Graphyne and graphene approaches to better desalination

From NextBigFuture.com

Technology Review describes graphyne sheets for filtering salt from seawater at rates several orders of magnitude faster than conventional desalination techniques. The new technique involves a material known as graphyne, a two-dimensional sheet of carbon atoms connected together much like graphene but with an altered structure because of double and triple bonds in certain places. Graphyne is interesting because these double and triple bonds create holes between the carbon atoms that are large enough for water molecules to pass through. However, these holes are not big enough for sodium and chloride ions, which are larger because they attract a shell of water molecules since they are charged.

Water passes through graphyne at a rate some two orders of magnitude faster than through the polymer membranes used in conventional reverse osmosis techniques. They are in the lab stage for production of graphyne.

Conventional desalination plants that rely on reverse osmosis require 1.5 kiloWatt-hours of electricity to produce 1 tonne of freshwater.

Arxiv – Exceptionally Fast Water Desalination at Complete Salt Rejection by Pristine Graphyne Monolayers

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