Expanded Polytetrafluoroethylene/Graphite Composites for Easy Water/Oil Separation

Abstract

Oil spills in the ocean greatly threaten local environments, marine creatures, and coastal economies. An automatic water/oil separation material system was proposed in this study, and a tubular geometry was chosen to demonstrate the water/oil separation efficiency and effectiveness. The water/oil separation tubes were made of expanded polytetrafluoroethylene (ePTFE) and graphite composites. The permeation pressures of water and oil through the tube walls were tuned by adjusting the ePTFE microstructure, which, in turn, depended on the degree of expansion and the graphite content. Fourier-transform infrared spectroscopy was performed to confirm the compositions of the ePTFE/graphite composites, and a scanning electron microscope was used to examine the microstructure and morphology of the expanded PTFE/graphite composite tubes. When a proper pressure was applied, which was higher than the oil’s permeation pressure (3.0 kPa) but lower than the water’s permeation pressure (57 kPa), the oil leaked out of the tube walls while the water went through the ePTFE/graphite tubes. As such, the water/oil mixture could be separated and collected in different containers or an outer tube. Due to this automatic separation, the whole process could be done continuously and conveniently, thus exhibiting great potential in the practical applications of oil spill and water separation/remediation.

Expanded Polytetrafluoroethylene/Mxene Nanosheet Composites with Hydrophilicity and Lipophilicity for Purification of Oil Spills and Wastewater

“…The addition of Mxene is predicted to enhance the hydrophilicity and oil absorption efficiency of the ePTFE materials, which provides the possibility of the construction of new amphiphilic oil adsorption and oil−water separation materials. In contrast with previous work (ePTFE/graphite), 20 the introduction of Mxene may increase the water affinity of the composites, which can increase their separation efficiency to some extent. Furthermore, the increase in hydrophilicity can prohibit the material fouling.…”

“…Due to their large-scale processing capabilities, expansion methods have been widely used to prepare nanoporous samples, including polypropylene and polyethene. Meanwhile, polluted waters usually exhibit harshly corrosive and other conditions, which require the adsorption materials to not only have good oil absorption capacities but also have excellent chemical resistance and large service temperature ranges. − Among the porous materials with favorable separation performances, polytetrafluoroethylene (PTFE) has stable chemical properties, excellent durability, and self-cleaning abilities, and it can cope with various complex water environments; therefore, it is widely used in the field of water treatment …”

“…16−18 Among the porous materials with favorable separation performances, polytetrafluoroethylene (PTFE) has stable chemical properties, excellent durability, and self-cleaning abilities, and it can cope with various complex water environments; 19 therefore, it is widely used in the field of water treatment. 20 Based on the application properties of the water environment, PTFE is required to not only have good lipophilic properties but also have good hydrophilicity, and it is believed that increasing the hydrophilicity of PTFE can greatly increase its efficiency during water treatment. 3,21,22 However, due to the chemical inertia of PTFE, it is hydrophobic, which greatly impairs its performance during water treatment.…”

Viscosity characterization and flow simulation and visualization of polytetrafluoroethylene paste extrusion using a green and biofriendly lubricant

“…The highly multifunctional nature and soft, inert, and flexible characteristics of ePTFE make it ideal for various applications, particularly in filtration, implants, and medical devices applications. [ 7,8 ]…”

Hydrophobicity-Adjustable MOF Constructs Superhydrophobic MOF-rGO Aerogel for Efficient Oil–Water Separation

“…In recent years, frequent oil spills have caused serious water pollution. − The large amount of oily substances covering the sea seriously endangers the lives of various aquatic animals, plants, and even affects human health through the food chain. , Therefore, the efficient treatment of marine oil pollution is essential. Focusing on the characteristic of oil and water immiscibility, plenty of hydrophobic materials were utilized to remove the oil from water, such as various foams, sponges, and membrane materials. − Notably, the hydrophobicity of material is one predominant factor for the oil–water separation performance and thereby some methods of hydrophobic modification have been developed. Although various fluorides with excellent hydrophobicity have been widely applied in water treatment, their toxicity attracts strict resistance. , Therefore, a novel hydrophobic modification method is imminent to be designed on the basis of environmentally friendly materials.…”