Abstract:

In this paper, the preparation process of N-propylethylenediamine bonded silica gel (PSA) with controllable bonding amount was optimized; the batch repeatability of PSA preparation was examined; and the pilot scale-up experiment of PSA preparation was conducted. The properties of the PSA were investigated by infrared spectroscopy, elemental analysis, and potentiometric titration. The results showed that N—H stretching vibration peaks appeared at 3 460 cm^-1, asymmetric and symmetric stretching vibration peaks of —CH appeared at 2 960 cm^-1 and 2 860 cm^-1, and deformation vibration absorption peaks of —NH₂ appeared at 708 cm^-1, indicating that N-propylethylenediamine was successfully grafted onto the surface of silica gel.Furthermore, with the increasing proportion of silane reagent in the preparation system, the content of carbon, nitrogen, and hydrogen elements and the ion exchange capacity obtained by potentiometric titration showed an upward trend, indicating that the bonding amount of ethylenediamine-N-propyl functional group gradually increased. Moreover, the prepared PSA packing component was separated from the purification column, and the removal efficiency of ginkgolic acid from the extract of ginkgo biloba leaves using PSA with different bonding amounts was investigated. The results showed that PSA had a strong adsorption capacity for ginkgolic acid and could be used to remove ginkgolic acid from the extract of ginkgo biloba leaves, the maximum sample loading volumes for PSA separation and purification columns 2^#, 3^#, 4^#, and 5^# are 21, 22, 23, 24 mL, respectively. In addition, the removal efficiency was found to increase with the increasing amount of ethylenediamine-N-propyl bonding.

Key words: ethylenediamine-N-propyl modified silica gel, bonding quantity, ginkgo acid removal