Over 97% of the water on earth is unsuitable for human consumption due to its salinity. The vast majority (about 99%) of this is seawater, with most of the remainder consisting of saline groundwater (US Geological Survey, 2010). Purification of this saline water holds the promise of nearly unlimited water resources for human civilizations in coastal regions. However, purification of seawater is expensive, energy intensive and often has large adverse impacts on ecosystems. Despite these drawbacks, desalination can be an appropriate technological choice in certain settings.