title: Desorption of Hg(II) and Sb(V) on extracellular polymeric substances: effects of pH, EDTA, Ca(II) and temperature shocks.
abstract: Extracellular polymeric substances (EPS) existed ubiquitously in biological systems affect the mobility and availability of heavy metals in the environments. The adsorption-desorption behaviors of Hg(II) and Sb(V) on EPS were investigated. The sorption rates follow Sb(V) > Hg(II), and the desorption rates follow reverse order. Applications of ethylene diamine tetraacetic acid (EDTA), Ca(II) and pH shocks affect desorption rates and desorbed quantities of Hg(II) from EPS-Hg complex. Temperature shock minimally affects the desorption rate of Hg(II). Conversely, the EPS-Sb complex is stable subjected to EDTA, Ca(II), temperature or pH shocks. The excitation-emission matrix (EEM) fluorescence spectroscopy and fast-Fourier (FT-IR) analysis showed that Hg(II) and Sb(V) principally interacted with polysaccharides and protein-like compounds in the EPS, respectively. The EPS-Hg complex presents a time bomb that may release high levels of Hg(II) in short time period under environmental shocks.
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Daoyong
authors.initials: D
authors.lastname: Zhang
authors.forename: Duu-Jong
authors.initials: DJ
authors.lastname: Lee
authors.forename: Xiangliang
authors.initials: X
authors.lastname: Pan
mesh_terms: D000327:Adsorption; D000965:Antimony / Q000737:chemistry*; D001704:Biopolymers / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry*; D005110:Extracellular Space / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008628:Mercury / Q000737:chemistry / Q000302:isolation & purification*; D012722:Sewage / Q000382:microbiology*; D013696:Temperature
chemical_list: D001704:Biopolymers; D012722:Sewage; D004492:Edetic Acid; D000965:Antimony; D008628:Mercury; D002118:Calcium