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Journal of Nanomaterials
Volume 2016, Article ID 2192647, 10 pages
http://dx.doi.org/10.1155/2016/2192647
Research Article

Supercritical CO2 Assisted Synthesis of EDTA-Fe3O4 Nanocomposite with High Adsorption Capacity for Hexavalent Chromium

1Department of Chemical Science and Engineering, Kathmandu University, Dhulikhel, Nepal
2Department of Environmental Science and Engineering, Kathmandu University, Dhulikhel, Nepal
3Department of Natural Science, Kathmandu University, Dhulikhel, Nepal

Received 27 June 2016; Revised 27 October 2016; Accepted 31 October 2016

Academic Editor: Paulo Cesar Morais

Copyright © 2016 Gunjan Bisht et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Efficiency of EDTA functionalized nanoparticles in adsorption of chromium (VI) from water was investigated in this study. Magnetic iron oxide nanoparticles (IONPs) were synthesized by a simple chemical coprecipitation route and EDTA coating onto IONPs was attained via supercritical carbon dioxide (Sc CO2), a technology with green sustainable properties. The obtained nanoparticles were then characterized by UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and vibrating magnetometric analysis (VSM). The synthesized nanoparticle and its modified variant were evaluated as adsorbent for chromium (VI) removal from water through batch adsorption technique and the effect of analytic concentration; contact time and adsorbent concentration were studied at pH 2. The results showed higher removal efficiency for modified magnetic iron oxide nanoparticles (MIONPs) (i.e., 99.9%) than their nonmodified variant IONPs, that is, 34.06% for the same concentration after 18 hours of incubation. Also maximum adsorption capacity ( = 452.26 mg/g) of MIONPs attained can be related to their preparation in Sc CO2 as calculated from IONPs, that is, 170.33 mg/g, is lower than that of MIONPs. The adsorption data fit well with Freundlich isotherm equation while kinetic adsorption studies of chromium (VI) were modeled by pseudo-second-order model.