Efficient Peroxymonosulfate Activation via a Novel Iron-Based Metal Coordination Compounds for Acid Red 18 Degradation

• Fe-PDA, Iron-based metal coordination compounds, was synthesized by a hydrothermal method. • Fe-PDA significantly accelerates the cycling rate of Fe 3+ /Fe 2+ . • Fe-PDA can degrade AR18 at concentrations as high as 1000 mg/L, far exceeding reported levels in the literature, and can achieve a degradation rate of 93.9% within 12 minutes. • ·OH, SO 4 · - , 1 O 2 , and O 2 · - were generated in the reaction system, and SO 4 · - and O 2 ·- played a vital role in the degradation process. Fenton-like systems are promising for efficient pollutant removal, yet slow metal ion valence cycling hinders their large-scale application. peroxymonosulfate (PMS)-based Fenton-like systems produce highly reactive radicals, such as sulfate radicals (SO 4 ·- ) and hydroxyl radicals (·OH), spurring the development of sulfate radical-based advanced oxidation processes (SR-AOPs). Despite their high degradation efficiency, the core challenge of sluggish metal valence cycling in transition metal-mediated PMS activation remains to be resolved. To address this challenge, we synthesized a novel iron-based metal coordination compounds (Fe-PDA) with 2,3-pyridinedicarboxylic acid as ligand, aiming to accelerate valence cycling and thus boost the degradation of high-concentration dye pollutants via PMS-activated Fenton-like oxidation. PDA accelerates the Fe 3+ and Fe 2+ valence cycle and boosts PMS activation, thus facilitating efficient AR18 degradation. Under optimal conditions ([catalyst] = 1 g/L, [PMS] = 3 mM), 93.9% degradation of 1000 mg/L AR18 was achieved within 12 min, outperforming previously reported rates. Quenching experiments and EPR analysis confirmed the generation of SO 4 · - , ·OH, O 2 · - , and 1 O 2 , with SO 4 ·- and O 2 ·- as the dominant reactive species for AR18 decomposition. Moreover, four-cycle stability tests and multi-pollutant degradation assays verified the catalyst’s robust stability and universality. This study provides novel insights into the rational design of high-performance Fenton-like catalysts and a promising strategy for high-concentration pollutant degradation.