Poly(dimethylsiloxane)/graphene oxide composite sponge: A robust and reusable adsorbent for efficient oil/water separation
The effective strategy for the separation of oil pollution is the development of polymer sponge with large adsorption capacity, high oil/water selectivity and mechanical stability. The improvement of adsorption performance for polymer sponge should not be accompanied with the sacrifice of mechanical property and recycle stability, which is fundamental to the long-term operation in the cleanup of oil-spill accident. In this work, we synthesized robust and reusable sponge based on poly(dimethylsiloxane) (PDMS) frame coated stereoscopically with graphene oxide (GO) via the amidation between PDMS and GO. The combination of PDMS skeleton with the robust macro-porous structure and GO nanosheets acting as mechanical fortifiers contributes to the nanocomposite sponge with great integrity and durability. The resultant PDMS/GO nanocomposite sponge exhibits a high compressive strength of 42.7 kPa with strain of 60 % after 50 cycles. The high adsorption capacity for various oils and organic solvents is obtained in nanocomposite sponge, and the maximum capacity of 14.6 g/g is achieved for chloroform, which is ascribed to the large porosity and hydrophobicity caused by the rough PDMS skeleton covered by the GO nanosheets. Furthermore, the vacuum device with nanocomposite sponge demonstrates an effective separation for large amounts of oil/water mixture with maximum separation of 724 times of sponge weight during adsorption. This work provides a productive approach to develop porous polymer nanocomposite with high absorption property and mechanical cycle stability, and paves the path for the application of polymer sponge in the oil pollution.