Computational study on liquid-liquid extraction of formic acid using methyl isobutyl ketone solvent with the aid of biological buffer as green auxiliary agent

In a challenge to develop green solvent, biological buffers are gaining interest as a separation agent to enhance extraction performance. The aim of this study is to predict the Good's biological buffer suitable for formic acid extraction. The computational study on the liquid-liquid extraction of formic acid using methyl isobutyl ketone solvent with the aid of biological buffer (MOPS or HEPES) at 303.15 K under atmospheric pressure were studied. MOPS and HEPES are zwitterionic amino acids that have a positive and negative charge in the same molecule and can preserve the pH of the biochemical system between 6 and 9. The Non-Random-Two-Liquid (NRTL) model was used to optimize the extraction column and mixer-decanter. From the obtained results, the biological buffer can be used as a good green auxiliary agent for extraction of formic acid from aqueous solution. The most efficient process obtained in this study was the formic acid extraction system with the aid of 20% HEPES buffer using a 7-stages extraction column with solvent flow rate of 60 kg/hour and feed to solvent ratio of 1:1.5. The capital cost of this system was $ 4,078,153.25 and the mass fraction of formic acid in the raffinate was relatively low (0.00111) with a percent recovery of 99.09%.