Tallarek U, van Dusschoten D, Van As H, Guiochon G, Bayer E
Institute of Organic Chemistry, University of Tübingen, Germany.
Magn Reson Imaging. 1998 Jun-Jul;16(5-6):699-702. doi: 10.1016/s0730-725x(98)00019-8.
Pulsed field gradient (PFG) nuclear magnetic resonance (NMR) is applied to study convective and diffusional transport in chromatographic columns packed with totally porous support particles. Here stagnant zones exist in the particle pores, and diffusional mass-transfer limitations between fluid molecules diffusing in the intraparticle pore network and flowing in the interparticle void space are detected quantitatively. Axial displacement probability distributions were measured for water over a range of Peclet numbers and observation times, with diffusion lengths between 0.15 and 0.91 times the average support particle diameter. The transition towards complete diffusional exchange is demonstrated, thereby also revealing the development of the classical convective dispersion process in a packed bed of (porous) particles.
脉冲场梯度（PFG）核磁共振（NMR）被用于研究填充有全多孔载体颗粒的色谱柱中的对流和扩散传输。此处，颗粒孔隙中存在停滞区，并且定量检测了在颗粒内孔隙网络中扩散和在颗粒间空隙空间中流动的流体分子之间的扩散传质限制。在一系列佩克莱数和观测时间范围内测量了水的轴向位移概率分布，扩散长度在平均载体颗粒直径的0.15至0.91倍之间。证明了向完全扩散交换的转变，从而也揭示了（多孔）颗粒填充床中经典对流扩散过程的发展。
