Versatile fabrication of magnetic carbon fiber aerogel applied for bidirectional oil–water separation

Abstract

Fabricating functional materials that can solve environmental problems resulting from oil or organic solvent pollution is highly desired. However, expensive materials or complicated procedures and unidirectional oilwater separation hamper their applications. Herein, a magnetic superhydrophobic carbon fiber aerogel with high absorption capacity was developed by one-step pyrolysis of Fe(NO 3 ) 3 -coated cotton in an argon atmosphere. The obtained aerogel can selectively collect oils from oil-polluted region by a magnet bar owing to its magnetic properties and achieves fast oil-water separation for its superhydrophobicity and superoleophilicity. Furthermore, the aerogel performs recyclable oil absorption capacity even after ten cycles of oil-water separation and bears organic solvent immersion. Importantly, the obtained aerogel turns to superhydrophilic and underwater superoleophobic after thermal treatment, allowing it as a promising and efficient material for bidirectional oil-water separation and organic contaminants removal.

3D Self‐Supporting Porous Magnetic Assemblies for Water Remediation and Beyond

“…Several materials, including modified PU sponges and Fe/C nanocomposites have been demonstrated to show this ability (Figure 13d,e). [41,92,106,112] Whereas, it could be foreseen that the 3D-SPMAs can only be collected by the magnetic when they adsorb a small amount of oil. If a large quantity of oil was adsorbed, the 3D-SPMAs would undergo several tens or even several hundred times weight gain.…”

“…[15] Actually, the average maximum oil adsorption capacity of those 3D-SPMAs is below 30 times weight gain, which is far lower than normal 3D-SPAs. Although magnetic CNT sponges, [41] carbon fibers based aerogels, [112] and ultralight Fe 2 O 3 /C foams [38] showed relatively higher capacity of approximately 45 to 60, 30 to 70, and 50 to 103 times weight gain, respectively. They were still insufficient for practical applications.…”

“…For example, Li et al [112] demonstrated that the carbon fibers based superhydrophobic aerogels can selectively block the water penetration during separation. Interestingly, after lighting in air after impregnation with hexane, the resultant materials converted to superhydrophilic/underwater-superoleophobic due to the introduction of hydrophilic oxygen-containing groups, enabling the oil/water separation in a contrary direction.…”

Returning to Nature for the Design of Sorptive Phases in Solid-Phase Microextraction

“…On another note, raw cotton has been commonly employed in the production of activated carbon fibers (ACFs or CFs) as an alternative to synthetic precursors such as PAN, viscose/rayon, phenolic, asphalt, and polyamide fibers. Typically, this green and easy modification of raw cotton consists of the pyrolysis of the cellulose fibers in an inert atmosphere, approximately at 400-700 • C, being used for many years to remove dyes and oil from environmental samples [50,51]. Figure 1 shows the macroscopic appearance of raw cotton ( Figure 1a) and CFs (Figure 1b), which maintain the fibrous structure ( Figure 1c) of the original substrate.…”

Mechanically robust, thermally stable, highly transparent superhydrophobic coating with low-temperature sol–gel process

“…It is closely related to basic science theory and practical applications. The phenomenon that water droplets cannot adhere to such a surface but roll off is advantageous for potential applications in self-cleaning, 5,6 anti-fogging, 7,8 oil-water separation, 9,10 and anti-icing. 11,12 Transparent superhydrophobic surfaces expand the range of potential applications to optical elds such as windshields for automobiles, solar-cell panels, safety goggles, and windows for electronic devices, [13][14][15] and therefore have recently attracted more and more attention.…”