Optimization of batch operating conditions for the decolourization of vinasses using surface response methodology

In this study, the use of entrapped activated carbon was proposed for the removal of coloured compounds from vinasses. The operational conditions of the batch adsorption process were optimized by means of an incomplete 3(3) factorial design. The independent variables studied included the volume of entrapped activated carbon (x(1)): time of treatment (x(2)) and speed of agitation (x(3)), whereas the dependent variables studied were based on the decrease in absorbance at 620, 520 and 420 nm, as well as on the tristimulus values (x,y), based on chromaticity co-ordinates that map all colours in a two-dimensional space, called a chromaticity diagram. CIELAB parameters (L*, a*, b* and C*(ab)), which map all colours in a three-dimensional space, were also tested as dependent variables. The optimal conditions for removing coloured compounds from vinasses in batch adsorption experiments were: ratio of entrapped activated carbon/vinasses -1; operational time, 75 min and the minimum agitation speed tested (75 rpm). The results obtained demonstrated the potential application of immobilized activated carbon beads in the design of new eco-friendly, efficient and low-cost bioremediation strategies. (C) 2011 Elsevier B.V. All rights reserved.