CHAOTIC PH OSCILLATIONS IN THE SULFUR(IV) HYDROGEN-PEROXIDE MARBLE FLOW SYSTEM

A self-accelerating oxidation of sulfur(IV) by hydrogen peroxide in an unbuffered aqueous solution in the presence of solid marble has been utilized to develop an oscillatory system in a continuous-flow stirred tank reactor. First, a model was constructed from the component react ions: (1) H2O2+HSO3--->+H++SO42-+H2O: (2) CaCO3+H+-->Ca2++HCO3-; (3) H SO3-<->H++SO32-;(4) CO2(aq)+H2O<->H++HCO3-; (5) CO2(aq)-->CO2(gas). Si mulations based on the kinetics of reactions 1-5 predicted regular pH oscillations, bursting, and chaotic responses, Most of the simulated p henomena were found experimentally in the vicinity of the predicted co nditions, The parameters of the experimental oscillations also agree w ell with their calculated counterparts.