The Effect of Solubility and Structure on Dye Wastewater Treatment with Electrochemical Process

摘要

Many dye application processes use a variety of dyes with distinct properties that present a challenge to engineers in selecting appropriate treatment processes for dye effluent. This study explores the effects of dye solubility and structure on dye degradation with an electrochemical (EC) oxidation process, and provides guidelines for selecting various dye effluent treatment processes. In this study, the de-colorization of ten different dyes grouped into three solubility classifications: easily soluble, soluble and barely soluble; and three dye structures: azo, disazo and anthraquinone, using an EC oxidation process, was evaluated. The results of the experiment show that dye solubility is dominant over dye structure in influencing dye degradation when comparing the de-colorization efficiencies of azo, and anthraquinone dyes with easily soluble and barely soluble dyes. For dyes with high solubility, the degradation efficiency becomes difficult to distinguish among all types of dye structure, and decolorization can only be used as an indicator. Therefore, the kinetic constants of de-colorization for high solubility dyes with various dye structures were compared. The comparison concludes that the azo dye has the highest degradation efficiency, followed by the disazo dye, and the anthraquinone dye, except for the anthraquinone dye (AB40), whose kinetic constant was higher than that of the azo dye (AR266). A different dye degradation indicator using chemical oxygen demand (COD) degradation tests for the specific dyes confirmed that the degradation efficiency of the azo dye is higher than that of the anthraquinone dye in an EC oxidation process.