Preparation And Characterization Of Magnetic Materials For Lipase Immobilization

Magnetic nano materials with controllable size can be well controlled under external magnate so that they can be applied in various fields. In the paper, the preparation and characterization of magnetic materials based on iron-cobalt and Fe3O4were studied. The main research work is as follows:1. The preparation and characterization of FeCo particles. The FeCo particles were synthesized through a hydrothermal way and characterized by many means including EDS, SEM, XRD, and VSM. It showed that to some content, the particle size and saturation magnetization (Ms) of FeCo particles increased with the increase of Fe content and the highest Ms could reach186emu/g.2. The synthesis and characterization of magnetic carbon materials. The compound of FeCo and carbon (FeCo@C) was obtained by calcination. Many different combinations and ratios of reactants were tried, resulting products with different morphology. It demonstrated that the presence of KOH affected the morphology of products greatly. The XRD results confirmed that the product was FeCo@C.3. Lipase immobilization on Magnetic materials based on FeCo. The obtained magnetic materials based on FeCo were used for lipase immobilization. FeCo and FeCo@C with loaded lipase were tested for their esterification stability. FeCo had a higher conversion with an initial conversion rate of85%. In terms of stability, FeCo@C had a better performance with a relative conversion rate of51%after19cycles.4. The preparation and characterization of Fe3O4with different modifications. Four kinds of Fe3O4particles were synthesized through a hydrothermal way including Fe3O4without modification, amino-modified and hydrophobic-modified Fe3O4. Many means of characterization had been carried out for these samples such as SEM, XRD, Zeta potential, contact angle and so on.5. Lipase immobilization on Fe3O4with different modifications. Lipase was combined to the surface of Fe3O4with different modifications through physical adsorption and chemical crosslinking to determine the stability of hydrolysis reaction and esteriflcation. PEI modified Fe3O4had the highest initial conversion rate of90%and better stability with a relative conversion rate of60%in the63rd cycle.