A novel absorbent, HOF-3@PU: Preparation and application for sustainable and efficient purification of catalpol and ajugol from Rehmannia glutinosa leaves

Abstract

This study introduced the preparation of a novel HOF-loaded PU sponge (HOF-3^@PU) composite for the sustainable and efficient purification of catalpol and ajugol from Rehmannia glutinosa leaves for the first time. HOF-3 was selected as the best adsorbent from the five synthesised HOFs. HOF-3^@PU was prepared by ultrasonication, and the loading conditions were optimised. The results showed that the optimum adsorption conditions are as follows: adsorption liquid volume: 160 mL, flow rate: 3.0 mL/min, pH: 6.0, concentration: 1.62 mg/mL for catalpol and 2.18 mg/mL for ajugol. The optimum desorption conditions are as follows: desorption agent: ethanol, volume fraction: 60%, flow rate: 2.0 mL/min, volume: 300 mL and pH: 6.0. Under the optimal process conditions, the adsorption capacities of catalpol and ajugol were 75.62 and 68.41 mg/g, the desorption rates were 78.5 and 86.4% and the purities were 38.7 and 36.5%, respectively.

Graphical Abstract

Keywords:

• HOF-3^@PU
• purification
• Rehmannia glutinosa Leave
• catalpol
• ajugol

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

This work was financially supported by University-Student Innovative Experiment Project Fund Support for Northeast Forestry University (202110225447) and the 111 Project, China (B20088).