Kinetic Study of Methylene Blue Removal on Immobilized Biomass Left after Enzyme Production Using Response Surface Methodology

Abstract

Aims: Kinetic study of methylene blue dye removal, screening and optimization of different process parameters. Place and Duration of Study: Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar. June 2010 and July 2011. Methodology: The spent biomass immobilized with Aspergillus flavus left after enzyme production dried at 40°C and dried biomass utilized for dye removal. Biosorption kinetic experiments were carried out in 150 ml flasks by varying contact time from 5 to 180 min initial dye concentration and agitation rate was 200 mg/l and 100 rpm respectively at 30°C. Response surface methodology was applied for screening and optimization of process parameters for dye removal. Results: Plackett-Burman design (PBD) and Box-Behnken design (BBD) was applied for screening of variables i.e. dye concentration, adsorbent dose, pH, temperature, contact time and agitation affecting dye decolorization. Variables were adsorbent dose (0.1- 0.5 g), dye concentration (100- 200 mg/L) and contact time (10- 60 min). Maximum decolorization 62.07% obtained at adsorbent dose 0.5 g and dye concentration of 100 mg/L after 35 min at pH 7 and temperature 30°C. Kinetic studies of dye adsorption showed that it followed pseudo-second order kinetics. Conclusion: The spent biomass immobilized with Aspergillus flavus left after enzyme production effectively removes methylene blue dye.