Fouling of Ultrafiltration Membranes due to Adsorption of a fatty acid

Sammanfattning: A study of fouling of ultrafiltration membranes due to adsorption of a fatty acid in the membrane matrix has been done. Octanoic acid was used as a model substance. It has been shown that a low-molecular-weight hydrophobic solute can have detrimental effects on the flux of hydrophobic ultrafiltration membranes even though the size of the solute is much smaller than the cut-off of the membrane and the retention is less than 10%. A theory that the flux reduction is due to capillary condensation and how this might be used for characterisation is developed. The effect of solute concentration, membrane pore-size, membrane material and pH of the solution on the flux has been studied. Different methods of analysis have been used to identify fouling substances on membranes, to analyse membrane materials and to determine the cleaning efficiency.