Optimization of an azo dye batch adsorption parameters using Box–Behnken design

Dye removal using adsorption requires a proper process parametric study to determine its optimal performance characteristics. In this study, response surface methodology was employed for the removal of methyl orange (MO) from aqueous solution using activated carbon-commercial grade (ACC) as an adsorbent. Experiments were carried out as per Box–Behnken surface statistical design with four input parameters namely adsorbent dose (w: 5–20 g/l), contact time (t: 2–6 h), temperature (T: 25–55 °C) and pH (pH: 2–8). Initial MO concentration (Co = 100 mg/l) was taken as a fixed input parameter. Regression analysis showed good fit of the experimental data to the second-order polynomial model with coefficient of determination (R2) value of 0.9114 and Fisher F-value of 10.28. Optimization of w (15.75 g/l), t (4 h), T (40 °C) and pH (2) gave a maximum of 99.11% MO removal by ACC.