Adsorption kinetics of zinc in a calcareous soil as affected by pH and temperature

Abstract

Abstract Sorption of zinc (Zn) in a calcareous soil was studied using a miscible displacement procedure. Sorption of Zn in soil can be described by a second‐order equation and by a diffusion equation based on the overall higher value of correlation coefficient and the lower value of standard error. The results show that the sorption of Zn in soil was increased by elevated temperature and pH. The maximum of Zn sorbed in soil increased, but the rate coefficient decreased with increasing pH. The maximum of sorbed Zn and rate coefficient tended to increase with elevated temperature. The value of activation energy (Ea) estimated with different kinetic equations was found to be variable and in the range of 5.0–17 kJ.mol‐1. The relative diffusion rate coefficient (D/r2), estimated using a diffusion equation, was found to be in the order of 10‐6 sec‐1. The intra‐aggregate diffusion and/or film diffusion of Zn may be a rate‐limiting process in the sorption of Zn in soils.