High resolution imaging and image analysis in porous media

Date

2019

Author

Yalçın, Özge Hande

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Flow and mass transfer in porous media are intimately coupled to their microstructure. Advances in computational capabilities have brought about the possibility of modeling these materials by employing the high-resolution 3D topography in flow and mass transfer simulations. This work investigates and analyzes the microstructure and adsorbate localization behavior of porous media. Specifically, high- resolution microscopy techniques were implemented to obtain morphology information for porous media. Gigacap Q-650M and HALOTM were chosen as adsorbents and α-lactalbumin was used as staining protein. Microstructures of Gigacap Q-650M and HALOTM were imaged by using Scanning Electron Microscopy (SEM). The crosslinking structure of Gigacap Q-650M was observed, and the core-shell structure of HALOTM particle was also investigated by using SEM. Gigacap Q-650M with and without adsorbed protein were characterized by Transmission Electron Microscopy (TEM). Contrast in the protein-loaded adsorbent was much better than the sample without adsorbed protein. In TEM images, protein localization on the adsorbent was investigated. It can be surmised that the protein on Gigacap Q-650M remains confined to polymethyl methacrylate (PMMA) base and aldehyde fixation itself results in extensive cross-linking of proteins (and presumably functional groups), thus potentially resulting in the contiguous solid-phase observed. Characterizations of Gigacap Q-650M and HALOTM were also done by using Focus Ion Beam (FIB). HALOTM particle structure composed of core and the shell part was investigated and 2-D images of HALOTM were used to construct 3-D topography of it by using FIB whereas FIB images of Gigacap Q-650M could not be used to form 3-D structure because of the low resolution of images.

Subject Keywords

Porous materials., Keywords: Imaging techniques, Ion exchange chromatography, Protein adsorption, Core-shell particles, Polymer modified stationary phase.

URI

http://etd.lib.metu.edu.tr/upload/12624149/index.pdf
https://hdl.handle.net/11511/44297

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Graduate School of Natural and Applied Sciences, Thesis