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通过液相离子交换试验研究了Zn2+和Ag+两种抗菌金属离子与NH4+型斜发沸石离子交换的热力学特征,绘制了Zn2+和Ag+的离子交换等温线,计算了不同条件下达到离子交换平衡时,NH4+型斜发沸石对Zn2+和Ag+的选择性校正系数Kc和交换平衡常数Ka,得出了ln Ka值与1/T之间的线性关系,导出了反应标准摩尔焓变(ΔrHθm)、反应标准摩尔Gibbs自由能变(ΔrGθm)和反应标准摩尔熵变(ΔrSθm)。结果表明:达到离子交换平衡时,NH4+型斜发沸石对Zn2+和Ag+的最大交换度分别为0.668和0.856,ΔrHθm分别为7.165 k J/mol和5.276 k J/mol,ΔrGθm<0,ΔrSθm>0,即该过程是吸热和熵增加反应,并且该反应在20℃能自动发生,升高温度有利于NH4+型斜发沸石交换Zn2+和Ag+;在相同条件下,NH4+型斜发沸石对Ag+的离子交换能力大于Zn2+。
The thermodynamic characteristics of ion exchange between Zn2 + and Ag + two kinds of antibacterial metal ions and NH4 + clinoptilolite were studied by liquid phase ion exchange. The ion exchange isotherms of Zn2 + and Ag + were plotted. When the ion exchange equilibrium was calculated under different conditions, NH4 + clinoptilolite for Zn2 + and Ag + selective correction coefficient Kc and exchange equilibrium constant Ka, obtained ln Ka value and 1 / T linear relationship between the derivation of the standard molar enthalpy change (ΔrHθm), the reaction standard Molar Gibbs free energy change (ΔrGθm) and reaction standard molar entropy change (ΔrSθm). The results show that the maximum exchange degree of NH4 + -type clinoptilolite for Zn2 + and Ag + is 0.668 and 0.856, the ΔrHθm is 7.165 kJ / mol and 5.276 kJ / mol respectively, the ΔrGθm <0 and ΔrSθm> 0 , That is, the process is an endothermic and entropy-increasing reaction, and the reaction can occur automatically at 20 ℃. The increase of temperature is beneficial to exchange Zn2 + and Ag + for NH4 + -type clinoptilolite. Under the same conditions, NH4 + Ion exchange capacity is greater than Zn2 +.