title: Chemical Insight into the Adsorption of Chromium(III) on Iron Oxide/Mesoporous Silica Nanocomposites.
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.
authors.affiliation: Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States.
authors.forename: Shani
authors.initials: S
authors.lastname: Egodawatte
authors.affiliation: Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States.
authors.forename: Ashish
authors.initials: A
authors.lastname: Datt
authors.affiliation: Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Burns
authors.affiliation: Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States.
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Larsen
mesh_terms: D000327:Adsorption; D002857:Chromium / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D010316:Particle Size; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D005290:Ferric Compounds; D002857:Chromium; C000499:ferric oxide; D012822:Silicon Dioxide