| OBJECTIVE To investigate the degradation kinetics of sodium formaldehyde sulfoxylate.To determine the rate constants of oxidation reaction between sodium formaldehyde sulfoxylate and oxygen in aqueous solutions at different pH values, different temperatures, different buffer concentrations and different dissolved oxygen concentrations.METHODS The residual concentrations of sodium formaldehyde sulfoxylate in the solutions were determined by iodimetry, the datas were fitted by linear regressions and then the reaction rate constants were obtained. The rate constants of oxidation reaction between sodium formaldehyde sulfoxylate and oxygen in aqueous solutions was studied as a function of pH, temperature, dissolved oxygen concentrations, and buffer concentration.RESULTS The degradation of sodium formaldehyde sulfoxylate obeys the pseudo-first-order kinetics in aqueous solutions. The rate constants at pH 4, pH 5 pH 5.8, pH 6.8, pH 8 and pH 9.2 were (5.373±0.13)×l0-2, (2.540±0.070)×10-2, (1.620±0.036)×10-2,(1.040±0.070)×10-2, (1.152±0.007)×10-2 and (5.70±0.02)×10-3 h-1 respectively at 25 °C inflating air. The rate constants at pH 4, pH 6.8, and pH 9.2 were 2.770×10-3,4.403×10-4 and 5.185×10-4h-1 respectively at 25°C inflating air. The rate constants at pH 4, pH 6.8, and pH 9.2 were (4.49±0.21)×10-2, (6.00±0.13)×10-2 and (2.88±0.13)×10-2 h-1 respectively at 40°C inflating pure...
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