Chiral separation of (d,l)-lactic acid through molecularly imprinted cellulose acetate composite membrane

摘要

An Al2O3 nanochannel membrane modified with ZrO2 was coated with cellulose acetate (CA) containing l-lactic which is used as molecular imprinting and used as a template, for a novel enantioselective membrane. The top surface and cross section morphology of the resulting membranes with different parameters were examined using a scanning electron microscope. Infiltration experiments revealed the flux and permselectivity of the membrane using aqueous (d,l)-lactic acid as feed solutions. The effects of different amounts of CA on the performance of the membrane were investigated, and the best performance was observed when the cellulose content was 15 wt% and the separation factor was as high as 8.7. Therefore, we used a casting solution containing 15 wt% cellulose for the preparation of the molecular imprinted nano-channel membrane. The performance of membrane on 110-150 nm of channel aperture and printed molecules were extensively recorded. The chiral recognition not only was the result of the matching of the steric between the enantiomers and the membrane but also the result of the interaction between the molecules and the membrane. The results reveal that the practiced method simultaneously enhanced the permselectivity and the flux of membrane, suggesting trade-off relationship.