Enhanced Adsorption of Methylene Blue Dye from Water by Alkali-Treated Activated Carbon

In this work, activated carbon (AC) was prepared from Raphia taedigera seed and modified with sodium hydroxide (0.1 M) solution. The activated carbon (RTB) and the untreated Raphia taedigera raw (RTR) seed powder were characterised and engaged to remove Methylene blue (MB) dye from aqueous solution. Both materials were characterized by Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). FTIR revealed the presence of functional groups such as hydroxyl, carboxylic, alkenes, aldehydes, and ketonic groups. SEM image showed the surface morphology of the material is characterized by aggregated structure with pores. The performances evaluation of the materials gave the highest percentage of MB dye removal of 84.21 and 97.00% were observed for RTR and RTB, respectively, at pH 5. The adsorption modelling showed that the MB dye adsorption onto both adsorbents could best be represented by Langmuir isotherm and followed the pseudo-second-order kinetic model. The thermodynamic studies predicted exothermic, feasible, spontaneous, and physisorption nature of MB dye adsorption onto the RTR and RTB within the temperature range for this study.