Recovery of volatile fatty acids by reactive extraction using tri‐<i>n</i>‐octylamine and tri‐butyl phosphate in different solvents: Equilibrium studies, pH and temperature effect, and optimization using multivariate taguchi approach

Abstract

Abstract Recovery of volatile fatty acids from fermentation broth has been investigated by adopting an intensified approach using extractants tri‐ n ‐octylamine and tri‐butyl phosphate dissolved in 1‐decanol and methyl isobutyl ketone. The effects on distribution coefficient ( K D ) and extraction efficiency (% E ) were studied by varying the operating conditions like temperature (293.15–323.15) K, pH (2.5, 3.5, and 4.5), and compositions of extractant (10, 20, and 30 %). Taguchi ( L 36 ) orthogonal design with five factors, namely diluents, extractant type, composition, temperature, and pH, was employed for the multivariate optimization of reactive extraction of volatile fatty acids. In the Taguchi approach, a “larger is better” criterion was adopted to maximize and % E . The statistical analysis indicated that the degree of influence on by experimental variables follows the following trend: extractant type ( ) &gt; pH ( ) &gt; diluent type ( ) &gt; temperature ( ) &gt; extractant concentration ( ). The trend for % E observed is as follows: extractant type ( ) &gt; pH ( ) &gt; temperature ( ) &gt; extractant concentration ( ) &gt; diluent type ( ). The combination of optimum parameters were obtained as X 1 = 1‐decanol, X 2 = tri‐n‐octylamine, X 3 = 20 %, X 4 = 293.15 K, and X 5 = 3.5. A confirmation run was conducted using these parameters and and % E values from this run were determined to be 8.65 and of 89.64 %, respectively, which were very close to the predicted values 10.36 and % E = 91.26 %.