Brian Wang at Next Big Future has pointed to what might be the first nanotech application “to impact a major problem”—water scarcity. The application is hydrophobic sand, which retains moisture near the roots of desert plants by virtue of a proprietary nanostructured coating on the grains of sand. The details are in “Green dream: A world in a grain of sand“, written by Derek Baldwin:
On a cool winter day, Emirati engineer Fahd Mohammad Saeed Hareb peers into a bubble of water atop a tiny pile of sand cupped in his hands.
Amazingly, the water bubble does not drain through the sand — it remains intact, jiggling like crystal clear Jello, under a high-noon sun.
This is waterproof sand — or as German scientist Helmut F. Schulze calls it — hydrophobic sand, a nanotechnology wonder seven years in the making.…
By simply laying down a 10-centimetre blanket of DIME Hydrophobic Materials sand beneath typical desert topsoils, the new super sand stops water below the roots level of the plants and maintains a water table, giving greenery a constant water supply.
By comparison, when regular desert sand lies beneath, water bleeds endlessly downward leaving roots dry until the next watering.
With new hydrophobic sand in place, traditional watering of desert plants five or six times a day can be reduced to one watering, saving 75 per cent more water, a precious resource that is dwindling across the Arab Peninsula.
One of the advantages of the hydrophobic sand, Schulze said, is that while it allows aerobic activity to move upward from the soil, it prevents underground desert salinity deposits from passing through to plant roots above; salt is corrosive and kills plants.
He added that each grain of sand used in the process is coated with SP-HFS 1609, a top-secret additive, the precise nature of which he declined to disclose noting that it’s proprietary.
Other forms of hydrophobic sand on the market — used for cleaning up oil spills – are coated with silicas that are water repellent.
“It’s super thin,” Schulze said. “Every single sand kernel gets a skin, a coating, which encloses it.”
The nanotechnology coating is so thin, in fact, that it can’t be seen by the naked eye and measures 12,500 to 13,500 micro millimetres.
To date, it’s been approved by the Federal Environment Agency (FEA) in Germany which, according to Schulze, has issued a no-objection certificate for the product declaring it as ecologically safe.
This looks promising, and the need it addresses is certainly great, but it is annoying that the proprietary nature of the product means that we don’t learn the molecular details of how this product works.