Adsorption of oxytetracycline on kaolinite

• Published in: PloS one Vol. 14; no. 11; p. e0225335
• Main Authors: Song, Yali, Sackey, Ebenezer Ampofo, Wang, He, Wang, Hua
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 15.11.2019; Public Library of Science (PLoS)
• Subjects: Adsorption; Analysis; Antibiotics; Aqueous environments; Biology and Life Sciences; Civil engineering; Clay; Clay minerals; Contamination; Earth Sciences; Ecology and Environmental Sciences; Electrolytes; Experimental data; Experiments; Fourier transforms; Hydrogen-Ion Concentration; Kaolin - chemistry; Kaolinite; Kinetics; Laboratories; Medicine and Health Sciences; Minerals; Nonprescription drugs; Oxytetracycline; Oxytetracycline - chemistry; Particle size; Physical Sciences; Reaction kinetics; Research and Analysis Methods; Smectite; Studies; Temperature; Tetracyclines; Thermodynamics; Wastewater; Wastewater pollution; Water; Water treatment; China; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0225335

As antibiotic contamination increases in wastewater and aqueous environments, the reduction of antibiotics has become a pertinent topic of research regarding water treatment. Clay minerals, such as smectite or kaolinite, are important adsorbents used in water treatment, and sufficient removal of antibiotics by clay minerals is expected. In this study, the adsorption of oxytetracycline (OTC) on kaolinite was investigated. The experimental data of OTC adsorption on kaolinite fit the pseudo-second-order kinetics model well (R2>0.98). After 24 h, adsorption equilibrium of OTC on kaolinite was reached. The Langmuir model was better fitting with the adsorption isotherms generated from experimental data and OTC adsorption occurred on the external surface of kaolinite. The analysis of several thermodynamic parameters indicated that the adsorption of OTC on kaolinite was spontaneous and thermodynamically favorable. With the increase of the pH of a solution, the adsorption capacity increased and then decreased. The adsorption coefficient (Kd) of 102-103 were obtained for adsorption process of OTC on kaolinite.