Nanofiltration of dye solutions through membranes based on poly(trimethylsilylpropyne)

Nanofiltration of dilute dye solutions in normal alcohols through membranes based on the glassy polymer poly(trimethylsilylpropyne) has been investigated. It has been found that the membrane separation properties substantially depend not only on the dye nature, but also on the properties of the solvent used. In particular, the retention of Solvent Blue 35 may be either positive (when the permeate is depleted in dye) or negative (permeate enriched in dye) depending on the type of the solvent. It has been revealed that the retention of the dyes by the polymer membrane correlates with the thermodynamic affinity of the components in the polymer-solvent-dye system and is almost linearly related to the partition coefficient between the membrane dye and the feed solution.