Valorization of Bauxite Residue for Use as Adsorbent for Reactive Blue Removal: Regeneration Evaluation

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In recent years, there has been increasing concern regarding the widespread occurrence of dyes in aquatic environments, due to their harmful effects on both water quality and human health. This investigation uses bauxite residue as a cost-effective sorbent to eradicate the hazardous reactive blue (RB) dye from aqueous solutions. The reusability potential of bauxite residue was also evaluated. The bauxite residue was characterized by X-ray diffraction, Cation Exchange Capacity, Chemical analysis, FTIR, and Analysis of particle size and particle distribution. The RB dye adsorption parameters revealed that the removal efficiency and adsorption capacity of bauxite residue was 100% and 186.01 mg/g, respectively, under the following adsorption conditions: adsorbent dosage of 0.5 mg/L, initial pH of 2, dye concentration of 50 mg/g, and reaction temperature of 25 °C. Furthermore, the adsorption of RB dye on bauxite residue followed the pseudo-second-order kinetic and Freundlich isotherm models. After one adsorption cycle, the adsorption capacity of bauxite residue for reactive RB removal reached 186.01 mg/g. The regeneration study revealed that the bauxite residue remained 99% of its original condition following the water regeneration cycle.