Environmental Engineering Reference
In-Depth Information
record the temperature, wind velocity, humidity, and amount of trapped water. The sur-
face of the collectors mimics the back of a Namib beetle because of the creation of hydro-
phobic bumps and hydrophobic troughs with epicuticular wax crystals and nanopores.
Preliminary laboratory trials showed a yield 10× higher than that of meshed polypropy-
lene. Further work is in progress [40]. The process has been recently repeated in the Dhofar
region in Oman. The Dhofar region includes the southwest mountains and experiences
rich and thick fog. The frequency of these fog banks is >25% per year.
29.5 Conclusions
Fog collection technology has made rapid strides from the original collection of fog and
dew from sheepskins to today's nanostructured superhydrophobic/hydrophilic surfaces.
The improvements in design have dramatically increased the yield from a meager 4 L/m
2
/
day to >40 L/m
2
/day, and work is in progress to achieve even greater yields. The improve-
ments in design have been incorporated not only taking into consideration substrates such
as meshed polypropylene, steel, or both, or other fabrics as well, which when combined with
superhydrophobic/hydrophilic coatings can withstand the effects of high winds and storms
(including sand storms), increase the purity of drinking water, provide shading, and max-
imize the coniguration of nets to provide a sustainability model and cost-effectiveness. In
recent years, Doppler effect radars have been ixed to provide information about fog den-
sity and measurements of water captured via wireless data networks. Atomic force micros-
copy and refractometry have been used to explore the dynamics of hydrophobic surfaces in
an attempt to explore the mechanism of water capture from fog formations. Polypropylene
meshed nets treated with nanoparticles have been deployed. Galvanized mesh steel panels
containing nanostructured substrates with microscaled mounds and troughs and nanopores
are analyzed to convert the fog droplets and transform them to viable sources of drinking
water, by mimicking the Namib beetle's exoskeleton to form a readily available source of water
in previously inhospitable regions. With the current global water crisis and the rising demand
from regions hit by shortage of drinking water, stretching from South Africa, Australia, to
South America, as well as the Middle East, India, and Pakistan, each drop of water needs to be
harnessed from the atmosphere and new techniques need to be devised to obtain a maximum
yield. The author (Diego, 42TEK) is currently working on a project with the aforementioned
institutes in Valencia, Spain, and in conjunction with Profs. Carlos Ángel Sánchez Recio
and
Zaki Ahmad, where a newer redesign from the original resembles the sails on sailboats, with
lighter and more resistant materials capable of wind vaning to avoid excessive loads, and pre-
pared for rapid deployments. The expertise derived from Ahmad's work in nanocoatings for
optimal water is being incorporated into worldwide technology with great ramiications.
References
1. HEDS-UP, 1998. Mars Exploration Forum, January 1, pp. 171-194, Report Number LPI -
Contrib. - 955 19980101.
2. Ahmad, Z., Ahmed, I., Patel, F., 2010. Fog collection by mimicking nature,
Journal of Biomimetics,
Bomaterials and Tissue Engineering
, 8:35-43.
