Removal of drug dexamethasone from aqueous matrices using low frequency ultrasound: Kinetics, transformation products, and effect of microplastics

Alexandra A Ioannidi; Olga S Arvaniti; Kleopatra Miserli; Ioannis Konstantinou; Zacharias Frontistis; Dionissios Mantzavinos

doi:10.1016/j.jenvman.2022.117007

Removal of drug dexamethasone from aqueous matrices using low frequency ultrasound: Kinetics, transformation products, and effect of microplastics

J Environ Manage. 2023 Feb 15:328:117007. doi: 10.1016/j.jenvman.2022.117007. Epub 2022 Dec 13.

Authors

Alexandra A Ioannidi¹, Olga S Arvaniti², Kleopatra Miserli³, Ioannis Konstantinou⁴, Zacharias Frontistis⁵, Dionissios Mantzavinos⁶

Affiliations

¹ Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504, Patras, Greece.
² Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504, Patras, Greece; Department of Agricultural Development, Agrofood and Management of Natural Resources, National and Kapodistrian University of Athens, Psachna, 34400, Greece.
³ Department of Chemistry, University of Ioannina, GR-45110, Ioannina, Greece.
⁴ Department of Chemistry, University of Ioannina, GR-45110, Ioannina, Greece; Institute of Environment and Sustainable Development, University Research Center of Ioannina (URCI), Ioannina, 45110, Greece.
⁵ Department of Chemical Engineering, University of Western Macedonia, GR-50132, Kozani, Greece; School of Sciences and Engineering, University of Nicosia, 2417, Nicosia, Cyprus.
⁶ Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504, Patras, Greece. Electronic address: mantzavinos@chemeng.upatras.gr.

PMID: 36521216
DOI: 10.1016/j.jenvman.2022.117007

Abstract

Sonochemical oxidation was employed for the degradation of the drug dexamethasone (Dex). The oxidation at 20 kHz followed pseudo-first-order kinetics and increased with applied ultrasound power density. Acoustic cavitation at 71 W/L was able to eliminate 500 μg/L of dexamethasone from ultrapure water at inherent pH in less than 60 min. The oxidation was enhanced at pH 3 and decreased at increased Dex concentration. Scavenging experiments with tert-butanol showed that hydroxyl radicals play a crucial role in decomposition, where the reaction mainly occurs on the gas-liquid interface of the formed cavities. The addition of chloride did not affect Dex removal, while in the presence of 10 mg/L of humic acid or bicarbonate, the apparent kinetic constant decreased from 0.0423 ± 0.004 min^-1 to about 0.03 ± 0.002 min^-1. The rate in secondary effluent was 3.3 times lower than in ultrapure water due to the complexity of the actual matrix. Six transformation products were identified via high resolution LC-MS during the sonochemical oxidation of 3 mg/L Dex in ultrapure water. The presence of polyethylene or polystyrene microplastics slightly enhanced DEX sonodegradation. The effect of ultrasound irradiation at 71 W/L for 60 min on the microplastics surfaces was inconsiderable.

Keywords: Advanced oxidation processes (AOPs); Dexamethasone; Microplastics; Transformation products; Ultrasound; Water treatment.

MeSH terms

Dexamethasone
Kinetics
Microplastics
Oxidation-Reduction
Plastics
Water / chemistry
Water Pollutants, Chemical* / chemistry
Water Purification*

Substances

Microplastics
Plastics
Water Pollutants, Chemical
Water
Dexamethasone