Polyaniline hollow fibres for organic solvent nanofiltration

Abstract

Intrinsically-skinned asymmetric PANi hollow fibres, fabricated using a process of directly adding large organic acids to highly concentrated PANi solutions, show stability in a wide variety of organic solvents and have shown promising nanofiltration properties, giving high rejections of nanosolutes in acetone.

A refined one-filtration method for aqueous based nanofiltration and ultrafiltration membrane molecular weight cut-off determination using polyethylene glycols

“…In the methods currently available, a range of compounds with different MWs such as polyethylene glycols (PEGs) [2,[5][6][7][8], oligostyrenes [9][10][11], alkanes [9,12], dextrans [5,8,[13][14][15][16][17], pesticides [18] and acids [6] are subjected to one or more pressure filtration tests.…”

“…This is because there have been few rapid, reliable and relatively inexpensive chromatographic techniques that are able to separate a relatively cheap mixture of the different MW compounds to enable a single filtration test to be used for MWCO determination [2,17,[19][20][21]. For those that do exist, there are limitations: for example, the recently developed oligostyrene [9,10] and PEG methods [21] are for non-aqueous solvents, with the former method requiring the use of relatively expensive reagents and the precision and robustness of the latter not yet robustly and directly proven, in particular by benchmarking against commercially available membranes. This is necessary, since when using a mixture of solutes to characterize UF and NF membranes, pore blocking of bigger molecules on the membrane surface and concentration polarization [2,13,22] can potentially selectively hinder the transport of different MW solutes and consequently skew the MWCO value from the actual value.…”

An Efficient Method to Determine Membrane Molecular Weight Cut-Off Using Fluorescent Silica Nanoparticles

“…However, there are limitations concerning the application of these techniques. For instance, the developed oligostyrene [ 13 , 26 ] and the protocols using PEGs [ 1 ] are for non-aqueous solvents. Furthermore, this old method requires the use of relatively expensive reagents and the precision and robustness of the latter, not yet well proven, in particular by benchmarking against the membranes available on the market.…”

Solvent resistant nanofiltration membranes

“…In fact, there are only few publications on the fabrication of hollow fiber (HF) membranes. Loh et al [78], developed polyaniline (PANi) HF membrane stable in acetone and DMF having acetone flux of 9 l m -2 h -1 and MWCO of approximately 350 g mol -1 . Kopeć et al [79] reported a novel HF preparation method called "chemistry in a spinneret" which integrates crosslinking and membrane formation in a single step process.…”