الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Graphene oxide (GO) is one of the most common adsorbents used for removal of radionuclides from liquid radioactive waste. Graphene is a single atomic layer of sp2 Carbon atoms, it gets high attention from the scientists and researchers because of its important uses and applications in adsorption of different pollutants. Due to its large specific area and functional groups including (hydroxyl, carboxyl and the epoxy groups) at the sheets edges, it shows high adsorption performance of metal ions. The relatively high removal capacity of GO compared to other adsorbents is improved by its functionalization with EDTA and chitosan.
Throughout this study the following results and findings have been achieved :
A- Graphene oxide was prepared by improved hammer method and was successfully modified by EDTA and chitosan.
B- The prepared GO, GO-EDTA and GO-chitosan were characterized using high Resolution Transmission Electron Microscopy (HRTEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Thermogravimetric Analyzer (TGA), Field Emission Scanning Electron Microscope (FESEM) and Raman Spectroscopy.
C- The prepared GO, GO-EDTA and GO-chitosan were applied as adsorbent for removal of uranium, cobalt and strontium from solution.
D- The effects of contact time, adsorbate concentration, adsorbent concentration, pH, and temperature on adsorption have been studied and the optium conditions of removal have been identified
E- It was found that modification and functionalization of GO with chitosan and EDTA improved the removal of U(VI), Co(II) and Sr(II).
F- The obtained results indicated that pH ” ” ” ” ” ” ” " ~ " ” ” ” ” ” ” ” 6 and temperature ” ” ” ” ” ” ” " ~ " ” ” ” ” ” ” ” 40 °C are the best conditions for removal of Co(II) and Sr(II) from solution.
G- The results indicate that the maximum adsorption capacity of U(VI) was about 310 and 328 mg/g for GO and GO-EDTA pH ” ” ” ” ” ” ” " ~ " ” ” ” ” ” ” ” 6 and temperature ” ” ” ” ” ” ” " ~ " ” ” ” ” ” ” ” 40 °C respectively. But, in case of GO-chitosan the adsorption capacity was about 392 mg/g at temperature ” ” ” ” ” ” ” " ~ " ” ” ” ” ” ” ” 50 °C. It can be concluded that the adsorption capacity increases with increasing temperature for GO-chitosan.
H- The results show that the maximum adsorption capacity of Co(II) is about 168,197 and 420 mg/g for GO, GO-EDTA and GO-chitosan at pH ” ” ” ” ” ” ” " ~ " ” ” ” ” ” ” ” 6 and temperature ” ” ” ” ” ” ” " ~ " ” ” ” ” ” ” ” 40 °C respectively.
I- The obtained results show that the maximum adsorption capacity of Sr(II) was about 152, 158 and 179.6 mg/g for GO, GO-EDTA and GO-chitosan at pH ” ” ” ” ” ” ” " ~ " ” ” ” ” ” ” ” 6 and temperature ” ” ” ” ” ” ” " ~ " ” ” ” ” ” ” ” 40 °C respectively.
J- The results showed that the Langmuir model fits the adsorption equilibrium data better than Freundlich model due to the higher R2 values.
K- The adsorption results of U(VI), Co(II) and Sr(II) onto GO, GO-EDTA and GO-chitosan revealed that the pseudo second-order model is the best representive of adsorption kinetics where it has the highest correlation coefficients linear regressions (R2).