Abstract

Methylene blue (MB), as a thiazine cationic dye, has been commonly used in dye houses and textile industries. Long exposure to MB can cause health problems such as shocks, hypertension, anemia, nausea, serotonin syndrome, red blood cell breakdown, tissue necrosis and jaundice. The aim of this study was to optimize methylene blue (MB) removal from aqueous solutions by Saccharomyces cerevisiae using the response surface methodology. The influence of various factors including initial dye concentration (10-100 mg/L), solution pH (4-10), reaction time (10-60 min), and S. cerevisiae dosage (0.2-1.5 g/L), was investigated on the process. According to the findings, the obtained levels of MB removal were varied in the range of 36 to 96. The maximum removal of MB (99.16) occurred at pH 9.35, the reaction time of 50.81 min, dye concentration of 14.37 mg/L, and S. cerevisiae dose of 1.32 g/L. The results showed that the code of A with the coefficient of -11.41 was the most important factor in the removal process. The AD and D-2 with the coefficient of -11.30 and -7.76 had the maximum interaction impact, and the maximum square impacts on the process, respectively. The removal rate of MB was directly correlated with reaction time and S. cerevisiae dose. It can be concluded that S. cerevisiae can be considered as a low-cost adsorbent for the removal of MB in the aqueous media.