One of the famous dyes is methylene blue (MB) which is a symbol of hazardous dyes. In this research, methylene blue was adsorbed using the blends of saffron petals with activated carbon. Five independent variables involving pH (2-13), contact time (5-270 min), saffron petals powder dosage (0.1-10 g/l), initial concentration of methylene blue solution (20-300 ppm) and activated carbon dosage (0.1-10 g/l) for methylene blue adsorption were studied. For this purpose, pure saffron petals powderand its blends with activated carbon were used to adsorb methylene blue with various concentrations from water at the above ranges. The Central Composite Design (CCD) under Response Surface Methodology (RSM) was applied to estimate the independent variables effects on the methylene blue adsorption. The optimum conditions for the 96.5% of removal were experimentally found at pH of 10.5, initial methylene blue concentration of 85.9 ppm, saffron petals powder dosage of 7.07 g/l, contact time of 182.05 min and activated carbon dosage of 7.35 g/l while the operating conditions for the maximum removal of 95.3% were experimentally obtained at pH of 10.5, initial methylene blue concentration of 83.1 ppm, saffron petals powder dosage of 7.77 g/l, contact time of 64.7 min and activated carbon dosage of 7.77 g/l. It is concluded that saffron petals powder (as a waste) with activated carbon is able properly adsorb methylene blue.
