Biosorption of reactive blue BF-5G dye by malt bagasse: kinetic and equilibrium studies

The use of by-product in effluent treatment is interesting due to its low cost and high availability. In this study the potential of malt bagasse, a by-product of brewing process, was evaluated as biosorbent of reactive blue BF-5G dye. The malt bagasse was characterized by point of zero charge (pHPZC) and Fourier transform infrared spectroscopy. Batch experiments were carried out to investigate: effect of particle size, biosorbent dosage, effect of pH, kinetics, biosorption isotherm and desorption. The pHPZC of the biosorbent was determined at 5.4. The results showed that reactive blue BF-5G biosorption was little influenced by the particle size, and the biosorption optimum conditions were obtained using biosorbent dosage of 14 g L-1 and at pH 3. The pseudo-second order model and the Langmuir isotherm model (qmax = 42.58 mg g-1) best represented the kinetic and equilibrium biosorption data, respectively. The kinetic desorption of the dye showed higher efficiency at 50 °C. The results indicated that malt bagasse can be used as an alternative and promising biosorbent to be applied in the treatment of effluents containing the reactive blue BF-5G dye.