The uptake equilibrium of potassium from impure polyols was obtained experimentally on two different H-form ion exchangers: Dowex XZS-1, a homogeneous gel resin and Amberlite 252, a macroreticular ion exchange resin. The equilibrium isotherms are highly favourable for both types of resins and an acid'base neutralization reaction is proposed to explain the behaviour of the system. It was observed that these resins are not able to exchange their full potential capacity in pure potyol media. Based on the main properties of the resin matrix and the potyol, an explanation about this lack of capacity is proposed. Equilibrium isotherms of potassium from ternary mixtures polyol-methanol-water over Amberlite 252 were also obtained. A different mechanism for ion exchange of potassium was proposed for this kind of system, explaining the improvements inresin capacity.