الفهرس 
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Abstract
Summary
Magnetite nanoparticles (Fe3O4) have been widely studied because it has good characteristic for instance biocompatibility, super paramagnetic properties, non-toxicity, high chemical stability and easy synthesis process.
In this work magnetite (Fe3O4) was prepared by co-precipitation method using ferrous and ferric ions and loaded on different supports such as silica (SiO2), with different ratios: 7.5% ,15% , 30% Fe3O4/ SiO2 , active carbon AC, 7.5%, 15%, 30% Fe3O4/AC, oxidized active carbon OAC with ratio: 15% Fe3O4/OAC and magnesium oxide with ratios: 2.5%, 5%, 7.5%, 15% , 30% Fe3O4/MgO.
The prepared adsorbents were characterized by X-ray diffraction (XRD) analysis, infrared spectroscopy (IR), transmission electron microscopy (TEM), scanning electron microscope (SEM), surface area measurements (BET), and vibrating sample magnetometer (VSM) techniques.
XRD patterns of Fe3O4/SiO2 showed that the broad background peak around 220 is due to poorly crystalline SiO2 and the diffraction peaks (220), (311), (400), (511), and (440) planes occur at 2θ = 30.1°, 36.3°, 43.4°, 57.2°, and 62.3° are corresponding to Fe3O4 , and are quite identical to the phase nanoparticles of Fe3O4 with a face centered cubic structure.
It was found that from FT-IR spectra of pure Fe3O4, Fe3O4/SiO2 and SiO2 support, the vibrational bands around 520 cm-1 and 450 cm-1 for the sample of pure Fe3O4 and Fe3O4/ SiO2 are characteristic of the (Fe–O) lattice vibrations, and the broad band around 3400 cm-1 can be assigned to O-H stretching. The SiO2 and Fe3O4/ SiO2 sample shows a band at 1055 cm-1 and weak bands at 789 and 943 cm-1 corresponding to the stretching vibrations of (SiO–Si), (Si–OH) and (Si–O–Fe), respectively.
Transmission electron microscope (TEM) showed that the Fe3O4 nano particles loaded on silica were agglomerated in the form of spots increased by increasing the percentage of magnetite loaded.
from scanning electron micrographs (SEM) of Fe3O4 / SiO2, it was found that the dispersion of Fe3O4 on the surface of SiO2 support , the surface texture , porosity of the sample , the availability of pores and internal surface are requisite for an effective adsorbent.
The results of for removal of Pb(II) and Cu(II) ions from aqueous solutions showed that 15%Fe3O4/SiO2 is more active than that 7.5% and 30% Fe3O4/SiO2
The removal percentage of lead was 99.84% at 30 min., when the pH value was 4.8, the weight of adsorbent was 5.0 g/l and the initial lead concentration was 50 mg/l.
The removal percentage of copper was 97.72% at 30min. When the pH value was 5.2, the weight of adsorbent was 10.0 g/l and the initial copper concentration was 25 mg/l.
The adsorption process for removal of Pb(II) and Cu(II) ions from aqueous solutions by 15%Fe3O4/SiO2 was fitted very well the pseudo-second-order model and the adsorption equilibrium data was well described by the Langmuir isotherm.
XRD patterns of AC and OAC support, Fe3O4/AC, Fe3O4/OAC showed broad diffraction peaks with 2Ө in the range about 20◦-30◦ and 41◦-46◦, attributed to the (002), (100) and (101) crystallographic planes of porous carbon, respectively and the diffraction peaks of Fe3O4 corresponding to (220), (311), (400), (511), and (440) planes occur at 2θ = 30.1°, 36.3°, 43.4°, 57.2°, and 62.3°, respectively, are quite identical to the cubic phase nanoparticles of Fe3O4 with a face centered cubic structure.
It was found that from FT-IR spectra of AC and OAC support, Fe3O4/AC, Fe3O4/OAC, the vibrational bands at around 520 cm-1 and 450 cm-1 for pure Fe3O4 , Fe3O4/ OAC and Fe3O4/AC samples as characteristic of the (Fe–O) lattice vibrations, and the broad band around 3200-3600 cm-1 corresponding to the stretching vibration of O-H group. There are also bands between 1060-1059 cm-1 corresponding to C-O-H group stretching beside the bands between 1100-1300 cm-1 belongs to C-O bond and bands around 1600-1780 cm-1 corresponding to the stretching vibrations of C=O function group.
from the scanning electron micrographs (SEM) of Fe3O4 /AC and Fe3O4 /OAC, it was found that the surface texture and porosity of the sample were more developed in the oxidized active carbon than in the active carbon. The availability of pores and internal surface is requisite for an effective adsorbent.
The results showed that 15%Fe3O4/AC nanoparticles is more active than that 7.5% and 30% Fe3O4/AC for removal of Pb(II) and Cu(II) ions from aqueous solutions and it was selected to compared with the same ratio of Fe3O4/OAC.
The results showed that 15%Fe3O4/OAC is more active than 15%Fe3O4/AC for removal of Pb(II) and Cu(II) ions from aqueous solutions.
The removal percentage of lead was 98.8% at 30 min., when the pH value was 4.8, the weight of adsorbent was 10.0 g/l and the initial lead concentration was 50 mg/l.
The removal percentage of copper was 95.68% at 30min., when the pH value was 4.8, the weight of adsorbent was 10.0 g/l and the initial copper concentration was 25 mg/l.
The adsorption process for removal of Pb(II) and Cu(II) ions from aqueous solutions by 15% Fe3O4/OAC was fitted very well the pseudo-second-order model and the adsorption equilibrium data was well described by the Langmuir isotherm.
XRD patterns of Fe3O4/MgO showed that the main diffraction peaks of magnesium oxide (MgO) were observed at 2Ө values of 36.94, 43.01, 62.217, 74.62, 78.63 attributed to (111), (200), (220), (311), (222), respectively. and the diffraction peaks of Fe3O4 corresponding to (220), (311), (400), (511), and (440) planes occur at 2θ = 30.1°, 36.3°, 43.4°, 57.2°, and 62.3°, respectively, are quite identical to the cubic phase nanoparticles of Fe3O4 with a face centered cubic structure.
It was found that the XRD patterns of Fe3O4 supported by MgO with different ratios belong to Mg(OH)2 with (100), (101), (102), (110) planes revealing the full hydration of MgO nanoparticles during the process of preparation.
It was found that from FT-IR spectra of pure Fe3O4, Fe3O4/ MgO and MgO support, the vibrational bands around 520 cm-1 was characteristic of the (Fe–O) lattice vibrations and absorption bands between 900-400 cm-1 are due to (Mg-O) vibrations mode. The broad band around 3400 can be assigned to O-H stretching vibrating. The absorption band at 1648 cm−1 is due to bending vibration mode of water.
The results showed that 7.5% Fe3O4/MgO is more active than that 2.5%, 5%, 15% and 30% Fe3O4/MgO for removal of Pb(II) from aqueous solutions.
The removal percentage of lead was 99.5% at 60 min., when the pH value was 4.8, the weight of adsorbent was 0.4 g/l and the initial lead concentration was 50 mg/l.
The results showed that 5% Fe3O4/MgO is more active than that 2.5%, 7.5%, 15% and 30% Fe3O4/MgO for removal of Cu(II) from aqueous solutions.
The removal percentage of copper was 99.7 % at 60 min., when the pH value was 4.8, the weight of adsorbent was 3.0 g/l and the initial copper concentration was 100 mg/l.
The adsorption process for removal of Pb(II) or Cu(II) ions from aqueous solutions by 15%Fe3O4/MgO was fitted very well the pseudo-second-order model and the adsorption equilibrium data was well described by the Langmuir isotherm.