Kinetic and equilibrium comparison of methylene blue and basic blue 41 adsorption by silica fume

The complex molecular structures of synthetic dyes are not easily removed from water, so it is essential to treat dye pollutants before they enter the aquatic environments. In this study, cost-effective industrial waste silica fume (SF) was used as an adsorbent to investigate the adsorption of methylene blue (MB) and basic blue 41 (BB-41). The structure of the silica fume adsorbent was characterized using the FESEM technique, which confirmed that SF has a porous structure. The adsorption of these cationic dyes was examined using kinetics models (pseudo-first-order and pseudo-second-order) and isotherm models (Langmuir, Temkin, Dubinin-Radushkevich and Freundlich), and the results obtained were compared. Based on the findings, the adsorption process of MB and BB-41 on SF followed pseudo-second-order kinetics. The adsorption of MB and BB-41 on SF followed Freundlich isotherm model. According to Langmuir isotherm data, the maximum adsorption capacity for BB-41 and MB was found to be 41.95 and 189.31 mg/g, respectively.