Iranian Association of Chemical Engineering (IAChE) Iranian Journal of Chemical Engineering (IJChE) 1735-5397 12 4 2015 10 01 Effect of graphite oxidation on the yield and quality of graphene synthesized by supercritical exfoliation and its application in photocatalytic degradation of methylene blue 52 68 11698 EN A. Hadi Department of Chemical Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran J. Karimi-Sabet NFCRS, Nuclear Science and Technology Research Institute, Tehran, Iran S. M. A. Moosavian 1Department of Chemical Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran S. Ghorbanian Department of Chemical Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran Journal Article 2015 11 15 After fullerene and nanotubes, graphene is a new allotrope of carbon. This attractive nanomaterial can be produced by different methods. In this work, we have used the less common approach for preparation of graphene. This technique is based on the utilization of supercritical fluid. Ethanol was used as the solvent for exfoliation of pristine graphite, at the temperature of 400 oC and pressure of 40 MPa. In addition, supercritical ethanol was used to reduce and exfoliate graphite oxide. FT-IR spectra indicate that reduction and exfoliation of graphite oxide can be done in supercritical ethanol, simultaneously. Effect of graphite oxidation on the yield and quality of graphene was investigated and results showed that oxidation of graphite can improve the yield of supercritical process from 12.5% to 26.8%, but Raman spectra revealed that quality of graphene samples produced by graphite oxide is lower than neat graphite. Moreover, the impacts of initial graphite concentration and sonication power on the exfoliation yield were studied. Finally, hybrid structure of graphene and titanium dioxide nanoparticles were prepared by ultrasonic method and used for photocatalytic degradation of methylene blue dye pollutant. Results revealed that titanium dioxide nanoparticles show better photocatalytic performance in presence of graphene sheets.<br style="font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" />

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