The Research Of Activity Coefficient Model For Electrolytes

The thermodynamics of electrolyte is an important part of the solution theory.Many natural and industrial process need the nature of the phase equilibrium of theelectrolyte solution, Its applications include chemical, metallurgical, geological,environmental protection and Marine science.So, The thermodynamics of electrolytehas the vital significance.For electrolyte solution system, this paper puts forward a new theory ofhydration, deduced the formula for UNIQUE and NRTL model based on the theoryof the new hydration, the UNIQUE model based on the theory of the new hydrationformula is as follows:The NRTL model based on the theory of the new hydration formula is asfollows: Based on new hydration theory model, this paper fitted binary electrolytesolution activity coefficient under298.15K, and the system is calculated by themodel parameters, compares calculated values and experimental values of analysis,compare the UNIQUAC and NRTL model based on the theory of the new hydrationmodel, through comparing the findings based on the theory of the new hydrationNRTL model outperforms the UNIQUAC model based on the theory of the newhydration; And compares several kinds of electrolyte solution at differenttemperatures of different model to calculate the activity coefficient of the solute onnumerical to the experimental value of standard deviation.The author selected the NRTL model based on the theory of the new waterfitted NaCl binary electrolyte solution activity coefficient of the experimental dataunder different temperature, the temperature from273.15K to473.15K iscalculated by the values of the parameters, each of the parameters of the model isestablished and the relation formula of temperature in each temperature is analyzedand the error; Regression to calculate the298.15K under NaCl-KCl-H2O systemmodel parameters, application of solubility calculation method to calculate the phaseequilibrium properties of thermodynamics, calculate the phase equilibrium data ofthe system.Comparing the several kinds of electrolyte solution at different temperatures ofdifferent model to calculate the activity coefficient of the solute on the values in theexperimental value of standard deviation, found that the NRTL model based on thetheory of the new hydration is obviously better than the average standard deviation of the Pitzer model and Chen NRTL model; Through the further study of NaClsolution under different temperature, illustrates the feasibility of the model in a widetemperature range; By the balance calculation of NaCl-KCl-H2O system, furtherillustrates the NRTL model based on the theory of the new hydration broadapplicability.