الفهرس 
INTRODUCTION and Aim of the workOnly 14 pages are availabe for public view
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Abstract
The present work is concerned with Friedel’s salt (LDH) which is widely used in removing harmful anions and cations from aqueous solution because of its ion exchange characteristic. The aim of this study is to examine the removal of heavy metal ions such as iron (Fe3+) and cobalt (Co2+) using Friedel´s salt as an adsorbent and investigate the effect of temperature on the efficiency of adsorption.
This study includes the following steps:
1- Preparation of tricalcium aluminate by well mixing calcium carbonate CaCO3 and aluminum oxide Al2O3 in the molar ratio 3:1, respectively.
2- Preparation of Friedel’s salt by the precipitation method through reaction between tricalcium aluminate and calcium chloride.
3- Examining the stability of Friedel’s salt by adding 0.10 gm of the prepared FS to 50 ml of distilled water at pH values: 4, 6 and 8, at different time intervals (0.5h, 3h, 6h, 1d, 3d and 14d).
4- Preparation of different concentrations of FeCl3.6H2O and CoCl2.2H2O and adjusting the initial pH of the mix at 4& 6 with dilute HCl or NaOH solutions.
5- Examining the adsorption kinetics of Fe(III) and Co(II) ion with Friedel’s salt by stirring 0.1 gm of FS with 50 ml of the prepared solutions at different time intervals (0.5, 3, 6h and 1, 3 and 14 d).
6- Studying the effect of temperature (50°C) on the adsorption kinetics.
7- Investigate the phase composition of the formed products through X-ray diffraction analysis.
8- Evaluating the concentration of the residual metal ions (Fe3+ or Co2+) by atomic absorption technique.
9- Identifying the functional groups, that appear after adsorption by FTIR.
The main results obtained from this study can be illustrated as follows:-
• The solubility and stability of Friedel’s salt at different pH values.
The highest stability of FS is at pH=6, while the lowest stability is at pH= 8. The decrease in the stability of FS may be because of the increase in the concentration of the released Ca2+.
• Adsorption of different concentrations of iron and cobalt ions at pH=4.
The XRD patterns of 0.1 mM of Fe3+solution treated with FS remain almost unchanged compared to that of the original FS. While the characteristic peaks of FS decrease from 1 hour up to 14 days for 0.5 mM of either Fe3+ or Co2+. On the other hand, all the characteristic peaks of FS disappear at 3 & 8 mM of Fe3+ and Co2+.
Atomic absorption results show complete adsorption of 0.1mM iron ions on the surface of FS at all ages, while 0.5mM Co2+ solution, complete adsorption occurs after 14 days.
• Adsorption of iron on FS at pH=6 and different initial concentrations.
All the characteristic peaks of FS are observed with a decrease in the intensity on increasing time from 1hour up to14 days for 0.1, 0.5 and 3mM of iron. While, for 8mM solution of iron, the main characteristic peaks of FS disappear completely at all ages from 0.5 hour up to 14 days.
Atomic absorption results show a complete adsorption of iron ions in the 0.1mM solution of FeCl3 at different time intervals, where as for the 0.5mM Fe3+ solution a complete adsorption occurs after 3 days. Therefore, the adsorption affinity decreases by increasing the initial concentration of iron.
• Effect of temperature on the adsorption of metal cations from 0.5 mM solutions of iron or cobalt salts on the surface of FS at pH=4.
The results indicate that rise in temperature from 25 to 50°C affects positively the rate of adsorption. The XRD pattern at 50°C show that all the characteristic peaks of FS disappear completely from the first 0.5 hour, and after 3 hours in Co2+ and Fe3+, respectively indicating the complete interaction of FS with the considered metals ions.