Optimization and Mathematical Modelling of Sodium Hypochlorite Mediated Decolorization of DIAZO DYE (Direct Blue 14)

Synthetic organic textile dyes are recalcitrant compounds released directly by the textile processing units into water bodies are important class of water pollutants. Decolourization of textile diazo dye Trypan Blue (Direct Blue 14) was investigated using a strong oxidative agent sodium hypochlorite using chemometric tools. Statistical tools such as Box-Behnken Design was applied for the study and optimization of decolourization process by investigating three important process operating variables such as pH (X1), incubation time (minutes) (X2) and dye concentration (mg/L) (X3). A total of 17 experiments were conducted in the study towards the construction of a second order quadratic model. Among the three variables, incubation time (X2) and dye concentration (X3) were found to be influencing factors towards the response. Statistical indicators such as ANOVA, Fischer’s Test and student’s tvalue support and explain model adequacy. Under optimized conditions of pH 3.0, incubation time of 32 minutes and 150 mg/L of dye concentration, sodium hypochlorite was able to decolorize 93% of Trypan Blue. The predicted conditions were subsequently validated to ensure reproducibility and validity of the statistical model. Experimental and predicted values were found to be in close agreement with each other. D. Diana Florence et al 214