Assessment of Organobentonite’s Adsorption Kinetics for Efficient Removal of Methylene Blue Dye from Aqueous Solutions

Organobentonite beads (CS/SA/SS/Ben-300 mg) were synthesised using the ionic gelation method by crosslinking bentonite (Ben), chitosan (CS), sodium alginate (SA) and sodium sulphate (SS).The synthesised beads were characterised using X-ray diffraction (XRD), Fouriertransform infrared (FTIR) spectroscopy and a digital microscope, which indicated successful crosslinking between the components.The batch adsorption method was employed to investigate the adsorptive capabilities of CS/SA/SS/Ben-300 mg using methylene blue (MB) as a dye model.The highest adsorption of MB (50 mg/L) (88%) followed the pseudo-second-order kinetic model with a rate constant of 0.9195 g mg -1 min -1 and a linear regression coefficient (R 2 ) of 0.98 at 323 K and pH 12.This suggests that the MB adsorption followed a chemisorption mechanism.Furthermore, the Langmuir model was found to better describe the adsorption process compared to the Freundlich model.According to the Langmuir isotherm, the maximum monolayer adsorption capacity (q max ) of the organobentonite beads was observed to be 48.94mg/g under the optimum conditions.The reusability of CS/SA/SS-Ben-300 mg demonstrated no significant decrease in MB removal efficiency.