交联淀粉微球对Co^(2+)的吸附行为及机理研究

Adsorption behavior and mechanism of Co^(2+) on crosslinked starch microspheres

研究了交联淀粉微球(CSM)对Co2+的静态吸附行为,并根据吸附等温线研究了吸附热力学性质,利用红外光谱仪、X射线衍射仪对吸附产物进行了结构表征,探讨了吸附机理。结果表明:在研究的浓度范围内,CSM对Co2+吸附等温线同时符合Langmu ir等温方程和Freund lich等温方程,不同温度下,CSM吸附Co2+的吸附焓变ΔH、吸附自由能变ΔG、吸附熵变ΔS均为负值,表明吸附是一个自发的、放热的过程,降低温度有利于吸附;CSM通过物理吸附、配位吸附方式吸附Co2+,并导致CSM结晶结构被进一步破坏。

The static adsorption behavior of Co^2＋ on the cross-linked starch microsphere （CSM）） was investigated at different temperatures, and the adsorption thermodynamic performance was investigated according to the adsorption isotherms. The structures of CSM before and after adsorption were characterized by Fourier transform infrared spectroscopy （FTIR）, X-ray diffraction （XRD）, and the mechanism of adsorption was also discussed. The result shows that within 308-328 K and the concentration range researched, Langmiur and Freundlich adsorption isotherm equation are adapted for the adsorption characteristic of Co^2＋ on CSM. The enthalpy change AH, free energy change AG and entropy change AS for Co^2＋ adsorbed by CSM are all negative at different temperatures, which indicates that the adsorption is a spontaneous and exothermic process of decreased entropy, and the decrease of temperature benefits the adsorption. The CSM absorbs Co^2＋ by means of physical adsorption and weakly coordination adsorption, and causes the crystal structure of CSM to be further destroyed after adsorbing Co^2＋.