Adsorption of phosphorus on sediments from the Three-Gorges Reservoir (China) and the relation with sediment compositions.
The adsorption of phosphorus (P) on four sediment samples (CunTan, XiaoJiang, DaNing and XiangXi) from the Three-Gorges Reservoir on the Yangtze River in China was studied systematically in batch experiments. A sequential chemical extraction experiment was conducted to clarify the effect of sediment composition on P adsorption. The results showed that P adsorption on four sediment samples mainly occurred within 6h. P adsorption kinetics can be satisfactorily fitted by both power function and simple Elovich model. A modified Langmuir model may describe well the P adsorption on all the samples in our study. Theoretically, the maximum adsorption amount (Q(max)) was 0.402mg-P/g for XiaoJiang sediment, 0.358mg-P/g for DaNing sediment, 0.165mg-P/g for CunTan sediment, and 0.15mg-P/g for XiangXi sediment. The sediment compositions such as organic matter, metal hydroxides, calcium and clay content showed influences on the P adsorption. Wherein, organic matter and metal hydroxides were the main factors affecting the P adsorption. The maximum P adsorption capacity (Q(max)) enhanced with the increase of the content of (Fe+Al+Ca). Compared the zero-equilibrium P concentration (EPC(0)) values obtained by the modified Langmuir models with actual P concentrations in water, all the sediments studied in this paper except for XiaoJiang showed a trend of releasing P as a source role, which could enhance the risk of eutrophication occurrence in the Three-Gorges Reservoir.
School of Environment, Beijing Normal University, Beijing 100875, People's Republic of China.
Ying
Y
Wang
Zhenyao
Z
Shen
Junfeng
J
Niu
Ruimin
R
Liu
D000327:Adsorption; D000465:Algorithms; D002118:Calcium / Q000737:chemistry / Q000302:isolation & purification; D002254:Carbonates / Q000737:chemistry / Q000302:isolation & purification; D002681:China; D019015:Geologic Sediments / Q000737:chemistry*; D007700:Kinetics; D008670:Metals / Q000737:chemistry / Q000302:isolation & purification; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D010758:Phosphorus / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014881:Water Supply / Q000032:analysis*
D002254:Carbonates; D008670:Metals; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D002118:Calcium