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In this paper, pristine and chemically treated multi-walled carbon nanotubes (MWCNTs) were employed as solid-phase extraction sorbents for the isolation and enrichment of multi-class pharmaceuticals from the surface water and groundwater, prior to liquid chromatography-tandem mass spectrometry analysis. Thirteen pharmaceuticals that belong to different therapeutical classes (erythromycin, azithromycin, sulfamethoxazole, diazepam, lorazepam, carbamazepine, metoprolol, bisoprolol, enalapril, cilazapril, simvastatin, clopidogrel, diclofenac) and two metabolites of metamizole (4-acetylaminoantipyrine and 4-formylaminoantipyrine) were selected for this study. The influence of chemical treatment on MWCNT surface characteristics and extraction efficiency was studied, and it was shown that HCl treatment of MWCNT leads to a decrease in the amount of surface oxygen groups and at the same time favorably affects the efficiency toward extraction of selected pharmaceuticals. After the optimization of the SPE procedure, the following conditions were chosen: 50 mg of HCl-treated MCWNT as a sorbent, 100 mL of water sample at pH 6, and 15 mL of the methanol-dichloromethane mixture (1:1, v/v) as eluent. Under optimal conditions, high recoveries (79-119%), as well as low detection (0.2 to 103 ng L) and quantitation (0.5-345 ng L) limits, were obtained. The optimized method was applied to the analysis of five surface water and two groundwater samples, and three pharmaceuticals were detected, the antiepileptic drug carbamazepine and two metabolites of antipyretic metamizole.

This paper explores the applicability of unmodified and chemically modified activated carbon cloths (ACCs) for the removal of estrone, 17β-estradiol, and 17α-ethinylestradiol from water. In order to examine the influence of surface properties on hormone adsorption, chemical modification of ACCs with HNO 3 , HCl, or KOH was employed. Applied treatments increased the specific surface area and changed the content of oxygen functional groups. Increased content of acidic surface oxygen functionalities enhanced adsorption efficiency up to 30 % and had a more dominant influence on adsorption capacity than specific surface area. Adsorption of estrone, 17β-estradiol, and 17α-ethinylestradiol followed pseudo-second-order kinetic model, while the equilibrium adsorption data fitted well with the Freundlich isotherm model. Calculated mean sorption energy values of 1.4475, 1.3387, and 1.0541 kJ/mol, for E1, E2, and EE2 respectively, indicated that removal of selected hormones was dominated by physisorption mechanism. Obtained Langmuir adsorption capacities, 12.34, 12.66, and 11.11 mg/g for estrone, 17β-estradiol, and 17α-ethinylestradiol, respectively, as well as convenience of manipulation, recommend activated carbon cloth modified with HNO 3 as an efficient adsorbent for removing estrogen hormones from the water.

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Carbon materials of different structural and textural properties (multi-walled carbon nanotubes, carbon cryogel, and carbonized hydrothermal carbon) were used as adsorbents for the removal of estrone, 17βestradiol, and 17α-ethinylestradiol from aqueous solutions. Chemical modi cation and/or activation were applied to alter surface characteristics and to increase the adsorption and desorption e ciency of carbon materials. Surfaces of treated and untreated carbon materials were characterized through the examination of the textural properties, the nature of surface functional groups, and surface acidity.Although speci c surface area and content of surface functional groups did not have a dominant in uence on the adsorption process, it was found that a high ratio of surface mesoporosity affected the adsorption process most prominently by increasing adsorption capacity and the rate of the adsorption process. High values of adsorption e ciency (88-100 %) and maximum adsorption capacities (29.45-194.7 mg/g) imply that examined materials, especially mesoporous carbon cryogel and multi-walled carbon nanotubes, can be used as powerful adsorbents for relatively fast removal of estrogen hormones from water.