Determination of Trace Formaldehyde in Wastewater by Methyl OrangePotassium Bromate System Catalytic Spectrophotometric

A catalytic-kinetic spectrophotometric method was established for the determination of trace formaldehyde. In sulfuric acid medium, potassium bromate could oxidize and decolorize the methyl orange under the catalysis of formaldehyde and the decolorization reaction was proportional to the content of formaldehyde. At 50℃ water bath for reaction 30min, ascorbic acid saturated solution was added into the system solution in order to reduce the potassium bromate and stop the reaction. Absorbance was measured at the maximum absorption wavelength of 505nm. The formaldehyde had a good linear relationship in the range of 0~2.0μg/mL. The method was used in determination of trace formaldehyde in chemical industry wastewater and the relative standard deviation was2.97%(n=6), the standard material recovery rate was between 99.8% ~106.9%.