Visible light irradiation enhanced sulfidated zero-valent iron/peroxymonosulfate process for organic pollutant...

This study developed a novel process named sulfidated zero-valent iron/peroxymonosulfate/visible light irradiation (S-mZVI/PMS/vis) for enhanced organic pollutant degradation. The S-mZVI/PMS/vis process exhibited remarkable catalytic activity, achieving a 99.6% rhodamine B (RhB) removal within 10 min. The degradation rate constant of RhB by the S-mZVI/PMS/vis process was found to be 6.49 and 79.84 times higher than that by the S-mZVI/PMS and PMS/vis processes, respectively. Furthermore, the S-mZVI/PMS/vis process worked efficiently across a wide pH range (3.0-9.0), and the result of five-cycle experiments demonstrated the excellent reusability and stability of S-mZVI. Radical quenching tests and electron paramagnetic resonance analysis indicated that ·O₂^-, ¹O₂, and h⁺ significantly contributed to the degradation of RhB through the S-mZVI/PMS/vis process. The visible light irradiation increased the Fe²⁺ concentration, improved the Fe³⁺/Fe²⁺ cycle, and consequently enhanced the PMS decomposition, reactive species production, and RhB degradation. This work offers a promising strategy to highly efficiently activate PMS for organic pollutants elimination from aqueous solutions.