交联氨基淀粉对亚甲基蓝染料的吸附性能

为获得对亚甲基蓝（MB）染料具有良好吸附能力的淀粉基吸附材料，以玉米淀粉（NSt）为原料，采用酯化—交联—氨解三步反应制备了交联氨基淀粉（ACSt），并借助傅里叶红外光谱、X 射线衍射仪及扫描电子显微镜对产物进行表征，考察了ACSt 对MB 的吸附性能。结果表明：淀粉分子中引入了氨基，成功合成了ACSt，结晶度降低，颗粒紧致结构被破坏；在碱性环境中，ACSt对MB 表现出良好的吸附性能；ACSt 对MB 的吸附行为符合准二级动力学模型和Langmuir 等温吸附模型，化学吸附是整个吸附过程中的决定性步骤，吸附过程为单分子层吸附为主，该吸附是放热、自发、减熵的过程。

Adsorption properties of cross-linked amino starch onto methylene blue

In order to obtain starch-based adsorbent with good adsorption capacity for methylene blue (MB) dye, cross-linked amino starch (ACSt) was preparedfrom corn starch as raw material bythree steps of esterification, crosslinking and ammonolysis. The products were characterized by Fourier transform infrared spectroscopy, X ray diffraction and scanning electron microscopy. It was found that amino groups are introduced into the starch molecules, indicating ACSt is successfully synthesized. The crystallinity is reduced and the compact structure of particles is destroyed. The adsorption properties of ACSt on MB were investigated. The results show that in alkaline environment, ACSt shows good adsorption properties to MB. The adsorption behavior of ACSt on MB conforms to the pseudo second order kinetic plot and Langmuir isothermal adsorption model,indicating that chemisorption is the decisive step in the whole adsorption process and the adsorption process is mainly monolayer adsorption, respectively. Thermodynamics studies show that the adsorption is anexothermic, spontaneous and entropy reduction.