Influence of Process Variables on Adsorption of Congo Red Onto Mango Leaf Char Using Factorial Design Analysis

Influence of process variables like pH, adsorbent dosage (D), initial dye concentration (C0), particle size (S) and temperature (T) on adsorption of a direct dye on carbon derived from mango leaf were studied using a 25 factorial design.The main effects and interaction effects were determined using statistical methods.Maximum uptake obtained was 55.7 mg/g (pH = 2, T = 40 °C, D = 0.5 g/dm³, C0= 100 mg/dm³ and S = 53 μm).It was found that the effects of process variables namely pH, adsorbent dosage, initial dye concentration, particle size and temperature on dye uptake were statistically significant.In addition, 2-level, 3-level and 4-level interactions between the variables were also found to influence dye uptake significantly.The model explained 96.79% variation in the response leaving only 3.21% for residuals.Dye uptake capacity up to 55.7 mg/g could be obtained with the proposed carbonaceous adsorbent mango leaf char.