title: Kinetic and Diffusion-Driven Instabilities in the Bromate-Sulfite-Ferrocyanide System.
abstract: The spatiotemporal dynamics of the bromate-sulfite-ferrocyanide (BSF) reaction-diffusion system in a open one-side-fed reactor (OSFR) is investigated by numerical simulations. The results of the simulations are compared with experiments performed in an annular shape OSFR. Both kinetic and diffusion-driven instabilities are identified in the model. There are two hydrogen ion consuming pathways in the mechanism: the partial oxidation of sulfite to dithionate and the oxidation of ferrocyanide by bromate ions. Their dynamical effects are similar, as they support the same negative feedback loop via sulfite ion. However, the time scale of the oxidation of ferrocyanide by bromate ions can be conveniently controlled by the input feed concentrations, thus it provides a more flexible way to find spatiotemporal oscillations. Long-range activation due to the relative fast diffusion of hydrogen ions compared to the other reactants can also result in oscillations in this mechanism. We show that the spatial extent of the reaction-diffusion medium along the direction of the diffusive feed (the thickness) acts as a general control parameter of the dynamics. Oscillations, either originated in kinetic or in diffusive instabilities, can only develop in a narrow range of the thickness. This property explains the experimentally often observed spatial localization of the oscillations. A reciprocal relationship is found between two main control parameters of the dynamics, which are the thickness and the hydrogen ion input feed concentration.
authors.affiliation: Institute of Chemistry, Eötvös University , Budapest 1053, Hungary.|School of Ph.D. Studies, Semmelweis University , Budapest 1085, Hungary.
authors.forename: István
authors.initials: I
authors.lastname: Molnár
authors.affiliation: Institute of Chemistry, Eötvös University , Budapest 1053, Hungary.
authors.forename: István
authors.identifier: http://orcid.org/0000-0002-1859-1043
authors.initials: I
authors.lastname: Szalai