Nitrogen-Doped Carbon Nanotubes/Polyethersulfone Blend Membranes for Removing Emerging Micropollutants

Emerging micropollutants (EMPs) are ubiquitous in water systems and have become a worldwide issue of emerging environmental concern. This paper reports on the fabrication of nitrogen-doped carbon nanotubes/polyethersulfone (N-CNT/PES) blend membranes that have the potential to remove EMPs such as carbamazepine, galaxolide, caffeine, tonalide, technical 4-nonylphenol, and bisphenol A from water. The target compounds were extracted and enriched by solid-phase extraction and analyzed using comprehensive two-dimensional gas chromatography coupled-to-time-of-flight mass spectrometry. The N-CNT/PES blend membranes were synthesized using the modified phase-inversion method and characterized for a variety of physicochemical properties. The permeation properties of the membranes were determined by computing rejection and pure water flux. The 0.01 wt% N-CNT/PES blend membrane were observed to have highest surface area (94.3 +/- 0.60m(2)/g) and porosity (0.37 +/- 0.03cm(3)/g). The water flux of the membranes was enhanced by the addition of N-CNTs to the pristine PES membranes. The contact angles for the N-CNT/PES blend membranes gradually declined from 78.39 degrees for the PES membrane to 62.7 degrees, 58.9 degrees, and 58.75 degrees for the 0.01, 0.03, 0.05 wt% N-CNT/PES blend membranes, respectively. The N-CNT/PES blend membranes were highly proficient in removing the selected EMPs with the highest and lowest removal efficiencies being 99.20-99.92% (for galaxolide) and 84.61-87.21% (for caffeine), respectively. The results show the superior capability of the N-CNT/PES blend membranes in removing EMPs from water.