CAJ #12 - Ultrafiltration membranes

 As already mentioned in one of my earlier posts, the potential uses of graphene seem endless. It is hard to say where it should be applied first. However, in my opinion, we should invest more in the research of ultrafiltration membranes based on graphene.

Graphene possesses a number of qualities with regard to its interactions with water. Previous research showed that thin membranes made from graphene oxide laminates were impermeable to gases and vapours, except for water. New research is now testing the effectiveness of these membranes with regard to water filtration. Graphene could be used as a ultrafiltration medium that would act as a barrier between two substances.

What sets graphene apart from other similar membranes is that it is only one atom thick. A team of researchers at Columbia University has created a monolayer graphene filter with pore sizes as small as 5nm (nanometer). In comparison, other nanoporous membranes have pore sizes of 30-40nm. The membrane's ability to prevent salt passage depends on pore diameter. If the pores are too big, ions will be able to flow through it. If the pores are small enough, water will flow through while blocking out the ions. Because the pores in monolayer graphene filters are so small they can effectively filter NaCl (sodium chloride) salt from water.

Graphene is stronger and less brittle than aluminium oxide (currently used in sub-100nm filtration applications). These new types of membranes could be used in water filtration and desalination systems, as well as efficient and economically more viable biofuel creation. This would be a huge break through, especially the desalination system because all the water on Earth would become drinkable. This would help solve the problem of water shortage for many African countries. 

XOXO A.