Cu^(2+)型斜发沸石抗菌剂制备过程中离子交换热力学研究

THERMODYNAMIC STUDY ON ION EXCHANGE DURING PREPARING Cu^(2+)-CLINOPTILOLITE ANTIMICROBIAL AGENT

采用液相离子交换法制备了Cu2+型斜发沸石抗菌剂,计算了不同温度、不同初始Cu2+浓度下,Cu2+在交换液和斜发沸石中的C/C0和q/Q值,并绘制出了离子交换等温线。还求出了相应的选择性校正系数Kc和交换平衡常数Ka,得出了lnKα值与1/T之间的线性关系。在此基础上,导出了焓变ΔrHθm、吉布斯自由能ΔrGθm和熵变ΔrSθm。研究结果表明:该离子交换过程中,ΔrHθm=7.101kJ/mol,ΔrGθm<0、ΔrSθm>0,即该离子交换过程是吸热和熵增加反应,在各实验温度下都能自动发生,但升高温度有利于Cu2+的交换。

The Cu-clinoptilolite was prepared by liquid-phase ion exchange, and the corresponding value of C/Co and q/Q in the exchange liquor and clinoptilolite phase was calculated according the measured Cu^2＋ concentration while reaching exchange equilibrium under different temperature and primary Cu^2＋ concentration, the ion exchange isotherm was plotted according above data. Further, the corrected selectivity coefficient Kc and the exchange equilibrium constant Ka was also calculated, and the linear relation was educed between lnKa and 1/T. On the basis, enthalpy change △rHm^θ, Gibbs free energy △rGm^θ and entropy changes △rSm^θ were figured out. The researching results show △rHm^θ = 7. 101KJ/mol, △rGm^θ 〈0, △rSm^θ 〉0, these illustrates the ion exchange process is an endothermic and entropy increase reaction; ion exchange can occur automatically under different experimentation temperature, but increasing temperature is advantageous to Cu^2＋ exchange.