Separation of Concanavalin A by Iron Oxide Magnetic Nanoparticles

• Main Authors: Song-Wen Chang, 張松文
• Other Authors: Dong-Hwang Chen
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/85899709015306280104

碩士 === 國立成功大學 === 化學工程學系碩博士班 === 95 === This thesis concerns the preparation of polyacrylic acid (PAA) bound and chitosan bound iron oxide magnetic nanoparticles and their use for the adsorption of Concanavalin A (Con A). For the preparation of PAA bound iron oxide magnetic nanoparticles, Fe3O4 magnetic nanoparticles were synthesized by the coprecipitation method first. Then, PAA was covalently bound onto magnetic nanoparticles via carbodiimide activation to form the magnetic nano-carrier with carboxylic groups for ion exchange. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses revealed that the PAA binding did not result in the significant changes in the size and structure of Fe3O4 cores. The binding of PAA on magnetic nanoparticles was demonstrated by the observation of Fourier Transform Infra Red (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), and spectrophotometric assay (OPA method). The surface charge was measured by a zeta potential meter. Using PAA bound magnetic nanoparticles to adsorb Con A, it was found that the time required to achieve the adsorption equilibrium was about 40 min and a maximum adsorption capacity was obtained in the phosphate buffer at pH 4. The kinetic adsorption data revealed that the adsorption process could be described by a pseudo second-order model equation and had no internal diffusion resistance. Also, the adsorption capacity decreased with the increase in the salt concentration. By varying the solution pH or increasing the salt concentration, the desorption equilibrium of Con A could be achieved in 20 min. In addition, the adsorption data obeyed the Langmuir isotherm equation. The maximum adsorption capacity and equilibrium constant were found to be 175.33mg/g and 3.95ml/mg, respectively. Because PAA has no specific interaction with Con A, the PAA bound magnetic nanoparticles could adsorb effectively Con A from Jack Bean extract but the selectivity was low. For the preparation of chitosan bound iron oxide nanoparticles, chitosan was carboxymethylated first and then covalently bound onto the surface of iron oxide nanoparticles via carbodiimide activation. The product was characterized by TEM , XRD, FTIR spectroscopy, TGA, DTA, OPA method, and zeta potential. Using chitosan bound magnetic nanoparticles to adsorb Con A, it was found that the time required to achieve the adsorption equilibrium was about 30 min and the maximum adsorption capacity was obtained in the phosphate buffer at pH 5. It was suggested that the main interaction was hydrogen bonding. In addition, investigating the adsorption behaviors of Con A by the metal ions chelated chitosan bound magnetic nanoparticles, it was found that the adsorption capacity increased slightly for Cu(II) chelated chitosan bound magnetic nanoparticles but significantly decreased for Ni(II) or Co(II) chelated chitosan bound magnetic nanoparticles.