Study on the Influence of the Reduced Graphene Oxide Coating on the Hydrophobicity of PU Sponge for Oil Recovery
Main Article Content
Abstract
In order to produce a hydrophobic material for oil removal from surface waters, in this study, the reduced graphene oxide coated PU sponges (rGO@PU) were prepared by ultrasonication of PU sponges with suspension of rGO in ethanol. The chemical structure of the rGO coatings was investigated by X-ray diffraction and FT-IR spectroscopy methods. The surface morphology of the obtained materials was also examined by SEM. The influence of the rGO loadings and the number of coatings on the hydrophobicity of the materials was investigated. The testing on the surface hydrophobicity indicated that the water drops were remained on the surface of rGO@PU for 4.5 - 5 hours. The results indicated that the best hydrophobic sponge was obtained at the rGO loading of 3 mg/mL and after three times of coatings. The water contact angle (WCA) of the optimal rGO@PU was up to 119°. The kerosene oil absorption capacity of the rGO@PU in 5 minutes is 32.34 g/g. Besides, the oil-water separation ability of the material was also investigated by passing the kerosene-water mixture through a filter funnel containing the synthesized porous material rGO@PU. The result indicated that the separation efficiency of the material was 85%. The recyling test was conducted by squeezing the saturated absorbed sponges and applying the desorbed sponges for the next cycle tests. After 10 times of recycling, the amounts of kerosene absorption on the rGO@PU were maintained from 4.39 - 5.33 g, implying the excellent recyclability of the material.
References
https://doi.org/10.1016/j.jlp.2022.104912.
[2] A. J. B. Milne, A. Amirfazli, The Cassie Equation: How it is Meant to be Used, Advances in Colloid and Interface Science, Vol. 170, No. 1-2, 2012, pp. 48-55, https://doi.org/ 10.1016/j.cis.2011.12.001.
[3] H. Wang et al., Review: Porous Metal Filters and Membranes for Oil-Water Separation, Nanoscale Res. Lett., Vol. 13, No. 1, 2018, pp. 284, https://doi.org/10.1186/s11671-018-2693-0.
[4] H. Bellanger, T. Darmanin, E. T. D. Givenchy, F. Guittard, Chemical and Physical Pathways for the Preparation of Superoleophobic Surfaces and Related Wetting Theories, Chemical Reviews, American Chemical Society, Vol. 114, No. 5, 2014, pp. 2694-2716, https://doi.org/10.1021/cr400169m.
[5] S. C. Ray, Application and Uses of Graphene Oxide and Reduced Graphene Oxide, in Applications of Graphene and Graphene-Oxide Based Nanomaterials, Elsevier, 2015, pp. 39-55, https://doi.org/10.1016/b978-0-323-37521-4.00002-9.
[6] M. Sohail et al., Modified and Improved Hummer’s Synthesis of Graphene Oxide for Capacitors Applications, Mod, Electron, Mater., Vol. 3, No. 3, 2017, pp. 110-116, https://doi.org/10.1016/j.moem.2017.07.002.
[7] I. Bychko, A. Abakumov, O. Didenko, M. Chen, J. Tang, P. Strizhak, Differences in the Structure and Functionalities of Graphene Oxide and Reduced Graphene Oxide Obtained from Graphite with Various Degrees of Graphitization, J. Phys, Chem, Solids, Vol. 164, 2022, pp. 110614, https://doi.org/10.1016/j.jpcs.2022.110614.
[8] S. Zhou et al., One-pot Synthesis of Robust Superhydrophobic, Functionalized Graphene/Polyurethane Sponge for Effective Continuous Oil-water Separation, Chem, J. Eng, Vol. 302, 2016, pp. 155-162,
https://doi.org/10.1016/j.cej.2016.05.051.
[9] Z. Zhang, H. Liu, W. Qiao, Reduced Graphene-Based Superhydrophobic Sponges Modified by Hexadecyltrimethoxysilane for Oil Adsorption, Colloids Surfaces A Physicochem, Eng, Asp, Vol. 589, 2020, pp. 124433, https://doi.org/ 10.1016/j.colsurfa.2020.124433.
[10] A. Jamsaz, E. K. Goharshadi, Flame Retardant, Superhydrophobic, and Superoleophilic Reduced Graphene Oxide/Orthoaminophenol Polyurethane Sponge for Efficient Oil/Water Separation, J. Mol. Liq., Vol. 307, 2020, pp. 112979, https://doi.org/ 10.1016/j.molliq.2020.112979.
[11] X. Zhang et al., Super-Hydrophobic Graphene Coated Polyurethane (GN@PU) Sponge with Great Oil-Water Separation Performance, Applied Surface Science, Vol. 422, 2017, pp. 116-124, https://doi.org/10.1016/j.apsusc.2017.06.009.