Insights into boron accelerated Fenton-like chemistry: Sustainable and fast FeIII/FeIIcirculation

In this work, amorphous boron (A-Boron) as a metal-free co-catalyst was applied to address the slow kinetics of Fe-II regeneration and inactive Fe-III accumulation in Fenton-like peroxydisulfate (PDS) activation. The A-Boron/ Fe-III/PDS system can rapidly degrade bisphenol A (BPA) for ten cyclic runs without performance decline. Based on chemical probing, radical quenching and in situ capturing tests, Fe(IV) and radicals ((OH)-O-center dot and SO4 center dot-) are identified as the primary reactive species, and the combined ROS can achieve universal pollutants oxidation with high PDS utilization efficiency. QSAR study unveils that the kobs values of pollutants linearly depend on their EHOMO. A-Boron can bind with Fe-III species for catalytic reduction, and meanwhile, the semi-metallic surface experiences stepwise transformation. The fast dissolution of inactive surface boron oxide enabled a self-cleaned and reactive boron surface for long-lasting iron circulation. Also, BPA degradation pathways were proposed based on UHPLC-QTOF-MS tests and Fukui index calculation.

Automated summary

A metal-free co-catalyst, amorphous boron (A-Boron), was used to overcome the slow kinetics of Fe-II regeneration and inactive Fe-III accumulation in Fenton-like peroxydisulfate (PDS) activation. The A-Boron/Fe-III/PDS system efficiently degraded bisphenol A (BPA) without performance decline for ten cyclic runs. Fe(IV) and radicals ((OH)-O-center dot and SO4 center dot-) were identified as the primary reactive species responsible for universal pollutants oxidation. QSAR study revealed a linear dependence between the kobs values of pollutants and their EHOMO. A-Boron bound with Fe-III species for catalytic reduction, while the semi-metallic surface of A-Boron underwent stepwise transformation, enabling long-lasting iron circulation.