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.

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.

In this study, pristine and chemically treated carbon cryogel (CC) was employed as a solid-phase extraction (SPE) adsorbent for the isolation and enrichment of estrogens from water samples. A novel, sensitive, selective, and cost-effective analytical method for the determination of estrone, 17β-estradiol, and 17α-ethinylestradiol, based on solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS), was developed and validated. The SPE procedure was optimized by selecting the appropriate adsorbent mass, the sample volume, the sample pH, and the type and volume of elution solvent. The influence of the chemical treatment of carbon cryogel on extraction efficiency was also studied, and it was shown that HNO3 treatment led to a slight increase in recovery values over untreated CC. High recovery values (82–95%) obtained by the optimized extraction method were comparable with the recoveries obtained by commercial cartridges. Finally, the optimized method was successfully applied to the analysis of selected hormones in groundwater, surface water, and wastewater samples. The matrix effect of all tested water types was negligible, indicating the high adsorbent selectivity of examined materials toward observed hormones.

In this study, carbon cryogel was used as solid-phase extraction sorbent for the extraction of estrogenic hormones (estrone, 17β-estradiol, and 17α-ethinylestradiol) from water solution. The solid-phase extraction (SPE) method was optimized by choosing an appropriate mass of the sorbent, volume, and initial pH of estrogenic hormone water solution, as well as by choosing an appropriate organic solvent. The concentration of tested hormones after extraction was measured by liquid chromatography coupled with tandem mass spectrometry. Based on the obtained hormone recoveries, the following optimal conditions of the SPE procedure were chosen: 100 cm3 of hormone water solution at initial pH adjusted to 7, 20 mg of the sorbent, the methanol-dichloromethane mixture was used for hormone elution. Recoveries obtained under the optimal conditions ranged from 77 % for estrone, to 86 % for 17β-estradiol, with relative standard deviation from 7,4 to 18 %.