Solution-processable, durable, scalable, fluorine-grafted graphene-based superhydrophobic coating for highly efficient oil/water separation under harsh environment

Abstract

A simple, low-cost, efficient, and easily scaled-up process for fabricating materials with special wettability for efficient oil/water separation under harsh conditions remains a great challenge. Herein, a fluorine-grafted graphene-based coating was fabricated by a facile solution-processable dip-coating method. The coating, composed of fluorine-grafted graphene (f-rGO) and γ-oxo-1-pyrenebutyric acid (OPBA) as molecular glue, can densely adhere on the surface of commercial materials (e.g., polypropylene membrane, cotton fabric, and polyurethane foam) and can tolerate harsh practical environments such as boiling water, high acid, high base, and saturated salty solutions. Importantly, the coated membrane exhibits efficient separation of surfactant-stabilized water-in-oil emulsions under these harsh conditions with high recyclability and extreme flux as high as 1395 L m⁻² h⁻¹ only under gravity. The coated foam can uptake oils from an oil/water mixture with high absorption capacity and recyclability. The outstanding performances (including durability, recyclability, scalability, and resistance to harsh environments) of the coating highlights its practical applications for separation of emulsions and cleanup oil-spills.