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February 06, 2009

Hydrophobic Sand Details - Waterproof Nanosand


Desert sand is made hydrophobic be adding the additive SP-HFS 1609. The additive creates a capilliary breaking hydrophobic encapsulation of the sand making it resistant to salts, particularly sodium chloride salts. The Federal Environment Agency (FEA) in Berlin has approved Hydrophobic Sand as being environmentally safe. The product comes with a 30 year guarantee for its hydrophobic effect.

How much "nanotechnology" is involved in the SP-HFS 1609 additive ?
It appears to be an advanced chemical, but the additive is top secret and I have not found academic papers describing exactly what is being done. The known man-made hydrophobic material is solidifying an alkylketene dimer onto a surface, but I do not know if that is what SP-HFS 1609 is.

Hydrophobic Material in General
Wikipedia discusses hydrophobic material.

In chemistry, hydrophobicity (from the combining form of water in Attic Greek hydro- and for fear phobos) refers to the physical property of a molecule (known as a hydrophobe) that is repelled from a mass of water.

Hydrophobic molecules tend to be non-polar and thus prefer other neutral molecules and nonpolar solvents. Hydrophobic molecules in water often cluster together forming micelles. Water on hydrophobic surfaces will exhibit a high contact angle.

Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general.

Research in superhydrophobicity recently accelerated with a letter that reported man-made superhydrophobic samples produced by allowing alkylketene dimer (AKD) to solidify into a nanostructured fractal surface. Many papers have since presented fabrication methods for producing superhydrophobic surfaces including particle deposition, sol-gel techniques, plasma treatments, vapor deposition, and casting techniques. Current opportunity for research impact lies mainly in fundamental research and practical manufacturing.

Gardening, Landscaping and Agriculture
This site covered the massive impact of greening the deserts and saving 75% of irrigation water in the Middle East, China, India and Africa.

Hydrophobic Sand can be used in gardens, where mixing it with soil in potted plants allows the roots to breath even when the plant has been over watered. A layer of Hydrophobic Sand at the bottom of the pot stops water from passing through it, yet allows air to pass through the sand grains and provide the roots with the air needed to breathe.

Hydrophobic Sand can also be used as a landscaping feature, with water flowing over the sand creating a natural looking stream, over what looks like normal sand.

Agriculture farms can use the hydrophobic sand below their sweet soil to minimise water wastage. The water stops flowing through into the ground water, and instead, becomes trapped above the Hydrophobic Sand layer, allowing roots to reach into the pool of water collected below.


As noted in a previous article about greening deserts 75% of the water for irrigation can be saved using the nanosand and 85% of water in the middle east and north africa is used for irrigation.



Oil Absorption

Hydrophobic Sand does not allow water molecules to pass through its layers, yet allows oil to do so, making it very useful in cleansing water of oily contamination. When oil-contaminated water makes contact with Hydrophobic Sand, the oil quickly penetrates the sand, leaving clean water behind.

Hydrophobic Sand can be used for trapping petroleum spilled from oil tankers in coastal waters. When sprinkled on floating petroleum, it binds with the oily material, creating clumps of oil trapped within the sand, allowing it to be easily extracted. This prevents the petroleum from contaminating marshes and beaches.

It can also be used in areas such as dump sites, where the product is laid under the waste material. Should these materials leak any oily substances, the sand will absorb the waste and protect the natural ground water that lies below
.

Ground Water Protection


Ground water and the naturally high salt levels in the Middle East grounds are prime suspects of weak foundations, due to oxidisation of ream bars, and penetration of salts into the concrete mix during the drying process.

The multi-grain Hydrophobic Sand's extreme load carrying capacity of 104 N/sq.mm and waterproofing makes it the ideal product in the construction of foundations, and a fast and cost effective solution for the protection of buildings. By using multi-grained sand, instead of mono-grained sand, the sand forms a solid base when it is compressed. Mono-grained sand is soft and not compressible, and will behave like water, moving out of the way with any force acting upon it.

Using Hydrophobic Sand in the area under the foundations of any structure achieves a capillary breaking effect. Both water and salts are kept away when applied beneath the foundation, ensuring much higher longevity of the structure.

Underground utility protection:
For underground work such as laying pipes or cables, Hydrophobic Sand is the ideal back-filling for protecting the material being laid, as it not only secures underground utilities from shifting, but also waterproofs them. Covering cables and pipes with Hydrophobic Sand ensures effective and long lasting protection. .

Hydrophobic sand has also been tested by utility companies in the Arctic, who bury electric and telephone wires to protect them from the harsh weather. However, if something needs to be repaired during the winter, digging through frozen Arctic soil normally takes many hours of work with power tools may be required. To speed up these underground repairs, utility companies can cover electrical junction boxes with Hydrophobic Sand and cap the sand with just a few inches of soil. Rainwater flows around, not through it, and when the soil freezes, the sand remains dry and loose. It is easy to break through the frozen cap and then shovel away the loose Hydrophobic Sand.


Flood and Coastal Protection

The waterproof sand can also provide better protection against under-washing of reclaimed land in coastal areas and open waters. Ordinary sand in sandbags can become saturated and water flows through the barrier. Hydrophobic sand prevents water from flowing through the barrier.

But is Sand in Plastic Bags Nanotechnology

Some could say that it is silly to call sand filled plastic "nanotechnology".

This sand has been given what is claimed to be a nanotechnology coating.

The surface of the sand was changed to make it hydrophobic.

It is chemistry but nanotechnology is a variant, subset or superset of chemistry.

How the treated material is then being deployed is mundane.

It is the first major "nanotechish-chemistry" application.

Nanomembranes for purifying and desalinating water are coming and should be several times more energy efficient. But it will be some membranes stuck in regular pipes.

Because molecularly precise material is still in smallish quantities most of the time it will be a small fraction of the overall structure for early applications.

We could mix carbon nanotubes with some chemical binder and mix that with sand or dirt. This has already been proposed and developed for lunar cement, where you mix carbon nanotubes and some chemicals and lunar regolith to make lunar cement. The carbon nanotubes would be a tiny fraction of the overall material and the deployment could be mundane as well if there was an earth dirt or desert sand based variant, like making bricks or blocks and stacking them.

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