Heterogeneous UV/Fenton degradation of TBBPA catalyzed by titanomagnetite: Catalyst characterization, performance and degradation products

Tetrabromobisphenol A (TBBPA), a widely used brominated flame retardant, could negatively affect various aspects of mammalian and human physiology, which triggers effective techniques for its removal. In this work, the degradation characteristics of TBBPA in heterogeneous UV/Fenton reaction catalyzed by titanomagnetite (Fe3−xTixO4) were studied. Batch tests were conducted to evaluate the effects of titanomagnetite dosage, H2O2 concentration and titanium content in magnetite on TBBPA degradation. In the system with 0.125 g L−1 of Fe2.02Ti0.98O4 and 10 mmol L−1 of H2O2, almost complete degradation of TBBPA (20 mg L−1) was accomplished within 240 min UV irradiation at pH 6.5. The titanium incorporation obviously enhanced the catalytic activity of magnetite. As shown by the XRD and XANES results, titanomagnetite had a spinel structure with Ti4+ occupying the octahedral sites. On the basis of the degradation products identified by GC-MS, the degradation pathways of TBBPA were proposed. TBBPA possibly underwent the sequential debromination to form TriBBPA, DiBBPA, MonoBBPA and BPA, and β-scission to generate seven brominated compounds. All of these products were finally completely removed from reaction solution. In addition, the reused catalyst Fe2.02Ti0.98O4 still retained the catalytic activity after three cycles, indicating that titanomagnetite had good stability and reusability. These results demonstrated that heterogeneous UV/Fenton reaction catalyzed by titanomagnetite is a promising advanced oxidation technology for the treatment of wastewater containing TBBPA. [Display omitted] ► TBBPA was completely degraded by UV/Fenton process catalyzed by titanomagnetite. ► Catalytic ability of titanomagnetite increased with increasing titanium content. ► Debromination and β-scission are the two major pathways for TBBPA degradation. ► Titanomagnetite is a promising material for treating wastewater containing TBBPA.