Abstract

To find pH-independent biosorbent, the biosorption characteristic of lyophilized biomass of Bacillus megaterium was tested in this study. Biosorption equilibrium and kinetics of an azo dye (reactive blue 5) were investigated using the aforementioned biosorbent. The optimal adsorbent dosage for maximal dye uptake was 2.5 gL^-1 and the dye uptake values varied little in the pH range of 2 to 11, as well as in solutions with different metal ions. The Langmuir biosorption isotherm model was found suitable for describing the biosorption of the dye. It can also be observed that the dye uptake process followed both the first and second order model. The negative value of∆G indicated that the biosorption is spontaneous in nature. Fourier transform infrared(FTIR) analysis revealed that amine, hydroxyl, carboxyl and phosphonate groups were involved in the biosorption process.

Key words: Biosorption, lyophilized biomass, equilibrium, thermodynamics, FTIR