Flash joule heating synthesis of zero-valent iron and carbon vacancy dual-site catalysts for efficient singlet oxygen generation and selective organic pollutants degradation

FJH technology could effectively synthesize carbon-vacancy-anchored Fe 0 catalysts. • Fe 0 and carbon vacancies could synergistically activate PAA to generate 1 O 2 . • DFT calculations indicate that dual active sites enhance the adsorption of PAA. • The FJH-Fe/CGS-1600/PAA system can selectively degrade electron-rich pollutants. Singlet oxygen ( 1 O 2 ) exhibits strong resistance to interference and high selectivity toward electron-rich pollutants, making it highly promising for practical wastewater treatment. However, it remains challenging to generate 1 O 2 from activated peracetic acid (PAA) selectively. Herein, a dual-site synergistic catalyst was constructed by anchoring zero-valent iron (Fe 0 ) onto the residual carbon matrix of coal gasification slag (FJH-Fe/CGS-1600) via flash joule heating (FJH) induced transient thermal shock. Carbon vacancies act as electron traps to enhance PAA adsorption, while Fe 0 efficiently activates PAA and optimize the reaction pathway spatially, thereby promoting the generation of 1 O 2 . Consequently, the FJH-Fe/CGS-1600 achieved 95.7% degradation of bisphenol A within 60 min and demonstrated stable degradation performance across a wide pH range (5–8) and in chemical wastewater. Furthermore, it exhibited strong resistance to common anions found in chemical wastewater, high selectivity toward electron-rich pollutants, and extremely low metal leaching (< 0.1 mg L −1 ). Density functional theory (DFT) calculations reveal that carbon vacancies enhance the adsorption of the terminal oxygen in PAA (adsorption energy from −1.98 to −3.20 eV) and modulate the Fe 3d electronic structure. This research establishes a strategy for regulating non-radical species by utilizing joule heating to construct dual active sites, thereby providing a sustainable pathway for the co-treatment of coal-based solid waste and wastewater. Download: Download high-res image (134KB) Download: Download full-size image