Removal of estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) from wastewater by liquid–liquid extraction

Abstract

With the recent wide spread concerns of the environmental and public health effects of endocrine disrupting chemicals (EDCs), it is becoming important to develop new techniques to remove these substances from wastewater. EDCs find their way to the environment mainly via effluents from WWTPs. They are often cited as moderately hydrophobic, hence they have tendency to distribute to organic solvents and can then be removed using liquid-liquid extraction (LLE) techniques. However, despite being a mature chemical engineering unit operation, LLE has not been studied for the removal of EDCs in water. This study investigated the removal of three EDCs of concerns including estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) using decamethylcyclopentasiloxane (D5) as an extraction solvent in three water matrix types (Milli-Q, tap water, and a secondary treated wastewater). The study showed that all three EDCs were distributed to D5 but at varying distribution coefficients: K E1 = 2.66, K E2 = 0.61 and K EE2 = 1.67 ±5% at pH 6 and 20 o C. Due to the high pKa values of the three EDCs, pH had no significant effect on K EDCs up to about pH 9.5 but higher pHs reduced the distribution ratios up to almost zero at pH 12. Van't Hoff Equation described the effect of temperature on K EDCs and showed that the process was endothermic. The overall estrogenic potency of the three EDCs in mixtures was quantified with an E2 equivalent potency, which was found to distribute well into the solvent at a K E2EQ 2 = 1.43. The study suggests that LLE is an effective method to remove estrogenic potency of wastewater.

Polyamide-6 for the removal and recovery of the estrogenic endocrine disruptors estrone, 17β-estradiol, 17α-ethinylestradiol and the oxidation product 2-hydroxyestradiol in water

“…Similar effect of pH was also reported in the literature [36]. As weak acids, EDCs (pKas~ 10.5) remain non-ionised at pH <pKa [27,42] and dissociate to their base conjugates at aqueous pH >pKa. The deprotonation at high pHs of the EDCs increases their aqueous solubility (Table S2).…”

“…Several techniques used to remove and recover EDCs in water have extensively been studied [23][24][25][26]. For instance, we investigated the removal of estrogenic EDCs in water using liquidliquid extraction (LLE) and found that, at low pH than their pKa, they preferentially distribute to organic solvents because of their hydrophobicity while ozone-reactive LLE achieved almost instantaneous removal of the EDCs [27,28]. Ozonation has however produced oxidation products with endocrine disrupting character including 2OHE2 [12,28].…”

Two-Phase Ozonation for the Removal of Estrone, 17β-Estradiol and 17α-Ethinylestradiol in Water Using Ozone-Loaded Decamethylcyclopentasiloxane

“…As evoked by Ward et al (Ward, Tizaoui et al 2004), there are two key factors that can enhance or hinder LLO process: the interfacial mass transfer and the effectiveness of promoted chemical reaction pathways. In a preliminary work, the mass transfer of the EDCs into D5 was investigated and their distribution coefficients were determined (Ben Fredj, Nobbs et al 2015). The results showed EDCs to distribute into D5…”

“…with diffrent distribution coefficients: E1 (K E1 =2.66) highly distributed in D5, followed by EE2 (K EE2 =1.67) and by E2 (K E2 =0.61) at pH 6 and at 20°C (Ben Fredj, Nobbs et al 2015).…”

Facile preparation of polydopamine‐coated imprinted polymers on the surface of SiO2 for estrone capture in milk samples

“…The kinetic adsorption test was carried out by using EMIPs or ENIPs (20 mg) that were dispersed in the E1 aqueous solution (10 mL) and shaken at room temperature for different time (5,10,15,20,30,45,60,90, and 120 min), and then filtered. The supernatant was measured by HPLC and the adsorption capacity was calculated.…”