How do carbonized compressed powder blocks clean water?
AZoM talks to Professor Andrea Fratalocchi from KAUST about his research on a previously unknown aspect of coal that could pave the way to a new, environmentally friendly, solar-powered carbon cycle. Fratalocchi explored how compressed coal dust blocks can be used as the basis for solar-powered off-grid water purification.
Your device is capable of providing fresh water to 1.6 billion people around the world facing economic water scarcity. What inspired your research to develop such a technology?
My research group is interested in exploring new forms of clean energy generation, including traditional solar powered systems (photovoltaics, hydrogen generation, and carbon negative technologies) and more recent areas such as solar desalination. In the latter, a few years ago we developed a plasmonic system that broke all records in efficiency that existed at the time, and my group was looking for new materials to advance this work.
I read the initiative on circular carbon emissions, which was strongly supported by many countries, and began to link the concept of coal to desalination. Then we started discussions with our partners in this research (PERA Complexity and the University of Zurich) and finally developed this system.
Although renewable energies cost less and less, countries are continuing to expand their coal-fired power plants. How does your research aim to address this problem and how does it help reduce fossil fuel burning – the number one cause of man-made increases in CO.?2 in the atmosphere?
Our research opens up a different economy for coal that can counter climate change because it is environmentally friendly and protects the creation of jobs in the fossil fuel value chain.
The latest IRENA report on the LCOE from renewable sources says that electricity generation from coal has reached a plateau for almost a decade and that new coal-fired power plants have been operating with fewer hours since 2014, with ever-decreasing capacity.
In order to contain climate change, we have to take social sustainability factors into account. If we can find a way to create a new economy with clean coal and create jobs along the fossil line, we could find common ground that could finally help make change happen. It could enable us to redirect coal resources into clean economies.
For every GW of coal electricity that could be phased out by channeling coal resources into improved water management, more than 1000 tons of CO could be generated. removed2 every hour from the environment. It could help promote solutions for fossil products that could achieve the sustainable development goals of clean water, sanitation and climate protection.
Image Source: Little Smile / Shutterstock.com
Could you provide an overview of how your team used carbonized compressed charcoal and cotton fiber to achieve this? Solar powered, off-grid water treatment?
Image source: Mazzone, V., et al. (2021) Clean carbon cycle through powerful and inexpensive solar-powered freshwater production. Advanced sustainable systems. doi.org/10.1002/adsu.202100217.
The above figure illustrates the process quite well. Starting with coal (a), you create a powder (b) and then optimize the structure through mechanical compression to create a volumetric three-dimensional absorber (c). Then drill holes (d) and add cotton fibers as a secondary capillary for efficient water extraction.
The final structure looks like the one depicted in (d). This system is two to three times more efficient in terms of Kg of water created per hour and per sun and US dollar spent on raw materials than any other system currently available.
According to your research, this application has a value that is two to three times higher than any other solar desalination device proposed to date. What are the other benefits of this technology?
Aside from the previously mentioned benefits, this technology also addresses social sustainability factors, i.e.; it uses coal in non-traditional ways to create jobs along the fossil line while maintaining climate responsibility, enabling clean technologies.
The manufacture of current solar materials is expensive and hinders industrial applications. How does your nature-based solution address the issues associated with cost while maintaining efficient performances?
Coal is still very abundant in nature. Currently, it is among the cheapest material for energy applications. Traditionally, however, coal has always been seen as an energy source and was mainly employed in that sense. People often get so used to the specific ways they use an object that they become obsessed with certain ways objects are used that it is difficult for them to explore alternative paths.
Such ‘functional fixation’ inhibits thinking that requires non-traditional ways of using objects, thus hindering potential alternative pathways for tackling challenging problems.
My group and I, on the contrary, leverage complexity theories. These harness the creativity that arises from divergent thinking, which is open and involves a wide variety of potential solutions. To tackle a complicated problem, such as the detrimental effects of fossil fuels on the climate, perhaps we should ask ourselves if we can use coal in a non-traditional context?
How does your novel method improve on current water desalination processes to help address the pressing crisis of water scarcity?
This system allows a desalination rate per raw material cost evaluated at 1.39 kg/h/USD at one sun intensity. Many countries affected by water scarcity, including large coal producers such as India and China, have a large availability of sun resources.
With the system proposed in this work, a small-scale implementation can serve a family of four people, producing freshwater at the cost of around 0.002 $ per liter. This figure is already competitive with the average cost of water from reverse osmosis, evaluated at 0.0015 $ per liter, without considering the cost of large-scale facility realization.
The simplicity of the proposed system allows practical implementation almost everywhere and at minimal costs, especially in areas heavily affected by water shortage, which are usually poor, rural or isolated.
Aside from fulfilling drinking, cooking and agricultural needs, what other challenges could this energy-efficient water desalination method provide a solution for?
Aside from satisfying drinking, cooking and agricultural needs, this technology also arguably provides people access to sanitation – an ideal that necessitates fresh, clean water.
Did you come across any challenges during your research, and if so, how did you resolve them?
This research collaborates with PERA Complexity (an R&D startup in Nederland) and the University of Zurich. We addressed all challenges by working in a team and leveraging ideas from each of us constructively.
A primary challenge at the beginning was the optimization of the coal matrix to enable optimized performances. The solution to this problem required complex modeling, experimental analysis and simulations from each of us. We developed innovative algorithms for image analysis and pattern recognition that enabled the automated data analysis to be complied with in a sufficiently short amount of time.
The interest in environmentally-friendly and renewable technologies is on the rise. What does the future of renewable energy look like to you?
For me, the future of renewable energies depends heavily on hydrogen. With this in mind, my group and I are doing intensive research. Hydrogen is an ideal clean energy carrier: it can be transported anywhere with practically no loss of energy and used as required. It produces energy with extremely high efficiency and has a clean combustion that produces water and nothing else. It could eventually enable a completely clean energy cycle with no harmful by-products.
About Professor Andrea Fratalocchi
Andrea Fratalocchi is Associate Professor (since July 2016) in the Computer, Electrical and Mathematical Sciences and Engineering department at KAUST University. He joined KAUST in January 2011 as an assistant professor. Before joining KAUST, Andrea Fratalocchi was a Research Fellow at Sapienza University of Rome for a KAUST Fellowship Award.
From 2007 to 2009 Andrea Fratalocchi worked as a postdoc at the University of Sapienza as part of a “Young Investigator” award from the “Enrico Fermi” research center. In 2012 he was appointed editor of the Nature Scientific Report. In 2017 he won the Middle East GCC Enterprise Award for best electrical engineer of the year. In 2019 he was elected a Fellow of the Institute of Physics (IOP), Senior Member of the IEEE and Fellow of the Optical Society of America (OSA):
For groundbreaking innovations in the use of complex optical systems and the development of creative technologies in the areas of clean energy harvesting, bio-imaging and advanced optical materials
As of March 2019, Andrea Fratalocchi has written more than 170 articles and five patents.