Enhanced ultrasound-assisted controllable growth assembly of MoS2/Fe3O4 materials for piezoelectric Fenton reaction degradation of sildenafil.

The Fenton technique is known for its high efficiency and minimal environmental impact; however, its degradation reaction process requires a sustained acidic environment. In this study, nanoflower and cookie-like morphologies of composite piezoelectric materials were synthesized for ultrasound-driven piezoelectric-Fenton degradation of sildenafil. The most effective assembly method involves growing MoS₂ on the rough-surfaced Fe₃O₄ microspheres as a substrate. Characterization and degradation results indicate that these piezoelectric materials utilize different assembly modes when operating under neutral conditions, and evaluate in depth the effect of various factors such as pH, H2O2 dose and ultrasonic (US) power on the degradation of sildenafil. Both composites exhibit the ability to initiate reactions neutrally and sustain some degradation efficacy in a neutral environment. The composite catalyst almost completely removed 50 mg L-1 of sildenafil within 60 min, and AFM characterization showed a piezoelectric response of 56 p.m./V for the core-shell nanoflower catalyst. These data suggest that the assembly of Fe3O4-based surface-grown MoS2 allows constructing of more active sites and provides favourable reaction efficacy for the Fenton reaction. The free radical experiments have shown that ·OH radicals are the main reactive species in the process. This work explored the effect of different assembly methods of composite piezoelectric material on the degradation reaction and provided new ideas for the subsequent construction of composite material systems.