title: On the mechanistic modeling of As(III) adsorption on gibbsite.
abstract: Arsenite adsorption on gibbsite was examined as a function of pH, ionic strength (I) and contact time (t(C)). As(III) showed a weak affinity for gibbsite surface. The trends of pH=f(Gamma(ads)) curves have showed a marked deviation from a typical anion adsorption edge showing a maximum Gamma(ads) around pH approximately 8.2. The experimentally derived proton exchange ratio has always converged to zero when 0.26< summation operator [As(III)]<7 microM and 6.2<pH<8.2. The isosteric heat of adsorption, DeltaH(r), exhibited invariant behavior with respect to Gamma(ads). The As(III) adsorption data was quantified by charge distribution multi-site complexation (CD MUSIC) model using the surface complex postulated below:
authors.affiliation: Institut für Geologie und Mineralogie, Lehrstuhl für Angewandte Geologie, Friedrich-Alexander Universität, Schlossgarten 5, Nürnberg Erlangen D-91054, Germany. rweerasooriya@hotmail.com
authors.forename: R
authors.initials: R
authors.lastname: Weerasooriya
authors.forename: H J
authors.initials: HJ
authors.lastname: Tobschall
authors.forename: H K D K
authors.initials: HK
authors.lastname: Wijesekara
authors.forename: E K I A U K
authors.initials: EK
authors.lastname: Arachchige
authors.forename: K A S
authors.initials: KA
authors.lastname: Pathirathne
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D014873:Water Pollutants / Q000032:analysis
chemical_list: D014873:Water Pollutants; D001151:Arsenic