Background: Nowadays, broad synthesis and application of azo dyes result in environmental and health concerns. The aim of this study was to investigate the use of Micellar-Enhanced Ultrafiltration in the removal of reactive black 5 dye from aqueous solutions.
Materials and Methods: In this study, Cetyltrimethyl ammonium bromide (CTAB) was used as a cationic surfactant. A polyacrilonitrile (PAN) ultrafiltration membrane (20 kDa) was used in cross-flow operation where the retentate was recirculated to the feed tank and the permeate was collected over certain times. For better understanding the effect of operating variables and their interactions on the performance, response surface methodology (RSM) was used. Three independent parameters including pH (4, 7 and 10), initial CTAB / dye ratio (5, 10 and 15) and trans-membrane pressure (TMP) (2, 3.5 and 5 bar) were applied.
Results: Analysis of variance (ANOVA) revealed that dye rejection was primarily influenced by CTAB/dye ratio was statistically significant (p-value <0.05). It was found that flux was affected by TMP, while pH and CTAB/ Dye had less influence on the flux. In optimum conditions (around neutral pH (7) low pressure (2 bar) and CTAB/dye of 12.5, about 100% of dye could be rejected from the aqueous stream according to the build model. Furthermore, the coefficient of determination (R2>0.9) confirmed that RSM based on the Box–Behnken was a suitable method for optimizing the main operating variables of dye rejection by the EMUF process for this range of variables.
Conclusion: This study revealed that MEUF using CTAB under different operating conditions could efficiently remove reactive black-5 dye.