鞣酸在两种酰胺基树脂上的吸附行为研究

Study of Adsorption of Tannic Acid onto Two Polymeric Adsorbents with Amide Groups

合成了大孔交联聚(N-对乙烯基苄基己内酰胺)和大孔交联聚(N-对乙烯基苄基脲)两种酰胺基树脂.测定了这两种树脂对水溶液中鞣酸的吸附等温线,发现所有的吸附等温线都符合Freundlich吸附等温方程,相关系数大于0.99;同时,聚(N-对乙烯基苄基脲)对水溶液中鞣酸的吸附亲和性相对聚(N-对乙烯基苄基己内酰胺)更大.根据热力学函数关系计算了等量吸附焓、Gibbs吸附自由能和吸附熵.表明两种酰胺基树脂对水溶液中鞣酸的吸附均为吸热的、物理吸附过程;同时,聚(N-对乙烯基苄基脲)对水溶液中鞣酸的吸附相对聚(N-对乙烯基苄基己内酰胺)有更低的吸附焓变、吸附自由能变和吸附熵变.

Two polymeric adsorbents,PSt-CH2-ε-CLt and PSt-CH2-Ur,were synthesized The adsorption isotherms of tannic acid onto the two polymeric adsorbents from aqueous solution were measured and correlated to Freundlich adsorption equation.It was shown all of the adsorption isotherms can be fitted to Freundlich adsorption equation with the coefficients larger than 0.99,and PSt-CH2-Ur has larger adsorption affinity than PSt-CH2-ε-CLt.Isosteric adsorption enthalpies,Gibbs free energies and adsorption entropies were calculated,and the results indicated that the adsorption were all spontaneous,absorbing heat and adsorption entropies increasing processes of with physical characters,and the isosteric adsorption enthalpies,Gibbs free energies and adsorption entropies of PSt-CH2-Ur were more negative than those of PSt-CH2-ε-CLt.