Chemical Insight into the Adsorption of Chromium(III)
on Iron Oxide/Mesoporous Silica Nanocomposites
- Publication date
- Publisher
Abstract
Magnetic
iron oxide/mesoporous silica nanocomposites consisting
of iron oxide nanoparticles embedded within mesoporous silica (MCM-41)
and modified with aminopropyl functional groups were prepared for
application to Cr(III) adsorption followed by magnetic recovery of
the nanocomposite materials from aqueous solution. The composite materials
were extensively characterized using physicochemical techniques, such
as powder X-ray diffraction, thermogravimetric and elemental analysis,
nitrogen adsorption, and zeta potential measurements. For aqueous
Cr(III) at pH 5.4, the iron oxide/mesoporous silica nanocomposite
exhibited a superior equilibrium adsorption capacity of 0.71 mmol/g,
relative to 0.17 mmol/g for unmodified mesoporous silica. The aminopropyl-functionalized
iron oxide/mesoporous silica nanocomposites displayed an equilibrium
adsorption capacity of 2.08 mmol/g, the highest adsorption capacity
for Cr(III) of all the materials evaluated in this study. Energy-dispersive
spectroscopy (EDS) with transmission electron microscopy (TEM) and
X-ray photoelectron spectroscopy (XPS) experiments provided insight
into the chemical nature of the adsorbed chromium species