Electrotreated Carbon Nanotube Membranes for Facile Oil–Water Separations

Oil-contaminated effluents are widespread, yet purifying them of finely dispersed residual oil presents a significant challenge. Here we report on reactively spun carbon nanotube (CNT) mats, whose high electric conductivity is employed to irreversibly render them highly hydrophilic through electrooxidation (EO), while retaining the morphology, mesh size, conductivity, and mechanical strength of the pristine CNT material. EO treatment converts natively hydrophobic CNT mats to efficient filtration membranes, whose 30 nm mesh size favorably compromises between the hydraulic permeability and oil breakthrough pressure and allows complete and robust removal of dispersed oil (including surfactant-stabilized) down to its solubility in water.