title: Humic acid transport in saturated porous media: influence of flow velocity and influent concentration.
abstract: Understanding the transport of humic acids (HAs) in porous media can provide important and practical evidence needed for accurate prediction of organic/inorganic contaminant transport in different environmental media and interfaces. A series of column transport experiments was conducted to evaluate the transport of HA in different porous media at different flow velocities and influent HA concentrations. Low flow velocity and influent concentration were found to favor the adsorption and deposition of HA onto sand grains packed into columns and to give higher equilibrium distribution coefficients and deposition rate coefficients, which resulted in an increased fraction of HA being retained in columns. Consequently, retardation factors were increased and the transport of HA through the columns was delayed. These results suggest that the transport of HA in porous media is primarily controlled by the attachment of HA to the solid matrix. Accordingly, this attachment should be considered in studies of HA behavior in porous media.
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China. Electronic address: xrwei78@163.com.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China; Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Mingan
authors.initials: M
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Du
authors.affiliation: Department of Agronomy, Iowa State University, Ames, IA 50011, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Horton
mesh_terms: D006812:Humic Substances; D008956:Models, Chemical; D016062:Porosity; D012212:Rheology; D014876:Water Pollution / Q000517:prevention & control*
chemical_list: D006812:Humic Substances
keywords: Attachment; Flow velocity; Humic acid; Initial concentration; Porous media; Transport