Marta Stucchi – Save water, save life
Nuove frontiere per la purificazione dell’acqua delle nostre città
1. A master degree in chemistry and the love for the environment: impossible?
Milano, Città Studi
Industrial Chemistry is an historical faculty of the University of Milan. Great chemists have grown up in its laboratories, and I saw their names as a child looking up and without knowing much about what “industrial” chemistry really meant. I was just passionate about science, and I needed something that would make everything more practical, to wipe out the common idea that “pure sciences fight career”. After five years I got the degree, and in that moment I thought back about my initial doubts and beliefs with a smile.
Here, with the beginning of the PhD my path as a researcher begins. After 4 years I can say: industrial chemistry loves environment. It may seem strange.
My research has been focusing on a rather famous material, called titanium dioxide. Everybody heard about it. It is everywhere. It is in white paintings, in toothpaste, or in sun creams. This pigment can be exploited for pollution abatement. The chemical process is called photocatalysis. Through photocatalysis we can change the chemistry of pollution, transforming it in carbon dioxide. Think about the air we breath every day, think about every environment we everyday live, imagine that they are full of substances, which we all easily recognize as harmful.
In several laboratories of the University of Milan scientists are working with chemistry in order to find solutions to save the planet. Here the dark side of chemistry, here the beginning of my story.
2. Photocatalysis and pollution abatement, our first meeting.
I’ve never studied photocatalytic processes before. At that time, my supervisor showed me a small piece of ceramic, which just looked like a tile and said simply: “It can reduce the level of pollutants in the air, because on its surface we put TiO2.”
Its chemical formula is TiO2, that means titanium with two atoms of oxygen. Titanium alone is a metal, if bound to oxygen it changes its properties and it becomes a semiconductor. This is the crucial point. Every substance consists of atoms. Atoms contain protons and electrons. Every physical transformation you can see in nature happens because atoms and electrons move from a molecule to another. Changing the composition of a molecule changes the substance. Being a semiconductor means that electrons follow a specific behavior. Electrons stay in a specific zone called valence band, localized under another zone called conduction band. The conduction band is a high-energy zone. High energy means high reactivity. However, where does the energy come from? The answer is: light.
TiO2 is activated by light and it reacts with molecules. Precisely, TiO2 reacts with pollutants transforming them. The final oxidation product is CO2.
A day in the lab
TiO2 is simply a white powder. Everyday in the lab we try to look at it closer in order to see its structure, the shape of its nano-particles, and the numbers of atoms it contains. The more we know it, the better we modify it to improve its performance. For example we can modify TiO2 and make it active under visible light.
3. Air and Water: contaminated?
Unfortunately, the answer is yes. The contamination levels are in most cases much higher that we would expect. The worst part concerns us closely. Indoor air is 10 times more polluted than outdoor, the tap water that we use every day contains substances often dangerous for health.
Contrary to what is general assumed, air in several indoor environments is often more polluted than outdoor air. This is the case because of many sources including pollen, tobacco smoke, household products and pesticides, and materials usually used in buildings such as formaldehyde and organic compounds. Even if the level of concentrations that can produce specific health problems are uncertain, long and repeated periods of exposure can be debilitating or fatal. During these years I mostly worked on formaldehyde. Have you ever heard about it? Formaldehyde is a human carcinogenic. However, it is used in buildings, resins, disinfectants, in several common daily-life products, as well as a preservative for food. The situation is alarming. Formaldehyde increased in urban areas during the past few years, now it has the same dangerous levels both outdoor and indoor. In industrial countries, the population spends more than 90 % of its time in indoor locations or closed environments. That’s why even low levels of pollutants are dangerous. Formaldehyde is not the only pollutant that aﬀects everyday locations. Most part of the chemical indoor pollutants are volatile organic compounds or aldehydes. The best known are benzene or toluene. Overall, the quality of air inside homes, schools, oﬃces and public buildings is an essential determinant of healthy life and the well-being of people.
Water and my new challenge in Canada
Save water, save life: indeed, without water there would be no life on earth. Every single life form, from cells to the most complex organisms, relies on water for sustenance. Without water we would not exist. However, we often don’t care about it.
If we are taking it, we’re also drinking it
Pharmaceutical products consume is rising. Statistically we foresee an increase of 30% by 2018, with a consequent world sales growth up to 1500 dollars per year. States that spend more money for drugs are the most industrialized and advanced. The most requested products are cancer and antidiabetic drugs, together with painkillers and antidepressant. The fast and easiest solution is what we want the most: the curve of drugs consumption rises dramatically. The relation between all these facts and the situation of water is in the title of this section: if we are taking it, we’re also drinking it because all we take is expelled through the excretory apparatus. The way from toilette to water is short. The chemical analysis of waste waster leaves no doubt. Already in 2004 rivers revealed shocking news: fishes were changing sex because of the high levels of hormones in the water. Today, we revealed more than 300 organic contaminants in tap water, and 30% of them are above the levels defined by health guidelines. Moreover, the most part (about 200) have no legislative regulations. The problem is the pollutants concentration together with poor knowledge. Wastewater treatment plants are not designed for drugs removal. Here the sense of my project. Here the sense of scientific research eﬀorts.
4. A post-doc researcher in Canada
New frontiers for the purification of urban wastewater
This project comes from the need to fill the gaps already explained. We want to find new solutions for water treatment; we need to improve our scientific knowledge about the problem to deal with it as best as possible.
The study of the molecules
What happens in the lab? Studying the pure chemistry of molecules is the base to develop large processes and chemical technologies. We selected two molecules: paracetamol, called also acetaminophen, and amoxicillin. The first step is finding the right analytical method to detect them. Then, we study their reactions. Organic molecules transform during the degradation process, not always until complete oxidation to CO2. Each organic molecule degrades step by step, so much that paracetamol can transform in dozens of other organic compounds, which can be even more toxic. On the other hand amoxicillin has not ever been studied and we are still unaware of its degradation pathway. Here, the importance of knowledge: knowing molecules, their reactions, and their fine chemical behavior is not in vain. Basic scientific knowledge creates the foundation for advancing technology.
Finding new ideas
Photocatalysis is a green technology. It requires solar light as the energy supply, but its eﬃciency can be increased even more. Cumbersome molecules such as drugs are more diﬃcult to degrade. The new challenge of this project is ultrasound. Everybody knows ultrasound by name, without really knowing what it is. Sound propagates in the air creating compression and rarefaction zones. In liquid vectors ultrasound is responsible for a phenomenon called “acoustic cavitation”: it occurs in three phases, which are the formation of bubbles, their growth and their final collapse. The latter is the crucial point: at the time of collapse, temperature is higher than 5000°C and pressure is higher than 2000atm. Sono-photocatalysis combines ultrasound and photocatalysis: this is the idea. This is the technology we are trying to develop, in order to make it an available process to improve our environment.
5. Key points every researcher should not forget
Improving the performance: we study materials, we study molecules, we aim to produce something useful for life. The sense of scientific knowledge is giving answers to improve our possibilities.
Save energy and money: unfortunately, we have to deal with this issue every day. Every idea must be economically viable. Every scientist knows it. Thus, we look for sustainable research, without wastes and improving what we already have.
Be safe: a material can be very performing, but if we use it we must be sure that it is safe for our health.
Be curious: knowledge moves everything.
“Era tale l’entusiasmo generato in me dalla scoperta che ogni mio pensiero, di giorno e di notte era fisso su questo fenomeno”
Elogio dell’imperfezione – Rita L. Montalcini
Marta Stucchi was born in Vimercate, near Milano, on December 1st, 1989. She graduated in industrial chemistry at University of Milan, where she continued with a PhD that she obtained in March, 2017. Actually she is a post-doc researcher at Polytechnique de Montreal, studying advanced treatments for the urban water purification. Most part of her research concerned environmental issues, particularly focused on the study of pollution and on novel methodologies to break it down. Thus, she knows in depth TiO2-based materials used for this purpose. Marta aims to find concrete solutions to really improve the quality of daily life, but she loves investigating even the most remote and hidden physical properties of materials and elements. Her passion for knowledge and culture is what makes her proud to be part of the Wandering Genius project.