Adsorption behaviors for oleuropein from olive leaves extracts by porous materials with carbon nanotubes

Abstract

Porous materials with carboxyl-modified multiwalled carbon nanotube (C-CNT) were prepared and applied to enrich oleuropein. Surface area, pore volume, and average pore diameter increased with increasing C-CNT content, and adsorption capacity was greatly enhanced. The results indicated that pseudo-second-order kinetics could describe the whole adsorption process, while intraparticle diffusion model fit the experimental data for the second stage (10-300 min). It suggested Freundlich isotherm model could describe the adsorption process. It showed that the porous materials exhibited excellent reusability and during six adsorption-desorption cycles, adsorption capacities showed no obvious loss. The high adsorption capacities, easy desorption, and remarkable reusability made the prepared porous materials as novel adsorbents for the enrichment of oleuropein. This study indicates porous materials with carboxyl group, large surface area, pore volume, and average pore diameter are favorable for oleuropein enrichment, providing an idea to design porous materials with carboxyl groups for oleuropein enrichment.

Effect of the ionic liquid group in novel interpenetrating polymer networks on the adsorption properties for oleuropein from aqueous solutions

“…13 Porous materials with carboxyl modified multi-walled carbon nanotubes (PS/C-CNT-1 and PS/C-CNT-2) were prepared and used to enrich oleuropein. 14 It was further verified that the introduction of carboxyl groups, which leads to the formation of hydrogen bonds between C-CNT and oleuropein, enhanced the adsorption efficiency for oleuropein. The polarity matching, p-p interactions and sieving effect were also involved in the adsorption process.…”

Adsorption behaviors of (–)-epigallocatechin gallate and caffeine on macroporous adsorption resins functionalized with carbazole and N-methylimidazole

“…The technology of macroporous adsorption resins (MARs) are widely applied in separating and purifying active ingredients from natural products because of MARs possess many special characteristics and advantages such as various categories, good acid and alkali resistance, porous availability, high surface area, high efficiency, simple operation process, low operation cost, easy regeneration, long lifetime and friendly to environment and so on. A series of research results have been reported recently (Liu et al, 2018;Huo et al, 2016;Liu et al, 2015a;Zhao et al, 2017b;Liu et al, 2015b). This technology has been developed into one of the most important technologies for the separation and preparation of active compounds from natural products and is the significant research direction of functional polymer materials developed in recent years.…”