Ultrafiltration of surfactant solutions.

The ultrafiltration of colloid solutions containing hexadecyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and alkylpolyglucoside (APG) through hydrophilic membranes with a 10,000 mol wt cut-off from regenerated cellulose was studied. The effects of experimental conditions on the permeate flux and secondary resistance were determined. It was found that both CTAB and APG were convenient surfactants for ultrafiltration, as high permeability of their solutions was observed.

Direct Yellow and Methylene Blue liquid-liquid extraction with alkylene carbonates.

Propylene and 1,2-butylene carbonates enable very effective extraction of Methylene Blue. The use of a more hydrophobic 1,2-butylene carbonate is preferred for practical application. Separation is enhanced by addition of an electrolyte (NaCl).

Cloud point extraction of direct yellow.

The cloud point separation of Direct Yellow from micellar solution of various nonionic surfactants, containing a polyoxyethylene chain, was studied. The separation of dyes is an important environmental problem. Moreover, such separation can also be considered as a preliminary step for further studies of biochemical recovery.

Dynamics of nonionic surfactant-rich phase separation and recovery of dyes.

Cloud point separation of selected dyes was studied. The use of dyes made possible observation of the dynamics of surfactant-rich phase separation by color video. The pictures were interpreted by means of ImageC software and degrees of whiteness were calculated.

Cloud point of aqueous solutions containing oxyethylated methyl dodecanoates: effects of surfactant hydrophilicity, nature of added electrolyte, and water activity.

The aim of this work was to determine the cloud points of new oxyethylated methyl dodecanoates of various hydrophilicity (OMD-n, where n refers to the average degree of oxyethylation) and to correlate them with surfactant hydrophilicity and, for a given electrolyte, with water activity. Thus, it is shown that the cloud point in the absence of electrolyte (CP(0)) can be simulated by the following equation: CP(0)=165.5logn-112.