Constructing multiple hydrogen bonds in adsorbent for selective adsorption of acteoside

Abstract

The efficient adsorption of acteoside (ACT) was essential for the development and utilization of the active ingredients of Cistanche tubulosa. In this study, the adsorbent of hydrophilic imidazole polyionic liquids P(StDVB-[C4vim][BF4]) was synthesized based on a double emulsion interfacial polymerization method to adsorb hydrophilic ACT. The as-prepared P(StDVB-[C4vim][BF4]) showed an excellent adsorption performance, and the adsorption capacity and selectivity were 114.31 mg/g and 4.31, respectively. This was mainly attributed to as follows: firstly, P(StDVB-[C4vim][BF4]) possessed multiple hydrogen bond receptors due to the introduction of functional monomer [C4vim][BF4]. The multiple hydrogen bond receptors provided the F atoms and N atoms to form multiple hydrogen bonds with the ACT, realizing the efficient adsorption of ACT. Secondly, the hierarchical porous structure had plenty of micro-mesopores and macropores. The micropores prefer screened small molecules, enhancing the selective adsorption of ACT, the mesoporous pores greatly improved the diffusion ability of ACT in the pores of P(StDVB-[C4vim][BF4]), and the macropores reduced transportation restrictions and facilitated the entry of ACT. Finally, the P(StDVB-[C4vim][BF4]) contained hydrophilic imidazole group, enhancing the affinity between P(StDVB-[C4vim][BF4]) and ACT. Thus, P(StDVB-[C4vim][BF4]) can effectively adsorb ACT. The multiple hydrogen bonds were suggested as the major driving forces for adsorbing P(StDVB-[C4vim][BF4]) and ACT. In addition, P(StDVB-[C4vim][BF4]) was conveniently regenerated up to 6 times. Therefore, the P(StDVB-[C4vim][BF4]) had potential application for adsorbing active ingredients of natural products.