Isotherm and kinetic studies of Burazol Blue ED dye biosorption by dried anaerobic sludge

Biosorption potential of dried anaerobic sludge (DAS) for Burazol Blue ED (BB) was studied with respect to pH, equilibrium time, initial dye concentrations and temperature to determine equilibrium and kinetic models. The most suitable pH, equilibrium time and initial dye concentration were determined as 0.5 +/- 0.03, 75 min and 150 mg/L, respectively, at a biomass dosage of 0.4 g/L and 25 degrees C +/- 1.0. The equilibrium data was best described by the Langmuir isotherm model. Maximum uptake capacity (q(m)) of DAS for the dyestuff (BB) were 118.3, 125.8 and 127.5 mg/g biomass at temperatures of 25, 40 and 50 degrees C. respectively, indicating that the biosorption process is spontaneous and favored at higher temperatures. The overall biosorption process was best described by pseudo-second-order kinetic model. Gibbs free energy changes were Calculated as -356.8, -519.7 and -520.6 J/mol at 25, 40 and 50 degrees C, respectively. (C) 2008 Elsevier B.V. All rights reserved.