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Synthesis of Graphene and its Application for Adsorption of Cobalt and Strontium Ions, and as an Electrode in Electrochemical Cells (Battery)

Jalilzadeh, Hassan | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54453 (46)
  4. University: Sharif University of Technology
  5. Department: Energy Engineering
  6. Advisor(s): Outokesh, Mohammad; Hosseinpour, Morteza
  7. Abstract:
  8. Although much progress has been made in eliminating, conserving, and reducing migration and emissions of radioactive materials, the risk of radioactive material release into the environment is still one of the most important hazards in the use of nuclear energy. In this study, graphene compounds have been used as adsorbents for the removal of radioactive materials due to their high level, cost-effectiveness and simplicity of the synthesis process of various composites. In this regard, the removal of strontium and cobalt by graphene compounds has been investigated. Magnetite nanoparticles were anchored on the surface of graphene by sol-gel method and adsorption in batch mode was investigated. TEM images show that the magnetite nanoparticles are homogeneously distributed on the surface of graphene. The presence of graphene as a substrate reduces the size and accumulation of nanoparticles and thus increases the specific surface area for adsorption. Finally, the adsorption isotherms of these two ions were investigated by Langmuir and Freundlich models, as well as the adsorption kinetics by first- and quasi-second-order models. The results show that the adsorbent capacities for cobalt and strontium ions are 28.02 mg/g and 20.98 mg / g, respectively. The Langmuir isotherm gave the best results with a correlation coefficient of R = 0.944 for cobalt and R = 0.981 for strontium. The adsorption kinetics of cobalt were faster than those of strontium, but the adsorption for both ions followed quasi-quadratic kinetics. As the temperature increased, the adsorption rate by the adsorbent increased, so that the maximum adsorption rate was reported to be 36.95 mg / g for cobalt and 27.97 mg / g for strontium at 75 ℃. Subsequently, to make and perform battery tests, first by Dr. Blade method, a thin layer of magnetite -reduced graphene oxide composite with a thickness of 50 microns is coated on a 30-micron thick copper foil and then nanosilicon using radio frequency sputtering on It piled up. Electron and optical scanning microscope images show 100 nm silicon nanoparticles layered on this foil. The nanosilicon size was optimized and applied by controlling three parameters of accumulation time, argon gas flux and radio frequency power of 30 minutes, 122 cubic centimeters and 150 watts, respectively. Then, batteries with graphene and magnetite- reduced graphene oxide anode and also 3 batteries with different thicknesses of silicon anodes were tested. The results show that the battery with graphene anode and M-RGO at a C-rate of C/20 have 1164 and 2513 mAh/g respectively
  9. Keywords:
  10. Reduced Graphene Oxide ; Ion Adsorption ; Lithium Ion Batteries ; Magnetite ; Nanosilicon ; Graphene Anode ; Electrochemical Cells

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