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Metabolic Profiling to Determine Bactericidal or Bacteriostatic Effects of New Natural Products using Isothermal Microcalorimetry
Published on: October 29, 2020
Cation exchange interaction between antibiotic ciprofloxacin and montmorillonite
Chih-Jen Wang1, Zhaohui Li, Wei-Teh Jiang
1Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan.
Journal of Hazardous Materials
|August 3, 2010
Summary
Montmorillonite effectively removes the antibiotic ciprofloxacin from water through cation exchange and surface adsorption. This interaction is crucial for understanding antibiotic fate and transport in the environment.
Area of Science:
- Environmental Science
- Geochemistry
- Materials Science
Background:
- Antibiotics are frequently detected in various environmental compartments, including water and soil.
- Understanding antibiotic-soil/mineral interactions is vital for assessing their environmental fate, transport, and elimination.
- Montmorillonite (SAz-1) is a swelling clay mineral with Ca(2+) as the primary interlayer cation.
Purpose of the Study:
- To determine the adsorption properties and interaction mechanisms of ciprofloxacin with montmorillonite (SAz-1).
- To evaluate montmorillonite's potential as a sorbent for removing ciprofloxacin from aqueous solutions.
Main Methods:
- Adsorption experiments were conducted in aqueous solutions across different pH ranges.
- Characterization of adsorbed ciprofloxacin on montmorillonite using X-ray diffraction (XRD) to determine basal spacing changes.
- Fourier transform infrared (FTIR) spectroscopy was employed to elucidate interaction mechanisms.
Main Results:
- Adsorption capacity reached up to 330 mg/g (1.0 mmol/g) in acidic and neutral solutions via stoichiometric cation exchange.
- Adsorption significantly decreased above pH 8.7 due to electrostatic repulsion between anionic ciprofloxacin and negatively charged clay surfaces.
- Uptake of ciprofloxacin expanded montmorillonite's basal spacing from 15.04 to 17.23 Å, indicating interlayer cation exchange and surface adsorption.
- FTIR analysis revealed electrostatic attraction between protonated ciprofloxacin and clay surfaces, and hydrogen bonding of the carboxylic group to silicate layers.
Conclusions:
- Montmorillonite exhibits significant adsorption capacity for ciprofloxacin, primarily through cation exchange and surface complexation.
- The adsorption process is pH-dependent, with optimal removal in acidic to neutral conditions.
- Montmorillonite is a promising sorbent for the remediation of ciprofloxacin contamination in water.
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