Unexpectedly efficient ion desorption of graphene-based materials

Abstract

Ion desorption is extremely challenging for adsorbents with superior performance, and widely used conventional desorption methods involve high acid or base concentrations and large consumption of reagents. Here, we experimentally demonstrate the rapid and efficient desorption of ions on magnetite-graphene oxide (M-GO) by adding low amounts of Al3+. The corresponding concentration of Al3+ used is reduced by at least a factor 250 compared to conventional desorption method. The desorption rate reaches ~97.0% for the typical radioactive and bivalent ions Co2+, Mn2+, and Sr2+ within ~1 min. We achieve effective enrichment of radioactive 60Co and reduce the volume of concentrated 60Co solution by approximately 10 times compared to the initial solution. The M-GO can be recycled and reused easily without compromising its adsorption efficiency and magnetic performance, based on the unique hydration anionic species of Al3+ under alkaline conditions. Density functional theory calculations show that the interaction of graphene with Al3+ is stronger than with divalent ions, and that the adsorption probability of Al3+ is superior than that of Co2+, Mn2+, and Sr2+ ions. This suggests that the proposed method could be used to enrich a wider range of ions in the fields of energy, biology, environmental technology, and materials science.

Effect of defects on optical and electronic properties of graphene quantum dots: a density functional theory study

“…44 Previous studies have shown that the B3LYP method and def2/SVP basis set have been widely used to explore the structure and electronic properties of graphene and GQD models. 21,45–48 All obtained local minima have positive frequencies. For the excitation transitions of GQDs, the first 20 lowest excited states were calculated using B3LYP/def2-SVP, and the solvent (water) was included based on the polarizable continuum model (PCM) 49 in the TD-DFT 29 calculations.…”

High‐Yield Synthesis of Sodium Chlorides of Unconventional Stoichiometries

“…Synthesis and Characterizations: Freestanding rGOMs were prepared from a GO suspension via the drop-casting and thermal reduction methods, [46][47][48][49] The rGOMs were incubated at the working electrode in a saturated NaCl solution for 1 h using a three-electrode configuration under a constant electric potential condition. Then, the rGOMs were moved to the liquid surface and crystallized by an infrared lamp for half an hour to obtain Na-Cl crystals in rGOMs at different electric potentials (Figure 1a).…”

Monovalent Ion - Graphene Oxide Interactions are Controlled by Carboxylic Acid Groups: Sum Frequency Generation Spectroscopy Studies

“…This hypothesis is supported by ultraviolet (UV) absorption experiments (Figure S2). The UV spectrum of GO at ~ 230 nm is assigned to a conjugate double bond of the aromatic rings that can be generated π-π* transition [51][52][53][54][55]. The UV intensity of GO drastically decreases with the addition of Na, K, and Cs salts, but the intensity of GO with Li salt is almost identical with that from pure GO.…”