Optimizing carbon nanotube-reinforced polysulfone ultrafiltration membranes through carboxylic acid functionalization

Enhanced ultrafiltration PES membranes doped with mesostructured functionalized silica particles

“…Addition of selected hydrophilic particles in the membrane matrix increases the polymer hydrophilicity and enhances the water permeability while mitigating the membrane fouling [9,10]. Many types of nanomaterials have been tested as membrane fillers for this purpose in the last years, including titania (TiO 2 ) [9,10], zirconia (ZrO 2 ) [11], silica (SiO 2 ) [12], zinc oxide (ZnO) [13], alumina (Al 2 O 3 ) [14], silver (Ag) [15] and carbon nanotubes [16].…”

Fabrication and characterization of hydroxylated and carboxylated multiwalled carbon nanotube/polyethersulfone (PES) nanocomposite hollow fiber membranes

“…These stresses may result in physical and chemical wear on the hollow fibers, leading in some cases to breakage. We have previously shown that polymercarbon nanotube composites can be formulated to yield flat sheet polyamide membranes with improved mechanical properties [10,11] while others have shown that TiO 2 -decorated carbon nanotubes (CNTs) improved both fouling and mechanical stabilities in flat sheet polyethersulfone (PES) membranes [12]. In the current work we explore the fabrication and improved mechanical properties of extruded hollow fiber ultrafiltration membranes composed of PES-CNTs.…”

High-performance mixed-matrix membranes with altered interfacial and surface chemistry through benign reinforcement of functionalized carbon nanotubes of different configurations

“…It is observed that, the CNT as well as carboxylated CNT reinforced UF membranes generally exhibit superior T.S. (tensile strength) as compared to the Control-Psf UF membrane [13]. On enhanced reinforcement of pristine CNTs, the T.S.…”

“…This gets observed through the variations represented in Figure 9, as ~3500-3700, 3600-4400 and ~4000-4500 LMD, respectively, on enhanced reinforcement of the stimulated nanoadditives. The impact of functionalization pathway to enhance the solvent permeability of CNT reinforced mixed-matrix membranes has also been underpinned by other researches [11][12][13]. The carboxylated CNTs being enriched with hydrophilic functionalities expedite the kinetics of non-solvent's indiffusion and the solvent's outdiffusion, amending the phase inversion process through instantaneous demixing of the casting dope solutions.…”

“…With the aid of experiments and multiscale modeling approaches, the study highlighted the necessicity of functionalization of MWNTs with polar groups like -OH and -NH 2 in order to obtain a benign homogeneous dispersion of the nanofiller within a co-polyimide (P84) matrix to mitigate the phase separation problems. In another study on the CNT reinforced Psf UF membranes, the extent of carboxylation of MWNTs was correlated with the beneficial effect of membranes increased tensile strength, surface hydrophilicity, and permeability as well as the concurrent drawbacks of decreased retention, increased leaching, and decreased strength of CNTs with greater carboxylation [13]. The CNTs are composed of concentric arrangement of several cylinders [14].…”