Enhanced Selective Electrosorption of Nitrate from Wastewater by Controllably Doping Nitrogen into Porous Carbon with Micropores

• Published in: Langmuir Vol. 40; no. 12; pp. 6353 - 6362
• Main Authors: Wang, Yue, Ge, Yu, Liu, Zifan, Wang, Ruoding, Chen, Yanqi, Qian, Hang, Yin, Zhonglong, Liu, Fuqiang, Zhu, Lixin, Yang, Weiben
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 26.03.2024
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.3c03934

The biological NO3 – removal process might be accompanied by high CO2 emissions and operation costs. Capacitive deionization (CDI) has been widely studied as a very efficient method to purify water. Here, a porous carbon material with a tunable nitrogen configuration was developed. Characterization and density functional theory calculation show that nitrogenous functional groups have a higher NO3 – binding energy than Cl–, SO4 2–, and H2PO4 –. In addition, the selectivity of NO3 – is improved after the introduction of micropores by using the pore template. The NO3 – ion removal and selectivity of MN-C-12 are 4.57 and 3.46–5.42 times that of activated carbon (AC), respectively. The high NO3 – selectivity and electrosorption properties of MN-C-12 (the highest N content and micropore area) are due to the synergistic effect of the affinity of nitrogen functional groups to NO3 – and microporous ion screening. A CDI unit for the removal of nitrogen from municipal wastewater was constructed and applied to treat wastewater meeting higher discharge standards of A (N: 15 mg L–1) and B (N: 20 mg L–1) ((GB18918–2002), China). This work provides new insights into enhanced carbon materials for the selective electrosorption of wastewater by CDI technology.