Influence of multi-component composition of dyeing bath in the membrane distillation performance

Abstract

The influence of the multi-component composition of cotton and polyester dyeing baths was investigated in a DCMD process using a PTFE membrane, aiming to water reclamation from textile wastewater. The process was evaluated with each auxiliary, solutions combining auxiliary and dye, and residual water from pilot-scale dyeing baths. The salts used in the cotton dyeing bath did not influence the DCMD process, resulting in a similar rejection rate and permeate flux to those in dye solutions. The formic acid employed in the polyester dyeing bath resulted in high permeate fluxes but decreased the permeate quality by almost 33%. The surfactants (detergent and dispersant) demonstrated the most harmful behavior in the process, evidenced by a complete membrane wetting. An absence of synergy of the dyes and auxiliaries influencing the DCMD process was verified for the textile dyeing wastewater. This work enabled identifying the influence of each dyeing bath component in the rejection rate and permeate flux, allowing to find alternatives in mitigating the remaining gaps involving DCMD operation and the MD membranes. This work contributes to consolidating this promising technique in water reclamation from textile wastewater, encouraging research on membrane development and modification or integrated operations involving MD.