孔径对多孔马铃薯淀粉结构及吸附性能的影响

Influence of pore size on structure and adsorption properties of porous potato starch

通过微波辅助制备一种新型的多孔马铃薯淀粉。在制备过程中选择合适的乳化剂参数,使淀粉颗粒不均匀分散。研磨过筛之后得到不同目数的多孔淀粉。通过扫描电子显微镜(SEM)、比表面积仪(BET)和傅里叶红外变换光谱(FTIR)对原淀粉和不同目数多孔淀粉的形貌与结构进行表征,以亚甲基蓝为吸附对象,对不同目数的多孔淀粉进行等温吸附实验并探究吉布斯自由能对吸附的影响。实验结果表明,由于淀粉颗粒的不均匀分散,交联反应不仅发生在颗粒内部也发生在颗粒之间。随着目数的增大,淀粉表面结构被破坏,表面粗糙程度增加,孔洞增多,孔径也逐渐增大。多孔淀粉的吸附过程符合Langmuir等温吸附方程,且随着多孔淀粉目数的增大,拟合度逐渐增大,吸附量也逐渐增大。多孔淀粉在温度为298K时最大吸附量为188.679mg/g。

In this paper,a new type of porous potato starch was synthesized by microwave-assisted method. During the preparation process,the parameters of the emulsifier were changed so that the starch granules were not evenly dispersed. Different mesh of porous starches were obtained by grinding and sieving. Using Scanning Electron Microscopy（SEM）,Specific surface area analyzer（BET）and Fourier Transform Infrared Spectroscopy（ FTIR）, the detailed analysis was performed on the morphology and structure of potato starch and porous starch. Isothermal adsorption experiment of different mesh of porous starch was conducted with methylene blue solution（MB）and the influence of Gibbs＇ s free energy on adsorption was studied. The results show that the crosslinking reaction occurs not only within the particles but also between the particles due to the uneven dispersion of starch particles. With the increase of mesh number,the surface structure of porous starch was destroyed and the surface roughness was increased;more and more holes were in the starch and pore size increased gradually. The adsorption process of porous starch was in line with the Langmuir Isothermal adsorption equation. With the increase of mesh size,fitting degree and adsorption amount increase gradually. The maximum adsorption amount of porous starch is 188.7 mg/g at the temperature of 298 K.