3. Experimental
3.1. Materials In this study, a remazol dye bath containing high concentrations of Naci at level of 70- the 80 glI was simulated. The formu of the remazol dye bath taken from a local cotton textile industry is given in Table 1. The simulated remazol dye bath solutions prepared in a step-wise manner included auxiliary chemicals. During preparation of the synthetic dye bath, it is considered that approximately 20% of the dyes and 100% of all other chemicals remained in the exhausted dye bath wastewater[16]. Reactive black 5(RB5) and reactive orange 16(RO16) were used in the formula supplied by Dystar. Reactive black s is a four-valent sodium salt having a molecular weight of 991 mol and reactive orange 16 is a second-valent sodium salt with a molecular weight of 616 g/mol. The chemical structures of these dyes are shown in Fig. 1. Distilled water was also used in the preparation of synthetic solutions. Since pH needs to be adjusted for later reuse of permeate in the actual process, it is