Determinación de la cinética de adsorción del Cr 6+ a partir de la fibra de achira (Canna indica)

Abstract

The bioaccumulation of heavy metals such as hexavalent chromium (Cr 6+) poses serious environmental and health risks, particularly due to its presence in industrial effluents. This study developed a sustainable and efficient method to mitigate this contaminant by using achira fibers (Canna indica) as a bioadsorbent in fixed-bed systems. Two fiber pretreatments were evaluated: agitation washing and alkaline treatment with 2% NaOH. Experiments were conducted with Cr (6+) solutions at concentrations of 1, 2.5, 5, 7.5, and 10 mg/L. Statistical analysis identified optimal conditions for adsorption kinetics and fitted isotherm models to the experimental behavior. The results revealed that hydrolyzed fiber achieved a 50% Cr (6+) removal in 2.5 mg/L solutions, outperforming the 33% removal with washed fiber. The Freundlich isotherm model accurately described the process (KF = 0.09, 1/n = 1.09), while the adsorption kinetics followed the Thomas model (R² = 0.880, qe = 26.45 mg/g). Additionally, 99% efficiency was achieved within the first 5 minutes, confirming the material's effectiveness. In conclusion, achira fiber is an economical, effective, and sustainable bioadsorbent for the removal of Cr (6+) from low-concentration effluents, with immediate potential for application in water treatment.