Vancomycin removal using TiO₂–clinoptilolite/UV in aqueous media and optimisation using response surface methodology

ABSTRACT

Investigations have shown the traces of antibiotics in surface water, groundwater, wastewater treatment plants, and drinking water. However, conventional wastewater treatment is not entirely effective for vancomycin degradation. Advanced oxidation is one of the most widespread methods of antibiotic degradation in aqueous media. Vancomycin was quantified by high-performance liquid chromatography. The Response Surface Methodology (RSM) based on Central Composite Design (CCD) was used to explore and optimise the effect of the independent variables on vancomycin degradation. Independent variables were as follows: pH (3–11), vancomycin concentration (15–75 mg/L), TiO₂–clinoptilolite (25–125 mg in 250 mL reactor volume), the temperature (25–45°C), and the reaction time (15–75 min). The validity and adequacy of the model were confirmed by the corresponding statistics (F–value = 111.5, correlation coefficient R² = 0.98, adjusted R² = 0.97, and prediction R² = 0.95). The vancomycin degradation efficiency was 97% under optimal conditions (pH = 5, vancomycin concentration = 30 mg/L, TiO₂-clinoptilolite content = 50.2 mg in a 250 mL reactor volume, temperature = 32.24°C, and reaction time = 50.9 min). This process followed the zero-order reaction kinetics model (R² = 0.98), and the removal rate of Total Organic Carbon (TOC) under optimal conditions was 56%. The results indicated that supporting TiO₂ on clinoptilolite particles could increase the photocatalytic properties.

KEYWORDS:

• Antibiotic degradation
• vancomycin
• clinoptilolite
• titanium dioxide
• central composite design

Acknowledgments

This paper extracted from the thesis by Fatemeh Dehghani, a Ph.D. candidate in Environmental Health Engineering. I acknowledge the generous financial support from the Science and Research Branch, Islamic Azad University (IAU), Tehran, Iran, and the laboratory facilities provided by the School of Health, Shiraz University of Medical Sciences, Shiraz, Iran. I would also like to thank Ms. A. Keivan shekouh at the Research Consultation Center (RCC) of Shiraz University of Medical Sciences for her invaluable assistance in editing the manuscript.

Disclosure statement

The authors declare that: they don’t have any pecuniary or other personal interest and conflict.

Research involving human participants and/or animals

This article does not contain any studies on human participants or animals performed by any author.