Abstract
The adsorption of phosphorus (P) on sediment plays a significant role in phosphorus transport in aquatic systems. This research
examined the effect of the main components of sediments (including iron (Fe), manganese (Mn) oxides and organic matter (OM))
on P adsorption and to evaluate their relative contribution with different sediment particle sizes. The sediments were separated
into four particle-size fractions: 0-30 μm, 30-62 μm, 62-90 μm, and 90-125 μm, and then selective chemical extractions were
conducted to remove OM, Fe+Mn oxides, and Fe+Mn oxides and OM from the raw sediments, respectively. A series of
adsorption isotherm experiments were conducted to investigate the P adsorption on the raw and extracted sediments. Then, a
nonlinear regression model was used to determine the maximum P adsorption capacity of each component. The resultes showed
that the maximum P adsorption capacities of extracted sediments were lower than that of raw sediments. The nonlinear regression
analysis showed that the relative contribution on a mass basis was dominated by Fe+Mn oxides, followed by OM and residues. In
addition, their relative contributions in sediments with different particle sizes were on the same order of magnitude.