Bifunctional remediation of oil spills based on pickering emulsification of polypyrrole-Ag3PO4/AgCl@Palygorskite

Abstract

The frequent occurrence of marine oil spill accidents has brought great negative influence on the ecological environment and human development. In this study, polypyrrole-Ag3PO4/AgCl@Palygorskite (PAAP) was successfully synthesized by a simple co-precipitation approach and then it was used to realize the dual remediation of marine oil pollution based on Pickering emulsion-based photocatalytic technology. Here, palygorskite (PAL) functions as an effective Pickering emulsion stabilizer to disperse oil pollutants. In virtue of the dispersion of PAL, Ag3PO4-based photocatalyst is able to fully contact with the oil droplets, thus leading to a greatly improved photocatalytic degradation performance for oil pollution. PAAP-stabilized Pickering emulsion showed good stability in 7 days, which provided enough time for the subsequent oil photodegradation. The photocorrosion of Ag3PO4 was significantly alleviated by the introduction of polypyrrole and AgCl. Thus, the photocatalytic activity and reusability of PAAP were greatly enhanced compared with Ag3PO4@PAL. Additionally, this study explored the influence of illumination time, PAAP amount and environmental factors (such as salinity and wave fluctuations) on the emulsification-photocatalytic remediation ability of PAAP. Importantly, it was found that intermittent agitation could increase the removal of diesel greatly. Finally, the photocatalytic reaction mechanism and the possible diesel degradation pathways were analyzed through a series of experimental investigations.