Mesoporous Materials Supported Vernonia Oil Esters and Their Immobilization With Silver Nanoparticles for Catalytic Applications
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Date
2018-10-04
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Addis Ababa University
Abstract
In our world of rapidly increasing population and fast industrialization, design of value
added and ecofriendly high performance organic–inorganic nanocomposites with higher
stability for environmental remediation is becoming an active area of research in the field
of inorganic material chemistry. The major objectives of this study are to design some
typical surface hydrophobic ordered mesoporous nanocomposites by surface modification
of their hydrophilic surfaces by supporting with native vernonia oil derivatives and
immobilization by silver nanoparticles as potential heterogeneous catalyst for degradation
of model organic dyes.
In the first part of this work, vernonia oil with unique natural epoxy moiety was
extracted from vernonia galamensis seed, which was purified and then derivatized to
more active forms such as vernolic acid and vernolic acid mono alkyl esters like methyl,
ethyl and propyl esters as well as their mercapto imidazole functionalized derivatives, i.e.
methyl ester-IFVAME, ethyl ester-IFVAEE and propyl ester-IFVAPE. The presences of
the functional groups were confirmed by FT-IR, 1H and 13C NMR spectroscopy and
CHNS elemental analysis. In the second part of this work, vernolic acid methyl ester-
VAME, and its mercapto imidazole functionalized (IFVAME) derivatives were
supported on three types of ordered mesoporous nanomaterials with different surface
properties and pore sizes: OMMs: Al-MCM-41 (Si/Al=3 & 15), SBA-15 & periodic
mesoporous organo silica-PMO. The supported materials were studied by powder X ray
diffraction, thermogravimetric analysis, FT-IR spectroscopy and nitrogen sorption
isotherms. In the third part of this work, silver nanoparticles were synthesized on VAME
and IFVAME supported Al-MCM-41, SBA-15, and PMO. The formations of the silver
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nanoparticles were confirmed from wide angle powder XRD and the final distribution of
the metal nanoparticles were studied using Transmission Electron Microscopy. Finally,
the potential catalytic applications of Ag-impregnated mOMMs were tested for
degradation of model organic dyes (methyl orange and methylene blue) which was found
to be promising.
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Keywords
Mesoporous, Materials, Supported Vernonia, Oil Esters, Immobilization, Nanoparticles