Extraction of estrogenic hormones in wastewater samples by using rotating disk and modified clays with ionic liquids

Abstract

Both synthetic and natural hormones—17α-ethinylestradiol (EE2), 17β-estradiol (E2), and estriol (E3)—are present in wastewater samples in concentrations typically expressed in ng l^-1. These concentrations are significant, as the presence of such hormones in water sources poses risks to both living organisms and the environment. Steroidal hormones from human sources are categorized as emerging pollutants and endocrine-disrupting compounds (EDCs), which constitute a health hazard.

In this study, the Rotating Disk Sorption Extraction (RDSE) method was used with modified clays incorporating ionic liquids to detect estrogenic hormones in hospital wastewater treatment plant (HWWTP) samples. Sodium montmorillonite was modified to enhance its extractive capacity by intercalating ionic liquids ([C16MIM⁺][anion^-], where anion = Br^-, OH^-, or BF₄^-) between its interlayers. Following extraction, the concentrated analytes were measured using liquid chromatography coupled with photodiode array detection (HPLC-PDA). The method achieved absolute recoveries of 61 % for EE2, 41 % for E2, and 20 % for E3; these recoveries were lower than those obtained with a commercial C18 sorbent. However, the technique achieved enrichment factors of 13, 23, and 32 for E3, EE2, and E2, respectively. In wastewater, the intra-disk reproducibility (RSD) was below 12 %. The method also provided limits of detection and quantification in HWWTP samples of 0.18–0.42 ng mL^-1 for E3, 0.15–0.37 ng mL^-1 for E2, and 0.07–0.16 ng mL^-1 for EE2 when using the modified adsorbents. Average concentrations in hospital wastewater were measured at 4.30, 3.85, and 7.23 ng mL^-1 in the influent (before treatment) and 3.81, 1.33, and 4.00 ng mL^-1 in the effluent (after treatment) for E3, E2, and EE2, respectively.