Privatisation of public housing: a comparisonof Hong Kong & Shenzhen Special Economic Zone

published_or_final_versionUrban PlanningMasterMaster of Science in Urban Plannin

Structural characterization of magnetic cassava-starch microspheres and their application in adsorption of lysozyme

磁性微球是高分子材料与磁性物质通过一定作用复合而成的一类具有特殊功能的磁性高分子微球。以木薯淀粉为原材料,复合共沉淀法制备的改性磁流体Fe3O4,采用两步法（化学交联法）制备木薯淀粉磁性微球。利用傅里叶变换红外光谱仪、X射线衍射仪、同步热分析仪、扫描电镜、激光粒度仪、磁天平等对其性能及结构进行表征并研究其对溶菌酶的吸附行为。通过单因素法考察磁性微球用量、溶液pH值、吸附温度、吸附时间对吸附率的影响,并采用准一级动力学模型和准二级动力学模型研究其吸附动力学。结果表明：制备的木薯淀粉磁性微球Fe_3O_4含量为19.71%,D50（中位径）为15.40μm,磁化率为1.571×10-3cm~3/g,形貌规整;在微球用量为1.25g,溶液pH=10,吸附温度为25℃,吸附时间为80min时,微球对溶菌酶的吸附率最高,达到84.67%。以相关系数R2为参考,准二级动力学模型（R2=0.99993）较准一级动力学模型（R~2=0.99174）、颗粒内扩散模型（R~2=0.69996）能更好描述木薯淀粉磁性微球对溶菌酶的吸附行为。The magnetic cassava starch microspheres have been prepared using Fe_3O_4 and cassava starch as starting materials. Fourier transform infrared spectrum,X-ray diffraction,thermal analyzer,scanning electron microscope,laser granulometer,and magnetic balance were used to characterize the product. The adsorption behavior of lysozyme on these microspheres was studied. The influence of magnetic microsphere dosage,solution p H,adsorption temperature and time on the adsorption efficiency was evaluated by single factor experiments. The results showed that magnetic starch microspheres contain 19.71% of Fe_3O_4,with D50（median diameter） of 15.40μm,and magnetic susceptibility of 1.571×10~（-3）cm~3/g. When the dosage of microspheres was 1.25 g,with solution p H value of 10,adsorption temperature of 25℃,adsorption time of 80 min,the best adsorption efficiency of lysozyme on the microsphere was 84.67%. Based on the correlation coefficient R~2,the adsorptionrate can be better described by pseudo-second-order kinetics（R~2=0.99997） than by pseudo-first-order kinetics（R~2=0.99174）,and the particle diffusion model（R~2=0.69996）.广西高校人才小高地建设创新团队计划(桂教人[2011]47号);广西自然科学基金面上项目(2013GXNSFAA019037);广西高校科学技术研究项目(2013YB072);广西民族大学研究生教育创新计划(gxun-chxs2015084);广西民族大学-广西化工研究院研究生联合培养基地专项资金(BYB-014);广西壮族自治区大学生创新创业训练计划(201410608048)项