A small innovation could have a big impact on air pollution. In Belgium, researchers have engineered a device that uses sunlight to purify polluted air and produce hydrogen gas that can be stored and used for power, reports Live Science.
“We couple both processes together in one device,” Sammy Verbruggen, a professor of bioscience engineering at the University of Antwerp, told Live Science. “Hydrogen production on one side and air purification on the other side.”
Verbruggen is working with two teams of researchers who had been separately investigating both processes for years. At the University of Antwerp, the scientists had been testing different ways of combing light energy with nano-materials to purify air. At the University of Leuven, another team had been working on a tiny fuel cell with a membrane that could produce hydrogen gas from water. Now, the two teams have merged their expertise to create this newest device, which could purify fouled air and produce energy at the same time.
Verbruggen said the researchers are focusing on air polluted with volatile organic compounds (VOCs), which are small molecules produced by chemicals in adhesives, upholstery, carpeting, copy machines, cleaning fluids and more. In sufficient concentrations, VOCs can cause severe headaches, eye irritation, dizziness, nausea and asthma attacks.
The small molecules can be found in the air of enclosed buildings that are not well-ventilated, according to the Environmental Protection Agency, which may include newly built high-rises to factories that manufacture goods such as paint and carpeting.
“They can lead to a disease called the sick building syndrome,” Verbruggen said.
The prototype cell is a square with an active area that measures about 1cm by 1cm. At one side of the device, a tube delivers polluted air into the cell. Light enters naturally through a transparent window that covers a membrane treated with a light-activated catalyst. Once polluted air and light meet at the membrane, the catalyst tears apart the small organic molecules.
In the process, protons are set free and seep through the membrane, collecting on the other side. There, a platinum catalyst converts them to hydrogen gas, according to the researchers. Meanwhile, the purified air exits through a second tube.
Verbruggen and his colleagues were able to purify air and create gas from a variety of organic compounds, including methanol, ethanol and acetic acid. The scientists are also conducting new experiments with acetaldehyde, a liquid used to make acetic acid and perfumes. Verbruggen said the most obvious applications are in industries that produce a waste stream, such as manufacturers of paint or textiles.
“You can purify the waste streams so that they meet their environmental quota and at the same time recover the energy that was stored in those molecules,” Verbruggen said. The gas produced could be used to power the lights or other machines in the factory, he added.
At the moment, the team has not come up with an engineering solution to collect and store the gas. That’s another step in the engineering process, and one that will need to be solved by further research and development, Verbruggen said.