Modelization and optimization of the treatment of the reactive black-5 dye from industry effluents using experimental design methodology

Abstract

This work investigated the coagulation-flocculation (CF) process of Reactive Black-5 (RB5) dye. The individual effects and interactions of different parameters, which include the pH, coagulant (Ferric chloride), and flocculant dosage (Himoloc DR3000), on the removal efficiency of RB-5 dye were studied. This study aims to build a mathematical model that allows for the representation of the studied responses according to different factors by using the experimental design methodology. The statistical fitness of the developed model was checked using analysis of variance (ANOVA). A second-order quadratic model, with a high determination coefficient (R2 =0.98% and R2=0.80% for chemical oxygen demand (COD) removal and overall cost, respectively), was best fitted to develop the relationship between independent and dependent variables. The results obtained show that the model was highly significant and in good agreement with the experimental results. The optimum conditions obtained for coagulant dose, flocculant dose, and pH were 550 mg/l, 210 mg/l, and 5.4, respectively. Under these optimal conditions, about 98% COD removal and 3.12 $/m3 for effluent treatment were achieved.