Dynamic adsorption of octanols at air/water interface

Abstract

The dynamic adsorptions of 1-, 2-and 3-octanols at air/water interface were monitored using pendant drop method. It has been found that 1-octanol had strongest interfacial effects, yet slowest rate of adsorption. The experimental data were compared with diffusion-controlled and diffusion-kinetic-mixed models. Excepting 3-octanol at 1 mM, all systems required kinetic step. The effective kinetic constant was found varying with the concentration and the carbinol position. The results highlighted the influence of hydrophobic tails on the dynamic adsorption.Les adsorptions dynamiques de 1-, 2-et 3-octanolsà l'interface air/eau ontété suiviesà l'aide de la méthode de la goutte pendante. On a découvert que 1-octanol présente les effets interfaciaux les plus forts, mais le taux d'adsorption le plus lent. Les données expérimentales ontété comparées a l'aide de modèles par diffusion contrôlée età mélange diffusion-cinétique.À l'exception de 3-octanolà 1 mM, tous les systèmes ont nécessité uneétape cinétique. On a trouvé que la constante cinétique efficace varie avec la concentration et la position du carbinol. Les résultats ont mis eń evidence l'influence des queues hydrophobes sur l'adsorption dynamique.

Scale‐Up of Oscillatory Helical Baffled Reactors Based on Residence Time Distribution

“…An oscillatory baffled reactor (OBR) is a form of plug flow reactor (PFR) in which a high degree of plug flow can be achieved at low flow rates, corresponding to a few milliliters per minute to microliters per minute [1,2]. Mixing in the OBR is independent of the net flow and controlled by the oscillation conditions [3][4][5].…”

“…An oscillatory baffled reactor (OBR) is a form of plug flow reactor (PFR) in which a high degree of plug flow can be achieved at low flow rates, corresponding to a few milliliters per minute to microliters per minute [1,2]. Mixing in the OBR is independent of the net flow and controlled by the oscillation conditions [3][4][5]. Generally, the fluid mechanics in OBR are governed by dynamic and geometrical parameters (Strouhal number, Str; oscillatory Reynolds number, Re o ; net flow Reynolds number, Re n ; and baffle spacing, l) 1) as described below [6][7][8]:…”

“…Mixing in the OBR is independent of the net flow and controlled by the oscillation conditions [3][4][5]. Generally, the fluid mechanics in OBR are governed by dynamic and geometrical parameters (Strouhal number, Str; oscillatory Reynolds number, Re o ; net flow Reynolds number, Re n ; and baffle spacing, l) 1) as described below [6][7][8]:…”

“…l D ¼ 0:5 À 1:5 (5) where f is the frequency of oscillation (Hz), x o is the center-topeak amplitude of oscillation (m), D is the OBR diameter (m), u is the superficial velocity of the liquid (m s -1 ), r is the density (kg m -3 ), m is the viscosity (Pa s), and l is the baffle spacing/ helical pitch (m). The intensity of mixing inside the OBR can be measured by the oscillatory Reynolds number (Re o ).…”

“…A number of baffle designs such as the smooth periodic constriction (SPC) design, the helical and the single-orifice design ( Fig. 1) have been used at the ''milliliter scale'' (or ''meso-scale'') [5,8,9]. The helical baffle design has been demonstrated to exhibit high degrees of plug flow over a much wider range of oscillation conditions than other designs [5,8,10], due to the combined effects of vortex formation and swirling flow (Figs.…”