Enhanced sonophotocatalytic degradation of bisphenol A using bimetal sulfide-intercalated MXenes, 2D/2D nanocomposite

A novel 2D Ti₃C₂T_x MXene (MX) co-catalyst and Ni_xMg_4-xS₄ (NMS) nanocomposite (NMS@MX) was simply prepared through a hydrothermal method and utilized as a sonophotocatalyst for the degradation of bisphenol A (BPA). Because the remediation of wastewater containing endocrine-disrupting compounds is an important issue in environmental fields, BPA was selected as the main organic pollutant to clarify the sonophotocatalytic activity of NMS@MX in this study. We confirmed the successful synthesis of NMS@MX through Fourier-transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analyses. The mineralization of BPA via sonophotocatalysis with NMS@MX was much faster and more efficient than by applying photolysis and sonolysis, separately. The NMS@MX sonophotocatalyst showed high sonophotocatalytic activity based on ~92% degradation of BPA within 60 min using both visible light and ultrasonication. This outcome could have resulted from the mitigation of the photo-corrosion of metal sulfides through heterojunction structures combined with the highly conductive MX co-catalyst. Furthermore, NMS@MX showed excellent sonophotostability over four consecutive cycles for the degradation of BPA with negligible loss of sonophotocatalytic activity. Finally, we proposed the sonophotocatalytic degradation pathway of BPA in the Sono/Vis/MNS@MX system (Sono = sonolysis; Vis = photolysis).