The treatment of wastewater containing dispersed dyes is a challenge because of their low water solubility and high suspension that inhibit most advanced oxidation processes. Instead of trying to oxidize the dispersed dye in wastewater, extraction with TX-110 surfactants and organic solvents were tested to evaluate the feasibility of dispersed dye recovery. Two dispersed dyes, the Dispersed Red 60 (DR60) and Dispersed Blue 79 (DB70) were tested for this study. The parameters considered in the cloud point extraction are TX-100 concentration, temperature, pH and salt concentrations. This study confirms that the pH and the salt concentrations were not significant factors on the cloud point extraction. The system has a cloud point at 85℃. Various organic solvents were tested for the feasibility of liquid-liquid extraction for dispersed dyes recovery. The solvents tested include methyl ethyl ketone (MEK), octane, n-pentane, methyl salicylate, and ethyl acetate. This study concluded that ethyl acetate performed the best liquid-liquid extraction among the tested solvents. When compared between the two dyes, DR60 and DB79, the system performs better in extracting DR60 from aqueous solutions. Since the chemical structures of most of the photoresists are similar to dispersed dyes, it is believed that solvent extraction presents an opportunity to recovery those valuable industrial materials.
Symposium of American Air and Waste Management Association 2012 Annual Meeting