Phosphorus adsorption on natural sediments with different pH incorporating surface morphology characterization.
Sediment samples from University Lake (U.L.) and Anacostia River (A.R.) were collected to study the phosphorus (P) adsorption with pH at 3.65, 4.75, and 5.65. The surface micro-morphology and pore structures of sediment particles were obtained using a scanning electron microscopy and gas adsorption method, respectively. Fourier analysis was then applied to approximate the surface morphology, which was incorporated into the Langmuir isotherm to directly derive the model parameters for P adsorption simulation. Meanwhile, an empirical function of pH was introduced to represent the pH effect on P adsorption. A stronger P adsorption was observed for the A.R. sediment due to the more clay minerals, smaller median diameter, and a greater percentage of large pores, and the increasing pH resulted in a decrease of adsorption equilibrium constant as well as the P adsorption capacity, which was well reproduced by the adsorption isotherms. This study would benefit the mechanism study of the interactions between sediment particles and pollutants, providing references for understanding the pollutants' transport in aqueous systems.
State Key Laboratory of Hydro-Science and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China.
Lei
L
Huang
State Key Laboratory of Hydro-Science and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China. fanghw@tsinghua.edu.cn.
Hongwei
H
Fang
State Key Laboratory of Hydro-Science and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China.
Guojian
G
He
College of Water Resources and Civil Engineering, China Agricultural University, Beijing, 100083, China.
Minghong
M
Chen
D000327:Adsorption; D000538:Aluminum Silicates; D000077215:Clay; D019015:Geologic Sediments / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D060106:Lakes / Q000737:chemistry; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry*; D045483:Rivers; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
D000538:Aluminum Silicates; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D000077215:Clay
Langmuir isotherm; Phosphorus adsorption; Pore structure; Sediment particles; Surface morphology