Application of Response Surface Methodology to Optimize Malachite Green Removal by Cl-nZVI Nanocomposites

Disposal of effluents containing dyes into natural ecosystems pose serious threats to both the environment and its aquatic life. Malachite green (MG) is a basic dye that has extensive industrial applications, especially in aquaculture, throughout the world. This study reports on the application of the central composite design (CCD) under the response surface methodology (RSM) for the optimization of MG adsorption from aqueous solutions using the clinoptilolite nano-zerovalence iron (Cl-nZVI) nanocomposites. The sorbent structures produced are characterized by means of scanning electron micrograph (SEM), energy-dispersive X-ray spectroscopy (EDS), and vibrating sample magnetometer (VSM). The effects of different parameters including pH, initial MG concentration, and sorbent dosage on the removal efficiency (R) of MG were studied to find the optimum operating conditions. For this purpose, a total of 20 sets of experiments were designed by the Design Expert.7.0 software and the values of removal efficiency were used as input response to the software. The optimum pH, initial MG concentration, and sorbent dosage were found to be 5.6, 49.21 mg.L-1, and 1.43 g.L-1, respectively. A high MG removal efficiency (57.90%) was obtained with optimal process parameters. Moreover, a desirability value of 0.963 was obtained for the optimization process