Solar activated crude oil cleanup using net-shape-formed ultralight graphene tiles

Abstract

Accidental crude oil spills over a large water surface can wreck environmental and economic havoc. To mitigate such disasters, timely intervention to contain and recover oil before it spreads is critical. Standard lipophilic sorbents do not work because crude oil is too viscous to flow into them, especially in cold weather. This has led to the proposal of using graphene foam, also an excellent lipophilic sorbent, since it is a conductor and can be electrically heated, thus rendering the crude fluid enough to absorb. Yet wiring, powering and electrically heating any mass over a large area in high seas is clearly a challenge. Here we present a solution using a solar-activated graphene tile: within seconds upon exposure to daylight, it heats up and absorbs, eventually filling crude oil into 74 % of its own volume. It may be further coated by a lipophilic oil-permeating thermal insulation to become a light-absorbing, heat-retaining and oil-absorbing black hole. Capable of withstanding high heat up to 600 °C, tiles can be rejuvenated by ridding themselves of adsorbed oil in self-combustion, allowing even a small supply of tiles to last and contain oil spill for some time. The reusable tile is made by pyrolyzing a poly(vinylidene chloride) foam of an identical size and shape, obtaining a density of 16 kg m−3 and a strength of 11.7 kPa. Upon emergency, tiles initially installed as ultralight load-supporting constructs on oil-production platforms and crude-transport vessels become immediately available for repeated oil absorbing at 41 times their own weight. Therefore, they can provide the crucial first-response kit for mitigating oil-spill disasters.