الفهرس 
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Abstract
Advanced nanocomposite from silica-fume based MCM-41 and cobalt oxide (Co3O4/SF-MCM-
41) which precipitated by green techniques in the presences of Pomegranate leaves extract as
reducing reagent. The formation of the Co3O4/SF-MCM-41composite was confirmed by
different studied analytic techniques including XRD, SEM, HRTEM, FT-IR, and UV-Vis. The
characterization results confirmed the formation of a well-ordered mesoporous structure
decorated by nano Co3O4 particles with an average pore diameter of 3.56 nm, the stunning
surface area of 742 m2/g, and low bandgap energy of 1.53 eV which gives it promising
photocatalytic performances. The composite was applied as an advanced photocatalyst in the
oxidation of hazardous Omethoate pesticides under visible light sources. The obtained oxidation
results demonstrated promising catalytic properties of the composite that resulted in a complete
degradation for 50 mg/L, 100 mg/L, 150 mg/L, 200 mg/L and 250 mg/L of Omethoate after 30
min, 50 min, 80 min, 100 min, and 120 min, respectively using 0.25 g of Co3O4/SF-MCM-41.
This followed by investigation for the residual TOC content in the samples as well as the
liberated inorganic anions (SO4
-2, NO3
-, NO2
-, and PO4
-3). The detection of the inorganic anions
in considerable concentrations and the complete removal of the TOC content after 50 min using
0.25 g of the catalyst confirmed the complete oxidation of the pesticide structure into its
essential components and the predicted formation of intermediate compounds at the initial
stages of the reaction. The detected intermediate organic materials of (CH3O)3P(O),
(CH3O)2P(O)SCH3, CH3NHC(O)CH2SH, CH3NHC(O)CH2SCH3, and NH2C(O)CH2SCH3 were
identified as oxidizing products during the degradation steps and all of them were converted into
NO3
-, SO4
2-, PO4
3-, and CO2 as final products and the degradation pathway was described
considering the transformation of the detected intermediate compounds from form to another
form. The composite is of reusability value and applied effectively in the oxidation of the
pesticide for ten runs. Following the effective radicals by the trapping tests and the PL spectrum the hydroxyl radicals were identified as the controlling oxidizing radicals during the oxidation
process of Omethoate pesticide over Co3O4/SF-MCM-41 in the presence of a visible light
source.
Keywords: Silica fume, MCM-41, Pomegranate leaves, Co3O4, photocatalyst, Omethoate
pesticide.