不同金属离子改性的硅酸铝对薄荷醇吸附/脱附性能研究

本文应用浸渍法制备三种改性的硅酸铝(AS)材料Fe3+/AS、Cu2+/AS、Ag+/AS,采用静态吸附法测定了改性硅酸铝对薄荷醇的吸附量;应用程序升温脱附实验测定了薄荷醇在改性硅酸铝上的脱附活化能,并应用HSAB软硬酸碱理论分析和讨论了薄荷醇在不同改性硅酸铝上脱附活化能的差异。结果表明:与原始硅酸铝相比,金属离子改性后硅酸铝比表面积显著增加,增幅依次为105.83%、44.41%、32.69%。改性材料对薄荷醇吸附量增加,吸附量顺序为Fe3+/ASCu2+/ASAg+/ASAS。此外,该改性改变了薄荷醇与硅酸铝表面的结合力,薄荷醇在改性硅酸铝上的脱附活化能顺序如下:Ag+/ASCu2+/ASFe3+/AS。与原始硅酸铝相比,Ag+和Cu2+增强了薄荷醇与硅酸铝之间的结合力,Fe3+减弱了薄荷醇与硅酸铝之间的结合力,与HSAB软硬酸碱理论预测的结果一致。

Menthol Adsorption and Desorption Performance of Aluminum Silicates Modified by Different Metal Ions

In this study, three types of aluminum silicate (AS), Fe3+/AS, Cu2+/AS, and Ag+/AS, were prepared using the immersion method to measure the adsorption of menthol by modified AS using a static adsorption method. Temperature programmed desorption (TPD) experiments were conducted to measure the desorption activation energy, Ed, of menthol by modified AS. The variation in menthol Ed was analyzed and discussed using hard and soft acid and base (HSAB) theory. The results indicated that the surface area of the modified AS was significantly increased compared with that of the original AS. The differences were 105.83%, 44.41%, and 32.69% for Fe3+/AS, Cu2+/AS, and Ag+/AS, respectively. The modified materials also had increased menthol adsorption, which followed the order: Fe3+/AS > Cu2+/AS > Ag+/AS > AS. In addition, these modifications changed the binding force between menthol and the AS surface. The Ed of menthol by modified AS was as follows: Ag+/AS > Cu2+/AS > Fe3+/AS. Compared to the original AS, the loading of Ag+ and Cu2+ enhanced the binding force between menthol and AS, whereas the loading of Fe3+ weakened it, which were consistent with the results predicted by HSAB.