Investigating the Adsorption Process of Isoamyl Alcohol Vapor Onto Silica Gel with Near-infrared Process Analytical Technology

Abstract

This paper demonstrates the application of near-infrared process analytical technology to investigate the kinetics as well as the interaction between adsorbate molecule and adsorbent surface during a gas-solid (isoamyl alcohol vapor-silica gel) adsorption process. The adsorption process took place in a differential adsorption bed, which was temperature-and mass-homogeneous, and was in-line monitored by a near-infrared spectrometer via an optical fiber probe. After pretreating near-infrared data with band selection and partial least squares, a calibration model of back propagation-artificial neural network has been constructed to quantitatively determine the amount of adsorbate onto the adsorbent surface at any time within the entire adsorption process, the prerequisite for studying adsorption kinetics. The interaction between adsorbate and adsorbent could be acquired from the near-infrared spectra of the adsorbent adsorbing the adsorbate continuously. What is perhaps more important, since the kinetics data and the information about interaction are synchronous, it is feasible to incorporate them together for understanding the adsorption process more thoroughly than any current method.