تحضير وتشخيص خصائص الجسيمات النانوية للمتراكب الشوكي كوبلت كرومايت \ اوكسيد الزركونيوم وتطبيقة على محلول ملون

Preparation, Characterization of Spinel Cobalt Chromite/Zirconium Oxide Nanocomposite and Application on the Colored Solution

Abstract

This practical work involves three main parts. The first part illustrates the Luminol reagent, Luminol- tyrosine as ligand, and Fe(II)-(Luminol-Tyrosine) complex were prepared. Uv-Visible spectra, Fourier-Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance Spectroscopy (1HNMR), Elemental Micro Analysis (C.H.N), and melting point (m.p) were confirmed prepared the top mention compounds. The hybridization of FeL2Cl2 complex is octahedral, which was investigated by using magnetic sensitivity and mole ratio method and obtained the ratio between Fe(II) and L is equal to 1:2.
The second part focused on the preparation of spinel CoCr2O4 using the co-precipitation method. The surface of spinel COCr2O4 was modified by chosen the ZrO2 to improve its properties. The synthesis composites from incorporated spinel CoCr2O4 with ZrO2 in different ratios (1:2 and 1:3) were performed using the ultrasonic technique as a simple and friendly-environment method. Based on X-ray diffraction (XRD), the spinel CoCr2O4, commercial ZrO2, and spinel CoCr2O4 /ZrO2 composites in different ratios (1:2 and 1:3) are nano-sizes with ranged 8.1785 nm to 15.5823 nm. The sequence of mean crystal sizes values is
ZrO2 < composite 1:3 < composite 1:2 < spinel CoCr2O4.
The scan electron microscopy (SEM ) given an idea of the morphology of the surface of the studied photocatalyst. The spinel CoCr2O4 shape and the rest photocatalysts are found to be quasi-spherical, except ZrO2 has a spherical shape. Based on the SEM analysis, the range of the particle sizes for all studied photocatalysts is found to be from 17.89 nm to 52.62 nm, which conformed to all the studied samples regard as nano-crystals. Through the energy dispersive X-rays (EDX) spectra, that demonstrated the photocatalysts are prepared without any impurity. spectra detect the presence of Co, Cr,Zr and O in the synthesized cobalte cromite and its nanocomposite materials. Tauc equation was used to found the band gaps for studied photocatalysts and found the bandgaps are indirect for all samples. The value of the bandgap for spinel CoCr2O4 increases with increasing the ratio of ZrO2 via the preparation of its composites. The sequence of band gaps values is
Bg spinel CoCr2O4 < Bg Comp.1:2 < Bg Comp.1:3 < Bg ZrO2,
and equal to 3.18 eV < 4.7 eV < 4.8eV< 5 eV, respectively.
In the third part, the application of studied photocatalysts was performed. The photo-decolorization of FeL2Cl2 complex at pH 7.3 was estimated using spinel CoCr2O4, commercial ZrO2, and composites 1:2 and 1:3. The composite 1:3 is the best composite compared with composite 1:2. The optimum doses which used in photo-decolorization of FeL2Cl2 complex are 0.1g/ 100 mL, 0.2 g/100 mL and 0.3g/ 100 mL for using spinel CoCr2O4, ZrO2, composite 1:2 and composite1:3 respectively. The decreased temperature enhanced the decolorization of the complex using spinel CoCr2O4 and composite 1:3 but inhibited the use of ZrO2. The activation energy for using composite 1:3 is less than that using spinel CoCr2O4 , and equal to -93.1084 kJ/mol and -46.2499 kJ /mol, respectively.This behaver depends on structure of spinel that involving from two metals in different oxidation state and hydridization (i.e Co (II) as tetrahaydral and Cr(III) as octahydral).