Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6619350 | Fluid Phase Equilibria | 2018 | 24 Pages |
Abstract
Interactions between arsenic(V) and Fe3+ and Al3+ in aqueous solution were studied by potentiometry and, for Fe3+ system, by UV spectrophotometry too. Potentiometric measurements have evidenced the formation of FeAsO40, AlAsO40 and Al(AsO4)OHâ species with formation constant values log β = 17.77, 12.68 and 8.29, respectively, at I = 0.1 mol Lâ1 and T = 298.15 K. In order to applied speciation study to different kind of natural waters, the effect of the ionic strength on the thermodynamic parameters was analysed in the 0.1 â¤Â I â¤Â 0.7 mol Lâ1 range and modeled by a Debye-Hückel type equation. In addition, the formation enthalpy changes of the species were determined by direct calorimetric titrations, in order to define the effect of temperature on the strength of interactions. Examples of distribution of species were reported in different experimental conditions. Finally, the ability of arsenate “to sequester” Fe3+ and Al3+ cations was evaluated by pL0.5 empiric parameter, that represents the ligand concentration required to sequester 50% of the metal cation present in traces.
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Paola Cardiano, Donatella Chillè, Claudia Foti, Ottavia Giuffrè,