Response Surface Methodology Guided Adsorption and Recovery of Free Fatty Acids from Oil Using Resin

Themes: Conversion

Keywords: Feedstock Bioprocessing


Singh, R.Dien, B.S.Singh, V. June 9, 2021. “Response Surface Methodology Guided Adsorption and Recovery of Free Fatty Acids from Oil Using Resin.” Biofuels, Bioproducts, and Biorefining 15(5):1485-1495. DOI: 10.1002/bbb.2255.


Free fatty acid adsorption from refined soy oil using different resins: (a) palmitic acid, (b) stearic acid, and (c) oleic acid. Percentage FFA adsorption is expressed as average values +/- s.d.

The presence of free fatty acids interferes with the conversion of plant oils to biodiesel. Four strong and weak base resins were evaluated for the removal of free fatty acids (FFA) from oil. Amberlite FPA 51 showed the highest adsorption capacity of FFA. A resin concentration above 3% could enable a higher percentage FFA adsorption. The adsorption process fitted a pseudo-first-order kinetic model and achieved equilibrium in approximately 8 h. A full factorial design was used to optimize the resin and FFA concentrations at a fixed temperature (40° C). A ratio of resin to fatty acid concentrations above 1.875 was sufficient for 70% adsorption and the amount adsorbed continued to increase with further added resin. A two-step washing of resin using hexane and ethanol recovered approximately 67.55% ± 4.05% of the initially added fatty acid. The resin that was used was regenerated with 5% NaOH and re-used for a minimum of three consecutive cycles. However, the adsorption capacity diminished to 75% of the initial cycle in cycles 2 and 3. Thus, the work presents a resin-based process for deacidification of oil to reduce fatty acid content of oil for biodiesel production.


Download (5.8 KB) includes:

    • Resin Properties
    • Free Fatty Acids Adsorption
    • Experimental Design

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