KI/LiCl/LiBr-水-乙醇三元体系电导率特性研究

摘要

Both strong electrical conductivity and low heat separation energy consumption are required for the working solution of thermoelectric conversion cycle based on reverse electrodialysis theory.Ethanol with low heat of vaporization is partially substituted for water with high heat of vaporization to reduce the energy consumption during heat separation of electrolyte solution.In order to understand the conductivity characteristics of different electrolytes in electrolyte-ethanol-water ternary solutions, at temperature range of 20-40 ℃, a conductivity meter is applied to determine the conductivities of KI, LiCl and LiBr in mixed water/ethanol solvents with mass ratio of 2∶8 and 3∶7 at different concentrations.The effects of concentration, temperature and solvent composition on conductivity are discussed.It is shown that in the measured range, the conductivity of electrolyte solution increases with increasing temperature and concentration, and the higher the concentration is, the greater the effect of temperature on conductivity is.For the same solution, the variation tendency of conductivity with concentration is similar at different temperatures, and the increased mass ratio of water in solvent significantly enhances the conductivity of electrolyte solution.%基于逆向电渗析原理的热-电转换循环要求工作溶液有较强的导电性和尽可能低的热分离能耗.因此利用低汽化热的乙醇部分替代高汽化热的水来降低电解质溶液热分离过程的能耗.为了了解不同电解质在电解质+乙醇+水三元体系中的电导率特性,应用电导率仪在20~40 ℃测定了KI、LiCl与LiBr分别在水与乙醇质量比为2∶8和3∶7的溶剂中不同浓度下的电导率,讨论了温度、浓度、溶剂组成对电解质溶液电导率的影响.结果表明:在测试范围内,电解质溶液的电导率随浓度、温度的升高而增加,而且溶液浓度越高,温度对其电导率的影响越大;不同温度条件下同一溶液体系的电导率随浓度变化趋势相同;增加溶剂中水的比例会显著地提高电解质溶液电导率.