Microbubble Generation in Organic Solvents by Porous Membranes with Different Membrane Wettabilities

Abstract

Microbubbles have gained universal interest due to their wide applications in water treatment, cosmetics, and pharmaceutical industry and potential applications in gas–liquid reactions such as hydrogenation and oxidation. However, microbubble formation in organic solvents has been seldom investigated. A controllable and efficient platform is built to investigate microbubble formation in organic solvents using a hydrophilic ceramic membrane and a hydrophobic polytetrafluoroethylene (PTFE) membrane. The effect of membrane wettability on the size of microbubbles is studied with the change of the liquid property and membrane type. Experimental results show that the sizes of microbubbles are in ranges of 130–453 μm and 59–387 μm using the hydrophilic ceramic membrane and the hydrophobic PTFE membrane, respectively. Microbubbles generated in organic solvents using the hydrophilic ceramic membrane are much larger than those in water, and the size of microbubbles formed using the hydrophobic PTFE membrane shows an opposite trend. Furthermore, an equivalent pore is introduced to develop mathematical model to predict the microbubble size, which agrees well with the experimental data.

Liquid-Phase Hydrogenation of Phenol in an Advanced Gas–Liquid Concurrent Upflow Fixed-Bed Reactor with Membrane Dispersion

“…In the case that the membrane area remains unchanged, the apparent gas velocity of hydrogen increases. In all experiments, the pore size of the membranes is 200 nm; that is, the velocity of the bubbles escaping from the membrane surface increases when the membrane resistance remains unchanged, leading to an increase of the average diameter of the bubbles . At the same time, the number of bubbles in the unit time increases (Figure ), leading to a rising trend of the hydrogen solubility.…”

“…In all experiments, the pore size of the membranes is 200 nm; that is, the velocity of the bubbles escaping from the membrane surface increases when the membrane resistance remains unchanged, leading to an increase of the average diameter of the bubbles. 50 At the same time, the number of bubbles in the unit time increases (Figure 8), leading to a rising trend of the hydrogen solubility. The order of hydrogen dissolved obtained through different pipelines after entering the bed is consistent with the change of phenol conversion, as shown in Figure 9a, indicating that not only is the change of phenol conversion related to the size of the bubbles in the pipelines, but also, more importantly, the interaction between the catalyst bed and bubbles entering the bed affects the gas−liquid mass-transfer effect.…”

Microbubble Dispersion Process Intensification Using Novel Internal Baffles

“…Hence, mesh 790852 can be adopted to converge the flow field. The bubble size is a vital indicator in a bubble generator. , Figure (c) shows the mesh independence test on the final generated bubble size distribution. The probability distribution function (PDF) based on the number of bubbles refers to the ratio of the number of bubbles in a bin to the total number of bubbles in all bins.…”

Flow behaviors of multi-scale bubbles with porous ceramic membrane distributors: Visualization and Modeling

“…In addition, they coupled the numerical simulation method of Navier-Stokes equation and Darcy equation to predict the gas permeation process in porous ceramic membranes. Zhang et al [24][25][26] compared the effects of hydrophilic ceramic membranes and hydrophobic PTFE membranes, solvent type, and internals on bubble size. However, most works have focused on the structural parameters of ceramic membranes and the preparation of microbubbles.…”