Experimental study and mathematical modeling of biosorption of methylene blue from aqueous solution in a packed bed of microalgae Scenedesmus

The sorption of methylene blue from aqueous solutions by the microalgae Scenedesmus was studied in batch and continuous systems. In the first part of the study, the sorption capacity of methylene blue on the Scenedesmus was obtained at various temperatures (22 degrees C, 30 degrees C and 37 degrees C) and pH values (5, 7 and 9). The maximum uptake was obtained to be 87.69 +/- 3.22 (mg/g) at a pH of 9 and a temperature of 30 degrees C. The characterization technique of scanning electron microscopy (SEM) showed a high potential of the biosorbent. The Langmuir adsorption isotherm is employed to describe the equilibrium data with the root mean square error of 2.22 (mg/g) and R-2 of 0.978. In the second part of the study, the breakthrough curves were obtained for different conditions in fixed bed columns with different lengths and diameters. To predict and describe the dynamic behavior of the system under different conditions, a predictive model is developed. Although no kinetic experimental data were used in the model development, the model predicts the experimental breakthrough curves in different conditions accurately. The present model can be employed to design a packed bed column for biosorption of methylene blue, as well as the optimization and control of this system. (C) 2019 Elsevier Ltd. All rights reserved.