Group t and Beijing Jiaotong university open International ... - Groep T

Erasmus students in the spotlight
Symbol As, atomic number 33
Those who know something about chemistry, know immediately what it is about: arsenic. One of the
most dangerous chemical elements and at the same time one of the most common substances in the
earth’s crust. In particular, it can often be found in the groundwater in (too) great concentrations.
Meanwhile, various techniques have been developed to remove the substance from the water although
unfortunately, these cannot be used in all situations. That is why Christiaan Franz and Matthias De Rycke,
two Chemistry master’s students at GROUP T went to the University of Calabria, South Italy, with an
Erasmus scholarship to finalize a new purification technique.
The ancient Chinese, Greeks and Egyptians
were already familiar with the chemical,
but it would not be until 1250 until the German
(al)chemist Albertus Magnus identified
arsenic as an element for the first time. Only four centuries
later, the element was isolated successfully. The
name itself comes from the Greek ‘arsenikon’ which
translates into ‘yellow pigment’ but in its best known
form arsenic is grey.
“Over time, arsenic was used for many different
things,” Christiaan relates. “In the treatment of
syphilis, as a pesticide in fruit farming, for stuffing
animals, as pigment for paint, and so on. Today, too,
arsenic is used a lot in the chemical and electronics
industry. Did you know that the extremely toxic
arsenic gas plays an important role in the manufacturing
process of microchips and transistors?”
“In any form, arsenic has always had a bad reputation,”
Matthias continues. “Because it was practically
undetectable, arsenic compounds were very
popular for poisoning people. The most well-known
victim is probably Napoleon. After examination at his
place of exile, it turned out that his body contained
large quantities of arsenic. At the time, the finger
was pointed at his English guards. Later, it turned
out that it was not all that extraordinary because, in
Napoleon’s time, people were exposed to 100 times
more than people are these days.”
Membrane technology
Christiaan Franz and Matthias
De Rycke went to the University
of Calabria, South Italy.
Back to the present. Early February 2010, Christiaan
and Matthias packed their bags for 11 weeks of
research at the University of Calabria. Their supervisor
Prof. Chantal Block had got them ready for it and had
taken care of the required contacts. Both master’s students
could go to work at the Institute on Membrane
Technology that was established on the campus.
“Well, we did not exactly leave unprepared,” Christiaan
explains. “In September 2009, we went to prospect
for a week to learn what precisely was expected
of us. Our local co-supervisor provided us with a lot of
material so that we could start studying the literature
thoroughly during the first semester.”
As has already been said, arsenic can be found almost
everywhere in the soil. “The groundwater also contains
arsenic which is dissolved in the soil in the process
of rock erosion,” Matthias clarifies. “The water seeps
into the soil and picks up the toxic substance. In countries
like India, Vietnam and Bangladesh where millions
of people depend on groundwater with a high
level of arsenic, chronic arsenic poisoning is the order
of the day. Symptoms include skin and other cancers,
tumors on bladder, lungs, kidneys, liver, etc.”
Micro spheres
“At the University of Calabria, research has already
been carried out for some time now into how to
remove arsenic from the groundwater using membranes,”
Christiaan continues. “The membranes are
built into large filters that can be deployed at a large
scale. The problem is that poor, rural areas do not
have the means available to use such equipment.
So we opted to approach it on a smaller scale. We
started to make micro spheres based on polymers.
These micro spheres have a 1.5 mm cross section
and can be best compared to polystyrene globules.
They act as a carrier of titanium dioxide (TiO 2
for
the experts), a compound that absorbs arsenic. TiO 2
,
in other words, is the active ingredient that draws
out and binds the poisonous arsenic like a magnet.
The micro spheres with the TiO 2
are like the tea in
a tea bag.”
“One could indeed just toss the TiO 2
in the water, but
that raises the problem of getting it back out and
this time with the arsenic included,” Matthias adds.
“This is possible in principle, there are technologies
to do this, only poor regions wouldn’t be able to
afford that. So it is necessary to immobilize the TiO 2
in our micro spheres which are easy to remove and
can also be recuperated, TiO 2
and all. A good wash
in an extremely acidic or alkaline solution suffices to
make it ready for use again.”
International critical level
The required tests were carried out in collaboration
with the University of Karlsruhe in Germany. “Successfully,”
says Christiaan. “You have to know that
the World Health Organization sets a critical level of
10 micrograms of arsenic per liter. We are substantially
below that with out polymer capsules. With
5 grams of those micro spheres we can easily purify
50 liters. If you consider that in countries like Bangladesh
it is everyday practice to consume water with
50 micrograms arsenic per liter, it is clear that our
technique can be very useful there.”
An important step in the right direction, in other
words, but it is always possible to do better. Both students
realize this. “The technique can definitely be
perfected further,” Matthias confirms. “For instance,
the polluted water did not yet fully penetrate to the
core of the TiO 2
in the micro sphere. As a result, a
part remains unused. If we succeed in making the
outer part more porous still, the result will be noticeably
better. But that will be up to our successors.”
Italian pace
Of course, an Erasmus student enjoys more than only
laboratory work, although it was only after several
weeks of intensive experiments that Christiaan and
Matthias were allowed some time off to explore
the region, head to the nearby sea, visit Rome and
Cosenza and of course enjoy the excellent gastronomic
qualities of Southern Italy. “After a while, we
were indeed less stressed and got used to the more
easygoing Italian tempo,” Matthias says. To the
extent even that both GROUP T students were asked
to return after their studies to do a Ph.D. in Italy.
There is little chance of that, though. Christiaan prefers
to go study Industrial Management. And Matthias
sees himself in the footsteps of his father: starting
as an independent engineer in the construction
sector. One thing they both agree on: the Erasmus
adventure was certainly not poisoned gift.
Y.P.
GROUP T - LEUVEN ENGINEERING COLLEGE
15
jg. 20, nr. 1, 15 december 2010