Equilibrium and kinetic modelling of methylene blue biosorption by pretreated dead streptomyces rimosus: Effect of temperature

This paper aims to investigate the biosorption of basic dye, methylene blue onto dead Streptomyces rimosus. In our experiments the batch sorption is studied with respect to solute concentration, contact time, adsorbent dose and temperature. The results show that as the amount of the dead bacterial increases, the percentage of dye sorption increases accordingly. The bacterial biomass exhibits the highest methylene blue uptake capacity at 20 °C. Biosorption capacity decreased from 9.86 to 6.93 mg g−1 with an increase in temperature from 20 to 50 °C at the initial methylene blue concentration of 50 mg l−1. Intraparticle diffusion, pseudo-first order and pseudo-second order models can be used to describe the kinetics of basic dye sorption for different initial temperature values. In our study, we have used the Freundlich and Langmuir isotherm models to represent the equilibrium data of methylene blue biosorption at several temperature values. In addition, an activation energy of sorption has also been determined based on the pseudo-second order rate constants.