Multiple Reuse of Exhausted Acid Dyebaths for Wool Dyeing: Colorimetric Properties, Leveling Agent Effect, and Material Savings

The feasibility of reconstitution and reuse of an acid dye dyebath for wool dyeing with different dye concentrations was studied. The residual dyebath was analyzed and reconstituted to the required concentration of dye, auxiliaries, and water for repeated reuse without deterioration of colorimetric properties. Analysis of CIELAB coordinates of dyed samples showed that the qualities of samples dyed in reused dyebaths were the same as those obtained from initial fabric dyeing, despite the very high number of reuse cycles. The influence of leveling agent on dyeing behavior remained acceptable. Analysis revealed that such reuse could reduce the amount of water, dye, and leveling agent to reduce effluent treatment costs. A reduction of 90.48% in water consumption was achieved after twenty successive reuses.