Reaction Pathway Engineering for Nitrate Production in Atmospheric-Pressure Plasma via an Alternative Organic Nitrogen Source
Year: 2026
Type: preprint
Abstract: Plasma-activated water (PAW) has attracted attention for agricultural applications because plasma treatment can generate reactive oxygen and nitrogen species (RONS) and promote nitrate formation. However, increasing plasma power to enhance nitrate production also increases energy consumption, while the resulting nitrate increase may remain limited. In this study, plasma-activated coffee ground solutions (PAC) were prepared by introducing spent coffee grounds into deionized water treated at different plasma input powers. Nitrate production and the physicochemical properties of PAW and PAC were compared to evaluate the effects of plasma power and the presence of the organic species. Although increasing plasma power enhanced nitrate production in PAW, the increase was relatively limited. In contrast, the addition of spent coffee grounds substantially enhanced nitrate production under the same plasma conditions. Optical emission spectroscopy indicated prominent oxygen- and hydroxyl-related emissions, whereas nitrogen-related emissions were comparatively less pronounced, suggesting that reactive oxygen species (ROS) are more readily generated than reactive nitrogen species (RNS) under the present conditions. These results suggest that nitrate production can be enhanced by introducing an organic nitrogen source and utilizing plasma-generated reactive oxygen species, rather than relying solely on increased plasma power. This approach may reduce the need for additional plasma energy input while providing a potential route for the valorization and recycling of nitrogen-containing organic waste.
Source: Research Square
Institutions: National Tsing Hua University, Nagoya University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214963373