الفهرس 
Nanomaterials
Application of nanomaterialsOnly 14 pages are availabe for public view
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Abstract
The present thesis is divided into five chapters.
1- Chapter one: Introduction
This chapter reported the nanomaterials definition and the novelty in the nanomaterials properties. On this chapter different synthetic approaches to synthesize nanomaterials were investigated and implemented. Also this chapter presented the different types of adsorbents materials such as bentonite and its derivatives like activated bentonite, sodium bentonite, and all the organic and inorganic modification on the bentonite surface for the adsorptive removal of the diverse kinds of heavy metals. Nanopolyaniline and its composites were investigated as a good adsorbent for a lot of heavy metals like divalent zinc, lead, and nickel as well as trivalent-hexavalent chrome. Finally this chapter was illustrated the different adsorbents materials to remove the divalent zinc or cobalt in the presence of different controlling parameters with taking in the consideration both of the kinetic and adsorption models.
2- Chapter two: Experimental
In this section all the chemicals, reagents and instruments used to synthesize and characterize the diverse nanosorbents were reported and illustrated. This section included the experimental procedures used for the synthesis and preparation of the different nanosorbents accompanied with schematic diagram for each synthetic approach. This section also reported all the technical procedures for the diverse controlling factors during the adsorptive removal process of the divalent ionic zinc and cobalt by using (the batch technique and the column technique). The controlling factors for the batch technique include the reaction pH, contact time between the nanosorbent and sorbate, the nanosorbent dosage, the metal ion
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concentration, and the effect of interfering ions. In the other hand the controlling factors for the column technique were the flow rate of the effluent, the nanosorbent dosage, and the width-highest of the microcolumn.
3- Chapter three: Results and Discussion
This chapter is divided into two main parts:
The First part; this part established and investigated the nanosorbents characterization by using different instruments like Fourier Transform infrared analysis (FT-IR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscope (TEM), and the surface area determination. The acquired FT-IR spectra of nanosorbents were achieved in the frequency range of 400-4000 cm-1. The FT-IR spectrum was characterized by the presence of the diverse peaks for each nanosorbent due to the different chemical structures and functional groups of each nanosorbent. Thermal gravimetric analysis (TGA) was acquired in the heating temperature range 50-600oC to identify the possible thermal degradation steps for each nanosorbent. In some cases the TGA-thermogram of nanosorbent was identified to refer to undetected mass loss which means highly thermal stability of this nanosorbent.
The XRD diagrams of nanosorbents were identified by a series of peaks within the range 2θ (0-80) according to the different 2θ value for each nanosorbent. A SEM analysis of nanosorbents was also performed by SEM imaging of these nanomaterials, from which the surface morphology and particle size determination may be elucidated. Different particle size and morphology were obtained for each nanosorbent. The obtained particle size for all nanosorbents ranged between (16.3nm for NAg2O, 93.75nm for NPANI- NAg2O, and the very large particle was obtained for A-Bent ~
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150nm but this value was obtained from the aggregation of two particles. The high resolution transmission electron microscopic (HR-TEM) of nanosorbents was acquired using 200 kV. The shape of combined nanosorbent was completely different from the original one to confirm the success of combination of nanomaterials in a new nanosorbent. The particle size of nanosorbents was found in the range corresponding to 11.37nm for A-Bent - 85.71nm for NPANI- NAg2O. The surface area was determined by using different methods.
The second part; this part was reported the adsorptive removal of the divalent Zinc and cobalt using the diverse nanosorbents in the presence of different controlling parameters like;
pH Effect on the adsorption capacity values. The results of this study were expressed in mmol g-1 versus the initial pH value of metal ion solution. It was found that the surface of activated bentonite as well as nanometal oxides such as NTiO2, NAg2O, and NTiO2-NAg2O were loaded with –OH groups. These functional groups were directly responsible for the metal binding via ion exchange or complex formation mechanism. The reactivity of the surface loaded –OH groups was directly dependent on the pH value of contact solution. Metal ion solutions with low pH values (≤ 3.0) were generally facing strong competition due to the presence of the high concentrations of hydrogen ions which occupied and protonated the surface active binding sites to increase the positive charge density on the surface of metal oxides. This condition led to increase the repulsive forces between the positively charged metal ions and the positively charged protonated surface functional groups. By increasing the pH value of metal ion solution the degree of surface protonation became small and the surface -OH will had a strong binding affinity with the target metal ions.
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Contact time effect on the adsorption capacity values was indicated in the presence of various time intervals (1, 5.0, 10, 15, 20, 30, 40, 50 and 60 min) where the reaction pH and initial metal ion concentration were optimized. Nanosorbents were found to have different behaviors with the contact time values gradually increase the metal capacity upon increasing the time from 1 to 20, 30, 40, 50, and 60 min according to the equilibrium for each one. In some cases after the equilibrium was obtained a decreasing in the metal capacity was obtained. This behavior may be attributed to the possible desorption of the loaded metal ions from the nanosorbents surface at higher reaction times.
Nanoadsorbent dosage effect on the adsorption capacity values was identified by using different nanosorbents doses ranging from 5.0 to 100.0 mg to evaluate the variation in the metal adsorption capacity values. The metal adsorption capacity values were found to decrease upon increasing the nanosorbent dosage from 5 to 100 mg. The highest metal capacity value of the divalent ionic zinc and cobalt was obtained upon using 5.0 mg and the lowest value was identified upon using 100 mg of each nanosorbent. The observed behavior in low nanosorbent dosages was mainly attributed to the greater availability of metal ions compared to the active surface functional groups on the nanosorbents. In addition, the high metal capacity values at lower nanoadsorbent dosage may be also explained on the basis of an increased metal to sorbent ratio. The low metal adsorption capacity values at higher masses were mainly due to the less availability of functional groups compared to the number of available metal ions in the aqueous solution.
Initial metal ion concentration effect on the adsorption capacity values was characterized by using different initial metal concentrations ranged from 0.1 to 2.0 ml of 0.1mol L-1. The outlined results indicated that the increasing
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in the initial metal ion concentration would enforce an increase in the metal adsorption capacity values of the divalent ionic zinc and cobalt. The generated driving force by increasing the initial metal ion concentration affected the mass transfer barrier between the nanoadsorbent and the metal ion in the contact solution therefore, a higher initial concentration of metal ion was expected to enhance and increase the adsorption capacity of the divalent ionic zinc and cobalt using the diverse nanosorbents. Based on this assumption, the adsorption capacity values were found to gradually increase with increasing the metal ion concentration from 0.1 to2.0 ml of 0.1 mol L-1.
Coexisting ions effect on the adsorption capacity values of the divalent ionic zinc and cobalt using the diverse nanosorbents were studied upon using Na(I), K(I), NH4+, Mg(II) and Ca(II). The obtained results of metal capacity values were found to exhibit different trends of metal capacity values according to the chemistry of nanosorbents and the chemistry of interfering ions. Finally the applications of nanosorbents in the removal of 1.0 mg L-1 of the divalent ionic zinc and cobalt and their radioactive isotopes 65Zn and 60Co from water samples were determined and studied using multi-stage microcolumn system packed each with different doses of nanosorbents. The collected results confirm a good correlation values between the removal of the divalent ionic zinc and cobalt ions from water as well as 65Zn and 60Co from their radioactive wastewater. The highest percentage removal values were established after the third run of extraction with the percentage recovery values were corresponded to 88 to 97 % using the different nanosorbents.