The 3D pore structure and fluid dynamics simulation of macroporous monoliths: High permeability due to alternating channel width

Abstract

Polymethacrylate-based monoliths have excellent flow properties. Flow in the wide channel interconnected with narrow channels is theoretically assumed to account for favorable permeability. Monoliths were cut into 898 slices in 50nm distances and visualized by serial block face scanning electron microscopy (SBEM). A 3D structure was reconstructed and used for the calculation of flow profiles within the monolith and for calculation of pressure drop and permeability by computational fluid dynamics (CFD). The calculated and measured permeabilities showed good agreement. Small channels clearly flowed into wide and wide into small channels in a repetitive manner which supported the hypothesis describing the favorable flow properties of these materials. This alternating property is also reflected in the streamline velocity which fluctuated. These findings were corroborated by artificial monoliths which were composed of regular (interconnected) cells where narrow cells followed wide cells. In the real monolith and the artificial monoliths with interconnected flow channels similar velocity fluctuations could be observed. A two phase flow simulation showed a lateral velocity component, which may contribute to the transport of molecules to the monolith wall. Our study showed that the interconnection of small and wide pores is responsible for the excellent pressure flow properties. This study is also a guide for further design of continuous porous materials to achieve good flow properties.

Effect of pore size on performance of monolithic tube chromatography of large biomolecules

“…When the liquid is pumped to a convection‐aided chromatography media such as membranes and monoliths, the mobile phase liquid flows through open, highly connected pores that form a network of channels (flow‐through pores) of the media. Friction between a pore wall and the mobile phase liquid results in pressure drop that, as recently demonstrated, can provide not only information about the pore size but also further insight into a monolith structure, including pore connectivity . Since methacrylate monoliths of different pore sizes exhibit similar microstructure and porosity, differences in pressure drop reflect changes in monolith average pore size that determine the surface area and the DBC .…”

Production of β‐Lactoglobulin hydrolysates by monolith based immobilized trypsin reactors

“…In addition, the work of Jungreuthmayer et al. demonstrated that the flow in monolith showed a lateral velocity component, which may contribute to the transport of molecules to the monolith wall. This confirmed lateral velocity can be speculated to promote the contact between substrate and fixed trypsin.…”

Pressure drop in liquid chromatography

“…) is proposed based on computational fluid dynamics (CFD). To obtain reliable results, a detailed microstructure of particular bed has to be obtained, commonly using various imagining techniques . On this base, velocity and pressure drop distribution over the representative bed segment is calculated together with an average values of both.…”

“…On this base, velocity and pressure drop distribution over the representative bed segment is calculated together with an average values of both. Stabilized reinforced cellulose membrane as well as silica and methacrylate monolith hydrodynamic properties were recently analyzed using this approach . This methodology can be implemented also on beds with more complex pore structure.…”

“…[115]) is proposed based on computational fluid dynamics (CFD). To obtain reliable results, a detailed microstructure of particular bed has to be obtained, commonly using various imagining techniques [116][117][118][119][120][121][122][123]. On this base, velocity and pressure drop distribution over the representative bed segment is F I G U R E 1 0 Experimental error in estimation of adsorbed layer thickness Δ A represents pressure drop of convective bed with adsorbed molecules, Δ AR pressure drop of convective bed with adsorbed reference standard and Δ is pressure drop of convective bed without any adsorbed molecules [Reprinted with permission from 139] calculated together with an average values of both.…”