Aramid Nanofiber Membranes Reinforced by MXene Nanosheets for Recovery of Dyes from Textile Wastewater

Abstract

Efficient recovery of dyes from textile wastewaters using membrane-based technologies calls for membranes with low rejection of salts but high rejection of dyes. In this study, we intercalated the rigid 2D-ultrathin MXene (Ti3C2T x ) nanosheet into the loose framework assembled by 1D aramid nanofibers and obtained a MXene-reinforced aramid nanofiber (ANF) membrane. The optimized MXene-reinforced ANF membrane (20 wt % MXene loading) exhibited a high selectivity of dye/salt, that is, 99.1 ± 0.3% for Alcian Blue, 96.1 ± 2.4% for Congo Red, 98.6 ± 0.9% for Rose Bengal, and extremely low rejection of salts (<0.2%) at a concentration of 5 g L–1 of NaCl with separation factors of 826, 1068, and 758 for Alcian Blue, Congo Red, and Rose Bengal, respectively. Moreover, the membrane permeability could reach 195.3 ± 6.5 L m–2 h–1 bar–1. The MXene-reinforced ANF membrane demonstrated a superior separation performance to most of the other reported membranes for dye/salt fraction. Mechanistic investigation showed that the reinforced rigidity of the membrane by the intercalated MXene was the main mechanism for the enhanced permeability and selectivity of the MXene/ANF composite membrane (that is, a nanochannel of 2.34 nm was maintained for the MXene/ANF composite membrane after filtration while the nanochannel of the ANF membrane was increased from 2.27 to 2.43 nm). The results highlight that the nanofibrous membranes reinforced by rigid 2D materials are promising for an effective separation of dyes and salts in textile wastewaters.

Can MXene be the Effective Nanomaterial Family for the Membrane and Adsorption Technologies to Reach a Sustainable Green World?

“…Rather than mixing MXene with a polymer matrix, the final strategy is to intercalate MXene into nanofibers. For instance, Li et al reinforced the Kevlar nanofibers with Ti 3 C 2 T x and observed improved rejection performance for several dyes. The average molecular weight cutoff (MWCO) for the composite membrane was reported as in between 600 and 800 Da considering the analysis based on the different molecular weight of PEG molecules .…”

MXene-regulation polyamide membrane featuring with bubble-like nodule for efficient dye/salt separation and antifouling performance

“…21,22 MXene (transition metal carbonitride), as a new type of 2D nanomaterial with good hydrophilicity, tunable electronegativity, and mechanical properties, exhibited great potential for desalination and dye separation. [23][24][25][26] The unique structure of MXene nanosheets ensures sufficient strength during the separation process. The low concentration and good dispersion of MXene supernatant exhibit good affinity and interface compatibility with the PA matrix.…”

3D Printing of Aramid Nanofiber Composites by Stereolithography

“…Previous work has shown that a small amount of ANFs in a polymer matrix can significantly enhance its mechanical properties, such as tensile strength, 30−34 Young's modulus, 31,32 and toughness. 30,34 In addition to improved mechanical strength, ANF composites are useful for a variety of applications including biomedical technologies, 35 water purification, 36 and even as materials with advanced IR adsorption properties. 37 However, 3D-printed ANF composites are still uncommon, 38 likely because of the difficulties of incorporating ANFs into printable, homogeneous resin mixtures.…”

“…In addition to improved mechanical strength, ANF composites are useful for a variety of applications including biomedical technologies, water purification, and even as materials with advanced IR adsorption properties . However, 3D-printed ANF composites are still uncommon, likely because of the difficulties of incorporating ANFs into printable, homogeneous resin mixtures.…”