الفهرس 
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Abstract
In this thesis, different approaches have been used to remove various types of wastewater contaminants using adsorption technique under different adsorption parameters. First approach depends on preparation of modified mesoporous zeolite-A /reduced graphene oxide nanocomposite (MZ-A/RGO) in the presence of 3-aminopropyl- trimethoxysilane (APTMS) as a mesopore generating and cross linkage agent which enhance the attaching of the zeolite-A into the surface of the RGO that could be used for the removal of cationic heavy metals ions contaminants such as Cadmium (Cd2+), Lead (Pb2+), groundwater common cationic ions contaminants such as Iron (Fe3+) and Manganese (Mn2+) and cationic organic dyes such as Crystal Violet (CV) and Methylene Blue (MB). The physico-chemical properties of the nanosorbent were investigated using different analytical tools such as, XRD, ATR-FTIR, SEM, TEM and Zeta potential. The adsorption process was studied in a batch scale experiments with various adsorption conditions that were assumed to affect the capacity of prepared MZ-A/RGO to remediate the cationic heavy metal ions (Cd2+ and Lead Pb2+), mineral metal ions (Fe3+ and Mn2+), cationic dyes (MB and CV).
Second approach is based on the fabrication of superdydrophobic octadecylamine (ODA) surface modified mesoporous zeolite-A/reduced graphene oxide (MZ-A/RGO /ODA) nanocomposite. The heads of cationic surfactant (ODA) enhance an electrostatic interaction force on the negatively charged adsorbent surface and formation of hydrophobic layer on its surface that act as adsorptive layer for the oily organic contaminants such as emulsified oil. Also, the conformation of the binding between ODA and MZ-A/RGO was done using XRD, ATR-FTIR, SEM, TEM and zeta potential measurements.
The third approach was focused on the synthesis of positively charged RGO/Ppy nanocomposite that provide removal of a new type of wastewater contaminants which is anionic contaminants such as anionic heavy metals Cr(VI) ions and anionic dyes (CR and OG) from wastewaters.
According to the obtained experimental data the results can be summarized as following:
The choice of the nanoadsorbents is determined according to their unique physicochemical properties such as the large surface area, high reactivity and high adsorption capacity and its ability to adsorb different types of hazardous pollutants from wastewater immediately.
Fabrication of the nanoadsorbents is depend on the nature of the contaminants (in-organic, organic, cationic, anionic and oily).
The hydrothermal technique has been proved effective method to obtain a high quality nanosorbents with high surface area with high adsorption capacity.
The physico-chemical properties of the prepared nanosorbents were investigated using XRD, ATR-FTIR, SEM, TEM, EDX and zeta potential techniques to determine the chemical structure, bonding, morphology, composition, particle size and surface charges.
Adsorption technique is widely used in water and wastewater remediation due to its high removal efficiency, cost-effectiveness, flexibility, versatility, and easy control, simple in design and operation.
Several adsorption parameters could affect the adsorption capacity and removal efficiency of the selected contaminants such as contact time, initial adsorbate concentration, solution pH, sorbent dose and temperature.
The adsorption capacity increased with the contact time at fixed other parameters (0.05 g of sorbent dosage, 100 mL of 200 mg/L of adsorbate contaminant solution). The adsorption capacity was very fast at the beginning within first 20 min, thereafter slowing kinetics until the system attained an equilibrium state at 120 min.
Depending on the values of the correlation coefficient (R2), the experimental kinetic data for the adsorption of all contaminants were better fitted using pseudo-second-order model than the other two of the pseudo-first-order and Elovich kinetic models.
The adsorption capacity had a significant increase with increasing the initial adsorbate concentration for all contaminants when the other conditions were constants (0.05 g of sorbent dosage, 100 ml adsorbate solution volume for 120 shacking time).
Generally, Langmuir and Freundlich isotherm models are the most suitable isotherms used to describe the adsorption of Cd2+, Pb2+, Fe3+, Mn2+, Cr(VI) heavy ions, MB, CV, CR, OG dyes and emulsified oil onto the MZ-A/RGO, MZ-A/RGO/ODA and RGO/Ppy nanocomposites.
According to the experimental data fitting, the maximum adsorption capacities for Cd2+, Pb2+, Fe3+, Mn2+ ions, MB and CV dyes onto MZ-A/RGO were 222.23, 416.67, 333.33, 270.27, 526.32 and 714.29 mg/g, respectively. And for the emulsified oil onto MZ-A/RGO/ODA was 400.00 mg/g. While, for the Cr(VI), CR and OG onto RGO/Ppy were 454.55, 714.29 and 476.19 mg/g, respectively.
The results indicated that the adsorption capacity increase as the pH increase from 2-11 for the cationic heavy metals (Cd2+, Pb2+, Fe3+, Mn2+) ions and (MB & CV) dyes onto the surface negatively charged MZ-A/RGO nanocomposite due to the electrostatic attraction force. However, the adsorption capacity decreased for anionic heavy metal Cr(VI) ions and anionic dyes (CR & OG) onto the positively charged RGO/Ppy nanocomposite as the pH increased due to the repulsion forces between them.
Significant enhancement was clearly observed in the removal efficiency for the all contaminants with increasing of the sorbent dosage quantity due to the availability of more active sites on the surface of the adsorbents.
The results indicated that the adsorption process for all contaminants was more favorable at higher temperatures except in the case of the emulsified oil adsorption onto MZ-A/RGO/ODA due to the nature of the oil.