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 m2/g) and porosity (0.37 ± 0.03 cm3/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.

A comprehensive review on micropollutants removal using carbon nanotubes-based adsorbents and membranes

“…• Results show the potential to employ the prepared membrane for various organic micropollutants • Water flux improved with the addition of nitrogen-doped SWCNTs to raw PES • The prepared membrane displayed good porosity and a large specific area, i.e., 0.37+0.03 cm 3 .g -1 and 94.3+0.06 m 2 .g -1 , respectively. • Findings displayed good chemical, mechanical, and fouling resistance properties [4] Polyethersulfone/f-SWCNTs 17β estradiol >75…”

“…After disinfecting, few of the organic micropollutants transform into extremely toxic disinfection by-product through the addition of reaction or chlorine substitution, bringing chronic or acute disease for both human and animal [3]. Despite the adverse impacts and noxiousness, the level of micropollutants is expected to rise in the future due to the fast-growing global population, dependency on chemicals, and the nonbiodegradability of most micropollutants [4]. Furthermore, many anthropogenic events, such as oil spills, municipal, industrial, and untreated wastewater effluents, deliver various micropollutants to the water bodies on a daily basis [5].…”

Engineered Carbon Nanotubes: Review on the Role of Surface Chemistry, Mechanistic Features, and Toxicology in the Adsorptive Removal of Aquatic Pollutants.

“…Such cases have been commonly reported in the adsorption of aromatics ,. The mechanism of the π, π ‐ π and π ‐ π EDA interactions is metaphorized in Figure and the Table lists some CNT based nanocomposites for removal of organics.…”

Mixed-Matrix Membrane Adsorbers for the Simultaneous Removal of Different Pharmaceutical Micropollutants from Water

“…Both processes showed an improved removal of MPs and their metabolites. ,, However, ozone usage is accompanied by (toxic) byproducts needing an additional separation process, whereas long contact times for the adsorption onto activated carbon (AC) are necessary, although shorter contact times for mesoporous AC have been reported . The use of multifunctional membranes − or membrane adsorbers − for water purification is an emerging application overcoming limitations of existing filtration processes. Advanced materials like molecularly imprinted polymers (MIPs) − and MIP membranes , were designed to specifically remove one certain substance.…”