Separation of oil from water using porous PDMS capsules

초록

Various techniques for separating mixed oil and water have been developed for the purpose of controlling marine oil pollution and for the purification of wastewater containing oil from industrial processes. In this work, we fabricate porous polydimethylsiloxane (PDMS) capsules to develop a high-performance, selective oil absorber. A template method using a sugar cube is used to fabricate the porous PDMS structure by dissolving the sugar template after infiltrating it with the PDMS solution. A hollow capsule structure was prepared by controlling the infiltration time of the PDMS into the sugar template. Contact angle measurements revealed the highly porous surface of the PDMS capsule maximized the differences between hydrophobicity and oleophilicity, which improved the absorption selectivity of oil from water. The fabricated PDMS capsules exhibited superhydrophobic and superoleophilic wetting properties; the oil droplets were absorbed into the PDMS capsule upon contact, while the water droplets were not absorbed with a contact angle above 170o. Since the absorbed oil can be stored in the capsule pores, the oil absorption capability per unit weight of the absorber is highly increased. The adsorption performance and recyclability of the PDMS capsules were also evaluated using various waste oils. Copyright © The Korean Society for Precision Engineering

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