The ion-exchange equilibrium of Cu2+ and Zn2+ from sulfate solutions atpH = 1.9 on iminodiacetic (IDA) and aminomethylphosphonic (AMP) resins has been studied in the temperature range between 10 and 80 °C. The values of the equilibrium separation factor α for Zn-Cu exchange demonstrate a strong temperature dependence in the case of IDA resin, while for AMP tins dependence is pronouncedly much weaker. A decrease of α at elevated temperatures has been observed for both ion exchangers. The absolute αCuZn values for IDA resin lie within between 83.0 (at 10 °C) and 30.0 (at 80 °C). In the case of AMP resin, a values have been shown to vary from 1.67 to 1.4 in the same temperature interval. It has been shown that thermostripping with stock solution at 20 °C from IDA resin pre-equilibrated with the same solution at 60 °C leads to selective desorption of Cu2-, while under the same conditions AMP resin is selectively releasing Zn2-. Thermodynamic interpretation of the temperature dependencies of the separation factors obtained on IDA resin has been shown to allow a comparison of the properties of the ion exchanger with those of iminodiacetic acid in homogeneous solution. © 1995, American Chemical Society. All rights reserved.