Abstract
Oscillations in the concentration of divalent ions Cd2+, Ca2+, Zn2+, Co2+ and Ni2+ are induced by adding these species to the BrO3−–SO32− chemical oscillator in a flow reactor. Producing periodic pulses in the concentrations of these non-redox ions extends our earlier approach to generating forced periodic behavior. Instead of driving pH-dependent equilibrium reactions of the target ion by a pH oscillator backward and forward, we now couple a redox core oscillating reaction to two consecutive reactions taking place between the components of the oscillator and the target element. In the systems examined here, the oscillatory reductant SO32− binds the free metal ion in a MSO3 precipitate, reducing its level to a minimal value when [SO32−] is high, followed by release of the metal ion when the sulfite is oxidized by BrO3−.