Electrode Kinetics of Concentrated Sulfide Ion in Basic Solutions

The diffusion coefficients of sulfide ion in 5 M NaOH solution with concentrations of (0.02–0.3)M at temperatures 24–50°C were determined using a rotating-ring-disc Pt electrode to be (0.5–2.0)×10^?5 cm₂/sec. The reaction order of the sulfide oxidation to sulfur was calculated to be 0.42 which implies one-electron transfer as the rate-limiting step and the reaction rate constant was found to be k_f=2.57×10^?5 exp(-0.14ZF_π/RT).