Electromotive Force Study Kcl / Rbcl / Cscl Fatty Alcohol - Water Mixed Solvent System In Thermodynamic Properties

The thermodynamic properties of electrolyte solutions are always of much importance. One of such properties is the activity coefficients, which is important for estimating the nonideality of the mixture in equilibrium. Some other relevant properties, such as osmotic coefficients and the standard Gibbs energy of transfer, are also very useful for the separation processes. In this thesis, as a continuation of our previous investigations, the thermodynamic properties of KCl/RbCl/CsCl in1,2-propanediol+water,1,3-propanediol+water and MeOH+EtOH/EG+water mixtures have been investigated using the potentiometric measurements.In our work, the following galvanic cells without liquid junction were used:K/Rb/Cs-ISE|KCl/RbCl/CsCl(m), propylene glycol(w), water(l-w)|Ag-AgClK/Rb/Cs-ISE|KCl/RbCl/CsCl(m), MeOH+EtOH(w), water(1-w)|Ag-AgClK/Rb/Cs-ISE|KCl/RbCl/CsCl(m), MeOH+EG(w), water(l-w)|Ag-AgCl In the cells, K/Rb/Cs-ISE was used as cathode, and Ag-AgCl was anode. m (mol-kg-1) is the the molality of KC1, RbCl or CsCl in the mixed solvents, and w was the mass fraction of alcohol.The potential of KCl/RbCl/CsCl in mixed solvents have been measured. In1,2-propanediol and1,3-propanediol+water mixed solvents, the alcohol mass fractions was10%,20%,30%and40%. For the MeOH+EtOH/EG+water mixed solvents, the MeOH/EtOH/water or MeOH/EG/water mixtures was (5/5/90,5/10/85,10/5/85,10/10/80, and15/15/70)%.The Pitzer model, the modified Pitzer model, and the extended Debye-Hiickel model are used to describe the nonideal behavior of the electrolyte. The various of parameters for these three equations and the standard potential values of each mixed solvents have been obtained. Also, the activity coefficients and the osmotic coefficients for each system are obtained, and the Gibbs energy for the transfer of KCl/RbCl/CsCl from pure water to the mixed solutions is also reported and discussed.