G/O/W微分散体系实现甲酸/三辛胺-正辛醇体系萃取分离

The enrichment of formic acid in dilute solution was achieved by complex extraction method. An extraction system with high partition coefficient was determined. The continuum model was then applied for describing mass transfer process and predicting the mass transfer characteristics in O/W system. The rate-limiting step was determined to be mass transfer of formic acid in aqueous phase, by comparison of mass transfer rates between extractant in organic phase and solute in aqueous phase. The effect of dispersion size of organic droplets on mass transfer characteristics in O/W systems was determined, indicating inefficient extraction process with low mass transfer coefficients and surficial area in O/W systems. Inert gas was introduced into extraction system and a G/O/W system was developed. The calculation of mass transfer performance in G/O/W system indicates the addition of microbubbles effectively enhances the mass transfer process. Also, suitable volumetric fraction of inert gas was optimized. According to the calculation, a double-membrane-dispersion-device was designed, with which G/O/W double emulsion was prepared and effective enrichment of formic acid from its dilute solution was realized.