Competitive adsorption/desorption of tetracycline, oxytetracycline and chlortetracycline on two acid soils: Stirred flow chamber experiments

• Published in: Chemosphere (Oxford) Vol. 134; pp. 361 - 366
• Main Authors: Fernández-Calviño, David, Bermúdez-Couso, Alipio, Arias-Estévez, Manuel, Nóvoa-Muñoz, Juan Carlos, Fernández-Sanjurjo, Maria J., Álvarez-Rodríguez, Esperanza, Núñez-Delgado, Avelino
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2015
• Subjects: Acid soils; Acids; Adsorption; Aluminum Silicates; Anti-Bacterial Agents - analysis; Anti-Bacterial Agents - chemistry; Antibiotics; Chlortetracycline - analysis; Chlortetracycline - chemistry; Competitive adsorption/desorption; Constants; Desorption; Environmental pollution; Kinetics; Mathematical analysis; Models, Chemical; Oxytetracycline; Oxytetracycline - analysis; Oxytetracycline - chemistry; Soil - chemistry; Soil Pollutants - analysis; Soil Pollutants - chemistry; Soils; Stirred flow chamber; Tetracycline - analysis; Tetracycline - chemistry; Tetracyclines; Stirred flow chamber; Acid soils; Competitive adsorption/desorption; Environmental pollution; Tetracyclines
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2015.04.098

•Competitive adsorption of tetracyclines was compared previous non-competitive trials.•Competitive desorption of the antibiotics was compared previous non-competitive trials.•Hysteresis has affected adsorption/desorption processes.•The SFC technique gave new kinetic data for three tetracyclines competing by pairs.•The technique shed light on rapid kinetics affecting competitive sorption. The objective of this work was to study the competitive adsorption/desorption of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) on two acid soils. We used the stirred flow chamber technique to obtain experimental data on rapid kinetic processes affecting the retention/release of the antibiotics. Both adsorption and desorption were higher on soil 1 (which showed the highest carbon, clay and Al and Fe oxides content) than on soil 2. Moreover, hysteresis affected the adsorption/desorption processes. Experimental data were fitted to a pseudo-first order equation, resulting qamax (adsorption maximum) values that were higher for soil 1 than for soil 2, and indicating that CTC competed with TC more intensely than OTC in soil 1. Regarding soil 2, the values corresponding to the adsorption kinetics constants (ka) and desorption kinetics constants for fast sites (kd1), followed a trend inverse to qamax and qdmax respectively. In conclusion, competition affected adsorption/desorption kinetics for the three antibiotics assayed, and thus retention/release and subsequent transport processes in soil and water environments.