Valorization of sugarcane bagasse for the sustainable biosorption of crystal violet dye: Kinetic, Isothermal, Thermodynamic Studies and Mechanisms Analysis

Laboratory of Chemistry and Biology Applied to the Environment, URL-CNRST-N◦13, Faculty of Sciences, Moulay Ismail University, Meknes 50050, Morocco.

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Abstract

The contamination of aquatic environments by synthetic dyes poses a major environmental issue due to their toxicity, persistence, and harmful effects on ecosystems. This study investigates the use of sugarcane bagasse (SCB) as a low-cost biosorbent for the removal of crystal violet (CV) dye from aqueous solutions. SCB was characterized by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). The effects of operational parameters such as contact time, biosorbent dosage, pH, and temperature were examined. Under optimal conditions 40 minutes of contact, 2 g/L SCB dosage, room temperature, and pH 10 a maximum removal efficiency of 95% was achieved. Isotherm and kinetic studies indicated a multilayer adsorption process dominated by physisorption, with the pseudo-second-order kinetic model providing the best fit to the experimental data. Thermodynamic analysis confirmed that the adsorption process is spontaneous and endothermic. Post-adsorption FT-IR spectra revealed the involvement of hydrogen bonding, electrostatic interactions, and ion exchange in the adsorption mechanism. These findings demonstrate the potential of sugarcane bagasse as an efficient, sustainable, and environmentally friendly biosorbent for the removal of synthetic dyes from contaminated water, offering a promising solution for wastewater treatment in a cost-effective manner.