Comparative experimental study of bisphenol A degradation via sulfate radical and electron transfer mechanisms in persulfate-activated advanced oxidation processes

Abstract

Addressing the growing challenge of water contamination, this study comparatively evaluated a persulfate (PDS) system activated by non-radical nitrogen-doped carbon nanotubes (N-CNTs) versus a PDS system activated by radical-based iron (Fe²⁺), both used for the degradation of bisphenol A (BPA). The N-CNTs/PDS system, driven by the electron transfer mechanism, achieved remarkable 90.9% BPA removal within 30 min at high BPA concentrations, significantly outperforming the Fe²⁺/PDS system, which attained only 38.9% removal. The N-CNTs/PDS system maintained robust degradation efficiency across a wide range of BPA concentrations and exhibited a high degree of resilience in diverse water matrices. By directly abstracting electrons from BPA molecules, the N-CNTs/PDS system effectively minimised oxidant wastage and mitigated the risk of secondary pollution, ensuring efficient utilisation of active sites on N-CNTs and sustaining a high catalytic rate. The formation of the N-CNTs-PDS∗ complex significantly enhanced BPA degradation and mineralisation, thereby optimising PDS consumption. These findings highlight the unparalleled advantages of the N-CNTs/PDS system in managing complex wastewater, offering a promising and innovative solution for treating complex industrial wastewater and advancing environmental remediation efforts.