Graphene-oxide filtration membrane for harsh chemical environments

Filtration is being investigated as an alternative to thermal separation methods (such as distillation and evaporation) in many applications because of the potential energy savings, but conventional filtration membranes, such as those used in water desalination, are often not robust enough to withstand high temperatures and harsh chemical conditions. Now, Via Separations (Somerville, Mass.; www.viaseparations.com) has demonstrated a process for making graphene-oxide (GO) membrane material that can withstand harsh conditions. In its first commercial application, the GO membrane is being employed for the concentration of black liquor in pulp-and-paper operations, where the membrane experiences very high pH.     A byproduct from wood-pulping processes, black liquor contains lignin, hemicellulose and inorganic materials from wood, after cellulose has been removed during paper manufacturing. Initially, the black liquor contains about 12–15% solids, and it needs to be concentrated to 70% solids in order to recover and recycle the organic chemicals from the black liquor back into the pulping process. Via’s membrane consists of graphene-oxide (GO) flakes cast onto a hydrophilic support material through a proprietary deposition…