Abstract

Microbial fermentation yields aqueous solutions with concentrations of 1-3 % by weight of organic compounds. Moreover, the presence of organics in water may lead to hazardous effects on health and the environment. Separation and recovery of these organics from water poses difficulties for industries as several energy-intensive operations such as distillation prove to be uneconomical when compared with the energy content of 1-butanol. Fermentation broth concentrations upto 70 kg/m3 are required to produce an effective liquid-liquid split. The paper aims at assessing several unit operations for recovering 1-butanol from water in terms of their recovery, purity, energy input and evaluating their applicability. Separation processes studied are freeze crystallization, adsorption, pervaporation, reverse osmosis, phase separation using salts and ionic liquids.