Water and hexane permeate flux through UF polysulfone amide membrane

The aim of this work was to study the behavior of polysulfone amide (PSA) membrane in the presence of organic solvents (hexane) for their application in edible oil processing. The development of hexane-resistant membranes can create opportunities for applying membrane technology to refine the crude vegetable oil, simplify the whole process, reduce energy consumption and reduce wastewater production. Spiral wound configuration of PSA membrane with 20 kDa molecular weight cut off (MWCO) was used in these experiments in pilot-plant scale equipment. Permeate flux was observed to decrease with time and between successive runs with hexane, thus indicating a possible ‘‘interaction’’ between the solvent and the membrane material and/or adsorption of the solvent onto the membrane surface. Moreover, hexane flux was lower than water through UF membrane. The Hagen–Poiseuille equation was not able to predict the results on permeate flux, which indicates that other parameters apart from viscosity should be taken into account (surface tension, hydrophobicity, etc.).