RECONCENTRATION OF A POLYDISPERSE NONIONIC SURFACTANT IN AQUEOUS-SOLUTION BY ADSORPTION INDUCED ULTRAFILTRATION

Aqueous solutions of 1-octanol polyoxyethylene glycol monoether with an average of 4.5 ethylene oxide units per molecule were subjected to ultrafiltration-using hydrophobic membranes. Permeate concentrations always exceeded feed solution concentrations at temperatures below the cloud point and this fact together with the observed occurrence of permeation maxima and flux minima close to the critical micelle concentration was construed to indicate that surfactant adsorption onto the membrane pores induced the excess permeation. Observed concentration- and temperature-related variations in permeation for individual homologues are also discussed in terms of prevailing concepts regarding micelle-monomer partitioning and temperature effects on adsorption from aqueous solution.