title: Thermodynamics of monochlorophenol isomers and pyrite interfacial interactions in the activation state.
abstract: Thermodynamic parameters of the activation state for phenol and three monochlorophenol (MCP) isomer-pyrite complexes, i.e., MCP isomers used were 2-chlorophenol (2-CP), 3-chlorophenol (3-CP), 4-chlorophenol (4-CP), have been derived from the temperature-dependent kinetic data. Both the initial rate and adsorption density values increased in the order phenol < 2-CP < 3-CP < 4-CP. This suggests that the presence of chlorine substituent on the aromatic ring results in enhanced CP adsorption on pyrite. The activation energy (E(a)), Gibbs free energy (deltaG#), entropy (deltaS#), and enthalpy (deltaH#) of the activation stage for MCP adsorption on pyrite were calculated by Arrhenius and Eyring models. Always deltaS# values approximate to zero and -TdeltaS# values are positive, which indicates that the activation state of MCP adsorption process is entropy-controlled, and the observed linear dependence of deltaH# on -TdeltaS# signals an entropy-enthalpy compensation effect of the MCP adsorption process. The gammaMCP data were quantified well both by 1 - pK diffused double layer (1 - pK DLM) and Langmuir models.
authors.affiliation: Institut für Geologie und Mineralogie, Lehrstuhul 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: M
authors.initials: M
authors.lastname: Makehelwala
authors.forename: M M
authors.initials: MM
authors.lastname: Miedaner
authors.forename: H J
authors.initials: HJ
authors.lastname: Tobschall