Wang Ying, Chen Liang, Chen Xin, Bai Shengchi, Wang Xiaoqi, Wen Wen, Liu Wen, Ma Jun, Tiraferri Alberto, Liu Baicang
State Key Laboratory of Hydraulics and Mountain River Engineering, College of Architecture and Environment, Sichuan University, Chengdu, Sichuan 610207, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Section 2, Lingang Ave., Cuiping District, Yibin, Sichuan 644000, China.
Research Institute of Petroleum Exploration & Development (RIPED), PetroChina, No. 20 Xueyuan Road Haidian District, Beijing, China.
J Hazard Mater. 2025 Oct 5;497:139578. doi: 10.1016/j.jhazmat.2025.139578. Epub 2025 Aug 16.
This study elucidates the electronic structure-activity relationship between secondary amines and ferrate(VI) (Fe(VI)) activation. Comparative experiments demonstrated that pyrrolidine (Py) significantly outperformed diethylamine (Di) in enhancing Fe(VI)'s oxidation capability across various dosage conditions, pollutants, and water matrices. Specifically, for isoquinoline (IQL) degradation, Py-Fe(VI) achieved an approximately 7-fold higher rate constant than Fe(VI) alone, versus a 2-fold improvement observed with Di-Fe(VI). Mechanistic studies combining quenching experiments and EPR characterization corroborated Fe(IV)/Fe(V) as dominant reactive species for IQL degradation, with kinetic modeling revealing that Fe(IV) contributes > 80 % to IQL degradation in all processes. Electrochemical analysis via cyclic voltammetry and electrochemical impedance spectroscopy studies suggested that Fe(VI) activation by Di and Py might involve the formation of iron-secondary amine complexes. Density functional theory calculations highlighted Py's lower energy barrier for Fe(VI) complexation (27.7 vs. Di's 29.1 kcal/mol), accelerating activation. Secondary amines were shown to stabilize Fe(IV) via coordination, extending its reactive lifetime. Systematic evaluation of various secondary amines revealed a significant negative correlation between the highest occupied molecular orbital energy levels of amines and Fe(VI) activation performance. Moderate electron-donating capacity promotes iron complexation and pollutant degradation. This work establishes a molecular design framework for Fe(VI) activators while providing new insights into high-valent iron-mediated oxidation mechanisms, advancing sustainable water treatment strategies.
本研究阐明了仲胺与高铁酸盐（VI）（Fe（VI））活化之间的电子结构-活性关系。对比实验表明，在各种剂量条件、污染物和水基质下，吡咯烷（Py）在增强Fe（VI）氧化能力方面显著优于二乙胺（Di）。具体而言，对于异喹啉（IQL）降解，Py-Fe（VI）实现的速率常数比单独的Fe（VI）高约7倍，而Di-Fe（VI）仅提高了2倍。结合猝灭实验和电子顺磁共振表征的机理研究证实，Fe（IV）/Fe（V）是IQL降解的主要活性物种，动力学模型表明，在所有过程中Fe（IV）对IQL降解的贡献>80%。通过循环伏安法和电化学阻抗谱研究进行的电化学分析表明，Di和Py对Fe（VI）的活化可能涉及铁-仲胺配合物的形成。密度泛函理论计算突出了Py与Fe（VI）络合的较低能垒（27.7千卡/摩尔，而Di为29.1千卡/摩尔），加速了活化过程。仲胺通过配位作用稳定Fe（IV），延长其反应寿命。对各种仲胺的系统评估揭示了胺的最高占据分子轨道能级与Fe（VI）活化性能之间存在显著的负相关。适度的给电子能力促进铁络合和污染物降解。这项工作建立了Fe（VI）活化剂的分子设计框架，同时为高价铁介导的氧化机制提供了新的见解，推动了可持续水处理策略的发展。
