Sunlight Induced Rapid Oil Absorption and Passive
Room-Temperature Release: An Effective Solution toward Heavy Oil Spill CleanupAbstract: Rapid
cleanup and easy recovery of spilled heavy oils is always a great challenge
due to their high viscosity (> 103 mPa s). One of the efficient
methods to absorb highly viscous oils is to reduce their viscosity by
increasing their temperature. In this work, we integrate the sunlight-induced
light-to-heat conversion effect of polypyrrole (PPy) and thermo-responsive
property of poly(N-isopropylacrylamide) (PNIPAm) into the melamine sponge,
which successfully delivers a fast heavy oil absorption under sunlight and
passive oil release underwater at room temperature. Thanks to the rationally
designed functionalities, the PNIPAm/PPy functionalized sponges possess
oleophilicity and hydrophobicity under sunlight. Due to the photo-thermal
effect of PPy, the sponges locally heat up contacting heavy oil under sunlight
and reduce its viscosity to a point where the oil voluntarily flow into the
pores of the sponge. The material in this work is able to rapidly absorb the
heavy oil with room temperature viscosity as high as ~1.60 × 105 mPa
s. The absorbed oil can
be passively forced out the sponge underwater at room temperature due to the
hydrophilicity of PNIPAm. The sunlight responsive and multifunctional sponge represents a meaningful attempt in coming
up with a sustainable solution towards heavy oil spill.
