In situ conversion of ZnO into zeolitic imidazolate framework-8 in polyamide layers for well-structured high-permeance thin-film nanocomposite nanofiltration membranes

Abstract

Incorporation of zeolitic imidazolate framework-8 (ZIF-8) in interfacial polymerized thin film nanocomposite (TFN) has been extensively reported to enhance membrane performance. However, traditional membrane synthesis strategy suffers the poor dispersity...

Enhanced water permeability in nanofiltration membranes using 3D accordion-like MXene particles with random orientation of 2D nanochannels

“…The effects of AMXene loading on Fig. 5 (a) Separation performances of the TFC, TFN-MXene, and TFN-AMXene membranes, (b) separation performances of the TFN-AMXene membrane in terms of AMXene loading, (c) correlation between the PWP enhancement factor and effective area enhancement factor of the TFN-AMXene membranes (the PWP enhancement factor is the ratio between the PWP of the TFN-AMXene membrane to that of the TFC membrane, the effective area enhancement factor is the ratio between the effective area for water collection of the TFN-AMXene membrane and that of the TFC membrane, and the effective area of membrane was measured according to a reported method 52 ), (d) inorganic salt rejections of the TNF-AMXene membrane, (e) long-term filtration performance of the TFN-AMXene membrane, and (f) trade-off relationship between water permeability and water/Na 2 SO 4 permselectivity summarized from polyamide NF membranes in the literature, 15,[53][54][55][56][57][58][59][60][61][62][63][64][65][66] commercial TFC NF [67][68][69] and TFN-AMXene membranes in this study.…”

“…52 Fig. 5f shows the trade-off relationship between water permeability and water/Na 2 SO 4 permselectivity summarized from polyamide NF membranes in the literature, 15,[53][54][55][56][57][58][59][60][61][62][63][64][65][66] commercial TFC NF [67][68][69] and TFN-AMXene membranes in this study. It can be found TFN-AMXene overcomes the upper bound of separation performance of the polyamide membranes containing commercial TFC and other laboratory-made TFC and TFN NF membranes.…”

“…13 As the most attractive onedimensional material with well-dened nanochannels, carbon nanotubes (CNTs) have been exploited to prepare highly permeable thin lm nanocomposite (TFN) membranes. [14][15][16] The literature shows that the permeability of these membranes is highly dependent on the CNT orientation in the PA matrix. 17,18 CNTs aligned perpendicular to the substrate surface are more preferred than the horizontally embedded ones for complete water transport through the nanochannels.…”

Planting Anion Channels in a Negatively Charged Polyamide Layer for Highly Selective Nanofiltration Separation

“…High-salinity organic wastewater features a high concentration of inorganic salts and low-molecular-weight refractory organic components (e.g., phenol, pyridine, biphenyl, polycyclic aromatic hydrocarbons, fatty acids, dyes) and poor treatability. − The efficient separation of small organics and inorganic salts in wastewater is the key to realizing “zero discharge” and resource recycling. Nanofiltration (NF) membrane technology is a promising option for such a purpose. − However, commercially available NF membranes commonly have molecular weight cut-off (MWCO) around 200–300 Da and negative surface charges, thus exhibiting high rejection toward organics and divalent anion salts as the result of combined Donnan and size effects …”

“…4−6 However, commercially available NF membranes commonly have molecular weight cut-off (MWCO) around 200−300 Da and negative surface charges, thus exhibiting high rejection toward organics and divalent anion salts as the result of combined Donnan and size effects. 7 Extensive research work has been conducted to boost the permeation of divalent anion salts through the NF membrane by constructing a loose separation layer, while this would inevitably decline the retention of small organics due to weakened size exclusion. 8 The positively charged NF membrane enables facilitating Na 2 SO 4 permeation via electrostatic attraction between the dominant ions SO 4 2− and membrane surface.…”