CROSS-FLOW MICROFILTRATION OF ORGANIC-WATER SUSPENSIONS

A study of the cross microfiltration of immiscible organic solvent in water is reported using tridecanol as an example organic phase. The membranes used were of commercially available microporous, nylon, polysulphone and a mixed cellulose acetate/nitrate of pore sizes 1.2 mum and less. Good rejection of the dispersion was only achieved with membrane sizes of 0.45 and 0.2 mum and flux performance was affected by both concentration polarization and membrane fouling. Two procedures were attempted to eradicate the membrane fouling, surfactant cleaning of the membrane and coarse filtration of the dispersion to remove potential foulants. In the latter case this apparently removed a colloidal foulant present in the dispersion but also resulted in a near total loss of membrane rejection of the tridecanol. For the pore size membrane used (0.2 mum polysulphone) this foulant apparently imparts tridecanol rejection properties to the membrane. Surfactant cleaning/treatment of the membranes generally increased flux rates.