Binary adsorption isotherm and kinetics on debittering process of ponkan (Citrus reticulata Blanco) juice with macroporous resins

- Resins were screened on the debittering capability and adsorption selectivity.
- The adsorption data were applied to match three kinetic models.
- Langmuir isotherm model was well fitted to binary adsorption data.

Selective removal of bitter components from ponkan juice with macroporous resins improved it sensory quality with scarcely effect on its nutritive value. Ten macroporous adsorbent resins were evaluated for their capacity in adsorbing the debittering component, and the adsorption selectivity for limonin against flavonids was estimated using coefficient αl/f. LX920 resin exhibited the highest adsorption capacity (7.96 mg/g wet resin) and selectivity coefficient αl/f (99.42) at initial limonin concentration of 24 μg/mL. The adsorption equilibrium and kinetics were isothermally generated at 25 °C under static mode condition. Langmuir isotherm model and modified extended Langmuir model were well fitted with single and binary adsorption isotherms in binary system, respectively. The solute adsorptivity KL of LX920 resin for limonin (2.81 L/g) was higher than that for flavonoids (1.10 L/g). limonin was more efficiently adsorbed onto the resin's surface. Furthermore, the pseudo-first, pseudo-second and intra-particle diffusion kinetic equations were employed to match the experimental adsorption data. Pseudo second-order and pseudo-first kinetic models were best fitted to the adsorption of limonin and flavonoids, respectively.