5. Conclusions
In this study, it was detected that auxiliary chemicals reactive dye baths affected membrane fouling, salt and color rejections. Experi mental results indicated that a NaCI rejection of 20% and color rejection of more than 9S% were achieved and that the recyclingof permeate could be possible inreactive dyeing Adsorption of dye molecules on membrane surfaces was observed due to an increase in dye hydrophobicity under alkaline conditions and membrane fouling. Acidification of the original synthetic dye bath solution with HCI and HSO decreased the membrane fouling and also increased the NaCl recovery and color rejection. Using HCI instead of H2So, increased these positive effects. Permeate samples were almost colorless for all experiments. The highest color rejection was achieved at the solution acidified with HCL The behaviour of the Koyuncu and Topacik model parameters against the reactive dye/salt mixtures within the auxiliary chemicals was investigated. was a good correlation between the experimental results and the model. Model parameters(a and k were calculated from the statistical regression of the observed rejection and flux data for the DS5 membrane. Even though the Koyuncu and Topacik model achieved sensitive results for the salt rejection in the presence of dyes and auxiliary chemicals in synthetic reactive dye bath, a new model, which can be derived with the addition of auxiliary chemical concentrations in the electroneutrality equations, would bemuch more realistic for these types of solutions that contain cals. Future studies will be auxiliary chemi conducted using the addition of auxiliary chemical concentrations in the electroneutrality equations to define salt rejection in actual dye baths.