Adsorption separation of 2-phenylethanol and l-phenylalanine on polymeric resins: Adsorbent screening, single-component and binary equilibria

• Separation of 2-phenylethanol from l-phenylalanine on polymeric resins was studied.
• Langmuir isotherm parameters were used to predict binary adsorption equilibrium.
• Competitive binary isotherms described well the selective binding of 2-phenylethanol.

Eleven polymeric resin adsorbents were investigated for their potential to bind selectively 2-phenylethanol from solutions containing also l-phenylalanine. The capacity for single-component and the capacity/selectivity for binary adsorption of 2-phenylethanol and l-phenylalanine were determined to eliminate adsorbents with low performance. Single-component equilibrium data of both compounds were well described by the Langmuir equation for five selected adsorbents. Two most suitable adsorbents, which were both non-functionalised poly(styrene-divinylbenzene) resins with different pore structures, were then used in measurements of the binary adsorption equilibrium of 2-phenylethanol and l-phenylalanine. The modified competitive Langmuir equation and the LeVan–Vermeulen equation provided good description of co-adsorption of 2-phenylethanol and l-phenylalanine in a broad concentration range of both components when high capacity and selectivity for 2-phenylethanol binding was observed. In order to obtain data for characterization of desorption performance, adsorption isotherms of 2-phenylethanol were also determined for pure ethanol and ethanol/water solutions as solvents.