Synthesis of wheat bran sawdust/Fe3O4 composite for the removal of methylene blue and methyl violet.

Abstract

Magnetically modified nanomaterials have recently gained a great attention in wastewater treatment. In this study, the uptake process of methylene blue (MB) and methyl violet (MV) from aqueous media using wheat bran sawdust/Fe3O4 composite was studied. To specify the surface and structural properties of the wheat bran sawdust/Fe3O4 composite, various analyses such as FTIR, XRD, EDX, Map, TGA/DTG, SEM, VSM, and BET were performed. The results of BET analysis indicated that the specific surface area of the aforementioned composite was 74.25 m2/g, and the average pore size was 65.7A, which indicates that the composite has a mesoporous structure. Also, VSM analysis indicated that the composite has a paramagnetic property with a magnetic saturation of 28.29emu/g and can be easily eliminated from the aqueous solution by a magnet. Moreover, the highest removal efficiency of MB and MV dyes using the wheat bran/Fe3O4 composite was obtained as 97.46 and 98.75%, respectively, which were significant values. These removal efficiencies were obtained at contact time of 50min and pH values of 9 and 8 for MB and MV, respectively. Furthermore, the outcomes of equilibrium study showed that the Langmuir model with a correlation coefficient greater than 0.98 describes the equilibrium behavior of the uptake process better than the Freundlich and Dubinin-Radushkevich models. Besides, the maximum sorption capacity of MV and MB dyes using the Langmuir model was obtained as 46.08 and 51.28mg/g, respectively. Also, the uptake process followed the pseudo-second-order kinetic model, and the thermodynamic study indicated that the uptake process is exothermic and spontaneous.