Efficient technique removes ammonia from agricultural wastewater


According to the World Health Organization, one in three people in the world does not have access to safe drinking water and basic sanitation services. These problems have only increased around the world due to the effects of climate change. As a result, combined with capital and operating costs, developing countries and vulnerable communities are the most affected by the adverse effects of water scarcity.

“Water scarcity is one of the greatest challenges of the 21st century,” said David Estrada, associate professor of materials science and engineering. “In our lab, we are committed to finding solutions to problems, regardless of political, socio-economic or cultural boundaries. This new system can be adapted to meet the water sanitation needs of communities of different sizes and economic backgrounds around the world.

Boise State researchers from the College of Engineering teamed up with researchers from Drexel University and the Idaho National Laboratory to investigate a simple, energy-efficient technique for removing ammonia from agricultural wastewater. The research is co-led by Estrada and Tedd Lister, a chemical separations researcher with the Energy and Environmental Science and Technology Branch of the Idaho National Laboratory. The group’s work has been published in the Nature Partner Journal, Clean Water.

The research team used capacitive deionization, an emerging water treatment technique in which water flows between two oppositely charged electrodes. This technique polarizes ionic impurities in the wastewater, causing the ions to attract and store in the opposing electrodes.

“It takes about 20 times more energy to synthesize ammonia from fossil fuels than to recover ammonia using our approach,” Lister said. “These fossil fuel-based industrial processes can generate up to four times more carbon dioxide than the amount of ammonia synthesized, underscoring the importance of recycling our resources made using these energy-intensive techniques. “

The team reviewed previous studies that explored carbon-based materials as electrodes, however, these materials were limited in terms of chemical diversity, surface chemistry and surface area to volume ratio, which limits the performance of the technique. capacitive deionization. The team teamed up with Drexel University’s Chris Schuck and Yury Gogotsi to study a new approach using MXenes, an inorganic compound composed of layers of nitrides, carbonitrides or metal carbides.

“MXenes have a unique combination of properties that make them very attractive for electrochemical applications,” said Naqsh Mansoor, Boise State graduate student at the Micron School of Materials Science and Engineering and first author of the paper. “The fan-shaped structure of MXenes allows for a large intercalation space so that the polluting ions removed can not only absorb on the surface, but also insert themselves between the layers.”

The team’s research found a 100-fold improvement in deionization capacity when using MXenes compared to activated carbon-based electrode systems. This resulted in a higher number of pollutant ions extracted from the waste water stream while using less electrode material.

Reference: Mansoor NE, Diaz LA, Shuck CE, Gogotsi Y, Lister TE, Estrada D. Ammonia removal and recovery from simulated wastewater using Ti3C2Tx MXene in flux electrode capacitive deionization. npj Clean Water. 2022;5(1):1-11. doi:10.1038/s41545-022-00164-3

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