Microfluidic fabrication of magnetic porous multi-walled carbon nanotube beads for oil and organic solvent adsorption

Abstract

Due to their light weight and recyclable value, carbon nanotube-based materials have been widely used as adsorbents for oils and organic pollutants. The discovery and research of a novel approach to prepare carbon nanotube-based adsorbents with excellent performance is still required urgently. In this paper, we used a modified microfluidic device to construct a kind of three-dimensional (3D) magnetic porous multi-walled carbon nanotube bead and utilized them to adsorb oils and organic solvents floating on or under the water. In the preparation process, acidified multi-walled carbon nanotubes (MCNTs), water-soluble ferroferric oxide nanoparticles (Fe₃O₄) and water-soluble submicron polystyrene microspheres can improve their dispersion stability and uniformity in microfluidic droplets. In addition, polystyrene microspheres as the hard template can not only supply abundant porous structures but also stabilize the morphology of composite droplets during the solidification. The measurement data indicated that magnetic porous multi-walled carbon nanotube beads (MCNTBs) had adsorption capability (up to 6–18 times their own weight) for oils and organic solvents with 6 times recyclability, and they can serve as a kind of promising adsorbent.