絮凝剂PAN-DCD与甲基橙相互作用中的热力学研究

THERMODYNAMIC STUDY OF THE INTERACTION BETWEEN FLOCCULANT PAN-DCD AND METHYL ORANGE

用平衡渗析法研究了有机高分子絮凝剂PAN-DCD与甲基橙(MO)在20,25,30,35℃下相互作用的热力学,求得结合常数K和热力学参数西△G,△H,△S,在对不同絮凝剂结构进行表征的基础上,探讨了不同PAN,DCD配比对合成的絮凝剂与MO相互作用的影响.结果表明:PAN-DCD与MO的相互作用中能量作用是主要的;随PAN与DCD的比值增大,合成的絮凝剂PD_1,PD_2,PD_3在常温下与MO的结合程度依次减小,但在较高温度下,三种絮凝剂与MO的结合程度顺序与常温相反,为PD_3>PD_2>PD_1,故PAN-DCD的结构与其同MO的结合程度之间存在着温度依赖性.

The binding of methyl orange (MO) by organic flocculant PAN-DCD was studied thermody-namically with the method of equilibrium dialysis at 20, 25, 30 and 35℃ . The equilibrium constant K and △H, △S, △G were obtained. Moreover, the effect of PAN-DCD made of different proportions of polyacrylonitrile (PAN) and dicyandiamide (DCD) on the interaction between them and MO was explored. The results showed that the structures of flocculant PD1, PD2 and PD3 are different and the binding of MO by them are not same. At normal temperature, the binding ability of MO by these flocculants is in the order, PD1 > PD2 > PD3. However, at higher temperature, the result is on the contrary as PD1 < PD2 < PD3. It indicates that there is peculiar temperature dependence between the binding of MO by these flocculants and the structures of them.