The Catalyst Review May 2024 - 8

SPECIAL FEATURE
The trial in the Arizona desert, where the relative humidity drops from a high of 40% at night to as low as 8% during the day,
demonstrated that the Berkery harvester system worked well. A metal organic framework, (MOF) was assessed as the water absorber
substance because MOF materials are highly porous and have a high internal surface area. The researchers confirmed that with the
currently selected MOF-801, one can harvest about two hundred milliliters of water per kilogram of MOF, but this MOF contains
expensive metal zirconium. Prof. O.M. Yaghi, one of the inventors, however, reported that he has created a new MOF based on
aluminum called MOF 3O3. This material is at least 150 times cheaper and captures twice as much water in lab tests. The new MOF
will be able to remove more than four hundred milliliters of water per day from one kilogram of MOF. The UC Berkeley team is eagerly
awaiting the next field test, which will evaluate the aluminum-based MOF in the Death Valley, where temperatures can reach 110°F in
the daytime and remain in the 70s at night with the nighttime humidity as low as 25%.
Using solar energy and hydrogel materials.
Over two billion people on earth live in countries experiencing high water stress. While dozens of companies are working on AWGs,
one hopes that their devices will help solve this crisis, many experts have stated that AWG technology will not be sufficient. With
high upfront capital costs, it takes around 10 years for AWGs to be cost-competitive, while only producing a fraction of the water that
is needed. Furthermore, AWGs can consume a lot of electricity and many of the proposed AWGs only work in places with high air
humidity. These constraints are what prompted SOURCE Global to develop a more flexible and sustainable solution.
SOURCE Global applies a special hydrogel that has a hydrophilic structure which renders the material capable of holding substantial
amounts of water in its three-dimensional networks. Extensive employment of these products in several industrial and environmental
applications is considered to be increasing in importance (Ahmed 2015; Kart 2022; Xiang et al. 2023).
Referring to Figure 4, the solar panels provide power
to a fan that draws in air from the atmosphere. Inside
the hydro panel device, the air travels through the
sponge-like hydrogel material that traps the water. After
collecting the water, magnesium and calcium are added
to the water to improve its taste and mineralized drinking
water without generating any waste. SOURCE has
installed its hydro panels around the world at hospitals,
schools and work sites that have difficulties accessing
water, such as in desert environments (De Oliva 2021;
SOURCE Global).
SOURCE Global company's largest water farm is in Dubai
where the company produces 1.5 million liters of water
every year. The company has shown that the scalability
of these water generators can run on one operating
panel installed in a room of a family home or a room at a
large hotel resort. Soon, SOURCE Global will work with a
development company aiming to build eighteen hotels
at Saudi Arabia's Red Sea coast that will be served water
supplied by SOURCE Global.
Using fog collection method.
Around the world, people living in coastal areas can collect water by applying fog harvesters made from mesh nets, usually erected
perpendicular to the path of the wind. Fog harvesting for fresh water can become attractive for a lot of places along the Pacific Ocean.
In Spain, Morocco, Israel, South Africa, Tanzania, and other places, fog harvesting opens opportunities for producing fresh water. In
Morocco, one installed a fog harvesting system collecting 34,000 liters of drinking water on a foggy day. The investment is modest, and
one usually needs only a little electricity for pumping the water to a town or village that needs it (Verbrugghe et al. 2023).
As the wind blows fog through the device, the mesh catches the droplets and gravity pulls the water down into containers underneath.
Most of the time, fog harvesters can collect about three liters a day per square meter of mesh. When the original fog collectors were
installed in Eritrea in 2007, it became apparent that the system could not withstand the local wind speeds. The technology was improved
and now maintenance free fog collectors can withstand wind speeds of up to 120 kilometers per hour. One applies a 3D mesh material
for higher water yield with a robust plastic grid that prevents the mesh from bulging and draining water outside the trough. Rubber
expanders are added to reduce the impact of wind forces, and the troughs are flexible following the movement of the net in the wind.
Figure 4. Hydrogel panels for making water in the desert.
Source: De Oliva 2021.
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The Catalyst Review
May 2024

The Catalyst Review May 2024

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