2.0. These experimental results suggested that GMFP had great potential as an economic and efficient adsorbent of hexavalent chromium from wastewater, which has huge application potential.

Graphical abstract: Efficient removal of hexavalent chromium from water by an adsorption–reduction mechanism with sandwiched nanocomposites

Supplementary files

Article information

Article type
Paper
Submitted
01 mar 2018
Accepted
13 apr 2018
First published
23 apr 2018
This article is Open Access
Creative Commons BY license

RSC Adv., 2018,8, 15087-15093

Efficient removal of hexavalent chromium from water by an adsorption–reduction mechanism with sandwiched nanocomposites

W. Liu, L. Yang, S. Xu, Y. Chen, B. Liu, Z. Li and C. Jiang, RSC Adv., 2018, 8, 15087 DOI: 10.1039/C8RA01805G

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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