Overlooked role of boron precursors in tuning engineered zero-valent iron to activate peracetic acid for sustainable micropollutant oxidation

This work comprehensively investigated how the characteristics of boron (B) precursors affect the catalytic activity of microscale zero-valent iron (mZVI) towards peracetic acid (PAA) activation for micropollutant degradation. Three boron precursors were introduced into mZVI by ball milling with their physical-chemical properties carefully characterized, and their ability to activate PAA comprehensively evaluated via sulfamethoxazole (SMX) oxidation efficiency. It’s found that B 2 O 3 -ZVI demonstrated the highest capability to activate PAA for SMX degradation, with k obs 2 ∼ 3 times higher than Na 2 B 4 O 7 -ZVI and H 3 BO 3 -ZVI. Specially, B precursors regulate the ability of mZVI to activate PAA via the following two aspects: (1) affecting the formation and content of FeB to accelerate Fe(II) regeneration; (2) increasing the hydrophilicity of the iron particles and the affinity of B-ZVI for binding PAA to different extent. This study highlights the important role of boron precursors in tuning engineered mZVI to initiate Fenton-like process for water purification.