Dear Yusuf,

Graphene–surfactant composites in organic media such as N-methyl-2-pyrrolidone (NMP)  should be relatively easy to process, i.e. to remove residual organic molecules, e.g. by washing the dispersions/films with the solvents capable of dissolving the molecules. Noteworthy, according to our knowledge, there has been only one report discussing this issue, where the surfactant was successfully removed from graphene–surfactant films by sequential rinsing with ethanol, methanol, THF, DMSO and DMF, and chemical treatment with HNO3 and SOCl2. Nevertheless, such extraction of graphene from graphene–surfactant dispersions has to be still improved, since graphene treatment with SOCl2 can result in hole doping.

M. S. Kang, K. T. Kim, J. U. Lee and W. H. Jo, J. Mater. Chem. C, 2013, 1, 1870–1875.

http://genius.u-strasbg.fr/Documents/papers/Graphene%20via%20sonication%20assisted%20liquid-phase%20exfoliation.pdf

Graphene via sonication assisted liquid-phase

exfoliation† Artur Ciesielski and Paolo Samorı`*

Chem. Soc. Rev. 2013 ; Received 27th June 2013

DOI: 10.1039/c3cs60217f

Hoping this will be helpful,

Rafik

in my case, filtering the graphene solution made a big loss of graphene. so i want to evaporate it. but when i evaporated the solution, there are some resin left in my dish. i think the resin come from nmp, thats why i want to know how to remove it.

do you have any suggestion?

Dear Yusuf,

You should do rinsing with ethanol, methanol, THF, DMSO and DMF, and chemical treatment with HNO3 and SOCl2. Following this procedure you will remove the NMP and the resin which comes from it.

Good luck,

Rafik

Dear Yusuf,

Prof. Karaman's suggestion is ideal. You can centrifuge your sample to remove the supernatant (NMP solvent). Then you can wash it thoroughly with the suggested solvents by Prof. Karaman. After several washes, followed by centrifugations, i expect that your graphene sample will be purified without losses.