الفهرس 
Introduction and literature reviewOnly 14 pages are availabe for public view
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Abstract
In this work, different types of hydrogels such as Poly acrylic acid
(PAAc), Poly vinyl alcohol (PVA), Poly dimethyl amino ethyl
methacrylate (PDMAEMA), Poly acrylamide (PAAm), Poly
sodium alginate (NaAlg), copolymer of PVA/AAc,
DMAEMA/AAc, NaAlg/AAm and clay nanocomposite of organic
montmorillonite- Polyvinyl alcohol -co- poly acrylic acid (OMMTPVA/
AAc) have been prepared by γ irradiation polymerization for
the purpose of separation of some heavy and toxic metals from
water. The gel fraction and swelling percentage are studied as a
function of monomer concentration and copolymer composition as
well as the absorbed dose. Furthermore, the swelling percent as a
function of time and pH are also studied. The bond and functional
group structure are examined by Fourier transform infrared
spectroscopy (FTIR). The free volume nanostructure is studied by
positron annihilation lifetime spectroscopy (PALS). The elemental
analysis is made by UV spectroscopy and energy dispersive x-ray
analysis (EDX). In addition, the microstructure is studied by
electron scanning microscope (SEM), x-ray diffraction (XRD) and
transmission electron microscope (TEM). The thermal stability of
the nanocomposite hydrogel has been determined by thermo
gravimetrical analysis (TGA).
The factors affecting the adsorption amount of heavy and toxic
metals (Cu+2, Co+2 and Ni+2) such as contact time, pH and metal ion
concentration of solution as well as temperature are studied. From
Abstract
Abstract
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the results, it is found that, the three-macro hydrogels have different
affinity for the three metals in comparison with the nanocomposite
one. For instance, the maximum adsorption amount in case of
PVA/AAc at pH 5 at 40 ppm and after a contact time of 24hrs is 194
mg/g, 185 mg/g and 144 mg/g for Cu+2, Co+2 and Ni+2 respectively.
Whereas, the maximum adsorption amount for OMMT-PVA/AAc
at pH5, at 100 ppm after 2 hrs. is 835 mg/g, 785 mg/g and 636 mg/g
for Cu+2, Co+2 and Ni+2 respectively. The improvement of the
adsorption amount by using OMMT-PVA/AAc nanocomposite is
due to its larger surface area in addition to its higher thermal
stability. Furthermore, a maximum swelling percent has been
obtained with only 4 kGy absorbed dose compared to 20 kGy for
PVA/AAc. Thus, the hydrogel nanocomposite has shown better
swelling and adsorption properties compared to the macro
hydrogels.
This thesis consist of four chapters, list of figures & tables and list
of references. The first chapter contain introduction for the
decontamination methods, properties of the samples prepared and
literature review and the main aim of this work. The second chapter
contain theory of positron, positronium atom formation and free
volume models. The third chapter consist of three parts the first
about samples preparation, the second about description for the
different techniques used and PALS and how to analysis its data.
The fourth chapter includes the results, obtained using different