Ph Oscillations And Ph-ca <sup> 2 + </ Sup> Complex Oscillating Reaction

In this work,we construct a system that genetates periodic pulses of free[Ca²⁺]by coupling the IO₃^-,SO₃^2-,Fe(CN) ₄^4-(ISF) oscillating reation with the complexation of calcium ion with EDTA.Oscillations in the free[Ca²⁺]can be visualized by adding Arsenazo(Ⅲ) dye to the input solution of IO^3- and CaEDTA.At low pH(high free[Ca²⁺]) the reaction mixture is violet, corresponding to formation of the Ca²⁺-Arsenazo(Ⅲ) complex.At high pH(low free[Ca²⁺]),the solution is cherry red,the color of free Arsenazo(Ⅲ).Oscillations in the I₂,the Intermediate product,can be visualized by adding soluble starch.The color is changed between blue and weak yellow.Besides,our studies found that this pH oscillation exhibits complicated oscillatory in critical regimes.They consisit of a single large-amplitude oscillation(L) followed by a number of small-amplitude oscillations(S).And we found that the emerge and mode of oscillations mostly depend on the[H⁺]and flow rate.More interesting phenomenon is that we found that afre the addition of calcium iron,the system also appeared complicated oscillation,but the complicated oscillation in the ISF system did not occur simultaneously with the ISF-Ca system.When the ISF oscillation appeared complicated oscillations,the addition of calcium iron will lead to stop of the oscillation.If the ISF oscillation system at the critical region,The addition of calcium iron will lead to complicated oscillation.We also changed the flow rate of potassium ferrocyanide in order to study the effect on complicated oscillations.The study of experiment showed that with the flow of potassium ferrocyanide smaller,both ISF system and complex system exhibit simple oscillation,complicated oscillation,no oscillation.