Determinación mediante técnica ultravioleta-visible de la capacidad de adsorción de mezclas de fármacos sobre residuos vegetales

Abstract

The adsorption capacity of drug mixtures on sugar cane bagasse and corn cob was studied using the agitated tank technique, and using ultraviolet-visible spectroscopy. Several operational parameters such as solution pH, contact time, solution concentration and temperature were evaluated. The results of the solutions of known concentration by ultraviolet-visible technique showed that the Beer-Lambert equation system can be used for mixtures. The application of the high-efficiency liquid chromatography technique made possibile to quantify sulfamethoxazole and paracetamol. The results obtained indicate that at a pH of 7, the greatest removal of the drugs in the biomasses used was obtained. The contact time to achieve the highest adsorption is 60 minutes for cane bagasse, and 20 minutes for corn cob. The temperatures at which the most effective cane bagasse removals were achieved are 20˚C for analgesics, 40˚C for antibiotics, and 20˚C in corn cob for all drugs. The highest removal rates were achieved when the drugs were in low concentrations. Equilibrium and adsorption kinetics were evaluated using Langmuir and Freundlich models, and pseudo-first and pseudo-second order. The experimental data in the study range were adjusted to the Freundlich model, and to the pseudo-second order kinetic model in both biomasses, showing that it is a heterogeneous adsorption in multiple layers.