Preparation And Study Of PAAm Matrix For Expanded Bed Adsorption

Expanded bed adsorption (EBA) integrates clarification, concentration, and primary purification into a single step. It is a promising technique for bioseparation. EBA simplifies the technical process and shows high efficiency for protein separation. EBA matriexes count in adsorption process. In order to expand the applications of EBA, new matrices would be developed and applied to separate more bio-active molecules. With the purpose of developing new polyacrylamide (pAAm) matrices with expanded bed mode, this work will focus on the preparation and characterization of the matrices, including four main aspects as following".(1) Preparation of pAAm-TuC matrix by inverse suspension polymerization with tapioca bearizing:Tungsten carbide (TuC) powder is selected as a densifier embedded in pAAm polymer skeleton. The inversed phase suspension process is studied in detail and the optimal parameters are:the mixture of cyclohexane and edible oil with mass ratio of1:2as the oil phase; the content of dispersant Span-80at3.0%by wight based on the oil phase; the mass ratio of oil to water is4:1; stirring speed is450rpm. The matrices obtained have regular spherical shape and a proper diameter of50-400μm, and the mean pore diameter of500-1000nm after bearizing. The density and mechanical strength of the matrices are improved as the TuC increasing.(2) Preparation of pAAm-TuC cryogel matrix by inverse suspension polymerization with cryogel solvent bearizing:Tungsten carbide (TuC) powder is selected as a densifier embedded in pAAm cryogel polymer skeleton. The inversed phase suspension process is studied in detail and the optimal parameters are:the content of AAm and MBAAm at7%by weight based on the water phase; the mean pore diameter reaches largest when the reaction temperature at-12℃; the mass ratio of oil to water is4:1; stirring speed is550rpm. The matrices obtained have regular spherical shape and a proper diameter of50-400μm, and the mean pore diameter of30μm. When the mass ratio of TuC increased from25%to100%, the density of pAAm-TuC cryogel matrix increased from1.12g/cm3to1.40g/cm3. The mechanical strength of the matrices are improved as the TuC increasing.(3) The hydrodynamic properties of pAAm-TuC matrix and pAAm-TuC cryogel matrix:The rate of expansion (E), the Bodensterin number (Bo), the axial dispersion coefficient (Dax), the height equicalent of theoretical plate (HETP) are used to analyze the liquid mixing in the expanded bed. In summery, compared to pAAm-TuC cryogel matrix, pAAm-TuC matrix has smaller E, bigger Bo, as well as smaller Dax and HETP, that means pAAm-TuC matrix has a better performance in expanded bed. (4) The protein adsorption properties of pAAm-TuC-AMPSA matrix and pAAm-TuC-AMPSA cryogel matrix:The isothermal adsorption equilibrium follows the Langmuir adsorption equation. The result shows that the cryogel matrix grafting AMPSA has the ability of protein adsorption, the adsorption capacity of lysozyme reach56.5mg/g, which is larger than pAAm-TuC-AMPSA matrix. In summery, pAAm-TuC-AMPSA cryogel matrix has a better performance in protein adsorption.This thesis focused on the pAAm-TuC matrices, including pAAm-TuC beads preparing and basic properties measurement, the hydrodynamic properties measurement, the functionalization and protein adsorption measurement. The new pAAm-TuC matrices prepared in the present work show good expanded bed and protein adsorption performance, which provide new matrix materials of EBA.