Toward Green Synthesis of Graphene Oxide Using Recycled Sulfuric Acid via Couette–Taylor Flow

Abstract

Developing eco-friendly and cost-effective processes for the synthesis of graphene oxide (GO) is essential for its widespread industrial applications. In this work, we propose a green synthesis technique for GO production using recycled sulfuric acid and filter-processed oxidized natural graphite obtained from a Couette–Taylor flow reactor. The viscosity of reactant mixtures processed from Couette–Taylor flow was considerably lower (∼200 cP at 25 °C) than that of those from Hummers’ method, which enabled the simple filtration process. The filtered sulfuric acid can be recycled and reused for the repetitive GO synthesis with negligible differences in the as-synthesized GO qualities. This removal of sulfuric acid has great potential in lowering the overall GO production cost as the amount of water required during the fabrication process, which takes a great portion of the total production cost, can be dramatically reduced after such acid filtration. The proposed eco-friendly GO fabrication process is expected to promote the commercial application of graphene materials into industry shortly.

Antibacterial Properties of Graphene Oxide–Copper Oxide Nanoparticle Nanocomposites

“…Figure shows representative SEM and TEM images of the materials investigated, along with the EDX spectral mapping of the bare GO and the GO–CuONP nanocomposite. Inspection of the SEM images for the GO shows the presence of distinct, large sheets, with a wrinkled texture, commensurate with the previously reported images of GO (see Figure A). ,, An EDX mapping of the material confirms the presence of carbon and oxygen, as expected from the chemical composition of GO (see Figure F); analysis of the copper spectrum shows a distinct lack of copper present for the bare GO material. Similarly, the TEM analysis of the synthesized GO shows the presence of small flakes of pristine material, with low dimensionality.…”

Continuous Synthesis of Structurally Uniform Graphene Oxide Materials in a Model Taylor–Couette Flow Reactor

“…A residence time of 75 s in the TCR would increase the viscosity of the mixture at the inlet by almost 5%. 36,43 We determined the effective Reynolds and Taylor numbers based on the apparent viscosity at the inlet (before the reaction) and at the outlet (after the reaction) to represent the change in viscosity and Reynolds and Taylor numbers in the reactor. 2.3.…”

“…Park and his co-workers have demonstrated how using a TCR would almost double the viscosity of the reaction medium in comparison to the conventional Hummers method. A residence time of 75 s in the TCR would increase the viscosity of the mixture at the inlet by almost 5%. , We determined the effective Reynolds and Taylor numbers based on the apparent viscosity at the inlet (before the reaction) and at the outlet (after the reaction) to represent the change in viscosity and Reynolds and Taylor numbers in the reactor.…”

Recent Developments in Graphene Oxide/Epoxy Carbon Fiber-Reinforced Composites

“…Dialysis was proposed (Chen et al, 2015) which proved to be simple and effective however the filtration time of 1 week is not practical for industrial GO production. Green synthesis of GO was demonstrated (Park et al, 2017) using recycled H 2 SO 4 from the first-stage oxidation reaction mixture. The oxidation took place in a Coyette-Taylor reactor and the vortex induced mixing reportedly reduced the reaction time from 24 to 1 h to achieve GO recovery rate and quality comparable to the original Hummers and Offeman control method.…”