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This work describes the fabrication of nitrogen doped and phosphorus doped carbon nanotube (fP-CNT and fN-CNT)/ polysulfone blend membranes via a phase inversion method. The structural morphology, hydrophilicity, rejection, and permeability properties of the blend membranes were found to be dependent on the amount and type of functionalized CNTs (fCNTs) incorporated (i.e., fN-CNTs, fP-CNTs). The results showed that PSf membranes modified with P-or N-doped CNTs have significantly improved hydrophilicity, thermal stability, water uptake, and surface charge compared to membranes modified with pristine fCNTs. Scanning electron microscopy studies demonstrated that the addition of the doped CNTs resulted in the formation of 'finger-like' structures subsequently leading to increased membrane porosities and pore sizes. Thus, doped CNTs imparted on the transport mechanism of the parent membranes resulting in enhanced flow rates and better selectivity. This increase could be due to a combination of steric limitations from the carboxylic functional groups present in their surfaces leading to electrostatic repulsions between functional groups present in the membranes and the humic acid molecules.

This study investigates the effect of solvent properties on the structural morphology and permeation properties of polysulfone/β‐cyclodextrin polyurethane (PSf/β‐CDPU) mixed‐matrix membranes (MMMs). The membranes were prepared by a modified phase‐inversion route using four different casting solvents [dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), dimethyl acetamide (DMA), and N‐methyl‐2‐pyrrolidone (NMP)]. While DMSO‐based membranes demonstrated particularly high permeability (ca 147 L/m2h.bar), their crystallinity was low compared to MMMs prepared using DMA, DMF and NMP due to the formation of thin active layers on their surfaces. Cross‐sectional morphology revealed that the MMMs have a dense top skin with finger‐like inner pore structures. Membranes prepared using NMP displayed the highest hydrophilicity, porosity, and crystallinity due to the low volatility of NMP; DMF membranes exhibited superior mechanical and thermal stability due to its (DMF) high hydrogen bonding (δH) values. Thus, the morphological parameters, bulk porosity, and flux performance of MMMs have a significant inter‐relationship with the solubility properties of each solvent (i.e., δH, density, volatility, solubility parameter). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2005–2014, 2013