Cross-linked polydimethylsiloxane (PDMS)/polyvinylidene fluoride (PVDF) composite nanofiltration (NF) membranes were prepared for recovery of hexane from soybean oil/hexane miscalls. Various reagents

such as tetraethoxylsilane (TEOS)

phenyltrimethoxylsilane

octyltrimethoxylsilane and γ-aminopropyltriethoxylsilane

were used as cross-linking agents.Physical and chemical characteristics of the tailor made NF membranes were characterized by contact angle

FTIR

SEM

density

etc.The membranes were applied in the solvent recovery from soybean oil/hexane miscella.For each membrane

the effect of feed pressure upon the flux and oil retention was investigated.The permeate flux increases linearly with feed pressure

while oil retention increases first quickly and then slowly.With the increase of feed oil concentration

both flux and retention decrease significantly.It is found that the PDMS membrane cured with TEOS is the best for the separation.The observed osmotic phenomena similar to those of aqueous systems are interpreted using the van't Hoff equation.