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Removal of ivermectin from aqueous media using commercial, bentonite-based organophilic clay as an adsorbent

Published online by Cambridge University Press:  01 July 2022

Ramiro Picoli Nippes*
Affiliation:
Maringa State University, Av. Colombo, 5790 – Zona 7, Maringá - PR, 87020-900, Brazil
Paula Derksen Macruz
Affiliation:
Maringa State University, Av. Colombo, 5790 – Zona 7, Maringá - PR, 87020-900, Brazil
Thaísa Frossard Coslop
Affiliation:
Maringa State University, Av. Colombo, 5790 – Zona 7, Maringá - PR, 87020-900, Brazil
Deise Molinari
Affiliation:
Maringa State University, Av. Colombo, 5790 – Zona 7, Maringá - PR, 87020-900, Brazil
Mara Heloísa Neves Olsen Scaliante
Affiliation:
Maringa State University, Av. Colombo, 5790 – Zona 7, Maringá - PR, 87020-900, Brazil

Abstract

The worldwide use of pharmaceuticals is of concern to those researchers who develop new techniques for the removal of these compounds from the aquatic medium. The objective of the present work was to characterize and evaluate the performance of a commercial, bentonite-based organophilic clay in removing ivermectin from aqueous solution. The adsorbent was characterized by nitrogen physisorption, thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Batch-scale adsorption experiments were performed to evaluate the kinetics, isotherms, thermodynamics and effect of pH on removal of this drug and reuse of the clay. The bentonite has a small specific surface area with an irregular surface. The Elovich kinetic model fits the experimental data better than other models, indicating that chemisorption contributes to drug removal in this case. The Langmuir and Sips isothermal models best fit the experimental equilibrium data. The process was shown to be favorable (ΔG°ads<0), endothermic (ΔH°ads>0), with an increase in the degrees of freedom at the solid–liquid interface (ΔS°ads>0), and with characteristics of a physical-chemical adsorption process (Ea = 11.065 kJ mol–1) under the study conditions. Adsorption was favored at the natural pH of the solution and the organophilic clay could be regenerated with water and reused in consecutive adsorption cycles. The amount of ivermectin adsorbed on the organophilic clay ranged from 1.78 to 3.88 mg g–1. The organophilic clay was shown to be a cost-effective potential adsorbent for ivermectin-contaminated water-treatment applications.

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Article
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Copyright © The Author(s), 2022. Published by Cambridge University Press on behalf of The Mineralogical Society of Great Britain and Ireland

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Footnotes

Associate Editor: Liva Dzene

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