Mn, N co-doped carbon nanospheres for efficient capture of uranium (VI) via capacitive deionization

Meiyue Jin; Xinhua Huang; Zhirou Wang; Vincent Chan; Jinsong Hu; Ai Wu; Guangzhi Hu

doi:10.1016/j.chemosphere.2023.140190

Mn, N co-doped carbon nanospheres for efficient capture of uranium (VI) via capacitive deionization

Chemosphere. 2023 Nov:342:140190. doi: 10.1016/j.chemosphere.2023.140190. Epub 2023 Sep 16.

Authors

Meiyue Jin¹, Xinhua Huang², Zhirou Wang¹, Vincent Chan³, Jinsong Hu⁴, Ai Wu⁵, Guangzhi Hu⁶

Affiliations

¹ School of Materials Science and Engineering, Anhui University of Science and Technology, Huainan, 232001, China.
² School of Materials Science and Engineering, Anhui University of Science and Technology, Huainan, 232001, China. Electronic address: xhhuang@aust.edu.cn.
³ Department of Biomedical Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.
⁴ School of Chemical Engineering, Anhui University of Science and Technology, Huainan, 232001, China; Institute of Energy, Hefei Comprehensive National Science Center, Hefei, 230031, China. Electronic address: jshu@aust.edu.cn.
⁵ Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming, 650504, China.
⁶ Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming, 650504, China. Electronic address: guangzhihu@ynu.edu.cn.

PMID: 37716558
DOI: 10.1016/j.chemosphere.2023.140190

Abstract

Heteroatom doping, involving the introduction of atoms with distinct electronegativity into carbon materials, has emerged as an effective approach to optimize their charge distribution. In this study, we designed a strategy to synthesize in-situ Mn, N co-doped carbon nanospheres (Mn-NC) through the polycondensation of 2,6-diaminopyridine and formaldehyde in synchronization with Mn²⁺ chelation to form Mn-polytriazine precursor, followed by calcination to form carbonaceous solid. Then Mn-NC was fabricated into a capacitive deionization (CDI) electrode for the selective removal of uranium ions (U (VI)), which is commonly found in radioactive water. Interestingly, Mn-NC exhibited good selectivity for UO₂²⁺ capture with a demonstrated adsorption capacity of approximately 194 mg/g @1.8 V. The systematic analysis of the adsorption mechanism of UO₂²⁺ revealed that N dopants within Mn-NC can coordinate with the U (VI) ions, thereby facilitating the removal process. Our study presents a straightforward and convenient strategy for removing UO₂²⁺ ions by harnessing the coordination effect, eliminating the requirement for pore size control.

Keywords: Adsorption sites; Capacitive deionization; Charge enrichment; Coordination; Uranium ions.