title: Adsorption of tetracycline on soil and sediment: effects of pH and the presence of Cu(II).
abstract: Tetracycline (TC) is frequently detected in the environment, however, knowledge on the environmental fate and transport of TC is still limited. Batch adsorption experiments of TC by soil and sediment samples were conducted. The distribution of charge and electrostatic potential of individual atoms of various TC species in the aqueous solution were determined using MOPAC version 0.034 W program in ChemBio3D Ultra software. Most of the adsorption isotherms on the soil, river and marine sediments were well fitted with the Freundlich and Polanyi-Manes (PMM) models. The single point organic carbon (OC)-normalized adsorption distribution coefficients (K(OC)) and PMM saturated adsorption capacity (Q(OC)(0)) values of TC were associated with the mesopore volume and clay content to a greater extent, indicating the mesopore volume of the soil and sediments and their clay content possibly influenced the fate and transport of TC in the natural environment. The adsorption of TC on soil and sediments strongly depended on the pH and presence of Cu(II). The presence of Cu(II) facilitated TC adsorption on soil and sediments at low pH (pH<5), possibly due to the metallic complexation and surface-bridging mechanism by Cu(II) adsorption on soil and sediments. The cation exchange interaction, metallic complexation and Coulombic interaction of mechanisms for adsorption of TC to soils and sediments were further supported by quantum chemical calculation of various TC species in different pH.
authors.affiliation: State Key Laboratory of Water Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
authors.forename: Zheyun
authors.initials: Z
authors.lastname: Zhang
authors.forename: Ke
authors.initials: K
authors.lastname: Sun
authors.forename: Bo
authors.initials: B
authors.lastname: Gao
authors.forename: Guixiang
authors.initials: G
authors.lastname: Zhang
authors.forename: Xitao
authors.initials: X
authors.lastname: Liu
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents; D003300:Copper / Q000737:chemistry*; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007474:Ion Exchange; D012987:Soil / Q000032:analysis*; D055672:Static Electricity; D013752:Tetracycline / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D012987:Soil; D003300:Copper; D013752:Tetracycline