Optimization of malachite green dye removal by Chrysanthemum indicum using response surface methodology

This study investigates the adsorption capacity of Chrysanthemum indicum flower for removal of Malachite Green dye from aqueous solution. Batch experiments were conducted to study the effects of six independent variables including pH (4–8), adsorbent dose (2–4 g/L), initial dye concentration (100–200 mg/L), stirring speed (100–200 RPM), contact time (60–90 min), and temperature (25–35°C) on dye removal. The effect of these variables and its interactive effects have been studied using central composite design by response surface methodology. The characteristics of the adsorbent were studied by Fourier transform infrared spectroscopy and Scanning electron microscopy techniques, before and after the adsorption process. The maximum dye removal (99.3%) was achieved with the optimum conditions as: pH 11, adsorbent dosage of 3 g/L, stirring speed of 150 RPM with contact time of 75 min at temperature of 30°C for the initial dye concentration of 150 mg/L. pH, adsorbent dosage, and stirring speed have significant individual effects on dye removal among six independent variables. Interactive effect of pH with adsorbent dose and initial dye concentration are also significant. The higher percentage removal of Malachite Green dye by Chrysanthemum indicum flower suggests the effectiveness of the adsorbent for cationic dyes. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1415–1419, 2016