Seasonal characteristics of phosphorus sorption by sediments from plain lakes with different trophic statuses

Phosphorus (P) sorption in sediments plays a significant role in trophic status of a lake. This study investigated the characteristics of P sorption in sediments from three lakes with different trophic statuses (moderately eutrophic, lightly eutrophic, and moderately trophic) through kinetic, batch equilibrium, and thermodynamic experiments. Results show that pseudo-second-order kinetics best describe P sorption in sediments from the three lakes. Fitting by modified Langmuir and Freundlich isotherms indicate that the moderately trophic lake sediments has higher sorption capacity (maximum of 0.848 mg g-1 at 35 °C) than the sediments of the other two lakes at different temperatures (5, 15, 25, and 35 °C). Thermodynamic results indicate that the process of P sorption of the three sediments are spontaneous, entropy-driven, and endothermic reactions. The risk of P release in sediments was analyzed according to the calculated results of isotherms combined with the change in P fraction. Sedime...