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

Abstract

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 ± 0.60 m 2 /g) and porosity (0.37 ± 0.03 cm 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° for the PES membrane to 62.7°, 58.9°, and 58.75° 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.