P. Ignacio-de Leon, X. Chen, E. Rabe, M. Urgun-Demirtas, M. Puga, Z. Zhou, R. Brotzman
Argonne National Laboratory,
Keywords: magnetic nanotube, vertically-aligned nanotube, iron cobalt oxide nanotube, nanocomposite membrane, lignin filtration
Summary:Nanocomposite membranes, with magnetic nanotubes embedded in polyethersulfone (PES) membrane to form a permselective layer on microporous supports, are reported in this study for potential applications in wastewater treatment. Two new processes, alignment of nanotubes with an external magnetic field and post-synthesis enzyme treatment, were employed in membrane fabrication. Iron cobalt oxide (Fe2CoO4) nanotubes, with 20-25 nm diameter and aspect ratio ca. 10,000, function as nanochannels spanning the permselective layer. Pure water flux values of 9.4 and 4.8 L/m2-h through membranes with vertically-aligned and randomly-oriented nanotubes, respectively, were obtained at 40 psi. These membranes were used to filter lignin, a contaminant in effluent wastewater from paper and mill industries and lignocellulosic biofuels production. The lignin % rejection from a 10,000 ppm feed at 40 psi through a PES support increases from 7.3% to 39.1% (5.3x higher) and 62.8% (8.6x higher) through membranes prepared with and without a magnetic field, respectively.