Purification of graphene oxide dispersions by using a fluidic cell

The purification process of graphene oxide (GO) is a key stage in the production of this two-dimensional material by the Hummers method. This step demands a large amount of water, energy and time. The inefficient removal of the contaminants present in GO may affect its properties and make it unfeasible for some applications, such as in the field of biology. Here, we develop a simple and efficient method for the purification of an aqueous GO dispersion based on a fluidic diffusion cell system with a porous nitrocellulose membrane. The effectiveness of the fluidic diffusion cell system was compared with that of traditional purification methods, such as dialysis and centrifugation. The proposed strategy achieves the best performance in the removal of the major contaminants (K_(aq.)⁺, Na_(aq.)⁺, Cl_(aq.)^-, SO_4(aq.)^2-, Mn_(aq.)²⁺ and MnO_2(s)), demanding ∼95% less water than dialysis and in a shorter time (∼23 h). The system operates under flow conditions, with minimum handling by the operator and is able to select the GO flakes with bigger lateral dimensions. This work represents a simple and fast alternative for purification of GO dispersions that can be easily scaled-up.