Escola de Engenharia Mauá, Instituto Mauá de Tecnologia
Praça Mauá 1, 09580-900, SP, São Caetano do Sul, SP, Brazil
Abstract
The kinetic of Indigo Carmine (5,5'- disulfonic indigotin, 5,5'-DI) adsorption on fibrous peat (FP)
and decomposed peat (DP), have been investigated at different temperatures (283, 298, 313) K at pH 2. The
effect of particle size was studied considering the variation of grain size of each peat (2000-850, 850-600 and <
600) nm. The fibrous peat shows higher adsorption capacity than the decomposed peat, while under the same
work conditions. The kinetics of adsorption of 5,5'-DI is discussed using three kinetic models, the first-order
Lagergren model, the pseudo-second-order model, and the intraparticle diffusion model. The adsorption of 5,
5'-DI onto peat proceeds according to the pseudo second-order model and the correlation coefficients were very
close to 1. At 283, 298 and 313 K the maximum sorption, q
max,calc, for the initial concentration (Co = 4.05 × 10
-5
mol L
-1) of 5,5´-DI were q
max,calc is (5.57, 7.92 e 8.29) × 10
-4 g g
-1 for fibrous peat and (5.29, 6.74 e 5.83) × 10
-4
g g
-1 for decomposed peat. The intraparticle diffusion of 5,5'-DI molecules within the peat particles was
identified as the rate-limiting step.