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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472 EISSN: 1735-1472
Vol. 12, No. 12, 2015, pp. 4017-4024
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Bioline Code: st15378
Full paper language: English
Document type: Research Article
Document available free of charge
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International Journal of Environment Science and Technology, Vol. 12, No. 12, 2015, pp. 4017-4024
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Adsorption of chromium(VI) onto electrochemically obtained magnetite nanoparticles
Martínez, L. J.; Muñoz-Bonilla, A.; Mazario, E.; Recio, F. J.; Palomares, F. J. & Herrasti, P.
Abstract
Well-dispersed magnetite nanoparticles of different
sizes between 15 and 43 nm were synthesized by an
electrochemical method in a controlled manner by simply
changing the synthesis temperature. These nanoparticles
were used as a reusable adsorbent to remove Cr(VI) from
aqueous solution. The recovery efficiency was found to be
highly dependent on environmental parameters, such as
temperature and pH. In addition, it was demonstrated that
the initial concentrations of both Cr(VI) and magnetite
nanoparticles strongly influence the removal capability of
these nanomaterials. Remarkably, the nanoparticle size has
a key role on the Cr(VI) adsorption efficiency, which
gradually increases as the diameter decreases due to the
augmentation of the surface area. The low aggregation in
the case of small particles that results from the low magnetization
saturation values also contributes to the
enhancement of the surface area available for Cr(VI)
adsorption. In contrast, nanoparticles with larger sizes are
more easily manipulated by a magnet, and the efficiency is
largely maintained after five cycles. The adsorption process
fits the Langmuir isotherm model well, and the reaction
was found to follow a pseudo-second-order rate.
Keywords
Magnetite nanoparticles; Cr(VI) removal; Adsorption; Remediation
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