Adsorción de diclofenaco e ibuprofeno del agua usando bagazo de caña de azúcar y cáscara de cacao hidrolizado

Abstract

It was evaluated the adsorption of diclofenac and ibuprofen, two pharmaceuticals considered emerging contaminants, using modified agro-industrial residues as adsorbents: hydrolyzed sugarcane bagasse and cocoa shell. Experiments were carried out in batch reactors and fixed- bed columns to analyze removal efficiency under equilibrium and continuous flow conditions. In the batch system, the effects of adsorbent dosage, pH, initial concentration, and contact time were studied. Experimental data were fitted to kinetic models (pseudo-first order, pseudo- second order, and intraparticle diffusion) and equilibrium models (Langmuir, Freundlich, BET, and Dubinin–Radushkevich). The pseudo-second-order model provided the best fit (R² > 0.90), indicating that both chemical and physical interactions contribute significantly to the process. In fixed-bed columns, the influence of adsorbent mass and flow rate on breakthrough curves was evaluated. The Thomas, Bohart–Adams, Yoon–Nelson, and Dose–Response models were applied, with the latter showing the best correlation (R² > 0.99). For diclofenac, sugarcane bagasse exhibited the highest adsorption capacity (q₀ = 1.31 mg/g), while for ibuprofen the best performance was obtained with cocoa shell (q₀ = 0.86 mg/g), both under specific mass and flow conditions. The findings confirm that these agro-industrial by-products, being low-cost, readily available, and environmentally sustainable, represent a promising alternative for water treatment technologies aimed at the removal of pharmaceutical pollutants.