Towards Potential Removal of Malachite Green from Wastewater: Adsorption Process Optimization and Prediction

Granular activated carbon (GAC) is utilized as an adsorbent for the malachite green (MG) dye removal from aqueous solutions. The GAC was characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) to realize the GAC chemical and physical features effects on the adsorption efficiency. Batch adsorption processes were carried out with different variables like pH, GAC dose, initial MG concentration and time. The response surface methodology (RSM) was used to design the experiments, model the adsorption process, optimize the operating conditions and predict the response. A 24 full factorial central composite design (CCD) was performed for the experimental design and the analysis of the results. Analysis of variance (ANOVA) was employed to determine the significance of the factors and explore the interaction between the various experimental parameters. An empirical model was derived to correlate the experimental results and predict the behavior of the GAC for the adsorption process. The model showed a good agreement with the experimental results of R2 = 0.9968 and evidenced that the optimum operating parameters are pH 10, 2 g GAC/L, 200 mg/L of MG initial concentration and 113 min adsorption time for complete removal of MG.