Application Of EMIVM-ET In Electrolyte Solution Systems Containing Ni²⁺, Co²⁺, And Cu²⁺

The study of electrolyte solution is one of the important research directions in the field of physical chemistry.It is not only an important issue in the fields of chemistry,biology,medicine and other disciplines,but also involves practical problems such as industrial applications and environmental protection.In recent years,with the continuous development of thermodynamic theory and calculation models,thermodynamic models have become an important tool for studying the thermodynamic properties of electrolyte solutions.The thermodynamic model mainly obtains the thermodynamic parameters of the electrolyte solution system,such as chemical potential,entropy,heat capacity and reaction heat,through theoretical derivation and experimental measurement.These parameters can be used to study the structural stability and thermodynamic properties of electrolyte solutions.It should be noted that the study of thermodynamic models is usually combined with other physical and chemical methods to obtain more accurate results.In this paper,the thermodynamic properties of electrolyte solution systems containing Ni²⁺,Co²⁺and Cu²⁺ions were studied by using the electrolyte molecular interaction volume model（eMIVM）and the optimized energy term model（eMIVM-ET）.The activity coefficients of electrolyte solutions containing Ni²⁺,Co²⁺,Cu²⁺,Cs⁺and K⁺were calculated.The osmotic coefficient of the plasma system containing Ni²⁺,Co²⁺and Cu²⁺in the sewage treatment process was calculated,and the activity coefficient of the sulfate system which was less studied in the sewage treatment process was predicted.The activity coefficient and osmotic coefficient of the two-electrolyte solution system containing Ni²⁺,Co²⁺and Cu²⁺were predicted.At the same time,the calculation and prediction results of the two models are compared.The following results are obtained:（1）The activity coefficients of electrolyte solutions containing Ni²⁺,Co²⁺,Cu²⁺,Cs⁺and K⁺were studied.In the electrolyte solution system containing Cu²⁺,the average deviation and average relative error of eMIVM-ET were reduced by 0.0390 and 3.35%,respectively,compared with eMIVM.In the electrolyte solution system containing Cs⁺and K⁺,the average deviation and average relative error of eMIVM-ET are reduced by0.0063 and 0.71%respectively compared with eMIVM fitting.In the electrolyte solution containing Co²⁺,the average deviation and average relative error of eMIVM-ET were reduced by 0.0133 and 3.13%,respectively,compared with eMIVM.In the electrolyte solution containing Ni²⁺,the average deviation and average relative error of eMIVM-ET were 0.0377 and 3.96%lower than those of eMIVM,respectively.It is not difficult to find that in the calculation of the activity coefficient of the above system,the fitting result of eMIVM-ET is better than that of eMIVM,which is closer to the experimental value.（2）The permeability coefficient of electrolyte solution system containing Ni²⁺,Co²⁺and Cu²⁺ions in wastewater treatment process was studied.Compared with eMIVM,the average deviation and average relative error of eMIVM-ET are reduced by 0.003 and0.26%respectively.In the organic electrolyte solution,the average deviation and average relative error of eMIVM-ET were 0.0034 and 0.47%lower than those of eMIVM,respectively.It can be seen that the fitting results of eMIVM-ET and eMIVM are very close,but eMIVM-ET still has advantages over eMIVM.（3）By substituting the fitting parameters of the single electrolyte solution system into the two-electrolyte solution system,the activity coefficient and permeability coefficient of the two-electrolyte solution system are predicted,and the prediction results of the two models are compared.In the prediction of the activity coefficient of the two-electrolyte solution system containing Cs⁺and K⁺,the average deviation and average relative error of eMIVM-ET compared with eMIVM fitting are reduced by 0.0913 and10.59%,respectively.In the prediction of the activity coefficient of the two-electrolyte solution system containing Ni²⁺,Co²⁺and Cu²⁺,the average deviation and average relative error of eMIVM-ET were 0.0960 and 42.52%lower than those of eMIVM.In the prediction of the permeability coefficient of the two-electrolyte solution system containing Ni²⁺,Co²⁺and Cu²⁺,the average deviation and average relative error of eMIVM-ET are reduced by 0.1451 and 11.99%respectively compared with eMIVM fitting.It can be seen that the prediction effect of eMIVM-ET is better than that of eMIVM,so eMIVM can be used as an alternative thermodynamic prediction model.