New insights into magnetic fields selective enhancement of ferrate(Ⅵ) combined with hydrogen peroxide for removal of organic pollutants

Abstract

A magnetic field (MF) was applied to selectively enhance the generation of reactive species in a ferrate (Fe(VI)) water treatment system, effectively mitigating the limitations associated with the selective oxidation of Fe(VI) for organic matter. An MF was introduced into Fe(VI) and Fe(VI)/H2O2 systems, and a significant difference was observed in its enhancement of the removalefficiency of different types of contaminants. The results of radical scavenging experiments, high-valent Fe inhibition experiments, and methyl phenyl sulfoxide (PMSO) chemical probe experiments indicated that the MF promoted the production of Fe(V)/Fe(IV) in the Fe(VI) system and ·O2– in the Fe(VI)/H2O2 system, which modulated the generation of active species. Subsequently, by monitoring the change in product quantities during the decomposition of Fe(VI) and considering the theory of paramagnetism, it was hypothesized that the MF weakened the pathways for further self-reduction of Fe(V)/Fe(IV) in the Fe(VI) system and strengthened these pathways in the Fe(VI)/H2O2 system: Fe(IV) → Fe(III) → ·O2−. Furthermore, the systems enhanced by the MF were more resistant to partial anions and environmental interference in water quality experiments. This suggested that the MF modulation method may have significant potential for practical applications.