Adsorção do antidepressivo fluoxetina utilizando Leucaena leucocephala (Lam.) como biossorvente

Abstract

Pharmaceutical products are complex molecules that have low biodegradability in the environment, where they tend to accumulate. The increase in the comsumption of these compounds by the population, associated with the difficulties in removing these pollutants and the harmful effects that they can cause, both to nature and humans, makes it necessary to search for effective treatment methods for effluents containing pharmaceuticals. Adsorption stands out as an efficient, simple, and lowcost alternative in the treatment of this type of pollutant. In this sense, the objective of the present work was to characterize the Leucaene biomass and evaluate its use as a biosorbent in the removal process of the antidepressant Fluoxetine, through the analysis of equilibrium and kinetics adsorption of the mechanisms involved in the process. In addition, the toxicity of this drug against test organisms was evaluated. The Leucaena leaf was characterized by the presence of dry matter, mineral matter, lignin, and cellulose. The influence of the solution pH on the adsorption process was evaluated, testing the values of 2, 4, 6, 8, and 10. Kinetic and equilibrium batch adsorption tests were performed, with different initial Fluoxetine concentrations, and the kinetic models of pseudo-first and pseudo-second orders were tested, in addition to the Langmuir and Freundlich adsorption isotherm models. The reduction of toxicity was verified by exposing Artemia salina microcrustaceans to synthetic effluent before and after treatment. The Leucaena leaf presented 87,11% dry matter, 10,89% mineral matter, 20,22% lignin and 3,38% cellulose. The pH value significantly influenced the adsorption process, with pH 6 and 10 as the most efficient values. Fluoxetine adsorption reached equilibrium in the period of 40 to 50 minutes for the initials concentrations evaluated, and the adsorption was best represented by the pseudo-first-order model and by the Langmuir isotherm with a qmax of 56,6 mg g-1. The antidepressant showed toxicity against the microcrustaceans for all analyzed concentrations and the treatment of the effluent proved to be effective in reducing the mortality of organisms.