Ion Transport Through Graphene Fibers

Ghanbari, Hamid Reza | 2020

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52575 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Esfandiar, Ali
  7. Abstract:
  8. Nanostructured graphene based membranes demonstrated excellent capabilities in various applications in nanofiltration and energy conversion due to unique atomically smooth surfaces and adjustable pore size or interlayers spacing at Angstrom scales.In addition to graphitic surface and physical confinement on ions in Graphene-oxide (GO) laminates, surface charges on such 2D-slits provide an attractive aspects to have more channels walls interactions with ions. There are some reports on the osmotic power generation using physical confinements and electrostatic interactions between ions and GO membranes. However, the results indicated insufficient power densities (1 W=m2 ) can be achieved because of swelling of interlayer spacing of the GO membranes upon exposure to aqueous solutions which results in reducing the influence of confinement on ionic motilities. Here, the GO fibers is presented as one dimensional macrostructures including abundant aligned 2D nanochannels to produce electricity from salt concentration gradient. We used the GO fibers intercalated via cations to control the interlayer’s spacing depending on the cation’s hydrated size and consequently enhancing a stable confinement on ionic transport. The GO laminates intercalated by small cations pins the GO walls and sieve larger cations even with 2 Å differences. Remarkable surface charge on nanochannel walls as well as cation pining of interlayer distances, provide a high mobility discrimination between cations and anions ( K+=Cl = 11 ). The osmotic power density can reach to a value of 38 W=m2 at 1000-fold of KCl concentration, 10 times higher than those previously reported for GO structures. This study introduces the GO fibers as new scalable structures for nanofluidics systems which could find range of applications in energy harvesting and molecular sieving
  9. Keywords:
  10. Ion Transport ; Nanofluid ; Graphene Oxide Fiber ; Two Dimentional Nanochannels

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