Synergistic radical and non-radical pathways for enhanced mineralization of organic pollutants by non-metallic h-BN/MWCNT composites via mechanochemical activation

Abstract

Non-metallic catalysts have gained great attention in peroxymonosulfate based advanced oxidation processes (PMS-AOPs) for their enhanced safety and environmental compatibility. However, low catalytic efficiency, incomplete mineralization and harsh preparation methods still hinder their practical application. This work developed an innovative solvent-free ball milling-assisted pyrolysis strategy utilizing hexagonal boron nitride (h-BN) and multi-walled carbon nanotubes (MWCNTs) as synergistic precursors to construct the BN-CNT-700 composite. The mutually doped active sites were facilely formed through carbon/nitrogen hybridization, where electron-withdrawing CO groups dominated ¹O₂ generation while electron-donating CN sites primarily mediated SO₄^•− production. The radical and non-radical pathways worked in synergy to achieve complete removal of 20 mg·L⁻¹ bisphenol A (BPA) coupled with an ultra-high mineralization efficiency of 88.6 %, surpassing most reported non-metallic counterparts and even outperforming various metal-based systems. Moreover, the BN-CNT-700/PMS system demonstrated exceptional environmental robustness, maintaining high BPA removal efficiency across broad pH ranges, various inorganic ions, and complex water matrices. This research offers the important implications for the rational design of non-metallic catalysts with tunable active sites for high-efficiency pollutant decontamination.