الفهرس 
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Abstract
Chapter 1 : Introduction and Literature Review
Heavy metals constitute one of the most dangerous groups because of their persistent nature, toxicity and tendency to accumulate in organisms and are non biodegradable.
Bentonite clays are acquiring its prominence as low-cost adsorbents over the last decades due to their local and abundant availability and the capability to undergo modification to enhance the surface area, adsorption capacity and range of applicability. Bentonite is absorbent aluminium phyllosilicate clay consisting mostly of montmorillonite.
The adsorption capacity of natural bentonite is low due to its small surface area. This led to the need for research and development in the field of modification of clay surfaces to enhance their adsorptive properties. A number of physical and chemical methods have been investigated to modify the bentonite, including heat treatment, acid activation, treating the cationic surfactants and polymer modification
Aim of This Study:
1- characterization of Ca- bentonite and modified bentonite by using (BET) method, (FTIR), (SEM), (XRD), (EDX) and (TEM).
2- Converting Ca-bentonite to Na- bentonite.
3- Acid activation of Na- bentonite by sulfuric acid
4- Preparation of nano composite (Fe3O4 nano composite) by adding it to acid activated bentonite.
5- Determination of effect bentonite nano composite on heavy metal from waste water by using (ICP-MS).
Chapter 2 : Materials and methods
Material: The Egyptian clay mineral, calcium bentonite, used in the study was obtained from Red Sea for Phosphate Company. This calcium bentonite was converted chemically to sodium bentonite.
Chemicals: A stock solution containing 500 mg/L of (arsenic (III) in hydrochloric acid - selenium in nitric acid - chromium in nitric acid - (Ba) in nitric acid - antimony in nitric acid -molybdenum in hydrochloric acid) was dissolved appropriate in 1 liter distilled water.
Sodium chloride 99.5%, nitric acid silver salt 99 % , sulfuric acid 95-97 %, iron(III) chloride hexahydrate 98 % and ferrous sulfate 99 % , sodium hydroxide 98 %, nitric acid 99 %.
Preparation of bentonite: Calcium bentonite washed several times with distilled water then enriched with 1 M NaCl solution and left 24 hours to make exchange. Activation of Na- bentonite was conducted by adding sulfuric acid solution (3M) The washing was continued until the supernatant reached to a pH of 7 then dried in oven at 100 oC for 6h.
Synthesis of bentonite /Fe3O4 magnetic nano composite: Was prepared by co-precipitation method.
Characterization of modified bentonite: The effect of modification of bentonite was analyzed using (BET) method, (FTIR), (SEM), (XRD), (EDX) and (TEM).
Chapter 3 : Results and Discussion
Surface area analysis of modified bentonite: Increase in surface area of the modified bentonite was recorded as 25.259 m²/g, 31.86 m²/g, 62.194 m²/g and 107.998 m²/g by Ca- bentonite, Na-bentonite, acid activated bentonite and nano composite bentonite, respectively.
Morphological analysis :
The average size of Ca -bentonite particles was observed at (1.03 – 6.78) µm, (7.56 – 43.11) µm for Na-bentonite,( 2.58 – 5.11 ) µm for acid activation bentonite and (301.9) nm for bentonite nano composite.
X-ray diffraction analysis: Fe3O4/bentonite nanocomposite can conclude that quartz is the major constituent of modified bentonite. The Appearance of metallic iron for Fe3O4/bentonite nanocomposite was identified from the peak at 2θ=36.56°. The presence of calcite (CaCO3) was observed at 2θ = 29.84°.
FTIR analysis: The bands at 534.08, 789.22, 913.97, and 1004.6 cm-1 correspond to the Fe–O stretch with respect to Fe3O4. The formation of Fe3O4/bentonite nanocomposites can be indicated by the appearance of transmittance peak at wave number 581 cm-1 correspond to Fe-O stretch vibration bond of magnetic Fe3O4 nanoparticles .
Effect of optimum pH: The maximum removal efficiency was achieved at pH values were equal to 6 for metal ions.
Effect of the optimum dose: The maximum dose effects of removal efficiency for heavy metals were 0.5g/100ml of heavy metals.
Effect of the optimum contact time: The result showed that the rate of removal was achieved rapid within (1- 15) min and reach to maximum removal efficiency at 15 min.
Effect of the optimum initial concentration: The effects of the initial concentration from (100 µg/L - 500 mg/L).