title: Kinetics and Mechanisms of Phosphorus Adsorption in Soils from Diverse Ecological Zones in the Source Area of a Drinking-Water Reservoir.
abstract: On-site soils are increasingly used in the treatment and restoration of ecosystems to harmonize with the local landscape and minimize costs. Eight natural soils from diverse ecological zones in the source area of a drinking-water reservoir in central China are used as adsorbents for the uptake of phosphorus from aqueous solutions. The X-ray fluorescence (XRF) spectrometric and BET (Brunauer-Emmett-Teller) tests and the Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectral analyses are carried out to investigate the soils' chemical properties and their potential changes with adsorbed phosphorous from aqueous solutions. The intra-particle diffusion, pseudo-first-order, and pseudo-second-order kinetic models describe the adsorption kinetic processes. Our results indicate that the adsorption processes of phosphorus in soils occurred in three stages and that the rate-controlling steps are not solely dependent on intra-particle diffusion. A quantitative comparison of two kinetics models based on their linear and non-linear representations, and using the chi-square (χ2) test and the coefficient of determination (r2), indicates that the adsorptive properties of the soils are best described by the non-linear pseudo-second-order kinetic model. The adsorption characteristics of aqueous phosphorous are determined along with the essential kinetic parameters.
authors.affiliation: Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, Hubei 430077, China. lzhang@whigg.ac.cn.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Geography, University of California, Santa Barbara, CA 93106, USA. hugo.loaiciga@ucsb.edu.
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Loáiciga
authors.affiliation: Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, Hubei 430077, China. dream0131@asch.whigg.ac.cn.
authors.forename: Meng
authors.initials: M
authors.lastname: Xu
authors.affiliation: Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, Hubei 430077, China. cdu@whigg.ac.cn.
authors.forename: Chao
authors.initials: C
authors.lastname: Du
authors.affiliation: Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, Hubei 430077, China. duyun@whigg.ac.cn.
authors.forename: Yun
authors.initials: Y
authors.lastname: Du
mesh_terms: D000327:Adsorption; D002681:China; D060766:Drinking Water / Q000737:chemistry*; D004463:Ecology; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007700:Kinetics; D008956:Models, Chemical; D010758:Phosphorus / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D060766:Drinking Water; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D010758:Phosphorus
keywords: Danjiangkou reservoir; non-linear regression analysis; phosphate; pseudo-second-order model; rate-controlling step; south-to-north water transfer projects (SNWTP)