I have produced graphene vis laser ablation in DI water. I wish to collect the produced graphene in powder form for further processing. How do I collect this graphene powder without damaging its microstructure?
Dear Anurag Bajpai , probably your ablation process yields different size and shape graphene flakes or /and carbon quantum dots. A selective separation could be done by selective centrifugation as suggested in the following paper by Lin et al. :
https://pubs.rsc.org/en/content/articlelanding/2015/nr/c4nr05737f#!divAbstract
Water or in general the liquid media keeps the ablated particles separated and when the liquid is removed, they will be mixed , which depending on your application could be interesting or not. You could use vacuum filtration to remove the water, and then drying the powder in a lab oven.
Hope it helps.
Dear Manuel Gómez,
Thank you for considering my query. however, the graphene produced by the laser ablation is transparent. However, several micro characterization techniques have established that the product is graphene. However, due to transparency, I am unable to collect the produced graphene is solid form.
Dear Anurag Bajpai , even transparent materials have mass, and therefore they can be deposited on the bottom of a centrifugue tube if enough centrifugal force is applied. They also have some physical size, and therefore they could be separated by filtration with adequate filter porosity. Another option would be to use a rotovap to evaporate water, leaving the graphene residue on the walls of the evaporation flask. (Water evaporation, even in a rotovap could take time).
In all these options you start with some kind of transparent solution and you finish with some precipitate, filter solid or residue on the walls of the flask, probably white or whitish, due to light scattering, so visible and therefore "easy" to manipulate. You can remove it, dry it weight it, etc.
It will depend on your further processing steps or application what could determine how easy this manipulation would be. When your graphene flakes are dispersed in water, probably they are sparely distributed on the media, but once the water is removed, the flakes will be touching each other and mixed, which could be of interest for instace in the case you want to weight then or have them concentrated to perform some chemical or physical transformation.
Probably, if you are interested on applications of single layer graphene, it could be best to think about another separation method, may be something like pouring your suspension in an evaporation tray, so that a shallow water suspension with a large surface area would be evaporated, leaving a very thin, ideally a discrete layer formed by graphene flakes...
Hope it helps.
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