화학공학소재연구정보센터
Journal of Chemical Technology and Biotechnology, Vol.68, No.4, 417-424, 1997
Cleanup to Chirality - Liquid Membranes as a Facilitating Technology
Liquid membranes have been suggested as a clean technology due to characteristics such as high specificity, intensity and productivity as well as low emissions and energy utilisation. However when applying liquid membrane systems to real problems, in this paper chiral extraction of phenylalanine and lactic acid extraction from an industrial effluent, problems have been encountered with the specificity of the liquid membrane system used. Relatively low enantioselectivities (maximum 2.4) were observed with the chiral emulsion liquid membrane system investigated (maximum 1.6), although this was in excess of an analogous solvent extraction system studied. In lactic acid extraction, although batch extraction from model solutions was in excess of 75% in 2 min, when a real lactic acid containing industrial effluent was used the extent of extraction was reduced to around 20%. This effect was found to result from the coextraction of other anions present in the effluent. In the case of chloride ions, a co-transport mechanism was noted. Thermal and photometric back-extraction strategies have been suggested as a means of enhancing overall liquid membrane extraction selectivities.