Fluorinated graphene nanosheet supported halloysite nanoarchitectonics: Super-wetting coatings for efficient and recyclable oil sorption

Abstract

Designing selective oil sorption and recovery systems to tackle oil/organics spills in water bodies by using special-wetting property are gaining huge attention. In the present work, we develop a coating material based on functionalized halloysite nanotubes (HNT) supported over fluorinated graphene (FG) nanosheets displaying super-wetting functions. The HNTC-FG hybrids were methodically analysed by various spectroscopic, microscopic and solvent wetting studies. The water contact angle (145 ± 2°) for HNTC-FG hybrids with a surface free energy of 18.1 mJ/m2 significantly affects the solvent wettability. To carry out oil–water separation, the HNTC-FG dispersion was imbibed on polyurethane (PU) sponge via dip-coating method. The HNTC-FG-PU sponges were probed towards the remediation of oil/organics spill under static, turbulent and continuous modes. The sorption capacity of HNTC-FG-PU sponges for various oils and organics falls in the range of 38–62 g/g with excellent recyclability under static and turbulent conditions besides remarkable corrosive, thermal and mechanical stabilities. Furthermore, the HNTC-FG-PU sponges were effectively used in the selective continuous separation of organic solvents by vacuum pump-assisted process over 10 cycles with flux ranging from 1593 and 4690 L.m−2.h−1 for kerosene and mesitylene respectively. The stable hydrophobicity, chemical stability and remarkable recyclability of these HNTC-FG-PU sponges drive the oil/organics recovery prototypes.