تحضير وتوصيف CoFe¬2¬O¬4 / active carbon/ / polyaniline كمتراكب ثلاثي وتطبيقاته في معالجة الماء

Preparation and Characterization of CoFe¬2¬O¬4/ Activated carbon/ Polyaniline as a Ternary Composited their application in water treatment

Abstract
This work involves three parts, the first of which utilizes a new deposition process to synthesize cobalt ferrites (CoFe2O4) nanoparticles using cetramide (CT) as a positive surfactant. The CoFe2O4 nanoparticles were synthesized as an inverse spinel. The PANI/CoFe2O4/Ac nanocomposite was created by a chemical oxidation polymerization process with hydrochloric acid and Ammonium Persulfate (APS) as activators and oxidants.
Through the second part, spinel CoFe2O4 nanoparticles and their composites were identified by several techniques. Infrared spectroscopy showed characteristic peaks between 400 and 600cm-1, indicating the locations of tetrahedral Fe-O and octahedral Co-O isoforms in the CoFe2O4 nanoparticles. X-ray diffraction showed that the prepared samples of CoFe2O4 and its ternary composite have nanoscale size ranged from 31.83 nm for CoFe2O4 to 36 nm for the ternary composite. The SEM image showed an idea of the surface morphology of the prepared compounds, the shape of the CoFe2O4 spinel was found to be texture-like, but for composite was found to be layered, the particle sizes measured of the spinel were found to be between 33.03 to 41.35 nm, and for the composite equal to 29.34 to 49.90 nm, thus, all samples studied are considered to be nanocrystals. The EDX spectra showed that the Co, Fe, O, and C elements of the catalyst were present and pure with no impurities. The BET surface areas and pore size distribution were measured for both synthesis samples and demonstrated the hysteresis loops correspond to the adsorption isotherms of type IV, and the hysteresis loop in the relative pressure range (P/P0) of 0.3~1.0, which belongs to type H3 with nanopores. The specific surface area of ternary composite is of more value for cobalt ferrite and equal to 54.118 m2 g-1 and 8.9064 m2 g-1, respectively.
In the third part, CoFe2O4 /AC/ PANI were used as adsorbent for the removal of direct orange dye from aqueous solutions. Initially, the adsorption experiment was carried out for all the prepared surfaces towards the dye and the highest percentage of dye removal was found on the superimposed surface where the removal rate reached 95%.
The removal efficiency of direct orange dye was found at 45 minutes as optimum equilibrium time, surface mass at 0.3 g, and pH 6, temperature 25 c and 5 mg\L concentration After that, the factors affecting the adsorption process (time, concentration, weight, pH, temperature) were studied for the surface of cobalt ferrite and ternary composite, and the ternary composite gave a higher removal efficiency compared to cobalt ferrite. In reusability, it was found that after four cycles, the dye removal efficiency of the composite decreases from 95.24% to 70.11%, while the dye removal efficiency of cobalt ferrite decreases from 82.34% to 28.35%. These results indicate that the composite shows higher reusability compared to cobalt ferrite.
On the other hand, the thermodynamics functions were detected and was found that removal reaction of dye by CoFe2O4 is exothermic with physical adsorption (less than 40 kJ/mol). this result is in agreement with the result via applied Freundlich equation, while the same reaction using composite was demonstrated a chemical adsorption (greater than 80 kJ/mol) with endothermic reaction. The PFO model is obeyed the adsorption of direct orange 39 dye onto the CoFe2O4 /AC/ PANI and CoFe2O4 nanocomposite adsorbent, because correlation coefficient R² for PFO > correlation coefficient