Action of Low-Density Polyethylene Microspheres in the Transport of Metformin Hydrochloride in Aqueous Medium Through Adsorption and Desorption
2024
Luanna Gláucia Guimarães | Renata Medici Frayne Cuba | Francisco Javier Cuba Teran
The present study addresses the issue of transporting pharmaceuticals via microplastics in aquatic environments. For this purpose, the adsorption and desorption of metformin hydrochloride (MET), a hydrophilic compound, on polyethylene microspheres (PMEs) were studied via batch adsorption and desorption capacity and kinetics tests. The adsorption test results indicated minimal influence of pH values above 5, alongside a decrease in adsorption capacity with an increasing mass of PMEs. The Freundlich model best represented the adsorption capacity data: however, values of n <: 1 (0.6) and low K suggest a decrease in the sorption affinity of MET with increasing initial MET concentration and a low affinity of MET for PM beads. The rate and equilibrium of adsorption were fast, and the results adequately fit the pseudo-first- and pseudo-second-order models, suggesting that physical and chemical mechanisms contributed to the adsorption of MET onto the PEMs under the conditions of this study. The desorption equilibrium result was 1.3 mg g&minus:1 ±: 0.04 mg g&minus:1, without significant change, regardless of the initial amount of adsorbed MET. However, the desorption percentage varied between 26.14% and 7.01% as a function of the amount. of MET adsorbed onto the PMEs. These results suggest that PMEs could be potential vectors of MET transport in aquatic environments.
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