Synergistic effect and mechanism of zero-valent iron activated persulfate on Cu(II)-EDTA decomplexation enhanced with weak magnetic field

Herein, a weak magnetic field (WMF) was applied to improve the catalytic degradation of the copper-ethylene diamine tetraacetic acid complex (Cu(II)-EDTA) and recovery of Cu using zero-valent iron/peroxomonsulfate (ZVI/PS). The removal rates of Cu(II)-EDTA in the WMF/ZVI/PS system were 7.92 and 1.33 times those in the ZVI and ZVI/PS systems, respectively. The recovery rates of Cu in the WMF/ZVI/PS system were 4.78 and 1.25 times more than those in ZVI and ZVI/PS systems, respectively. Scavenger quenching experiments and electron spin resonance (ESR) results showed that more active radicals (SO4 center dot- and center dot OH) were produced and both SO4 center dot- and center dot OH played the important role in Cu(II)-EDTA degradation in the WMF/ZVI/PS system. The ZVI and PS dosages and initial solution pH considerably affected the removal efficiency of Cu(II)-EDTA. X-ray energy-dispersive spectroscopy (EDS) results showed that WMFs could accelerate the enrichment of paramagnetic Cu2+ on the ZVI surface. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results showed that Cu2+ ions were first adsorbed on the corroded ZVI and then reduced to Cu0 with time. A possible Cu(II)-EDTA decomposition and Cu reduction mechanism was also proposed. This study provides a promising and ecofriendly technique for treating industrial wastewater containing organic complexed metals.

Automated summary

This study investigates the use of a weak magnetic field to enhance the catalytic degradation of copper-ethylene diamine tetraacetic acid complex and recovery of copper using zero-valent iron/peroxomonsulfate. The results show that the WMF/ZVI/PS system produces more active radicals, leading to higher degradation and recovery rates compared to other systems. The study also examines the influence of ZVI and PS dosages and initial solution pH on the efficiency of the process.