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

Abstract

In this work, amorphous boron (A-Boron) as a metal-free co-catalyst was applied to address the slow kinetics of FeII regeneration and inactive FeIII accumulation in Fenton-like peroxydisulfate (PDS) activation. The A-Boron/FeIII/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 and SO4−) 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 FeIII 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.