Study Of Activity Coefficients Of Metal Salt-Organic Solvent-Water Systems

With the development of the economy,the demand for energy is increasing steadily,we will soon face the status of resource depletion,the development of renewable energy that can be recycled and the improvement of energy utilization has become the urgent needs.There is a lot of residual-heat created in the industrial producing process,which contains much lowgrade heat that cannot be recycled by traditional technique.The problem we need to solve is how to use these energy efficiently.We designed a new system for thermoelectric convers based on Reverse electro dialysis through the concentration difference between solutions.The focus of our research is to improve the efficient of this system.It is mainly influenced by the thermodynamic properties and electrochemical properties of working solution.This article mainly studied the activity coefficient of metal salt-organic solvent-water systems in EMF method based on our study for conductivity.What we want to is that what effect will be brought along with the change of solute or solvent.Based on the experiments,the following conclusions are obtained:(1)under the metal salt-water system,the activity coefficient of LiCl performs best.For the alkali chlorides studied in this paper,the activity coefficient increases with the decrease of cation radius.Increasing(2)in the metal salt-organic solvent system,the activity coefficient of each working solution have a worse performance that when it is under the water system,leaded by the influence of dielectric constant and solvation.(3)For the metal salt-organic solvent-water system,when the organic solvent is methanol or ethanol,the activity coefficient of LiCl and NaCl in the system decreases as the proportion of organic solvent increases,indicating that in methanol-water and ethanol-water systems,the influence of dielectric constant on activity dominates.The advices to select the working solution for heat-power conversion cycle system are given as follows:Mixed solvents are a good choice for the measurement of thermodynamic and electrochemical properties in various proportioning systems,and stand on an overall perspective to analyze various types of mixtures.The working efficiency of the thermoelectric cycle device under solution conditions seeks the best working solution.In addition to the mixed solvents,the thermodynamic and electrochemical properties of different types of mixed solute systems can also be studied.