Developments in liquid membrane separation of beta-lactam antibiotics.

This paper presents an overview on the developments in liquid membrane separation and purification of commercially important beta-lactam antibiotics. Reactive extraction via liquid-liquid ion exchange or ion-pair extraction mechanism can be exploited to develop liquid membrane processes for separation and concentration of penicillins and cephalosporins. Because of high selectivity and flux, liquid membrane processes can be adopted for direct extraction of beta-lactams from fermentation broth. Other advantages of liquid membrane technologies are low capital and operating costs, compact unit installation in commercial plants, low material inventory, etc. Both emulsion liquid membrane and supported liquid membrane techniques can be effective under the reactive extraction conditions. However, the stability problems of liquid membrane should be resolved before commercial application can be established. Alternately, reactive extraction in non-dispersive mode with hollow fiber membranes can be an attractive and viable strategy for practical application. Applicability of the liquid membrane processes has been discussed from process engineering and design considerations.