Versatile Fabrication of Ultralight Magnetic Foams and Application for Oil–Water Separation

Abstract

Ultralow-density (<10 mg cm(-3)) materials have many important technological applications; however, most of them were fabricated using either expensive materials or complicated procedures. In this study, ultralight magnetic Fe2O3/C, Co/C, and Ni/C foams (with a density <5 mg cm(-3)) were fabricated on the centimeter scale by pyrolyzing commercial polyurethane sponge grafted with polyelectrolyte layers based on the corresponding metal acrylate at 400 °C. The ultralight foams consisted of 3D interconnected hollow tubes that have a diameter of micrometer and nanoscale wall thickness, forming hierarchical structures from macroscopic to nanometer length scales. More interesting was that the wall thickness and morphology of the microtubes could be tuned by controlling the concentrations of acrylic acid and metallic cations. After modification with low-surface-energy polysiloxane, the ultralight foams showed superhydrophobicity and superoleophilicity, which quickly and selectively absorbed a variety of oils from a polluted water surface under magnetic field. The oil absorption capacity reached 100 times of the foams' own weight, exhibiting one of the highest values among existing absorptive counterparts. By controlling the composition and conformation of the grafted polyelectrolyte layers, the present approach is extendable to fabricate a variety of ultralow-density materials desirable for absorptive materials, electrode materials, catalyst supports, etc.

Preparation of graphene-MoS2 hybrid aerogels as multifunctional sorbents for water remediation

“…However, the carbon-based 3D porous networks have limited compatibility and most of them only show affinity to certain category of contaminants [7][8][9][10][11]. This limitation hinders the real industrial wastewater treatment since it normally contains diverse types of pollutants (e.g., heavy metal ions, dyes, oils, and other organic compounds) [12][13][14][15].…”

Recent Progress of Polyurethane-Based Materials for Oil/Water Separation

“…86 For instance, Chen et al 86 prepared monolithic ultralight Fe 2 O 3 /C, Co/C, and Ni/C foams by the calcinations of the polyacrylic acid-grafted PU foam at 400 C. The ultra-light foam was composed of three-dimensional (3D) connected hollow tubes with a diameter of micro and nano wall thickness [ Fig. 10(A)].…”

External‐Field‐Induced Gradient Wetting for Controllable Liquid Transport: From Movement on the Surface to Penetration into the Surface

“…They have constructed micro-/nanoscale hierarchical structures of 3D ultralight magnetic foams by pyrolyzing polyurethane sponge (Figure 10). [145] After hydrophobic material modification, the superhydrophobic and superoleophilic ultralight magnetic foams can be used to selectively absorb oil from oily water with high oil absorption capacity (nearly 100 times their own weight). They later reported superhydrophobic PU sponges fabricated by nanoparticle modification that exhibit high selectivity and recyclability for separation of oil-water mixtures.…”