Graphene sieve makes seawater drinkable

Scientists have developed a graphene-oxide membrane capable of separating salt molecules from seawater – a breakthrough which could produce fresh drinking water for much of the developing world

ATOMIC STRUCTURE OF GRAPHITE

Carbon atom

Graphite used as “lead” in pencils

Layered, honeycomb lattice

DESALINATION PROCESS

Input: Sea water

Sediment pre-filter Carbon pre-filter

Layers of graphene require 50% less pressure to push sea water through than
current desalination filters

Post-carbon filter

Output: Drinking water

Reverse osmosis membrane

GRAPHENE

Theorised for decades, graphene is one atom-thick layer of pure carbon – finally
created in UK lab in 2004

SALT WATER

GRAPHENE OXIDE LAYER

PURE WATER

Tiny holes cut into layer of graphene oxide allow water molecules through but hold back sodium and chlorine

TYPICAL NON-GRAPHENE DESALINATION COSTS

Graphene filtration could reduce energy use by 99%

Running costs 19%

Capital 37%

Energy 44%

Sources: Nature Nanotechnology, University of Manchester