In situ regeneration of oil absorbent via wettability switch of conjugated polymer surfaces

Absorbent-based technology shows the possibility of full removal and reclaim of oils from water while bringing little adverse effects to the environment. In spite of their promises, the recycle and regeneration of saturated absorbents have been less-explored.
Here, we demonstrate a light-weight high-efficient conjugated polymer foam as oil absorbent capable of in situ regenerating via wettability switch during electrochemical oxidation and reduction. We electropolymerize polypyrrole-dodecylbenzenesulfonate (PPy(DBS)) on the surfaces of commercially available carbon foam. The PPy(DBS) shows oleophilic property when oxidized, absorbing oils (i.e., oils stick to the polymer surface and trapped within the micro-pores of the foam). Under reduction, the surface switches to oleophobic, releasing the oils, while in situ regenerating the polymer surface. Using this approach, in situ absorption and release of various oils is demonstrated. We further demonstrate the wettability switch performance (characterizing the retention force when oxidized and switch time when reduced) of the absorbent during 250 redox cycles. Together, this novel adsorbent shows great promise towards high-efficient continuous oil/water separation applications.