Environmental Engineering Reference
In-Depth Information
29
Nanotechnology in Passive
Atmosphe
ric Water Capture
Carlos Ángel Sánchez Recio,
1
Zaki Ahmad,
2,3
and Tony F. Diego
3
1
Natural Aqua Canarias, Vistabella (La Laguna), Canary Islands, Spain
2
Department of Chemical Engineering, COMSATS Institute of
Information Technology (CIIT), Lahore, Pakistan
3
42TEK S.L., Almazora, Spain
CONTENTS
29.1 Introduction ........................................................................................................................ 587
29.2 History of PAFCs................................................................................................................ 590
29.3 Background and Technical Developments .................................................................... 592
29.4 Materials and Methods ..................................................................................................... 594
29.5 Conclusions ......................................................................................................................... 597
References ..................................................................................................................................... 597
Further Reading .......................................................................................................................... 599
Websites ........................................................................................................................................ 599
29.1 Introduction
The amount of renewable water in the earth's atmosphere is estimated to be roughly 12,500-
12,900 km
3
, or about 0.001% of the total water on Earth, consisting of a volume of approximately
1385 million km
3
. It is further estimated that 2%-3% of the total water used today as drinking
water is actually derived from seawater produced by large desalination plants and may cost
slightly less than $1/m
3
, or about $4/m
3
for smaller units. Bottled water can be 1000× more
expensive. At these current costs of producing desalinated water through reverse osmosis, the
atmospheric water capture (AWC) technique is still viewed as the most cost-effective method
for many cities and townships where water availability is continuing to be a constraint. With
the improvements outlined in this chapter, the case for the implementation of
hydrofarms
is
clear, perhaps by more than two or three orders of magnitude.
The ield of AWC for the purpose of human and animal consumption and for agricul-
tural irrigation use is now set to be revolutionized, and is fueled by the rapidly increasing
demands for water. It leverages the latest advancements and developments in the ields of
material sciences and nanotechnology, more speciically the applications of superhydro-
philic wonder materials such as TiO
2
, which have the additional properties of acting as a
photocatalytic decontaminant when properly applied to water treatment. These, combined
with the opposite range of materials such as SiO
2
with superhydrophobic properties, can
further optimize the capturing yields signiicantly.
587
