The Physiochemical Properties and Adsorption Characteristics of Processed Pomelo Peel as a Carrier for Epigallocatechin-3-Gallate

Abstract

The NaOH-HCl- and ethanol-pretreated pomelo peel samples were prepared to apply to the batch adsorption for epigallocatechin-3-gallate (EGCG). The characteristics of peel samples were determined by Fourier transform infrared spectroscopy, scanning electron microscopy and a laser particle analyzer. The results of the physiochemical properties of the peel samples demonstrate that these peel samples have a promising adsorption capacity for EGCG, because of the increased potential binding sites on the surface compared with those of untreated peel samples. These two peel samples showed enhanced adsorption capacities of EGCG compared with that of unmodified peel in terms of the isothermal adsorption process, which could be described by both Langmuir and Freundlich models, with the theoretical maximum adsorption capacity of 77.52 and 94.34 mg g−1 for the NaOH-HCl and ethanol-treated peel samples, respectively. The adsorption kinetics demonstrated an excellent fitness to pseudo-second-order, showing that chemisorption was the rate-limiting step. The thermodynamics analysis revealed that the adsorption reaction was a spontaneous and endothermic process. This work highlights that the processed pomelo peels have outstanding adsorption capacities for EGCG, which could be promising candidates for EGCG delivering in functional food application.

Chemical Treatment of Banana Blossom Peels Adsorbent as New Approach for Manganese Removal: Isotherm and Kinetic Studies

“…The BBP was grounded and sieved into powder with a standard mesh ring of 150-212 µ m. The BBP powder was submerged in 20 mL of 1 M HCl and sodium hydroxide (NaOH). The alkaline-acid treatment has demonstrated potential as a cost-effective method for modifying adsorbents, leading to their enhance efficiency for water treatment [30]. The BBP powder was mixed for 30 min with chemical activation solutions in an orbital shaker at 150 rpm.…”

Superparamagnetic Composite of Magnetite-CTAB as an Efficient Adsorbent for Methyl Orange

“…Moreover, based on the equation of ΔG ads 0 = −RT ln K L [44], where the values of R = 8.314 J K -1 mol -1 , T = 298.15 K, and K L = 7.46 × 10 4 L mol -1 , it has been found that the value of ΔG ads 0 is −27.8 kJ mol -1 . This result indicates that the adsorption of MO on Magnetite-CTAB-0.10 is dominated by both physisorption and chemisorption mechanisms (∆G ads 0 ranges from −20 to −80 kJ mol −1 [45][46]). It is predicted that the primary interaction in this adsorption is an electrostatic interaction between the positive surface charge on the adsorbent and the negative charge group on the adsorbate.…”