Dynamical regimes of a pH-oscillator operated in two mass-coupled flow-through reactors

Abstract

We present results of experiments focused on emergent and cooperative dynamics in a system of two coupled flow-through stirred reaction cells with diffusion-like mass exchange and a strongly nonlinear chemical reaction between hydrogen peroxide and thiosulphate catalysed by cupric ions in diluted solution of sulphuric acid. Due to complex mechanism, in which a crucial role is played by hydrogen and/or hydroxide ions, dynamics in a single cell entail multiple stationary states, excitability and oscillations conveniently indicated by measuring pH. When coupled, the system shows a plethora of dynamical regimes depending on the coupling strength and flow rate. Under certain conditions both cells display dynamics close to that in the absence of coupling, but majority of the regimes are emergent and cannot be deduced from dynamics of decoupled reactors. The most prominent is a stationary state maintaining highly acidic values of pH in one of the reactors and weakly acidic in the other. When each cell is set to display excitability and the coupled system is externally perturbed, the cells may cooperate and transmit excitations elicited by pulsed perturbations in one cell to the other. Periodic pulses induce firing patterns marked by a various degree of propagated excitations and by being periodic or irregular.

Pulse‐Coupled Chemical Oscillators with Time Delay

“…Our experimental method of introducing a purely inhibitory or excitatory coupling may be implemented in other coupled chemical oscillators, for example, pH oscillators, [12] where an acid/base pair can serve as the activator/inhibitor. Our experimental method of introducing a purely inhibitory or excitatory coupling may be implemented in other coupled chemical oscillators, for example, pH oscillators, [12] where an acid/base pair can serve as the activator/inhibitor.…”

Dynamics of electrochemical oscillators with electrode size disparity: asymmetrical coupling and anomalous phase synchronization

“…9,10 When concentrations (or reaction rates) in these units exhibit oscillatory behavior, the interactions can produce a wide array of synchronization related behaviors, e.g., periodic 4,11,12 and chaotic 13,14 synchronization, oscillator death, [15][16][17][18][19][20] collective synchronization, [21][22][23] dynamical clustering, [24][25][26] and quorum transition. 27 The synchronization behaviors have been observed in BelousovZhabotinsky (BZ) reaction, 3,4,12,13,15,28,29 pH oscillators, 30 and biochemical reaction 31 in coupled continuously fed, stirred tank reactors (CSTRs), in metal dissolution 21,24,25,[32][33][34][35][36][37] and electrocatalytic [38][39][40] reactions in electrochemical systems, in CO oxidation on heterogeneous catalysts, 41,42 and in BZ beads, 22,23,26,…”

On the Phase Shifts in the Dynamics of the H2O2–Na2S2O3–H2SO4–CuSO4 Oscillator Revealed by Comparison of Potentiometric Responses of Different Indicator Electrodes

“…As a consequence of these findings for the hydrogen peroxide–thiocyanate oscillator, we decided to investigate whether similar differences in the potentiometric responses occur also for other homogeneous oscillatory processes, especially for those which involve similar reactants. An example is the H 2 O 2 – S 2 O 3 2− – H + – Cu 2+ system, discovered by Orbán and Epstein and studied also later , including its recent interesting application as a driver for the ribozyme activity . This system also contains hydrogen peroxide as the oxidant for another sulfur‐containing compound and requires the catalytic copper(II)/copper(I) couple.…”