Rapid determination of hydrogen peroxide in the wood pulp bleaching streams by a dual-wavelength spectroscopic method

This study has demonstrated a spectrophotometric method for residual hydrogen peroxide analysis in wood pulp bleaching streams. In an acidic medium, hydrogen peroxide can instantly associate with molybdate to form a peroxomolybdic acid complex that has an absorption peak at 330 nm. To avoid the spectral interference from excess molybdate ion, 350 nm is used for spectroscopic quantification. A linear relationship between the absorbance at 350 nm and peroxide concentration was found up to a peroxide concentration of ca. 0.2 mmol l^-1. It was discovered that 297 nm was an isosbestic point that could be used to develop a dualwavelength method to account for the spectral interference from dissolved lignin in pulp bleaching streams, a critical procedure for the success of the present method. This method is simple, rapid, sensitive, accurate, and has the potential for on-line applications.