Chemical Engineering Journal, Vol.323, 191-202, 2017
Synthesis of lignin-based polyurethane/graphene oxide foam and its application as an absorbent for oil spill clean-ups and recovery
Superhydrophobic and superoleophilic foam-like materials are attracting significant interest as promising absorbent for oil spill clean-up from water bodies. In this work, we report the synthesis of lignin based polyurethane (LPU) foam and its surface modification to form a superhydrophobic and superoleophilic sorbent, for use in spill clean-ups. The interior matrix of the LPU foam substrate was grafted with adhesive polydopamine-reduced graphene oxide (rGO) and octadecylamine (ODA), which reacted to transform the LPU foam skeleton to a superhydrophobic and superoleophilic 3-D structure. The resulting foam (designated as LPU-rGO-ODA) was shown to retain the interconnected porous structure, with a water contact angle of 152. Spectroscopic and microscopic analyses were conducted to investigate the structure and morphology of the foam. Sorption experiments with crude oil, engine oil, kerosene and chloroform showed that the LPU-rGO-ODA foam was an excellent oil sorbent with a sorption capacity of 26-68 times its own weight, which was much greater than that of a commercial non-woven polypropylene sorbent. The LPU-rGO-ODA foam also exhibited a high selectivity to oil sorption and excellent reusability over repeated sorption-squeezing cycles. The absorbed oils in the sorbent could be removed and collected simply by squeezing the oil-laden sponge, and the foam sorbent became ready for reuse in next sorption cycle. As such, LPU-rGO-ODA foam is expected to be a promising oil sorbent for potential applications in oil-spill clean-ups. (C) 2017 Published by Elsevier B.V.
Keywords:Superhydrophobic;Superoleophilic;Polyurethane foam;Separation;Oil absorbent;Oil spill clean-up