Application of nickel foam-supported Co3O4-Bi2O3 as a heterogeneous catalyst for BPA removal by peroxymonosulfate activation.

Nickel foam (NF)-functionalized Co3O4-Bi2O3 nanoparticles (CBO@NF) synthesized using a facile one-step microwave-assistant method were employed as catalysts to activate peroxymonosulfate (PMS) with bisphenol A (BPA) as the target pollutant. The crystallinity, morphology, and chemical valence state of the synthesized CBO@NF were analyzed using XRD, SEM, and XPS, respectively. Moreover, effects of the preparation parameters, including the calcination temperature and calcination time as well as the loading dosage, were evaluated in detail. A degradation efficiency of 95.6% was achieved within 30 min with the optimal degradation system. The CBO@NF/PMS system shows great catalytic activity in a pH range from 3.0 to 11.0. The stability and reusability of the CBO@NF supported catalyst was evaluated through a recycling experiment. In addition, the possible degradation mechanism was also explored using a quenching experiment and electron paramagnetic resonance (EPR) detection. The result shows that both the surface-bound SO4- and OH play significant roles during the degradation process, where the electron transfer of Co2+/Co3+, Bi3+/Bi5+, and Ni2+/Ni3+ realizes the sustained regeneration of the active radicals. This work provides new insight for the practical applications of sulfate radical-based advanced oxidation processes (SR-AOPs) in wastewater treatment.