Fouling-resistant ceramic-supported polymer membranes for ultrafiltration of oil-in-water microemulsions

Fouling-resistant ultrafiltration ceramic-supported polymer (CSP) ultrafilt ration membrane was developed for the treatment of oil-in-water (o/w) micro emulsions. The CSP zirconia-based membrane was prepared via free-radical gr aft polymerization of vinylpyrrolidone onto the membrane surface. Pore redu ction of about 25-28% was encountered upon modification as revealed by hydr aulic permeability measurements. Oil rejection was higher for grafted membr anes with smaller resultant pore size. Atomic force microscopy imaging of p olymer-modified surfaces showed complete surface coverage by the polymer ch ains. The native zirconia membrane was irreversibly fouled after treating the o/w microemulsion for a brief period, while the CSP membranes maintained its p re-filtration hydraulic permeability even after many filtration runs. The p resent surface modification was found to be effective in preventing irrever sible membrane fouling despite significant membrane surface roughness. Rela tive to the native membrane, oil rejection of the CSP membrane increased mo re than two-fold for the range of studied oil droplet size (18-66 nm), whil e surfactant rejection remained low for both the native and modified membra nes. (C) 2001 Elsevier Science B.V, All rights reserved.