Abstract
The present work focused on the use of high-silica commercial zeolites as sorbent media for pharmaceuticals in an aqueous matrix. As drug probes, ketoprofen, hydrochlorothiazide, and atenolol were selected, because of their occurrence in surface waters and effluents from wastewater treatment plants. Pharmaceuticals adsorption was evaluated for two Faujasite topology zeolites with Silica/Alumina Ratio 30 and 200. The selected zeolites were demonstrated to be efficient sorbents towards all investigated pharmaceuticals, thanks to their high saturation capacities (from 12 to 32% w/w) and binding constants. These results were corroborated by thermal and structural analyses, which revealed that adsorption occurred inside zeolite’s porosities, causing lattice modifications. Finally, zeolites have been tested as a pre-concentration media in the dispersive-solid phase extraction procedure. Recoveries higher than 95% were gained for ketoprofen and hydrochlorothiazide and approximately 85% for atenolol, at conditions that promoted the dissolution of the neutral solute into a phase mainly organic. The results were obtained by using a short contact time (5 min) and reduced volume of extraction (500 µL), without halogenated solvents. These appealing features make the proposed procedure a cost and time saving method for sample enrichment as well as for the regeneration of exhausted sorbent, rather than the more energetically expensive thermal treatment.
Highlights
The increasing use of pharmaceutical compounds in human and veterinary medicine has become an environmental problem, which received widespread attention from scientists over the past 20 years [1,2].Hundreds of tonnes of pharmacologically active substances enter sewage treatment plants, where they are poorly removed
The adsorption of pharmaceuticals from the aqueous solution onto zeolites was evaluated in a wide concentration range and by fitting the experimental data with the proper mathematical model
The adsorptive properties of two commercial high-silica Y zeolites, with a Silica/Alumina Ratio 30 and 200, toward drugs in a diluted aqueous solution were evaluated, with the aim to investigate their possible use in the enrichment step of the analysis
Summary
Hundreds of tonnes of pharmacologically active substances enter sewage treatment plants, where they are poorly removed. They can enter into surface water collecting the plant effluents [3,4]. The occurrence of pharmaceuticals in surface water and sediments has been extensively reviewed [5,6]. “source-to-tap” studies concerning the fate of pharmaceuticals from wastewater to finished drinking water have been reported [7,8]. To reduce the negative impact of pharmaceutical on biota and human health, new technologies should be investigated to improve the Molecules 2020, 25, 3331; doi:10.3390/molecules25153331 www.mdpi.com/journal/molecules
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