Metal-free boron-assisted Fe(III)/peracetic acid system for ultrafast removal of organic contaminants: Role of crystalline nature and interfacial suboxide boron intermediates

Abstract

Peracetic Acid (PAA) has emerged as an alternative candidate oxidant for H2O2 and persulfate-mediated catalytic oxidation. However, the sluggish kinetics of Fe3+/Fe2+ recycling still severely causes its limited applications. In this work, boron, for the first time, a metal-free and inexpensive co-catalyst, was introduced into the Fe3+/PAA Fenton-like system to remarkably accelerate the Fe2+ regeneration, further facilitating organic wastewater decontamination (an almost 145.0-fold kinetic increase on BPA removal). More excitingly, the crystalline nature of boron significantly modulated the activation system, and the crystalline boron and amorphous boron exhibited contrasting Fe3+ reduction characteristics. The amorphous boron-contained system enabled ultra-fast deterioration of various micro-pollutants. Validation experiments and theoretical calculations demonstrate that the surface B-B bonds with the formed interfacial suboxide boron continuously donated electrons to boost the rapid reduction of Fe3+. This work opens a new research avenue to promote the application of Fe3+-activated PAA systems with high activity in continuity and also guides the development of a new series of co-catalysts in wastewater treatment.