Zeolitic imidazolate framework derived Fe catalyst electrocatalytic-driven atomic hydrogen for efficient reduction of nitrate to N2

Xi Ma; Jiapeng Zhong; Rongyue Wang; Dexuan Li; Kai Li; Lijun Luo; Chuanhao Li

doi:10.1016/j.jhazmat.2024.134354

Zeolitic imidazolate framework derived Fe catalyst electrocatalytic-driven atomic hydrogen for efficient reduction of nitrate to N₂

J Hazard Mater. 2024 Jun 5:471:134354. doi: 10.1016/j.jhazmat.2024.134354. Epub 2024 Apr 19.

Authors

Xi Ma¹, Jiapeng Zhong², Rongyue Wang², Dexuan Li², Kai Li³, Lijun Luo⁴, Chuanhao Li⁵

Affiliations

¹ Key Laboratory of Environmental Functional Materials of Yunnan Province Education Department, School of Chemistry and Environment, Yunnan Minzu University, Kunming, China.
² School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, China.
³ Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
⁴ Key Laboratory of Environmental Functional Materials of Yunnan Province Education Department, School of Chemistry and Environment, Yunnan Minzu University, Kunming, China. Electronic address: luolijun@ynni.edu.cn.
⁵ School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510006, China. Electronic address: lichuanh3@mail.sysu.edu.cn.

PMID: 38653134
DOI: 10.1016/j.jhazmat.2024.134354

Abstract

Excessive discharge of nitrogen-containing chemical products into the natural water environment leads to the serious environmental problem of nitrate-nitrogen pollution, threatening the ecological balance and human health. In this study, we propose an efficient denitrification electrochemical method utilizing iron-doped zeolite imidazolium framework derived defective nitrogen-doped carbon (d-FeNC) catalysts. The d-FeNC catalyst exhibited 97 % nitrate removal efficiency and 94 % total nitrogen (TN) removal, and the reaction rate constant was increased from 0.73 h^-1 of the Fe-undoped electrocatalyst (d-NC) to 1.11 h^-1. The successful synthesis of d-FeNC with carbon defect sites and encapsulated Fe was confirmed by in-depth characterization. In situ electron paramagnetic resonance (EPR) analysis in conjunction with cyclic voltammetry (CV) tests confirmed the carbon substrates with defect enhanced the trapping of atomic hydrogen (H*) on the catalyst surface. Density functional theory (DFT) calculations clarified the doping of Fe facilitated the adsorption of nitrate, resulting in contact of H* with nitrate on the catalyst surface. In the synergy of the defective state organic framework and metal Fe, H* and nitrate realized a collision process. The electrochemical denitrification system achieved an excellent nitrate removal capacity of 7587 mgN·g^-1cat in high-concentration nitrate solution and showed excellent stability under various conditions. Overall, this study underscores the potential of defective iron-doped carbon catalysts for efficient electrocatalytic denitrification, providing a promising approach for sustainable wastewater treatment.

Keywords: Atomic hydrogen; Electrocatalytic denitrification; Iron-doped carbon catalysts; Wastewater treatment; Zeolitic imidazolate framework.