UV-Ozone and UV-Oxygen Process for Color Removal from Textile Dyeing and Finishing Wastewaters

摘要

Photochemical degradation of dye molecules was studied by exposing solutions with acid, direct and dispersed dyes to UV. Acetone as a high triplet energy sensitizer enhanced the color removal rate by more than 100 times. Dissolved oxygen was an energy quencher which could be removed by N2 bubbling. N2 bubbling also provided adequate mixing to bring the dye molecules in closer contact with the radiation source. The only adequate means of measuring color removal was to measure color units as described by the American Dye Manufacturer's Institute (ADMI) because the color and its predominant wavelength changed in the course of photodegradation. Studies of continuous flow models included a tray model as well as single, and multi-column models. A tray model was found less effective. Single and multiple-column models were equally effective for some acid dyes but the multiple-column model was more efficient for resistent dyes. The power consumption per unit volume of dye solution treated was calculated for all dyes.