The gigantic petroleum exploration and production are
threatening
the lives and well-being of people and other species. Pizeocatalysis
is a bridge to transfer ceaseless mechanical energy to chemical energy
and thus triggers redox reactions. In this study, piezoelectric MoS2 was used as a surface-washing fluid to physically and chemically
decontaminate oiled sands. The MoS2 displayed single- and
few-layer structures, which were conducive to piezocatalysis. The
addition of MoS2 could decrease the interfacial tension,
thereby facilitating oil removal. The oil removal efficiency varied
under different environmental conditions. Quenching experiments with
different scavengers and electron paramagnetic resonance (EPR) spectra
showed the existence of reactive oxygen species (ROS) including 1O2, •O2
–, and •OH. It was found that shaking was a necessary
initiator to trigger piezocatalysis and singlet oxygen (1O2) was the dominant ROS. The MoS2 fluid exhibited
good stability, maintaining high removal efficiency after five reuse
cycles. Notably, results indicated that high-molecular-weight hydrocarbons
were degraded into lower-molecular-weight ones, indicating the existence
of chemical oxidation pathways in oil removal. This study provides
a facile self-powered piezocatalytic surface-washing process by harnessing
natural energy from water agitation to clean up oiled sands.