Kinetics of copper release in some calcareous soils from Sulaimani governorate, Iraqi Kurdistan Region

This study was conducted to estimate copper release kinetic in five calcareous soils includes (Sharazor, Qaradagh, Bazian, Mawat, and Surdash) at the Sulaimani governorate, Iraqi Kurdistan – region. The highest amount of Cu release during 48 hours was least in soil Qaradagh (0.75mg kg -1). While Soil Mawat exhibited the highest release (2.272mg kg-1). The value of diffusion rate constant (kp) from parabolic diffusion varied from 0.123 to 0.321 with a mean of (0.221).  The initial Cu release constant (αs) and Cu release rate coefficient ( βs ) from simple Elovich model, ranged from 0.42 to 1.164 with a mean of 0.6856, and from 2.197 to 5.952 with a mean of 3.6918. While the values of the rate constant (a and b) from the power function model with the mean were (0.249 and 0.605) respectively varied widely with the five soil. The parabolic diffusion was the best-fitted model used to describe Cu release process very well in the studied soils.