On the limitations of the simplified Elovich equation in describing the kinetics of phosphate sorption and release from soils

SUMMARY The kinetics of phosphate sorption and release from soils are often described by a simplified form of the Elovich equation. However, examination of data obtained with three soils from Greece as well as of published data, based on a modified version of the Elovich equation, showed that the assumptions underlying derivation of the simplified form are not valid in all cases. This modified version is free from any a priori assumptions, describes the kinetics of phosphate reactions with soils in a realistic manner and points out to the existence of more than one stage in the process.