Tetracycline adsorption/desorption by raw and activated Tunisian clays

Samiha Hamdi; Hakima Gharbi-Khelifi; Ana Barreiro; Mohamed Mosbahi; Raquel Cela-Dablanca; Jihen Brahmi; María J Fernández-Sanjurjo; Avelino Núñez-Delgado; Manel Issaoui; Esperanza Álvarez-Rodríguez

doi:10.1016/j.envres.2023.117536

Tetracycline adsorption/desorption by raw and activated Tunisian clays

Environ Res. 2024 Feb 1:242:117536. doi: 10.1016/j.envres.2023.117536. Epub 2023 Nov 23.

Affiliations

¹ Department of Biotechnology, Faculty of Science and Technology of Sidi Bouzid, University of Kairouan, 9100, Sidi Bouzid, Tunisia; Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, University of Santiago de Compostela, 27002, Lugo, Spain; Laboratory of Nutrition - Functional Foods and Health (NAFS)-LR12ES05, Faculty of Medicine, University of Monastir, Avenue Avicenne, 5019, Monastir, Tunisia; Laboratory of Transmissible Diseases and Biologically Active Substances · LR99ES27 · Faculty of Pharmacy of Monastir, University of Monastir, Avenue Avicenne, 5019, Monastir, Tunisia. Electronic address: samihahamdi2020@gmail.com.
² Department of Biotechnology, Faculty of Science and Technology of Sidi Bouzid, University of Kairouan, 9100, Sidi Bouzid, Tunisia; Laboratory of Transmissible Diseases and Biologically Active Substances · LR99ES27 · Faculty of Pharmacy of Monastir, University of Monastir, Avenue Avicenne, 5019, Monastir, Tunisia.
³ Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, University of Santiago de Compostela, 27002, Lugo, Spain.
⁴ Department of Biotechnology, Faculty of Science and Technology of Sidi Bouzid, University of Kairouan, 9100, Sidi Bouzid, Tunisia.
⁵ Department of Biotechnology, Faculty of Science and Technology of Sidi Bouzid, University of Kairouan, 9100, Sidi Bouzid, Tunisia; Laboratory of Nutrition - Functional Foods and Health (NAFS)-LR12ES05, Faculty of Medicine, University of Monastir, Avenue Avicenne, 5019, Monastir, Tunisia.

PMID: 38000635
DOI: 10.1016/j.envres.2023.117536

Abstract

Clay-based adsorbents have applications in environmental remediation, particularly in the removal of emerging pollutants such as antibiotics. Taking that into account, we studied the adsorption/desorption process of tetracycline (TC) using three raw and acid- or base-activated clays (AM, HJ1 and HJ2) collected, respectively, from Aleg (Mazzouna), El Haria (Jebess, Maknessy), and Chouabine (Jebess, Maknessy) formations, located in the Maknessy-Mazzouna basin, center-western of Tunisia. The main physicochemical properties of the clays were determined using standard procedures, where the studied clays presented a basic pH (8.39-9.08) and a high electrical conductivity (446-495 dS m^-1). Their organic matter contents were also high (14-20%), as well as the values of the effective cation exchange capacity (80.65-97.45 cmol_ckg^-1). In the exchange complex, the predominant cations were Na and Ca, in the case of clays HJ1 and AM, while Mg and Ca were dominant in the HJ2 clay. The sorption experimental setup consisted in performing batch tests, using 0.5 g of each clay sample, adding the selected TC concentrations, then carrying out quantification of the antibiotic by means of HPL-UV equipment. Raw clays showed high adsorption potential for TC (close to 100%) and very low desorption (generally less than 5%). This high adsorption capacity was also present in the clays after being activated with acid or base, allowing them to adsorb TC in a rather irreversible way for a wide range of pH (3.3-10) and electrical conductivity values (3.03-495 dS m^-1). Adsorption experimental data were studied as regards their fitting to the Freundlich, Langmuir, Linear and Sips isotherms, being the Sips model the most appropriate to explain the adsorption of TC in these clays (natural or activated). These results could help to improve the overall knowledge on the application of new low-cost methods, using clay based adsorbents, to reduce risks due to emerging pollutants (and specifically TC) affecting the environment.

Keywords: Adsorption; Chemical activation; Clay sorbents; Desorption; Tetracycline.

Published by Elsevier Inc.

MeSH terms

Adsorption
Aluminum Silicates / chemistry
Anti-Bacterial Agents
Clay
Environmental Pollutants*
Tetracycline* / chemistry

Substances

Clay
Tetracycline
Anti-Bacterial Agents
Environmental Pollutants
Aluminum Silicates