Abstract
Selective capture of nitrate from wastewater is crucial for ensuring safe drinking water and promoting resource circularity. This study investigated alkylated polyaniline redox polymers as highly-selective electrosorbents to address this challenge. By controlling polymer solvation properties through synthetic functionalization, poly(N-methylaniline) (PNMA) achieves a nitrate uptake of up to 1.38 mmol g−1-polymer and a separation factor of 7 over chloride. Poly(N-butylaniline) (PNBA) further enhances selectivity, achieving a separation factor beyond 14 due to increased hydrophobicity. The mechanisms underlying this selectivity are investigated using ab initio molecular dynamics (AIMD) and in-situ electrochemical quartz crystal microbalance (EQCM) studies, which reveal that hydrophobicity reduces chloride binding. A technoeconomic analysis indicates that methylation on PANI reduces nitrate removal costs by 50% compared to non-functionalized PANI, due to enhanced selectivity and uptake, and decreased energy consumption. PNMA electrodes demonstrate practical nitrate selectivity over 20 versus chloride in real wastewater, while avoiding sulfate binding. This study highlights the potential of controlling solvation at electroactive polymers to enhance nitrate selectivity, offering a promising design path for redox-mediated electrochemical separations.
| Original language | English |
|---|---|
| Article number | 10207 |
| Journal | Nature Communications |
| Volume | 16 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2025 |
Funding
This material is based upon work supported by the National Alliance for Water Innovation (NAWI), funded by the U.S. Department of Energy, Energy Efficiency and Renewable Energy Office, Advanced Manufacturing Office under Funding Opportunity Announcement DE-FOA-0001905. The authors thank Dr. Johannes Elbert for advice on polymer chemistry and Trent Lyons for providing municipal wastewater samples, as well as Giovanny Dominguez for assistance with chromatography measurements. We would like to acknowledge startup funds at the University of Illinois Urbana-Champaign, and support through an Annual Research Grant from the Illinois Water Resources Center (IWRC).