Factor design methodology for modelling and optimization of carcinogenic acid dye adsorption onto Moroccan prickly pear cactus peel

In this study, the modelling and optimization studies of the carcinogenic acid dye sorption from aqueous solutions were carried out using the Factor Design Methodology. This methodology provides a predictive model of the response in the range of variables studied and determines the optimum conditions for the best performance. The sorption of acid dye AB113 on Moroccan prickly pear cactus peel (MPPCP) was chosen as a case study of a typical removal process. Minitab17 software was used to study the effects of adsorption parameters, including initial dye concentration, solution pH, adsorbent dose, contact time, and temperature. Analysis of variance (ANOVA) was used to evaluate the experimental results obtained. The studied parameters at two levels (-1 and +1) were coded as X1 , X2 , X3 , X4 and X5 , consecutively. The optimum conditions obtained for the adsorption of AB113 dye were: 1 g for the mass of MPPCP, 6 for the initial solution pH, 180 min for the contact time and 20 mg/L for the initial dye concentration. The results show that the model is well adapted to the experimental data, indicating the suitability of the model and the success of the factorial design methodology in optimizing the adsorption conditions.