Microwave enhanced Fenton-like process for degradation of perfluorooctanoic acid (PFOA) using Pb-BiFeO₃/rGO as heterogeneous catalyst

Hybrid nanostructured materials play an increasing role in environmental applications. This study developed a hybrid nanocomposite (Pb-BFO/rGO) using a microwave-assisted hydrothermal method, which grafted Pb-doped BiFeO₃ (BFO) nanoparticles on reduced graphene oxide (rGO) sheets. Pb-BFO/rGO was used as a heterogeneous catalyst in a microwave enhanced Fenton-like process (MW-Fenton-like) for the decomposition of perfluoroocatanoic acid (PFOA), a perfluorinated compound present in water bodies with high bioaccumulation and toxicity for human being. The results reveal that Pb-BFO/rGO has large specific surface area (∼84.2 m² g⁻¹), small crystallite sizes (∼3.3 nm) and multiple functional groups such as carboxyl groups and Fe-O groups. Compared with the bare BFO and Pb-BFO, Pb-BFO/rGO showed greater catalytic efficiencies for H₂O₂ activation for PFOA degradation with the removal ratio of 90.0% from 30.0 mg L⁻¹ to 50.0 mg L⁻¹ within 5.0 min in the MW-Fenton-like process. Microwave irradiation was shown to significantly influence the degradation of PFOA through energy transfer and cross-coupling reactions. Pb-BFO/rGO absorbed the microwave energy, which facilitated the decomposition of H₂O₂ and the generation of hydroxy radicals (^[rad]OH), which is responsible for the PFOA degradation. The degradation pathway of PFOA was investigated by detecting the degradation byproducts using UPLC-MS/MS and ICP/MS. Five kinds of short-chain perfluorinated carboxylic acids and fluoride ion were identified. The overall findings provide new insight into the novel hybrid catalysis for Fenton-like and other water treatment applications.