MIL-101(Fe) Networks Supported on Fluorinated Graphene Nanosheets as Coatings for Oil Sorption

Abstract

Oil spill leakage and industrial oily wastewater discharge into water bodies cause a considerable threat to the marine network and human health. Selective oil/organic solvent collection devices with effectual recovery of the oils from the water surface have been studied through engineering advanced materials displaying a special wetting property. Herein, we develop a waterrepellent MIL-101(Fe) material supported over fluorinated graphene (FG) nanosheets by in situ synthesis under ambient conditions. FG nanosheets not only provide the necessary structural nodes for the growth of octahedral MIL-101(Fe) nanostructures but also bring in the necessary hydrophobicity with a water contact angle of 146 ± 1°, possessing a surface free energy of 12.7 mJ m −2 . Powdered FG-MIL-101(Fe) demonstrated differential wettability with extreme chemical stabilities toward acidic and basic water. The solution processability of FG-MIL-101(Fe) was amalgamated with a copper mesh and a polydimethylsiloxane sponge via spray coating and inoculation methods en route designing oil recovery prototypes. The submersible FG-MIL-101(Fe)-PDMS sponges displayed selective pickup of oil and organic solvents with the sorption ranging from 1.85 to 3.8 g/g, in addition to displaying recyclability up to 10 cycles along with physical and chemical robustness. Additionally, the FG-MIL-101(Fe)-PDMS macroporous sponge was subjected to demulsification of a toluene/water system taking the distinct toluene pickup property. Selective oil recovery containers were fabricated by directing FG-MIL-101(Fe) suspensions on a copper mesh resulting in oil-collecting devices. Organics/oils selectively infiltrated into the FG-MIL-101(Fe)-coated copper mesh superwetting containers with separation efficiencies in the range of 96−100%. The translation of FG-MIL-101(Fe)-modified substrates was utilized to tackle real-time oil/organic collection prototypes from oil−seawater mixtures under turbulent conditions demonstrating excellent sorption abilities ranging from 4.4 to 5.6 g/g (by superwetting sponges) along with super efficiencies in the range of 92−98% (via superwetting containers).

Exploring the Self‐Cleaning Facets of Fluorinated Graphene Nanoarchitectonics: Progress and Perspectives

“…By using the extended Fowkes theory the solid surface tension could be obtained, wherein the interfacial free energy between the solid and liquid ($${{\gamma }_{SL}}$$ ), and the surface free energy of the liquid and solid ($${{\gamma }_{L}}$$ and$${\ {\gamma }_{S}}$$ ) correspondingly [58] . The origin of Kitazaki Hata method from Young‐Dupré expression as represented in Equation 1. $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {W}_{SL}=\ {\gamma }_{L}+{\gamma }_{S}-{\gamma }_{SL}={\gamma }_{L}\left(1+{\rm cos}\theta \right)\hfill\cr}}$$$ …”

“…Our group explored FG and its functionalized counterparts as a functional scaffold en route for the evolution of super‐wetting MOF and ZIF nanostructures via solution assisted self‐assembly (Figure 8a and 10a). [58,76,125,126] …”

“…[49] By using the extended Fowkes theory the solid surface tension could be obtained, wherein the interfacial free energy between the solid and liquid (g SL ), and the surface free energy of the liquid and solid (g L and g S ) correspondingly. [58] The origin of Kitazaki Hata method from Young-Dupré expression as represented in Equation 1.…”

“…Our group explored FG and its functionalized counterparts as a functional scaffold en route for the evolution of super-wetting MOF and ZIF nanostructures via solution assisted self-assembly (Figure 8a and 10a). [58,76,125,126] Jayaramulu and Datta et al reported the in-situ development of ZIF-8 nanostructures over oxygen modified fluorinated graphene oxide. [76] The water wettability of pure ZIF-8 showed 56°, which increased to 162°for oxygen functionalized fluorinated graphene-ZIF-8 (HFGO@ZIF-8) composite.…”

Microporous Organic Network: Superhydrophobic Coating to Protect Metal–Organic Frameworks from Hydrolytic Degradation

“…Current strategies for adjusting the hydrophobicity of MOFs can be classified into three categories: direct synthesis with hydrophobic ligands or monomers, − postsynthesis with hydrophobic molecules, − and fabrication of hydrophobic composites with water-repellent materials. − Direct synthesis is the most efficient and convenient method for constructing hydrophobic MOFs. Fluorinated groups and long-chain alkyls are often used to synthesize ligands for hydrophobic MOFs owing to their low surface energies. − Hydrophobic MOFs can also be synthesized directly using polyaryl ligands. , However, direct synthesis is applicable only to a few MOFs because the options for hydrophobic ligands or monomers are very limited.…”