Optimization of Cyan flexo dye removal by nano zero-valent iron using response surface methodology

Application of nano zero-valent iron (nZVI) as a catalyst in a decolorization process is a simple and sensitive method for Cyan flexo dye removal from the aqueous solution. In this paper, a central composite design (CCD), under the response surface methodology (RSM), was applied in order to optimize experimental conditions of the Cyan removal from aqueous solution. The influence of four independent variables was studied: nZVI dosage (5–45 mg L-1), initial dye concentration (2–14 g L-1), pH (2–10) and removal time (20–100 min), in order to build second order quadratic model and to predict the responses. The highest removal percent of 96.35% was attained, and the optimum parameters are achieved after 1h/24h precipitation: nZVI dosage (5/45 mg L-1), initial dye concentration (2/14 g L-1), removal time (20/100 min) and pH (2/10). The Cyan removal efficiency of 38% and 62% were estimated under optimized experimental conditions.