Selective evaporation of a butanol/water droplet by microwave irradiation, a step toward economizing biobutanol production

Abstract

The separation step is a constraint in biobutanol production, due to high energy consumption of the current techniques. This study explores a new separation method via applying microwave irradiation. Butanol/water droplet was monitored during exposure to microwave irradiation at different power rates. The surface tension, droplet volume, and temperature were scrutinized during and after exposure to microwave irradiation. The data obtained indicated that the microwave-induced evaporation rates of alcohols were much higher than that of water. Consequently, the vaporized phase contained a much higher alcohol content than the liquid phase. In particular, butanol concentration in the aqueous phase could be reduced to ~ 0.1 wt. %, which was more effective than the theoretical limit via the boiling process. The method is an attractive option to complement the fermentation process, which produces a low butanol concentration solution. This development could potentially lead to a more efficient pathway for biobutanol production.