Synthesis of Magnetic Nanoparticles for Water Treatment Applications

Abstract

III Abstract In this study magnetic nanoparticles were prepared in two forms, the first is Ni1-xCoxFe2O4 and the second is Ni1-xMgxFe2O4 for the x values, (x= 0.0,0.1,0.3,0.5,0.7 ) respectively by chemical co-precipitation thermal method and annealed at temperature of (700 oC ) and pH=11. The structural properties of the prepared samples were studied by using the energy-dispersive X-ray spectroscopy EDX, the scanning electron microscope, the XRD spectroscopy, and the Fourier transforms Infra-red of the FT-IR infrared spectrometer. The synthetic results showed that the prepared particles possess practical proportions that correspond largely to the theoretical proportions, which means the validity of the proposed structures and all the samples show nearly perfect stoichiometry and high purity. This is what is observed from the EDX measurements. The SEM analysis reveals the increasing proportion of cobalt and magnesium for both compounds, and that the particles had spherical and irregular geometric structures within sizes that were often greater than 100 nm. The powder XRD pattern confirms a singlephase cubic spinel structure and the average particle size calculated via the Scherrer equation ranged between (16.31-29.53) nm. Based on X-ray diffraction, information were very close to those recorded using microscopy SEM, and the FTIR spectra confirmed two peaks (ν1 and ν2) around 400 and 600 cm-1, respectively. These bands are attributed to the stretching vibration of interactions between the oxygen atom and the cations in tetrahedral and octahedral sites. Therefore, bands indicate that the spectral composition of all samples is ferrite. IV The magnetic properties of the particles through the VSM test showed that the addition of cobalt and magnesium to the NiFe2O4 was improved the magnetic properties of the main ferrite with a good to high ratio from the narrowness of the hysteria loop give the characteristics of a soft ferrite. The work presented in this thesis focused on the efficient use of magnetic nanoparticles in water treatment processes. It involves choosing the best two samples of prepared magnetic nanoparticles from each mixture based on their structural and magnetic properties for use in the removal of lead and cadmium ions from aqueous solution under laboratory conditions. The Go- 2(Nmorpholino ethanesulfonic acid) was used to prepare novel magnetic adsorbents by mixing with the best four ferrites. Among these four nanoparticles are com.1 (GO- 2(N-morpholinoethansulfonic acid)- Ni0.9Co0.1Fe2O4), com.2 (GO- 2(N-morpholinoethansulfonic acid)- Ni0.5Co0.5Fe2O4), com.3 (GO-2(N-morpholinoethansulfonic acid)- Ni0.7Mg0.3Fe2O4), and Com.4 ( GO-2(N-morpholinoethansulfonic acid)- Ni0.5Mg0.5Fe2O4 ). After determining the optimal concentration of lead and cadmium, The following optimal conditions were studied: contact time, adsorbent quantity, acidity, and temperature. The optimal concentration was (100 ppm) for all conditions except composite 4, where the removal of lead ions was (250 ppm). Through the experiments, it was observed that with an increase in the contact time, pH, the dosage, and temperature, the percentage of removal of lead and cadmium ions increased from the aqueous solution. Among the four magnetic nanoparticles, results showed that the (com2) and (com4). gave the best percentage of removal of lead and cadmium ions from the aqueous V solution. The kinetic results of adsorption showed that the adsorption of lead and cadmium ions by the magnetic nanoparticles surfaces followed a pseudosecond order equation based on the values of (R2) and from studying the isotherms of Freundlich, Langmuir, and Temkin models of the four compounds. The results show the Freundlich isotherm is the ruling isotherm in these materials, as it was perfectly suitable for all adsorption cases despite the relatively few differences with the (R2 ) values for the rest of the isotherms. This confirms that the adsorption was of a heterogeneous type. The approaches and treatment methods described in this thesis are simple to use, robust and environmental friendly.