Open AccessOptimisation using central composite design (CCD) and the desirability function for sorption of methylene blue from aqueous solution onto Lemna major
Author(s) -
Bikash Sadhukhan,
N. K. Mondal,
Soumya Chattoraj
Publication year - 2016
Publication title -
karbala international journal of modern science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.345
H-Index - 17
eISSN - 2405-6103
pISSN - 2405-609X
DOI - 10.1016/j.kijoms.2016.03.005
Subject(s) - biosorption , central composite design , adsorption , response surface methodology , sorption , aqueous solution , fourier transform infrared spectroscopy , methylene blue , freundlich equation , chemistry , langmuir adsorption model , nuclear chemistry , langmuir , chromatography , analytical chemistry (journal) , materials science , chemical engineering , organic chemistry , photocatalysis , engineering , catalysis
Water pollution due to contamination of dye containing effluents is a great threat to water body. A study on the biosorption of methylene blue (MB) onto low-cost Lemna major biomass was conducted and the process parameters were optimized by response surface methodology (RSM). A two-level, four-factor central composite design (CCD) has been employed to determine the effect of various process parameters namely initial concentration (600–1000 mg L−1), bioadsorbent dose (0.20–1.50 g/100 mL), pH (5–12) and stirring rate (250–800 rpm) on MB uptake from aqueous solution. By using this design a total of 30 biosorption experimental data were fitted. The regression analysis showed good fit of the experimental data to the second-order polynomial model with coefficient of determination (R2) value of 0.9978 and model F-value of 953.48. The optimum conditions of initial concentration (1000 mg L−1), adsorbent dose (0.2 g), pH (5) and stirring rate (251.51 rpm) were recorded from desirability function. The adsorption isotherm data were best described by both Freundlich and Langmuir models with a maximum adsorption capacity of 488 mg MB g−1 L. major biomass at 30 °C which is higher than that available with adsorbents used by past researchers. Finally the pseudo second order kinetic model described the MB biosorption process with a good fitting (R2 = 0.999). The adsorbent was characterised by scanning electron micrograph (SEM) and Fourier transform infrared spectroscopy (FTIR)