Nearly 800 million people worldwide
don't have access to safe drinking water, and some 2.5 billion people
live in precariously unsanitary conditions, according to the Centers for
Disease Control and Prevention. Together, unsafe drinking water and the
inadequate supply of water for hygiene purposes contribute to almost
90% of all deaths from diarrheal diseases -- and effective water
sanitation interventions are still challenging scientists and engineers.
A new study published in Nature Nanotechnology proposes a
novel nanotechnology-based strategy to improve water filtration. The
research project involves the minute vibrations of carbon nanotubes
called "phonons," which greatly enhance the diffusion of water through
sanitation filters. The project was the joint effort of a Tsinghua
University-Tel Aviv University research team and was led by Prof.
Quanshui Zheng of the Tsinghua Center for Nano and Micro Mechanics and
Prof. Michael Urbakh of the TAU School of Chemistry, both of the
TAU-Tsinghua XIN Center, in collaboration with Prof. Francois Grey of
the University of Geneva.
Shake, rattle, and roll
"We've discovered that very small vibrations help materials, whether
wet or dry, slide more smoothly past each other," said Prof. Urbakh.
"Through phonon oscillations -- vibrations of water-carrying nanotubes
-- water transport can be enhanced, and sanitation and desalination
improved. Water filtration systems require a lot of energy due to
friction at the nano-level. With these oscillations, however, we
witnessed three times the efficiency of water transport, and, of course,
a great deal of energy saved."
The research team managed to demonstrate how, under the right
conditions, such vibrations produce a 300% improvement in the rate of
water diffusion by using computers to simulate the flow of water
molecules flowing through nanotubes. The results have important
implications for desalination processes and energy conservation, e.g.
improving the energy efficiency for desalination using reverse osmosis
membranes with pores at the nanoscale level, or energy conservation,
e.g. membranes with boron nitride nanotubes.
Crowdsourcing the solution
The project, initiated by IBM's World Community Grid, was an
experiment in crowdsourced computing -- carried out by over 150,000
volunteers who contributed their own computing power to the research.
"Our project won the privilege of using IBM's world community grid,
an open platform of users from all around the world, to run our program
and obtain precise results," said Prof. Urbakh. "This was the first
project of this kind in Israel, and we could never have managed with
just four students in the lab. We would have required the equivalent of
nearly 40,000 years of processing power on a single computer. Instead we
had the benefit of some 150,000 computing volunteers from all around
the world, who downloaded and ran the project on their laptops and
desktop computers.
"Crowdsourced computing is playing an increasingly major role in
scientific breakthroughs," Prof. Urbakh continued. "As our research
shows, the range of questions that can benefit from public participation
is growing all the time."
The computer simulations were designed by Ming Ma, who graduated from
Tsinghua University and is doing his postdoctoral research in Prof.
Urbakh's group at TAU. Ming catalyzed the international collaboration.
"The students from Tsinghua are remarkable. The project represents the
very positive cooperation between the two universities, which is taking
place at XIN and because of XIN," said Prof. Urbakh.
Other partners in this international project include researchers at
the London Centre for Nanotechnology of University College London; the
University of Geneva; the University of Sydney and Monash University in
Australia; and the Xi'an Jiaotong University in China. The researchers
are currently in discussions with companies interested in harnessing the
oscillation know-how for various commercial projects.
Story Source:
The above post is reprinted from
materials provided by
American Friends of Tel Aviv University.
Note: Materials may be edited for content and length.