Extraction of volatile fatty acids from fermented wastewater

Ehsan Reyhanitash, Bart Zaalberg, Sascha R.A. Kersten, Boelo Schuur

Research output: Contribution to journalArticleAcademicpeer-review

58 Citations (Scopus)

Abstract

Valorization of wastewater streams can be done by fermentation to produce volatile fatty acids (VFAs) which are applied as platform chemicals for synthesis of value-added chemicals. Since VFA concentration in fermented wastewater is very low (∼1 wt%) and fermented wastewater contains considerable amounts of dissolved salts, recovery of VFAs from fermented wastewater is challenging. To study the potential of some ionic liquids compared to traditional solvents for extraction of VFAs from fermented wastewater, a detailed study on the effects of various salt-originating ions on VFA extraction was performed. Ion exchange and intermolecular interactions (e.g. hydrogen bonding) were found to be responsible for extraction of VFAs. The presence of salts (e.g. KCl) resulted in extraction of acidic forms of salt-originating anions (e.g. H+ + Cl−). 20 wt% trioctylamine (TOA) in n-octanol (representing conventional solvents) and [P666,14][Phos] (an ionic liquid) were found to be the most promising VFA-extracting solvents. Their maximum VFA loadings while being in equilibrium with an artificial fermented wastewater were determined by performing cross-current extractions. [P666,14][Phos] achieved a higher maximum VFA loading which enables it to deliver a much more concentrated VFA stream at a lower solvent to feed ratio (S/F).
Original languageEnglish
Pages (from-to)61-68
Number of pages8
JournalSeparation and purification technology
Volume161
Issue number1
DOIs
Publication statusPublished - 2016

Keywords

  • METIS-320689
  • IR-103902

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