Spill-SOS: Self-Pumping Siphon-Capillary Oil Recovery

Abstract

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.

Underoil Superhydrophilic Metal Felt Fabricated by Modifying Ultrathin Fumed Silica Coatings for the Separation of Water-in-Oil Emulsions

“…As shown in Figure 4(g, h), the results demonstrated that the main components of raw metal felt are Fe, Cr and Ni elements, which is consistent with previously reported publications. 8 Extra Si and O elements were detected in the coated metal felt and exhibited an atomic ratio of ~1: 2, which confirmed the coating is composed of silicon dioxide. As shown in Figure S5, the FTIR spectroscopy reveals that plenty of hydroxyl appeared on the metal felt after being coated with SiO2 NPs.…”

“…Conventional treatment techniques including gravity separation, centrifuge, air-flotation and biodegradation, have been employed to separate stratified oil/water mixtures. [7][8][9] Nevertheless, the emulsified droplets in an emulsion usually have a diameter less than 20 μm and are extremely stable due to the adsorption of surfactant at the oil/water interface. [10][11][12] They do not easily coalesce and cannot easily be separated by aforementioned traditional methods.…”

Photothermal Devices for Sustainable Uses Beyond Desalination

“…Reproduced with permission. [ 89 ] Copyright 2019, American Chemical Society; d) aborption sponge coupling solar heating and Joule heating. Reproduced with permission.…”

“…[ 85 ] On the other hand, Wu et al developed a self‐pumping photothermal oil‐collection device based on the siphonic and capillary effects (Figure 2c). [ 89 ] An all‐carbon porous felt with hierarchical architecture was fabricated by growing vertically oriented graphene nanosheets on a monolith of graphite felt through plasma‐enhanced chemical vapor deposition. The oleophilic porous structure could absorb the oil through the capillary effect at the beginning and then transport the oil from one side to the other side under a height difference based on the siphon.…”

“…[85] On the other hand, Wu et al developed a self-pumping photothermal oil-collection device based on the siphonic and capillary effects ( Figure 2c). [89] An all-carbon porous felt with hierarchical Figure 1. a) Evaporation-enhanced absorption of photothermal catalytic paper.…”