posted on 2019-10-31, 12:14authored byShenghao Wu, Huachao Yang, Guoping Xiong, Yikuan Tian, Biyao Gong, Tengfei Luo, Timothy S. Fisher, Jianhua Yan, Kefa Cen, Zheng Bo, Kostya Ken Ostrikov
Oil
spills remain a worldwide challenge and need emergency “spill-SOS”
actions when they occur. Conventional methods suffer from complex
processes and high cost. Here, we demonstrate a solar-heating siphon-capillary
oil skimmer (S-SOS) that harvests solar energy, gravitational potential
energy, and solid surface energy to enable efficient oil spill recovery
in a self-pumping manner. The S-SOS is assembled by an inverted U-shape
porous architecture combining solar-heating, siphon, and capillary
effects, and works without any external power or manual interventions.
Importantly, solid surface energy is used by capillary adsorption
to enable the self-starting behavior, gravitational potential energy
is utilized by siphon transport to drive the oil flow, and solar energy
is harvested by solar-thermal conversion to facilitate the transport
speed. In the proof-of-concept work, an all-carbon hierarchical architecture
(VG/GF) is fabricated by growing vertically oriented graphene nanosheets
(VGs) on a monolith of graphite felt (GF) via a plasma-enhanced method
to serve as the U-shape architecture. Consequently, an oil-recovery
rate of 35.2 L m–2 h–1 is obtained
at ambient condition. When exposed to normal solar irradiation, the
oil-recovery rate dramatically increases to 123.3 L m–2 h–1. Meanwhile, the solar-thermal energy efficiency
is calculated to be 75.3%. Moreover, the S-SOS system presents excellent
stability without obvious performance-degradation over 60 h. The outstanding
performance is ascribed to the enhanced siphon action, capillary action,
photonic absorption, and interfacial heating in the plasma-made graphene
nanostructures. Multiple merits make the current S-SOS design and
the VG/GF nanostructures promising for efficient oil recovery and
transport of energy stored in chemical bonds.