title: The adsorption/desorption of phosphorus in freshwater sediments from buffer zones: the effects of sediment concentration and pH.
abstract: Riparian buffer zones adjacent to reservoirs and lakes protect aquatic ecosystems from polluted surface runoff. Sediments, collected from the buffer zones of Danjiangkou Reservoir (SR) and Honghu Lake (SL) in an ecologically fragile region in central China, were evaluated to reveal their phosphorus-adsorbing/desorbing properties and storage capacities. A nonlinear regression method was used to fit the pseudo-second-order kinetic and the modified crossover-type Langmuir isotherm models to the experimental data. It is shown that the adsorption of phosphorus onto the studied sediments followed the pseudo-second-order kinetic expression. The modified crossover-type Langmuir isotherm model was found to be a suitable method for describing adsorption/desorption processes in the experimental sediments. The maximum adsorption capacities (Q m), partitioning coefficients (K p), native adsorbed exchangeable phosphorus (NAP), and equilibrium phosphorus concentration (EPC0) were subsequently obtained for the experimental sediments. The effects of sediment concentration and pH were also investigated by batch experiments and Fourier transformation infrared and scanning electron microscopy analyses. The adsorption/desorption characteristics of different phosphate species on the sediments from reservoir and lake buffer zones were identified.
authors.affiliation: Key Laboratory of Environment and Disaster Monitoring and Evaluation of Hubei, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, 430077, China. lzhang@whigg.ac.cn.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Environment and Disaster Monitoring and Evaluation of Hubei, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, 430077, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Du
authors.affiliation: Key Laboratory of Environment and Disaster Monitoring and Evaluation of Hubei, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, 430077, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Du
authors.affiliation: Key Laboratory of Environment and Disaster Monitoring and Evaluation of Hubei, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, 430077, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Xu
authors.affiliation: Department of Geography, University of California, Santa Barbara, CA, 93106, USA.
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Loáiciga
mesh_terms: D000327:Adsorption; D002681:China; D017753:Ecosystem; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D007700:Kinetics; D060106:Lakes / Q000737:chemistry; D010710:Phosphates / Q000032:analysis; D010758:Phosphorus / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D010710:Phosphates; D014874:Water Pollutants, Chemical; D010758:Phosphorus
keywords: Adsorption/desorption; Crossover-type isotherm; Drinking water source reservoir; Phosphate species; Riparian areas