Kinetics of phosphorus sorption by hematite and kaolinite‐hematite (k‐h) system

The rate of phosphate (P) sorption from synthetic and kaolinite‐hematite (k‐h) system into 0.01M CaCl2 solutions of 1250, 2500, 3750, 5000, 7500 and 13500ppm of P is a dynamic factor that regulates its continuous supply. Five kinetics models, those of First‐order, Elovich, Parabolic Diffusion, Modified Freundlich and a new kinetic equation, were evaluated to describe the rate of sorption of P which was rapid initially but gradually declined with time. Comparison of coefficients of determination (r) indicated that Parabolic Diffusion and first order kinetic model were found better for bentonite‐hematite system, Freundlich and the new kinetic model were found to describe better the P sorption hematite, while Elovich model was applied to both hematite and kaolinite‐hematite system satisfactory.